Hytera MD78X Service Manual
  1. Manuals
  2. Brands
  3. Hytera Manuals
  4. Radio
  5. MD78X
  6. Service manual

Hytera MD78X Service Manual

Hide thumbs Also See for MD78X:
1
2
3
Table Of Contents
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
Table of Contents

Advertisement

Quick Links

See also: User Manual , Manual
SERVICE MANUAL
MOBILE RADIO

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the MD78X and is the answer not in the manual?

Questions and answers

Related Manuals for Hytera MD78X

Summary of Contents for Hytera MD78X

  • Page 1 SERVICE MANUAL MOBILE RADIO...
  • Page 2 This manual is applicable to the following model: MD78X (X may indicate 2, 5, 6, or 8) MD78XG (X may indicate 2, 5, 6, or 8) In this manual, the description related to GPS is applicable to MD78XG only.

  • Page 3: Copyright Information

    Copyright Information Hytera is the trademark or registered trademark of Hytera Communications Co., Ltd. (the Company) in PRC and/or other countries or areas. The Company retains the ownership of its trademarks and product names. All other trademarks and/or product names that may be used in this manual are properties of their respective owners.

  • Page 4: Table Of Contents

    Service Manual Contents Contents Documentation Information ........................1 1. Introduction............................2 2. Product Controls ..........................3 3. Front Panel Section ..........................5 4. Baseband Section ..........................7 4.1 Power Section ........................... 7 4.2 Power On/Off ............................ 8 4.2.1 Power On/Off Key ........................8 4.2.2 Ignition Signal .........................
  • Page 5 Contents Service Manual 8. UHF1 (400-470MHz 25W) Information ....................29 8.1 Transmitter Circuit .......................... 29 8.1.1 Power Amplifier ........................29 8.1.2 TX Buffer Amplifier........................ 29 8.1.3 Pre-driver Power Amplifier ....................30 8.1.4 Driver Power Amplifier ......................30 8.1.5 Final Power Amplifier......................30 8.1.6 Antenna Switch ........................
  • Page 6 Service Manual Contents 9.1.11 Pressure Pad Switch ......................103 9.2 Receiver Circuit ..........................103 9.2.1 Receiver Front-end ......................104 9.2.2 Receiver Back-end ......................105 9.3 Frequency Generation Unit (FGU) ....................105 9.3.1 PLL Synthesizer ......................... 105 9.3.2 Reference Oscillator ......................106 9.3.3 PLL IC ..........................
  • Page 7 Contents Service Manual 10.7 Parts List ............................. 201 10.8 Troubleshooting Flow Chart ....................... 239 11. UHF2 (450-520MHz 45W) Information ..................245 11.1 Transmitter Circuit ........................245 11.1.1 Power Amplifier ......................... 245 11.1.2 TX Buffer Amplifier ......................245 11.1.3 Pre-driver Power Amplifier ....................246 11.1.4 Driver Power Amplifier ......................
  • Page 8 Service Manual Contents 12.1.9 Output Power Control ....................... 320 12.1.10 Thermal and Over-voltage Protections ................320 12.1.11 Pressure Pad Switch ...................... 320 12.2 Receiver Circuit .......................... 320 12.2.1 Receiver Front-end......................321 12.2.2 Receiver Back-end ......................322 12.3 Frequency Generation Unit (FGU) ..................... 322 12.3.1 PLL Synthesizer .......................
  • Page 9 Contents Service Manual 13.5 Block Diagram ..........................402 13.6 Schematic Diagram ........................405 13.7 Parts List ............................. 419 13.8 Troubleshooting Flow Chart ....................... 458 14. VHF (136-174MHz 25W) Information ..................... 464 14.1 Transmitter Circuit ........................464 14.1.1 Power Amplifier ........................ 464 14.1.2 Pre-driver Power Amplifier ....................
  • Page 10 Service Manual Contents 15.1.8 Output Power Control ....................... 540 15.1.9 Thermal and Over-voltage Protections ................540 15.1.10 Pressure Pad Switch ...................... 540 15.2 Receiver Circuit .......................... 540 15.2.1 Receiver Front-end......................541 15.2.2 Receiver Back-end ......................541 15.3 Frequency Generation Unit (FGU) ..................... 542 15.3.1 PLL Synthesizer .......................
  • Page 11 Figures Service Manual Figures Figure 3-1 Diagram of Front Panel......................5 Figure 4-1 Diagram of Power Distribution ....................7 Figure 4-2 Diagram of Clock Distribution ....................9 Figure 4-3 Diagram of SPI Interface ......................10 Figure 4-4 Diagram of MCSI Interface ..................... 10 Figure 4-5 Diagram of MICROWIRE Interface ..................
  • Page 12 Service Manual Figures Figure 12-4 Diagram of PLL IC ......................323 Figure 12-5 Diagram of VCO ......................... 324 Figure 13-1 Diagram of Transmitter Circuit .................... 391 Figure 13-2 Diagram of Receiver Circuit ....................394 Figure 13-3 Diagram of IF Processor ..................... 395 Figure 13-4 Diagram of PLL IC ......................
  • Page 13 Tables Service Manual Tables Table 4-1 Description on Option Board Interface ..................14 Table 7-1 J404: to Front Panel Jack ......................24 Table 7-2 J4: to Aviation Jack of Front Panel ................... 25 Table 7-3 J2: to LCD Display Jack ......................26 Table 7-4 J403: to Accessory Pin Jack ....................

  • Page 14: Documentation Information

    Service Manual Documentation Information Documentation Information This section describes the conventions and revision history of this document. Instructional Icons Icon Description Indicates information that can help you make better use of your product. Note Indicates references that can further describe the related topics. Caution Indicates situations that could cause data loss or equipment damage.

  • Page 15: Introduction

    Introduction Service Manual 1. Introduction Intended User This manual is intended for use by qualified technicians only.

  • Page 16: Product Controls

    Service Manual Product Controls 2. Product Controls Front Panel Part Name Part Name Volume Control/Group Call Selector Knob (trunking mode) Up Key Volume Control/Channel Selector Knob (conventional mode) LED Indicator Down Key LCD Display Speaker Answer/Redial/Call Key (trunking mode) OK/Menu Key Programmable Key (conventional mode) Back/Group...
  • Page 17 Product Controls Service Manual Part Name Part Name Dial-back/End/Home Screen Key (trunking mode) Microphone Jack Programmable Key (conventional mode) Power On/Off Key Microphone Installation Index Rear Panel Part Name Part Name RF Antenna Connector Power Inlet Accessory Jack GPS Antenna Connector Note The GPS Antenna Connector is only available for MD78XG.

  • Page 18: Front Panel Section

    Service Manual Front Panel Section 3. Front Panel Section The front panel contains the speaker, keys, power switch, volume control knob, LCD display and other parts. The block diagram is shown as the figure below. Figure 3-1 Diagram of Front Panel Power Supply The main board supplies power to the front panel via U902, so that the LED, backlight and USB devices can be powered up.
  • Page 19 Front Panel Section Service Manual Conventional Mode Trunking Mode S2, S3, S7, S8, S9, S10 S3, S7, S9, S10 and Programmable Key and S12 Up/Down Key S5 and S11 OK/Menu Key Back Key Power On/Off Key Dial-back/End/Home Screen Answer/Redial/Call Key LCD Display The TFT LCD transfers data via the bus EMIFS of U302.

  • Page 20: Baseband Section

    Service Manual Baseband Section 4. Baseband Section Power Section Auto baterry Voltage Q802\Q803\U201 13.6±15% Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q100\Q103\Q106\Q110 Q104 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB IGN_SENCE U231...

  • Page 21: Power On/Off

    Baseband Section Service Manual  Supply for Baseband: The processor U302 is supplied by 3.3V (U900), 1.8V (U903) and 1.6V (U919); the memory is supplied by 3.3V (U900) and 1.8V (U903) respectively; the audio processor IC is supplied by 3.3V (U900&U909) and 1.8V (U903); the DAC is supplied by 5V (U905) and 3.3V (U900). ...

  • Page 22: Power-Up Process

    Service Manual Baseband Section 4.2.4 Power-up Process Step 1 Power on the radio using one of the three methods (Power On/Off key, Ignition Signal, or Emergency); U917 generates reset signal and remain low level for 1.25 seconds, allowing the processor Step 2 starts.

  • Page 23: Output Clock

    Baseband Section Service Manual 4.3.2 Output Clock The baseband outputs 3 clock signals fed to U231, U100 and Option Board respectively. Interface Distribution 4.4.1 SPI Interface U302 SPIF.CS2 SPIF.SCK U701 SPIF.DOUT Figure 4-3 Diagram of SPI Interface SPI of U302 operates in Master Mode, and is controlled by MPU or DMA. In this case, U302 can provide 4 chip select signals, of which CS2 is used to control the IF processor U701.

  • Page 24: Ssi Interface

    Service Manual Baseband Section The MICROWIRE interface can accommodate 4 external devices at most, generally transmitting control and status messages of external devices, and reading data from ROM. Its maximum clock frequency is a quarter of system clock frequency. In this case, MICROWIRE is used to configure or read from the audio processor.

  • Page 25: Usb Interface

    Baseband Section Service Manual 4.4.5 USB Interface USB_D- USB.DP USB_D+ USB.DM USB.PUEN(W4) USB.PUEN U302 DATA GPIO18 GPIO9 LCLK VBUS_EN Vbus CLOCK SCLK GPIO7 USB_VBUS MONITOR MPUIO11 VBUS_DEC Figure 4-7 Diagram of USB Interface The radio has two USB interfaces, which are connected to the same USB signal port of the processor. REF CLOCK is the reference frequency in specified mode.

  • Page 26: Option Board Interface

    Service Manual Baseband Section the section Interface Definition. 4.4.8 Option Board Interface J400, an option board interface, is used to achieve specific function by connecting with the designated option board. The definition of each pin is listed as below: Relative Voltage Signal Function...

  • Page 27: Table 4-1 Description On Option Board Interface

    Baseband Section Service Manual Relative Voltage Signal Function Remarks (VDD=3.3V) Option Board 80mv (standard output from AF OB TO MB MAX: 700mV option board to the main board) 80mv (standard output from AF MB TO OB MAX: 700mV main board to the option board) DGND DGND...

  • Page 28: Audio Section

    Service Manual Baseband Section Audio Section U231 U201 INT_SPK Vol _Ctl Right PA_Enable U302 U236B Vol _Ctl MCBSP1 Left Mic Bias U236C PUB_ADDRESS1 Enable EXT_Mic Bias U235B HANDSET_AUDIO EXT_Mic Enable EXT_MIC Figure 4-9 Diagram of Audio Section 4.5.1 RX Audio Circuit U302 sends digital audio to the audio processor codec via the SSI bus of MCBSP1.

  • Page 29: Tx Audio Circuit

    Baseband Section Service Manual 4.5.2 TX Audio Circuit The audio processor U231 has two MIC inputs: the internal MIC and external MIC. The internal MIC is connected to the MICIN_HND of U231, and is combined with AUX1 to provide differential input. After 9.3V is divided by R255 and R264, a bias voltage of about 7V is provided to the front panel MIC.

  • Page 30: Troubleshooting Flow Chart

    Service Manual Baseband Section 4.5.3 Troubleshooting Flow Chart Control Circuit Check Power-on RF circuit can not Check the display is normal? be driven? control circuit. Front-panel FFC Replace the FFC. is normal? Check U905 (5VA) X302(19.2 MHz) U905 and and U909 (3V3A) are works normally? U909.

  • Page 31: Pcb Difference

    Baseband Section Service Manual PCB Difference The UHF1 PCB has three versions: D, F and H. The watchdog circuit (in the figure below) is added in version F. 3V3D U910 R932 /PRST1 4.7K D913 SENCE /PRST RSET MBRM120LT1G C937 1000p C941 0.15u D912...

  • Page 32: Gps Circuit

    Service Manual GPS Circuit 5. GPS Circuit Circuit Description Figure 5-1 Diagram of GPS Circuit GPS positioning information can be acquired via the programmed GPS key on the front panel. The GPS function is realized via REB-1315LPx module, which integrates GPS baseband processor circuits.

  • Page 33: Schematic Diagram

    GPS Circuit Service Manual Schematic Diagram Figure 5-2 GPS Schematic Diagram Parts List Ref. No. Print No. Part No. Description C325 3101051040010 0.1UF C330 3101051040010 0.1UF C331 3101081060010 10UF C332 3101051040010 0.1UF C333 3101081060010 10UF L321 3212106390000 39nH L322 3221506300000 Bead 0Ω...

  • Page 34: Troubleshooting Flow Chart

    Service Manual GPS Circuit Troubleshooting Flow Chart Replace the module. Antenna Replace the works Start antenna. normally? Peripheral Replace components work defective normally? components. The radio can position RX signal is normally? weak? Replace U901. Replace connector W321. The PC-based U901 outputs 3.3V software (e.g.SiRF Connector works...

  • Page 35: Tuning Description

    Tuning Description Service Manual 6. Tuning Description For details about radio tuning, please refer to the help file of appropriate tuner software supplied by the Company.

  • Page 36: Interface Definition

    Service Manual Interface Definition 7. Interface Definition J404: to front panel jack Pin No. Name Function INT_MIC Audio input MIC_GROUND Audio input ground ACC_IO1 Accessory identifier pin 1 USB_VBUS USB power supply HOOK HOOK USB_D- USB data cable D- USB_D+ USB data cable D+ ACC_IO2 Accessory identifier pin 2...

  • Page 37: Table 7-1 J404: To Front Panel Jack

    Interface Definition Service Manual Pin No. Name Function KB_R2 CSLED Backlight control IC chip select CLOCK Backlight control IC clock DATA Backlight control IC data OE_LCD LCD read enable WE_LCD LCD write enable CS2_LCD LCD chip select F_A1_LCD LCD register enable F_D7 F_D6 F_D5...

  • Page 38: Table 7-2 J4: To Aviation Jack Of Front Panel

    Service Manual Interface Definition Pin No. Name Function USB_D- USB data cable Ground USB_VBUS Power supply MIC_IN Analog input USB_D+ USB data cable HOOK Hook signal input ACC_IO2 Digital input Table 7-2 J4: to Aviation Jack of Front Panel J2: to LCD display jack Pin No.

  • Page 39: Table 7-3 J2: To Lcd Display Jack

    Interface Definition Service Manual Pin No. Name Function DB10 DB11 DB12 DB13 DB14 DB15 DB16 DB17 RESET Reset signal Select data cable LEDA LED positive LED_K1 LED_K2 LED negative LED_K3 Table 7-3 J2: to LCD Display Jack J403: to accessory pin jack Pin No.
  • Page 40 Service Manual Interface Definition Pin No. Name Function Ground Ground GP5_3 Digital input/output SW B+ sense Power supply External Alarm Analog voltage output Power Ground Power supply ground Tx Audio Analog input RX Audio Analog output Spkr- Analog output D+ USB USB data cable + USB_GROUDN Ground...

  • Page 41: Table 7-4 J403: To Accessory Pin Jack

    Interface Definition Service Manual Pin No. Name Function Ign Sense Analog voltage input Table 7-4 J403: to Accessory Pin Jack...

  • Page 42: Uhf1 (400-470Mhz 25W) Information

    Service Manual UHF1 (400-470MHz 25W) Information 8. UHF1 (400-470MHz 25W) Information Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 43: Pre-Driver Power Amplifier

    UHF1 (400-470MHz 25W) Information Service Manual 8.1.3 Pre-driver Power Amplifier The pre-driver power amplifier is formed by Q805, with variable gain controlled by voltage VGG. The input matching circuit is composed of C826, L826, L814, C843 and R824. 8.1.4 Driver Power Amplifier The driver power amplifier is formed by Q804, with variable gain controlled by voltage VGG.

  • Page 44: Output Power Control

    Service Manual UHF1 (400-470MHz 25W) Information D803, and the voltage is applied to the power control circuit (U801). Then the voltage VGG is output to control the gate voltage of pre-driver and driver PA, ensuring a constant power output. The directional coupler can adjust the TX power and detect the VSWR load. The reverse power is coupled to D804.

  • Page 45: Receiver Front-End

    UHF1 (400-470MHz 25W) Information Service Manual Figure 8-2 Diagram of Receiver Circuit 8.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (73.35MHz).

  • Page 46: Receiver Back-End

    Service Manual UHF1 (400-470MHz 25W) Information 8.2.2 Receiver Back-end Figure 8-3 Diagram of IF Processor The first IF signal (73.35MHz) output by the IF amplifier goes into IF IC via Pin 47, where the signal is converted to the second IF signal (2.25MHz). Then the un-demodulated digital I/Q signal output from the SSI interface is sent to U302 for demodulation.

  • Page 47: Reference Oscillator

    UHF1 (400-470MHz 25W) Information Service Manual 8.3.2 Reference Oscillator X100 is a 19.2MHz TCXO, and its reference frequency is calibrated by the digital-to-analog converter (U500) for accuracy. 8.3.3 PLL IC The PLL IC (U100) is a fractional frequency divider. The logic IC U101 and U102 work with the PLL IC (U100) to achieve locking.

  • Page 48: Figure 8-5 Diagram Of Vco

    Service Manual UHF1 (400-470MHz 25W) Information oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals and the other two VCOs (Q106 and Q110) to receive LO signals. U302 controls the operating frequency of the VCO.

  • Page 49: Pcb View

    PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 50 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 51 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Top Layer 顶层...
  • Page 52 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 53: Block Diagram

    8.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q104 Q100\Q103\Q106\Q110 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 54 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 55 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL MCSI1 McBSP2 GPIOs TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 56: Schematic Diagram

    8.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 57 MD78X/MD78XG Schematic Diagram (RX Circuit) MD780/780G 原理图（接收电路） L6100 L6100 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6100 C6100 R6100 R6100 C6102 C6102 C6185 C6185 R6101 R6101 470p 470p R6102 R6102 TRANSISTOR TRANSISTOR L6101 L6101 Q6101 Q6101 BLM18PG600SN1 BLM18PG600SN1 TRANSISTOR TRANSISTOR RF_ATTEN C6103 C6103 220p...
  • Page 58 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 0.1u 0.1u 10uF/10V 10uF/10V R570 R570 R542 0 R542 0 C509 C509 C484 C484 1000p 1000p C508 C508 C483 C483 C510 C510 R528 R528 8200p 8200p 0.1u 0.1u...
  • Page 59 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 60 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/16V 10u/16V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 61 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 62 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 63 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 64 MD78X/MD78XG Schematic Diagram (Power Circuit) U900 U900 RP102N331B RP102N331B 3V3D TP4031 TP4031 VOUT TP4032 TP4032 C900 C900 C901 C901 B900 B900 MMBZ6V8ALT1G MMBZ6V8ALT1G D237 D237 U901 U901 C902 C902 D900 D900 TP4035 TP4035 RP102N331B RP102N331B 3V3DP C903 C903 470p/50V 470p/50V...
  • Page 65 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1000p 1000p 0.1u 0.1u C1010 C1010 1000p 1000p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 66 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 Q101 Q101 4V3A EMD22 EMD22 R142 R142 3.3k 3.3k 220p 220p 0.1u 0.1u 470n 470n R145 R145 TX_VCO_H 220p 220p C195 C195 C194 C194 R143 R143 220p 220p 0.1u 0.1u 6.8k 6.8k...
  • Page 67 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 330n 330n 0.01u 0.01u IF-out TP701 TP701 L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702...
  • Page 68 MD78X/MD78XG Schematic Diagram (TX Circuit) C909 C909 C889 C889 C913 C913 C888 C888 C825 C825 C885 C885 L801 L801 W801 W801 C855 C855 47pF 47pF 470p 470p BLM41PG600SN1 BLM41PG600SN1 100p 100p 3300p 3300p 0.018uF 0.018uF 33pF 33pF C916 C916 C930...
  • Page 69 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 70: Parts List

    Service Manual UHF1 (400-470MHz 25W) Information Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101051020010 1000PF 3101060700020 C100 3101052210010 220PF C1000 3101052210010 220PF C1001 3101054710010 470PF C1002 3101051020010...
  • Page 71 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C152 3101054090010 C153 3101052700000 27PF C154 3101053900000 39PF C155 3101061200000 12PF C156 3101052210010 220PF C157 3101055600000 56PF C158 3101051800070 18PF C159 3101054090010 3101050600010 C160 3101052210010 220PF C161 3101055600000 56PF C162...
  • Page 72 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 3101054710010 470PF 3101050800000 3101052210010 220PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 Chip capacitor C238 3101061050020 C239 3101051040010 0.1UF 3101051040010...
  • Page 73 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C267 3101051040010 0.1UF C268 3101064740010 0.47UF C269 3101052210010 220PF 3101050590010 0.5PF C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010 10UF C276...
  • Page 74 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description C308 3101051040010 0.1UF C309 3101051010030 100PF 3101060300010 C310 3101051050000 C311 3101051040010 0.1UF 3101050500010 C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051010030 100PF C330 3101051040010 0.1UF C334 3101051040010 0.1UF...
  • Page 75 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C363 3101058200000 82PF C364 3101053900000 39PF C365 3101058200000 82PF C366 3101051040010 0.1UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF C380 3101051040010 0.1UF C381 3101051030020 0.01UF...
  • Page 76 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description C415 3101051010030 100PF C416 3101051010030 100PF C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF 3101050100030 C420 3101051010030 100PF C421 3101052210010 220PF C422 3101051040010 0.1UF C423 3101052210010 220PF C424 3101052210010...
  • Page 77 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C454 3101051010030 100PF C455 3101051010030 100PF C456 3101051010030 100PF 3101052210010 220PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467 3101051010030 100PF C468 3101051010030 100PF C469 3101051010030 100PF C470...
  • Page 78 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description C519 3101071060010 10UF 3101052210010 220PF C520 3101071060010 10UF 3101051590000 1.5PF 3101063690000 3.6PF 3101050600010 3101051030020 0.01UF 3101051200020 12PF 3101052210010 220PF 3101051020010 1000PF 3101051200020 12PF C6100 3101061050020 C6102 3101054710010 470PF C6103 3101052210010...
  • Page 79 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C6134 3101055600000 56PF C6135 3101055600000 56PF C6136 3101055600000 56PF C6137 3101054700010 47PF C6138 3101054700010 47PF C6139 3101055600000 56PF C6140 3101055600000 56PF C6141 3101055600000 56PF C6142 3101054700010 47PF C6143 3101054700010 47PF...
  • Page 80 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description C6180 3101051040010 0.1UF C6185 3101061050020 C6190 3101061050020 C6193 3101061040010 0.1UF C6194 3212106100000 10nH 3101050100030 C6246 3101050600010 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3101051040010 0.1UF 3110071040000 0.1UF...
  • Page 81 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C728 3101051020010 1000PF C729 3101051040010 0.1UF C730 3101052200010 22PF C731 3101050600010 C732 3101052200010 22PF C733 3101051040010 0.1UF C734 3101053000010 30PF C735 3101051040010 0.1UF C736 3101051030020 0.01UF C737 3101051040010 0.1UF C738...
  • Page 82 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description C801 3101081020010 1000pF C802 3101063320000 3300PF C803 3101063300000 33PF C804 3101092260010 22UF C807 3101081060010 10UF C808 3101062210000 220PF C809 3101062210000 220PF C811 3101064710000 470PF C814 3101061800000 18PF C816 3101080200010 C817...
  • Page 83 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C852 3101061010010 100PF C853 3101062210000 220PF C854 3101061040010 0.1UF C856 3101080800010 C857 3101062200010 22PF C859 3101071500000 15PF 3101051040010 0.1UF C861 3101066800000 68PF C862 3101061590010 1.5PF C863 3101064720000 4700PF C864 3101061800000...
  • Page 84 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description C900 3101061050020 C901 3101061050020 C902 3101062200010 22PF C905 3101061050020 C906 3101061050020 C907 3101061040010 0.1UF C908 3101061050020 C909 3101063310010 330PF 3110071040000 0.1UF C910 3101051020010 1000PF C911 3101053310020 330PF C912 3101072250030 2.2UF...
  • Page 85 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C941 3101051540000 0.15UF C942 3101061040010 0.1UF C943 3101062700010 27PF C944 3101051020010 1000PF C945 3101054710010 470PF C946 3101061050020 C947 3101051040010 0.1UF C948 3101061040010 0.1UF C949 3101058200000 82PF 3101051030020 0.01UF C950 3101051040010...
  • Page 86 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description D108 3304010100220 Varactor D109 3304010100220 Varactor D110 3304010100220 Varactor D111 3304010100220 Varactor D112 3304010100220 Varactor D113 3304010100220 Varactor D116 3304010100220 Varactor D117 3304010100220 Varactor D121 3304010100220 Varactor D122 3304010100220 Varactor...
  • Page 87 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description D6104 3304010100890 Varactor D6105 3399990000260 Rectifier diode D6106 3699019000000 Mixer IC D701 3304060300050 Varactor D702 3304060300010 Varactor D801 3303210100000 Switching diode D802 3303210100000 Switching diode D803 3303030300000 Schottky barrier diode D804 3303030300000...
  • Page 88 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description L122 3210306150000 15nH L123 3210306150000 15nH L124 3237199120000 12.5nH L126 3214307390000 39nH L127 3217607471000 470nH L128 3210306150000 15nH L129 3217607471000 470nH L131 3221506601000 Bead L132 3210306270000 27nH L133 3217607471000 470nH...
  • Page 89 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L406 3221506300000 Bead L407 3221506300000 Bead L408 3221506300000 Bead L409 3221506300000 Bead L410 3221506300000 Bead L411 3221506300000 Bead L412 3221506300000 Bead 0Ω L413 3005060000010 0Ω L414 3001050000000 0Ω...
  • Page 90 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description L705 3213212103000 10uH L706 3221506601000 Bead L707 3221506601000 Bead L708 3217107221010 220nH L709 3221506601000 Bead L710 3221506601000 Bead L711 3221506601000 Bead L712 3221506601000 Bead L713 3213306561000 0.56uH L714 3221506601000 Bead...
  • Page 91 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L828 3217112102020 L830 3101061210000 120PF L832 3212106829000 8.2nH L833 3101064700000 47PF 3221506601000 Bead L900 3221513600000 Bead L901 3221506300000 Bead L902 3217299103000 10uH L903 3213099472000 4.7uH L904 3221506181000 Bead L908 3221506181000...
  • Page 92 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description Q323 3403008000010 Q400 3413001000010 PNP transistor Q401 3403008000010 Q402 3403008000010 Q403 3403008000010 Q404 3403008000010 Q405 3403008000010 Q406 3414999000000 Q407 3414999000000 Q408 3414999000000 Q409 3414999000000 Q410 3414999000000 Q411 3414999000000 Q412 3414999000000...
  • Page 93 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description Q914 3403008000010 Q921 3404999000020 NPN transistor Q922 3403008000010 Q923 3403008000010 47Ω 3001054700000 10Ω R109 3001051000000 100Ω R111 3001061010000 33Ω R1110 3001053300010 56Ω R114 3001065600000 39KΩ R117 3001053930000 39KΩ...
  • Page 94 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 100Ω R160 3001051010040 18KΩ R161 3001051830000 33Ω R167 3001053300010 0Ω R171 3001060000000 0Ω R174 3001050000000 10Ω R175 3001051000000 4.7KΩ R176 3001054720000 10KΩ R177 3001051030000 33Ω R178 3001053300010 R179 3221506601000 Bead...
  • Page 95 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 100Ω R251 3001051010000 100KΩ R252 3001051040010 470Ω R255 3001064710000 30KΩ 1000 R257 3001053030010 10KΩ 1001 R258 3001051030000 10KΩ 1002 R259 3001051030000 100Ω 1003 R260 3001051010000 10KΩ 1004 R261 3001051030000 100KΩ...
  • Page 96 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 10KΩ 1037 R316 3001051030000 33Ω 1038 R319 3001053300010 33Ω 1039 R320 3001053300010 10KΩ 1040 R322 3001051030000 33Ω 1041 R324 3001053300010 10KΩ 1042 R326 3001051030000 33Ω 1043 R327 3001053300010 100Ω...
  • Page 97 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1KΩ 1077 R383 3001051020010 10KΩ 1078 R385 3001051030000 10Ω 1079 R386 3001051000000 33Ω 1080 R387 3001053300010 10Ω 1081 R388 3001051000000 10KΩ 1082 R390 3001051030000 10KΩ 1083 R391 3001051030000 10KΩ...
  • Page 98 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 33Ω 1117 R430 3001053300010 33Ω 1118 R431 3001053300010 33Ω 1119 R432 3001053300010 33Ω 1120 R433 3001053300010 100Ω 1121 R434 3001051010000 4.7KΩ 1122 R435 3001054720000 4.7KΩ 1123 R436 3001054720000 4.7KΩ...
  • Page 99 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 4.7KΩ 1157 R472 3001054720000 33Ω 1158 R473 3001053300010 33Ω 1159 R474 3001053300010 10KΩ 1160 R476 3001051030000 1KΩ 1161 R477 3001051020010 33Ω 1162 R479 3001053300010 10KΩ 1163 R481 3001051030000 10KΩ...
  • Page 100 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 33Ω 1197 R519 3001053300010 33Ω 1198 R520 3001053300010 33Ω 1199 R521 3001053300010 33Ω 1200 R522 3001053300010 33Ω 1201 R523 3001053300010 33Ω 1202 R524 3001053300010 33Ω 1203 R525 3001053300010 33Ω...
  • Page 101 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 33KΩ 1237 R561 3001053330010 33KΩ 1238 R562 3001053330010 33KΩ 1239 R563 3001053330010 0Ω 1240 R564 3001050000000 0Ω 1241 R565 3001050000000 0Ω 1242 R566 3001050000000 0Ω 1243 R567 3001050000000 12KΩ...
  • Page 102 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 1277 R6130 3001055120030 5.1K 1.2KΩ 1278 R6131 3001051220000 51Ω 1279 R6132 3001055100010 330Ω 1280 R6133 3001053310010 30KΩ 1281 R6134 3001053030000 4.7KΩ 1282 R6135 3001054720000 20KΩ 1283 R6136 3001052030000 30KΩ...
  • Page 103 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 82Ω 1317 R810 3001068200000 18KΩ 1318 R811 3001061830010 4.7Ω 1319 R813 3001084790000 82Ω 1320 R814 3001068200000 27KΩ 1321 R815 3001082730000 220Ω 1322 R816 3001072210000 220Ω 1323 R817 3001072210000 4.7Ω...
  • Page 104 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 56Ω 1357 R862 3001065600000 0Ω 1358 R863 3001050000000 470KΩ 1359 R864 3001054740010 39KΩ 1360 R865 3001053930000 2.2KΩ 1361 R866 3001052220010 8.2KΩ 1362 R867 3001058220000 1KΩ 1363 R869 3001051020000 12KΩ...
  • Page 105 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 24KΩ 1397 R915 3001052430010 330KΩ 1398 R917 3001053340010 6.04kΩ 1399 R918 3099066041010 150KΩ 1400 R919 3001051540000 1KΩ 1401 R924 3001061020010 4.7KΩ 1402 R925 3001064720000 100Ω 1403 R929 3001051010000 15KΩ...
  • Page 106 Service Manual UHF1 (400-470MHz 25W) Information Ref No. Print No. Part No. Description 150Ω 1437 R966 3001161510010 0Ω 1438 R967 3001050000000 2.2KΩ 1439 R968 3001052220000 47KΩ 1440 R969 3001064730000 1KΩ 1441 R970 3001061020010 2.74kΩ 1442 R971 3099052741000 2.2KΩ 1443 R972 3001062220000 1KΩ...
  • Page 107 UHF1 (400-470MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1477 U702 3608006000000 Power management IC 1478 U703 3608015000060 Power management IC 1479 U801 3605026000020 Operational amplifier 1480 U802 3605002054590 Operational amplifier 1481 U804 3605008005070 Operational amplifier 1482 U900 3608006000000...

  • Page 108: Troubleshooting Flow Chart

    Service Manual UHF1 (400-470MHz 25W) Information Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (73.35MHz) The second LO is Check Q701.
  • Page 109 UHF1 (400-470MHz 25W) Information Service Manual Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 73.35MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 110 Service Manual UHF1 (400-470MHz 25W) Information Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Control voltage Current is Check U801. is low or high? normal? [1] Check PA, High antenna switch and low-pass TX VCO works circuits.
  • Page 111 UHF1 (400-470MHz 25W) Information Service Manual Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 112 Service Manual UHF1 (400-470MHz 25W) Information FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 113 UHF1 (400-470MHz 25W) Information Service Manual Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 3.6V [3] Check whether the emitter voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 1.8V under normal RX/TX status.

  • Page 114: Uhf1 (400-470Mhz 45W) Information

    Service Manual UHF1 (400-470MHz 45W) Information 9. UHF1 (400-470MHz 45W) Information Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 115: Pre-Driver Power Amplifier

    UHF1 (400-470MHz 45W) Information Service Manual 9.1.3 Pre-driver Power Amplifier The pre-driver power amplifier is formed by Q805, with variable gain controlled by voltage VGG. The input matching circuit is composed of C826, L826, L814, C843 and R824. 9.1.4 Driver Power Amplifier The driver power amplifier is formed by Q804, with variable gain controlled by voltage VGG.

  • Page 116: Directional Coupler

    Service Manual UHF1 (400-470MHz 45W) Information 9.1.8 Directional Coupler A directional coupler that consists of microstrip directional coupler, D803, D804 and etc, is used to detect both forward and reverse directed power of the transmitter. The forward power is coupled to the diode D803, and the voltage is applied to the power control circuit (U801).

  • Page 117: Receiver Front-End

    UHF1 (400-470MHz 45W) Information Service Manual Figure 9-2 Diagram of Receiver Circuit 9.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (73.35MHz).

  • Page 118: Receiver Back-End

    Service Manual UHF1 (400-470MHz 45W) Information 9.2.2 Receiver Back-end Figure 9-3 Diagram of IF Processor The first IF signal (73.35MHz) output by the IF amplifier goes into IF IC via Pin 47, where the signal is converted to the second IF signal (2.25MHz). Then the un-demodulated digital I/Q signal output from the SSI interface is sent to U302 for demodulation.

  • Page 119: Reference Oscillator

    UHF1 (400-470MHz 45W) Information Service Manual 9.3.2 Reference Oscillator X100 is a 19.2MHz TCXO, and its reference frequency is calibrated by the digital-to-analog converter (U500) for accuracy. 9.3.3 PLL IC The PLL IC (U100) is a fractional frequency divider. The logic IC U101 and U102 work with the PLL IC (U100) to achieve locking.

  • Page 120: Vco

    Service Manual UHF1 (400-470MHz 45W) Information 9.3.4 The VCO is composed of transistors (Q100, Q103, Q106 and Q110), varactors and four Colpitts oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals and the other two VCOs (Q106 and Q110) to receive LO signals. U302 controls the operating frequency of the VCO.

  • Page 121: Pcb View

    PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 122 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 123 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Top Layer 顶层...
  • Page 124 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 125: Block Diagram

    9.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q104 Q100\Q103\Q106\Q110 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 126 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 127 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL MCSI1 McBSP2 GPIOs TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 128: Schematic Diagram

    9.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 129 MD78X/MD78XG Schematic Diagram (RX Circuit) MD780/780G 原理图（接收电路） L6100 L6100 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6100 C6100 R6100 R6100 C6102 C6102 C6185 C6185 R6101 R6101 470p 470p R6102 R6102 TRANSISTOR TRANSISTOR L6101 L6101 Q6101 Q6101 BLM18PG600SN1 BLM18PG600SN1 TRANSISTOR TRANSISTOR RF_ATTEN C6103 C6103 220p...
  • Page 130 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 0.1u 0.1u 10uF/10V 10uF/10V R570 R570 R542 0 R542 0 C509 C509 C484 C484 1000p 1000p C508 C508 C483 C483 C510 C510 R528 R528 8200p 8200p 0.1u 0.1u...
  • Page 131 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 132 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/16V 10u/16V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 133 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 134 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 135 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 136 MD78X/MD78XG Schematic Diagram (Power Circuit) U900 U900 RP102N331B RP102N331B 3V3D TP4031 TP4031 VOUT TP4032 TP4032 C900 C900 C901 C901 B900 B900 MMBZ6V8ALT1G MMBZ6V8ALT1G D237 D237 U901 U901 C902 C902 D900 D900 TP4035 TP4035 RP102N331B RP102N331B 3V3DP C903 C903 470p/50V 470p/50V...
  • Page 137 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1000p 1000p 0.1u 0.1u C1010 C1010 1000p 1000p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 138 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 Q101 Q101 4V3A EMD22 EMD22 R142 R142 3.3k 3.3k 220p 220p 0.1u 0.1u 470n 470n R145 R145 TX_VCO_H 220p 220p C195 C195 C194 C194 R143 R143 220p 220p 0.1u 0.1u 6.8k 6.8k...
  • Page 139 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 330n 330n 0.01u 0.01u IF-out TP701 TP701 L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702...
  • Page 140 MD78X/MD78XG Schematic Diagram (TX Circuit) C909 C909 C889 C889 C913 C913 C888 C888 C825 C825 C885 C885 L801 L801 W801 W801 C855 C855 47pF 47pF 470p 470p BLM41PG600SN1 BLM41PG600SN1 100p 100p 3300p 3300p 0.018uF 0.018uF 33pF 33pF C916 C916 C930...
  • Page 141 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 142: Parts List

    Service Manual UHF1 (400-470MHz 45W) Information Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101051020010 1000PF 3101060700020 C100 3101052210010 220PF C1000 3101052210010 220PF C1001 3101054710010 470PF C1002 3101051020010...
  • Page 143 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C152 3101054090010 C153 3101052700000 27PF C154 3101053900000 39PF C155 3101061200000 12PF C156 3101052210010 220PF C157 3101055600000 56PF C158 3101051800070 18PF C159 3101054090010 3101050600010 C160 3101052210010 220PF C161 3101055600000 56PF C162...
  • Page 144 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 3101054710010 470PF 3101050800000 3101052210010 220PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 0.47uF C238 3101061050020 C239 3101051040010 0.1UF 3101051040010 0.1UF...
  • Page 145 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C267 3101051040010 0.1UF C268 3101064740010 0.47UF C269 3101052210010 220PF 3101050590010 0.5PF C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010 10UF C276...
  • Page 146 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description C308 3101051040010 0.1UF C309 3101051010030 100PF 3101060300010 C310 3101051050000 C311 3101051040010 0.1UF 3101050500010 C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051010030 100PF C330 3101051040010 0.1UF C334 3101051040010 0.1UF...
  • Page 147 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C363 3101058200000 82PF C364 3101053900000 39PF C365 3101058200000 82PF C366 3101051040010 0.1UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF C380 3101051040010 0.1UF C381 3101051030020 0.01UF...
  • Page 148 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description C415 3101051010030 100PF C416 3101051010030 100PF C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF 3101050100030 C420 3101051010030 100PF C421 3101052210010 220PF C422 3101051040010 0.1UF C423 3101052210010 220PF C424 3101052210010...
  • Page 149 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C454 3101051010030 100PF C455 3101051010030 100PF C456 3101051010030 100PF 3101052210010 220PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467 3101051010030 100PF C468 3101051010030 100PF C469 3101051010030 100PF C470...
  • Page 150 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description C519 3101071060010 10UF 3101052210010 220PF C520 3101071060010 10UF 3101051590000 1.5PF 3101063690000 3.6PF 3101050600010 3101051030020 0.01UF 3101051200020 12PF 3101052210010 220PF 3101051020010 1000PF 3101051200020 12PF C6100 3101061050020 C6102 3101054710010 470PF C6103 3101052210010...
  • Page 151 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C6134 3101055600000 56PF C6135 3101055600000 56PF C6136 3101055600000 56PF C6137 3101054700010 47PF C6138 3101054700010 47PF C6139 3101055600000 56PF C6140 3101055600000 56PF C6141 3101055600000 56PF C6142 3101054700010 47PF C6143 3101054700010 47PF...
  • Page 152 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description C6180 3101051040010 0.1UF C6185 3101061050020 C6190 3101061050020 C6193 3101061040010 0.1UF C6194 3212106100000 10nH 3101050100030 C6246 3101050600010 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3101051040010 0.1UF 3110071040000 0.1UF...
  • Page 153 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C728 3101051020010 1000PF C729 3101051040010 0.1UF C730 3101052200010 22PF C731 3101050600010 C732 3101052200010 22PF C733 3101051040010 0.1UF C734 3101053000010 30PF C735 3101051040010 0.1UF C736 3101051030020 0.01UF C737 3101051040010 0.1UF C738...
  • Page 154 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description C801 3101081020010 1000pF C802 3101063320000 3300PF C803 3101063300000 33PF C804 3101092260010 22UF C807 3101081060010 10UF C808 3101062210000 220PF C809 3101062210000 220PF C810 3101072000000 20PF C811 3101064710000 470PF C812 3101372200000 22pF...
  • Page 155 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C846 3101072000000 20PF C847 3101061510000 150PF C848 3101061510000 150PF 3101051040010 0.1UF C850 3101084710010 470pF C851 3101080200010 C852 3101061010010 100PF C853 3101062210000 220PF C854 3101061040010 0.1UF C855 3101072000000 20PF C857 3101062200010...
  • Page 156 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description C896 3101052210010 220PF C897 3101052210010 220PF C898 3101052210010 220PF C899 3101051210000 120PF 3101050100030 3101051010030 100PF C900 3101061050020 C901 3101061050020 C902 3101062200010 22PF C905 3101061050020 C906 3101061050020 C907 3101061040010 0.1UF C908...
  • Page 157 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C934 3101062250000 2.2UF C935 3101061040010 0.1UF C936 3101061040010 0.1UF C937 3101051020010 1000PF 3110071040000 0.1UF C940 3101066800000 68PF C941 3101051540000 0.15UF C942 3101061040010 0.1UF C943 3101062700010 27PF C944 3101051020010 1000PF C945...
  • Page 158 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description D100 3303990000060 Switching diode D101 3304010100220 Varactor D102 3304010100220 Varactor D105 3304010100220 Varactor D106 3304010100220 Varactor D107 3304010100220 Varactor D108 3304010100220 Varactor D109 3304010100220 Varactor D110 3304010100220 Varactor D111 3304010100220...
  • Page 159 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description D450 3699037000010 USB IC 10KΩ D601 3001051030000 D6100 3303060300010 Switching diode D6101 3304010100890 Varactor D6102 3304010100890 Varactor D6103 3304010100890 Varactor D6104 3304010100890 Varactor D6105 3399990000260 Rectifier diode D6106 3699019000000 Mixer IC...
  • Page 160 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description L114 3237199080000 L115 3214307270010 27nH L116 3217607471000 470nH L117 3217607471000 470nH L118 3217607471000 470nH L121 3217607471000 470nH L122 3210306150000 15nH L123 3210306150000 15nH L124 3237199120000 Air-core coil 12.5nH L126 3214307390000 39nH...
  • Page 161 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 3217607471000 470nH L401 3221506300000 Bead L402 3221506300000 Bead L403 3221506300000 Bead L404 3221506300000 Bead L405 3221506300000 Bead L406 3221506300000 Bead L407 3221506300000 Bead L408 3221506300000 Bead L409 3221506300000 Bead L410...
  • Page 162 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description L6217 3101052210010 220PF 3221506601000 Bead L701 3221506601000 Bead L702 3221506601000 Bead L703 3221506601000 Bead L704 3213212103000 10uH L705 3213212103000 10uH L706 3221506601000 Bead L707 3221506601000 Bead L708 3217107221010 220nH L709...
  • Page 163 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description L822 3221506601000 Bead 0Ω L823 3001060000000 L824 3221506601000 Bead L825 3221506601000 Bead L826 3101061600000 16PF L827 3212106390000 39nH L828 3217112102020 L829 3101065600000 56PF L830 3101065600000 56PF L832 3212106100000 10nH L833...
  • Page 164 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description Q117 3403999000000 Composite transistor Q230 3499000000150 Composite transistor Q231 3499000000150 Composite transistor Q232 3499000000150 Composite transistor Q233 3499000000150 Composite transistor Q234 3499000000150 Composite transistor Q235 3499000000150 Composite transistor Q323 3403008000010 Q400...
  • Page 165 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description Q903 3403008000010 Q905 3499000000150 Composite transistor Q906 3414001000020 NPN transistor Q908 3403008000010 Q909 3403002000010 PNP transistor Q910 3414001000020 NPN transistor Q912 3403008000010 Q913 3403008000010 Q914 3403008000010 Q921 3404999000020 NPN transistor Q922...
  • Page 166 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 15KΩ R151 3001051530010 36KΩ R152 3001053630000 R153 3221506601000 Bead 20KΩ R155 3001052030000 68Ω R156 3001056800000 R157 3221506601000 Bead 6.8KΩ R158 3001056820000 7.5KΩ R159 3001057520000 100Ω R160 3001051010040 18KΩ...
  • Page 167 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 5.6KΩ R239 3001055620000 56KΩ R241 3001055630000 0Ω R242 3001050000000 22KΩ 1000 R244 3001052230010 22KΩ 1001 R246 3001052230010 100KΩ 1002 R247 3001051040010 100KΩ 1003 R248 3001051040010 15KΩ 1004 R250 3001051530000 100Ω...
  • Page 168 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 47KΩ 1037 R288 3001054730000 0Ω 1038 R289 3001050000000 1KΩ 1039 R290 3001051020000 1040 R291 3001051220000 1.2KΩ 33Ω 1041 R292 3001053300010 1KΩ 1042 R295 3001051020000 100KΩ 1043 R296 3001051040000 0Ω...
  • Page 169 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 0Ω 1077 R375 3001050000000 33Ω 1078 R376 3001053300010 10KΩ 1079 R377 3001051030000 10KΩ 1080 R378 3001051030000 10KΩ 1081 R379 3001051030000 33Ω 1082 R380 3001053300010 33Ω 1083 R381 3001053300010 10KΩ...
  • Page 170 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 1KΩ 1117 R422 3001051020010 33Ω 1118 R423 3001053300010 33Ω 1119 R424 3001053300010 33Ω 1120 R425 3001053300010 0Ω 1121 R426 3001050000000 10KΩ 1122 R427 3001051030000 4.7KΩ 1123 R428 3001054720000 10KΩ...
  • Page 171 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 10KΩ 1157 R464 3001051030000 10KΩ 1158 R465 3001051030000 10KΩ 1159 R466 3001051030000 33Ω 1160 R467 3001053300010 4.7KΩ 1161 R468 3001054720000 1162 R469 3001054720000 4.7KΩ 4.7KΩ 1163 R470 3001054720000 4.7KΩ...
  • Page 172 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 4.7KΩ 1197 R511 3001054720000 10KΩ 1198 R512 3001051030000 100KΩ 1199 R513 3001051040000 1200 R514 3001051040000 100KΩ 33Ω 1201 R515 3001053300010 33Ω 1202 R516 3001053300010 33Ω 1203 R517 3001053300010 33Ω...
  • Page 173 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 33Ω 1237 R553 3001053300010 1KΩ 1238 R554 3001051020010 10KΩ 1239 R555 3001051030000 100Ω 1240 R556 3001051010000 100Ω 1241 R557 3001051010000 33KΩ 1242 R558 3001053330010 33KΩ 1243 R559 3001053330010 33KΩ...
  • Page 174 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 5.6Ω 1277 R6121 3001055690000 1.2KΩ 1278 R6122 3001051220000 0Ω 1279 R6123 3001050000000 820Ω 1280 R6124 3001058210000 820Ω 1281 R6125 3001058210000 82Ω 1282 R6126 3001068200000 1283 R6127 3001051030000 10KΩ...
  • Page 175 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 47KΩ 1317 R727 3001064730000 47KΩ 1318 R728 3001064730000 0Ω 1319 R729 3001050000000 0Ω 1320 R731 3001050000000 12KΩ 1321 R802 3001061230000 220Ω 1322 R803 3001062210000 4.7Ω 1323 R804 3001084790000 4.7Ω...
  • Page 176 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 10KΩ 1357 R846 3001061030000 47KΩ 1358 R847 3001054730000 2.2KΩ 1359 R849 3001052220010 470Ω 1360 R852 3001064710000 470Ω 1361 R853 3001064710000 56KΩ 1362 R854 3001055630000 51Ω 1363 R855 3001085100000 51Ω...
  • Page 177 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 470KΩ 1397 R898 3001054740010 470KΩ 1398 R899 3001054740010 0Ω 1399 R902 3001050000000 0Ω 1400 R904 3001050000000 33KΩ 1401 R905 3001053330000 47KΩ 1402 R906 3001064730000 4.7KΩ 1403 R908 3001054720000 2.2KΩ...
  • Page 178 Service Manual UHF1 (400-470MHz 45W) Information Ref No. Print No. Part No. Description 1KΩ 1437 R954 3001061020010 180KΩ 1438 R955 3001051840000 180KΩ 1439 R956 3001051840000 1KΩ 1440 R957 3001051020010 680Ω 1441 R958 3001066810000 47KΩ 1442 R959 3001054730000 4.7KΩ 1443 R960 3001054790010 330Ω...
  • Page 179 UHF1 (400-470MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 1477 U233 3612999000290 Memory 1478 U235 3605010000020 Operational amplifier 1479 U236 3605010000020 Operational amplifier 1480 U237 3616010000000 Switch IC 1481 U238 3605008005070 Operational amplifier 1482 U302 3610010000010 1483 U327 3607023000150...

  • Page 180: Troubleshooting Flow Chart

    Service Manual UHF1 (400-470MHz 45W) Information Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (73.35MHz) The second LO is Check Q701.
  • Page 181 UHF1 (400-470MHz 45W) Information Service Manual Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 73.35MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 182 Service Manual UHF1 (400-470MHz 45W) Information Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Control voltage Current is Check U801. is low or high? normal? [1] Check PA, High antenna switch and low-pass TX VCO works circuits.
  • Page 183 UHF1 (400-470MHz 45W) Information Service Manual Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 184 Service Manual UHF1 (400-470MHz 45W) Information FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 185 UHF1 (400-470MHz 45W) Information Service Manual Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 3.6V [3] Check whether the emitter voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 1.8V under normal RX/TX status.

  • Page 186: Uhf2 (450-520Mhz 25W) Information

    Service Manual UHF2 (450-520MHz 25W) Information 10. UHF2 (450-520MHz 25W) Information 10.1 Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 187: Pre-Driver Power Amplifier

    UHF2 (450-520MHz 25W) Information Service Manual signal (enabled by antenna switch), so as to further control the power supply for the whole circuit. 10.1.3 Pre-driver Power Amplifier The pre-driver power amplifier is formed by Q805, with variable gain controlled by voltage VGG. The input matching circuit is composed of C826, L826, L814, C843 and R824.

  • Page 188: Directional Coupler

    Service Manual UHF2 (450-520MHz 25W) Information 10.1.8 Directional Coupler A directional coupler that consists of microstrip directional coupler, D803, D804 and etc, is used to detect both forward and reverse directed power of the transmitter. The forward power is coupled to the diode D803, and the voltage is applied to the power control circuit (U801).

  • Page 189: Receiver Front-End

    UHF2 (450-520MHz 25W) Information Service Manual Figure 10-2 Diagram of Receiver Circuit 10.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (73.35MHz).

  • Page 190: Receiver Back-End

    Service Manual UHF2 (450-520MHz 25W) Information 10.2.2 Receiver Back-end Figure 10-3 Diagram of IF Processor The first IF signal (73.35MHz) output by the IF amplifier goes into IF IC via Pin 47, where the signal is converted to the second IF signal (2.25MHz). Then the un-demodulated digital I/Q signal output from the SSI interface is sent to U302 for demodulation.

  • Page 191: Reference Oscillator

    UHF2 (450-520MHz 25W) Information Service Manual 10.3.2 Reference Oscillator X100 is a 19.2MHz TCXO, and its reference frequency is calibrated by the digital-to-analog converter (U500) for accuracy. 10.3.3 PLL IC The PLL IC (U100) is a fractional frequency divider. The logic IC U101 and U102 work with the PLL IC (U100) to achieve locking.

  • Page 192: Figure 10-5 Diagram Of Vco

    Service Manual UHF2 (450-520MHz 25W) Information oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals and the other two VCOs (Q106 and Q110) to receive LO signals. U302 controls the operating frequency of the VCO. Q102 and Q107 constitute the buffer amplifiers for the transmitter circuit, while Q111 and Q109 for the receiver circuit.

  • Page 193: Pcb View

    10.4 PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 194 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 195 MD780/MD780G PCB 元件位置图（主板） MD78X/MD78XG PCB View (Main Board) Top Layer 顶层...
  • Page 196 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 197: Block Diagram

    10.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q100\Q103\Q106\Q110 Q104 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 198 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 199 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL MCSI1 McBSP2 GPIOs TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 200: Schematic Diagram

    10.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 201 MD78X/MD78XG Schematic Diagram (RX Circuit) MD780/780G 原理图（接收电路） L6100 L6100 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6100 C6100 R6100 R6100 C6102 C6102 C6185 C6185 R6101 R6101 470p 470p R6102 R6102 TRANSISTOR TRANSISTOR L6101 L6101 Q6101 Q6101 BLM18PG600SN1 BLM18PG600SN1 TRANSISTOR TRANSISTOR RF_ATTEN C6103 C6103 220p...
  • Page 202 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 0.1u 0.1u 10uF/10V 10uF/10V R570 R570 R542 0 R542 0 C509 C509 C484 C484 1000p 1000p C508 C508 C483 C483 C510 C510 R528 R528 8200p 8200p 0.1u 0.1u...
  • Page 203 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 204 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/16V 10u/16V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 205 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 206 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 207 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 208 MD78X/MD78XG Schematic Diagram (Power Circuit) U900 U900 RP102N331B RP102N331B 3V3D TP4031 TP4031 VOUT TP4032 TP4032 C900 C900 C901 C901 B900 B900 MMBZ6V8ALT1G MMBZ6V8ALT1G D237 D237 U901 U901 C902 C902 D900 D900 TP4035 TP4035 RP102N331B RP102N331B 3V3DP C903 C903 470p/50V 470p/50V...
  • Page 209 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1000p 1000p 0.1u 0.1u C1010 C1010 1000p 1000p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 210 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 Q101 Q101 4V3A EMD22 EMD22 R142 R142 3.3k 3.3k 220p 220p 0.1u 0.1u 470n 470n R145 R145 TX_VCO_H 220p 220p C195 C195 C194 C194 R143 R143 220p 220p 0.1u 0.1u 6.8k 6.8k...
  • Page 211 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 330n 330n 0.01u 0.01u IF-out TP701 TP701 L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702...
  • Page 212 MD78X/MD78XG Schematic Diagram (TX Circuit) C909 C909 C889 C889 C913 C913 C888 C888 C825 C825 C885 C885 L801 L801 W801 W801 C855 C855 47pF 47pF 470p 470p BLM41PG600SN1 BLM41PG600SN1 100p 100p 3300p 3300p 0.018uF 0.018uF 33pF 33pF C916 C916 C930...
  • Page 213 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 214: Parts List

    Service Manual UHF2 (450-520MHz 25W) Information 10.7 Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101051020010 1000PF 3101060900010 C100 3101052210010 220PF C1000 3101052210010 220PF C1001 3101054710010 470PF C1002...
  • Page 215 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C152 3101053690030 3.6P C153 3101053000010 30PF C154 3101053000010 30PF C155 3101061000000 10PF C156 3101052210010 220PF C157 3101055600000 56PF C158 3101052000020 20PF C159 3101053690030 3.6P 3101050500010 C160 3101052210010 220PF C161 3101055600000...
  • Page 216 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description C200 3101061050020 3101054710010 470PF 3101050800000 3101052210010 220PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 0.47uF C238 3101061050020 C239 3101051040010 0.1UF...
  • Page 217 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C266 3101061050020 C267 3101051040010 0.1UF C268 3101064740010 0.47UF C269 3101052210010 220PF 3101050590010 0.5PF C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010...
  • Page 218 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description C307 3101051010030 100PF C308 3101051040010 0.1UF C309 3101051010030 100PF 3101060500010 C310 3101051050000 C311 3101051040010 0.1UF 3101050500010 C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051010030 100PF C330 3101051040010 0.1UF...
  • Page 219 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C362 3101058200000 82PF C363 3101058200000 82PF C364 3101053900000 39PF C365 3101058200000 82PF C366 3101051040010 0.1UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF C380 3101051040010 0.1UF...
  • Page 220 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description C414 3101051010030 100PF C415 3101051010030 100PF C416 3101051010030 100PF C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF 3101050100030 C420 3101051010030 100PF C421 3101052210010 220PF C422 3101051040010 0.1UF C423 3101052210010...
  • Page 221 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C453 3101051010030 100PF C454 3101051010030 100PF C455 3101051010030 100PF C456 3101051010030 100PF 3101052210010 220PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467 3101051010030 100PF C468 3101051010030 100PF C469...
  • Page 222 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description C517 3101051010030 100PF C518 3101051010030 100PF C519 3101071060010 10UF 3101052210010 220PF C520 3101071060010 10UF 3101052290020 2.2PF 3101063690000 3.6PF 3101050600010 3101051030020 0.01UF 3101051200020 12PF 3101052210010 220PF 3101051020010 1000PF 3101051000020 10PF C6100...
  • Page 223 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C6130 3101051500020 15PF C6133 3101050300000 C6134 3101053300000 33PF C6135 3101053300000 33PF C6136 3101053300000 33PF C6137 3101053300000 33PF c6138 3101055600000 56PF C6139 3101053300000 33PF C6140 3101053300000 33PF C6141 3101053300000 33PF C6142...
  • Page 224 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description C6178 3101051030020 0.01UF C6179 3101051040010 0.1UF C6180 3101051040010 0.1UF C6185 3101061050020 C6190 3101061050020 C6193 3101061040010 0.1UF C6194 3212106689000 6.8nH 3101050100030 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF...
  • Page 225 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C726 3101074750000 4.7UF C727 3101054710010 470PF C728 3101051020010 1000PF C729 3101051040010 0.1UF C730 3101052200010 22PF C731 3101050600010 C732 3101052200010 22PF C733 3101051040010 0.1UF C734 3101053000010 30PF C735 3101051040010 0.1UF C736...
  • Page 226 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 3101051020010 1000PF 3101054710010 470PF 3101051030020 0.01UF C801 3101081020010 1000pF C802 3101063320000 3300PF C803 3101063300000 33PF C804 3101092260010 22UF C807 3101081060010 10UF C808 3101062210000 220PF C809 3101062210000 220PF C811 3101064710000 470PF...
  • Page 227 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C847 3101061510000 150PF C848 3101061510000 150PF 3101051040010 0.1UF C850 3101084710010 470pF C851 3101080100010 C852 3101066800000 68PF C853 3101062210000 220PF C854 3101061040010 0.1UF C856 3101080200010 C857 3101062200010 22PF 3101051040010 0.1UF C861...
  • Page 228 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description C899 3101051210000 120PF 3101052290020 2.2PF 3101051010030 100PF C900 3101061050020 C901 3101061050020 C902 3101062200010 22PF C905 3101061050020 C906 3101061050020 C907 3101061040010 0.1UF C908 3101061050020 C909 3101063310010 330PF 3110071040000 0.1UF C910 3101051020010...
  • Page 229 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C937 3101051020010 1000PF 3110071040000 0.1UF C940 3101066800000 68PF C941 3101051540000 0.15UF C942 3101061040010 0.1UF C943 3101062700010 27PF C944 3101051020010 1000PF C945 3101054710010 470PF C946 3101061050020 C947 3101051040010 0.1UF C948 3101061040010...
  • Page 230 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description D105 3304010100220 Varactor D106 3304010100220 Varactor D107 3304010100220 Varactor D108 3304010100220 Varactor D109 3304010100220 Varactor D110 3304010100220 Varactor D111 3304010100220 Varactor D112 3304010100220 Varactor D113 3304010100220 Varactor D116 3304010100220 Varactor...
  • Page 231 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description D6101 3304010101100 Varactor D6102 3304010101100 Varactor D6103 3304010101100 Varactor D6104 3304010101100 Varactor D6105 3399990000260 Rectifier diode D6106 3699019000000 Mixer IC D701 3304060300050 Varactor D702 3304060300010 Varactor D801 3303210100000 Switching diode D802...
  • Page 232 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description L117 3217607471000 470nH L118 3217607471000 470nH L121 3217607471000 470nH L122 3210306150000 15nH L123 3210306150000 15nH L124 3237199080000 L126 3214307270010 27nH L127 3217607471000 470nH L128 3210306150000 15nH L129 3217607471000 470nH L131...
  • Page 233 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L404 3221506300000 Bead L405 3221506300000 Bead L406 3221506300000 Bead L407 3221506300000 Bead L408 3221506300000 Bead L409 3221506300000 Bead L410 3221506300000 Bead L411 3221506300000 Bead L412 3221506300000 Bead 0Ω...
  • Page 234 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description L701 3221506601000 Bead L702 3221506601000 Bead L703 3221506601000 Bead L704 3213212103000 10uH L705 3213212103000 10uH L706 3221506601000 Bead L707 3221506601000 Bead L708 3217107221010 220nH L709 3221506601000 Bead L710 3221506601000 Bead...
  • Page 235 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L824 3221506601000 Bead L825 3221506601000 Bead L826 3101061600000 16PF L827 3212106390000 39nH L828 3217112102020 0Ω L829 3001070000000 0Ω L830 3001070000000 L832 3212106689000 6.8nH L833 3101064700000 47PF 3221506601000 Bead L900 3221513600000...
  • Page 236 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description Q231 3499000000150 Composite transistor Q232 3499000000150 Composite transistor Q233 3499000000150 Composite transistor Q234 3499000000150 Composite transistor Q235 3499000000150 Composite transistor Q323 3403008000010 Q400 3413001000010 PNP transistor Q401 3403008000010 Q402 3403008000010...
  • Page 237 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description Q909 3403002000010 PNP transistor Q910 3414001000020 NPN transistor Q912 3403008000010 Q913 3403008000010 Q914 3403008000010 Q921 3404999000020 NPN transistor Q922 3403008000010 Q923 3403008000010 47Ω 3001054700000 10Ω R109 3001051000000 100Ω...
  • Page 238 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 68Ω R156 3001056800000 R157 3221506601000 Bead 6.8KΩ R158 3001056820000 7.5KΩ R159 3001057520000 100Ω R160 3001051010040 18KΩ R161 3001051830000 33Ω R167 3001053300010 0Ω R171 3001060000000 0Ω R174 3001050000000 10Ω...
  • Page 239 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 22KΩ R246 3001052230010 100KΩ R247 3001051040010 100KΩ R248 3001051040010 15KΩ 1000 R250 3001051530000 100Ω 1001 R251 3001051010000 100KΩ 1002 R252 3001051040010 470Ω 1003 R255 3001064710000 30KΩ 1004 R257 3001053030010 10KΩ...
  • Page 240 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 33Ω 1037 R292 3001053300010 1KΩ 1038 R295 3001051020000 100KΩ 1039 R296 3001051040000 0Ω 1040 3001050000000 10KΩ 1041 R316 3001051030000 33Ω 1042 R319 3001053300010 33Ω 1043 R320 3001053300010 10KΩ...
  • Page 241 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 10KΩ 1077 R379 3001051030000 33Ω 1078 R380 3001053300010 33Ω 1079 R381 3001053300010 10KΩ 1080 R382 3001051030000 1KΩ 1081 R383 3001051020010 10KΩ 1082 R385 3001051030000 10Ω 1083 R386 3001051000000 33Ω...
  • Page 242 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 0Ω 1117 R426 3001050000000 10KΩ 1118 R427 3001051030000 4.7KΩ 1119 R428 3001054720000 10KΩ 1120 R429 3001051030000 33Ω 1121 R430 3001053300010 33Ω 1122 R431 3001053300010 33Ω 1123 R432 3001053300010 33Ω...
  • Page 243 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 4.7KΩ 1157 R468 3001054720000 4.7KΩ 1158 R469 3001054720000 4.7KΩ 1159 R470 3001054720000 4.7KΩ 1160 R471 3001054720000 4.7KΩ 1161 R472 3001054720000 33Ω 1162 R473 3001053300010 33Ω 1163 R474 3001053300010 10KΩ...
  • Page 244 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 33Ω 1197 R515 3001053300010 33Ω 1198 R516 3001053300010 33Ω 1199 R517 3001053300010 33Ω 1200 R518 3001053300010 33Ω 1201 R519 3001053300010 33Ω 1202 R520 3001053300010 33Ω 1203 R521 3001053300010 33Ω...
  • Page 245 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 100Ω 1237 R557 3001051010000 33KΩ 1238 R558 3001053330010 33KΩ 1239 R559 3001053330010 33KΩ 1240 R560 3001053330010 33KΩ 1241 R561 3001053330010 33KΩ 1242 R562 3001053330010 33KΩ 1243 R563 3001053330010 0Ω...
  • Page 246 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 82Ω 1277 R6126 3001078200000 10KΩ 1278 R6127 3001051030000 330Ω 1279 R6129 3001063310010 1280 R6130 3001055120030 5.1K 1.2KΩ 1281 R6131 3001051220000 51Ω 1282 R6132 3001055100010 330Ω 1283 R6133 3001053310010 30KΩ...
  • Page 247 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 220Ω 1317 R803 3001062210000 10Ω 1318 R808 3001061000000 1319 R809 3001061010000 100Ω 82Ω 1320 R810 3001068200000 18KΩ 1321 R811 3001061830010 4.7Ω 1322 R813 3001084790000 82Ω 1323 R814 3001068200000 27KΩ...
  • Page 248 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 9.1KΩ 1357 R858 3001069120000 1KΩ 1358 R859 3001061020010 4.7Ω 1359 R860 3001084790000 4.7Ω 1360 R861 3001084790000 56Ω 1361 R862 3001065600000 0Ω 1362 R863 3001050000000 470KΩ 1363 R864 3001054740010 39KΩ...
  • Page 249 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 4.7KΩ 1397 R910 3001054720000 44.2kΩ 1398 R911 3099064422010 510Ω 1399 R912 3001055110000 4.7KΩ 1400 R913 3001054720000 24KΩ 1401 R915 3001052430010 330KΩ 1402 R917 3001053340010 6.04kΩ 1403 R918 3099066041010 150KΩ...
  • Page 250 Service Manual UHF2 (450-520MHz 25W) Information Ref No. Print No. Part No. Description 0Ω 1437 R962 3001060000000 0Ω 1438 R963 3001060000000 2.2KΩ 1439 R964 3001052220010 0Ω 1440 R965 3001060000000 150Ω 1441 R966 3001161510010 0Ω 1442 R967 3001050000000 2.2KΩ 1443 R968 3001052220000 47KΩ...
  • Page 251 UHF2 (450-520MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1477 U500 3606010000010 D/A IC 1478 U6000 3605002057090 Operational amplifier 1479 U701 3603999000000 IF processor 1480 U702 3608006000000 Power management IC 1481 U703 3608015000060 Power management IC 1482 U801 3605026000020...

  • Page 252: Troubleshooting Flow Chart

    Service Manual UHF2 (450-520MHz 25W) Information 10.8 Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (73.35MHz) The second LO is Check Q701.
  • Page 253 UHF2 (450-520MHz 25W) Information Service Manual Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 73.35MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 254 Service Manual UHF2 (450-520MHz 25W) Information Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Control voltage Current is Check U801. is low or high? normal? [1] Check PA, High antenna switch and low-pass TX VCO works circuits.
  • Page 255 UHF2 (450-520MHz 25W) Information Service Manual Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 256 Service Manual UHF2 (450-520MHz 25W) Information FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 257 UHF2 (450-520MHz 25W) Information Service Manual Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 3.6V [3] Check whether the emitter voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 1.8V under normal RX/TX status.

  • Page 258: Uhf2 (450-520Mhz 45W) Information

    Service Manual UHF2 (450-520MHz 45W) Information 11. UHF2 (450-520MHz 45W) Information 11.1 Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 259: Pre-Driver Power Amplifier

    UHF2 (450-520MHz 45W) Information Service Manual 11.1.3 Pre-driver Power Amplifier The pre-driver power amplifier is formed by Q805, with variable gain controlled by voltage VGG. The input matching circuit is composed of C826, L826, L814, C843 and R824. 11.1.4 Driver Power Amplifier The driver power amplifier is formed by Q804, with variable gain controlled by voltage VGG.

  • Page 260: Directional Coupler

    Service Manual UHF2 (450-520MHz 45W) Information 11.1.8 Directional Coupler A directional coupler that consists of microstrip directional coupler, D803, D804 and etc, is used to detect both forward and reverse directed power of the transmitter. The forward power is coupled to the diode D803, and the voltage is applied to the power control circuit (U801).

  • Page 261: Receiver Front-End

    UHF2 (450-520MHz 45W) Information Service Manual Figure 11-2 Diagram of Receiver Circuit 11.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (73.35MHz).

  • Page 262: Receiver Back-End

    Service Manual UHF2 (450-520MHz 45W) Information 11.2.2 Receiver Back-end Figure 11-3 Diagram of IF Processor The first IF signal (73.35MHz) output by the IF amplifier goes into IF IC via Pin 47, where the signal is converted to the second IF signal (2.25MHz). Then the un-demodulated digital I/Q signal output from the SSI interface is sent to U302 for demodulation.

  • Page 263: Reference Oscillator

    UHF2 (450-520MHz 45W) Information Service Manual 11.3.2 Reference Oscillator X100 is a 19.2MHz TCXO, and its reference frequency is calibrated by the digital-to-analog converter (U500) for accuracy. 11.3.3 PLL IC The PLL IC (U100) is a fractional frequency divider. The logic IC U101 and U102 work with the PLL IC (U100) to achieve locking.

  • Page 264: Vco

    Service Manual UHF2 (450-520MHz 45W) Information 11.3.4 The VCO is composed of transistors (Q100, Q103, Q106 and Q110), varactors and four Colpitts oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals and the other two VCOs (Q106 and Q110) to receive LO signals. U302 controls the operating frequency of the VCO.

  • Page 265: Pcb View

    11.4 PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 266 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 267 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Top Layer 顶层...
  • Page 268 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 269: Block Diagram

    11.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q104 Q100\Q103\Q106\Q110 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 270 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 271 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL MCSI1 McBSP2 GPIOs TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 272: Schematic Diagram

    11.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 273 MD78X/MD78XG Schematic Diagram (RX Circuit) MD780/780G 原理图（接收电路） L6100 L6100 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6100 C6100 R6100 R6100 C6102 C6102 C6185 C6185 R6101 R6101 470p 470p R6102 R6102 TRANSISTOR TRANSISTOR L6101 L6101 Q6101 Q6101 BLM18PG600SN1 BLM18PG600SN1 TRANSISTOR TRANSISTOR RF_ATTEN C6103 C6103 220p...
  • Page 274 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 0.1u 0.1u 10uF/10V 10uF/10V R570 R570 R542 0 R542 0 C509 C509 C484 C484 1000p 1000p C508 C508 C483 C483 C510 C510 R528 R528 8200p 8200p 0.1u 0.1u...
  • Page 275 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 276 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/16V 10u/16V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 277 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 278 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 279 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 280 MD78X/MD78XG Schematic Diagram (Power Circuit) U900 U900 RP102N331B RP102N331B 3V3D TP4031 TP4031 VOUT TP4032 TP4032 C900 C900 C901 C901 B900 B900 MMBZ6V8ALT1G MMBZ6V8ALT1G D237 D237 U901 U901 C902 C902 D900 D900 TP4035 TP4035 RP102N331B RP102N331B 3V3DP C903 C903 470p/50V 470p/50V...
  • Page 281 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1000p 1000p 0.1u 0.1u C1010 C1010 1000p 1000p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 282 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 Q101 Q101 4V3A EMD22 EMD22 R142 R142 3.3k 3.3k 220p 220p 0.1u 0.1u 470n 470n R145 R145 TX_VCO_H 220p 220p C195 C195 C194 C194 R143 R143 220p 220p 0.1u 0.1u 6.8k 6.8k...
  • Page 283 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 330n 330n 0.01u 0.01u IF-out TP701 TP701 L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702...
  • Page 284 MD78X/MD78XG Schematic Diagram (TX Circuit) C909 C909 C889 C889 C913 C913 C888 C888 C825 C825 C885 C885 L801 L801 W801 W801 C855 C855 47pF 47pF 470p 470p BLM41PG600SN1 BLM41PG600SN1 100p 100p 3300p 3300p 0.018uF 0.018uF 33pF 33pF C916 C916 C930...
  • Page 285 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 286: Parts List

    Service Manual UHF2 (450-520MHz 45W) Information 11.7 Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101054710010 470PF 3101060900010 C100 3101052210010 220PF C1000 3101052210010 220PF C1001 3101054710010 470PF C1002...
  • Page 287 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C152 3101053690030 3.6P C153 3101053000010 30PF C154 3101053000010 30PF C155 3101061000000 10PF C156 3101052210010 220PF C157 3101055600000 56PF C158 3101052000020 20PF C159 3101053690030 3.6P 3101050500010 C160 3101052210010 220PF C161 3101055600000...
  • Page 288 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description C200 3101061050020 3101054710010 470PF 3101050800000 3101052210010 220PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 0.47uF C238 3101061050020 C239 3101051040010 0.1UF...
  • Page 289 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C266 3101061050020 C267 3101051040010 0.1UF C268 3101064740010 0.47UF C269 3101052210010 220PF 3101050590010 0.5PF C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010...
  • Page 290 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description C308 3101051040010 0.1UF C309 3101051010030 100PF 3101060500010 C310 3101051050000 C311 3101051040010 0.1UF 3101050500010 C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051010030 100PF C330 3101051040010 0.1UF C334 3101051040010 0.1UF...
  • Page 291 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C363 3101058200000 82PF C364 3101053900000 39PF C365 3101058200000 82PF C366 3101051040010 0.1UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF C380 3101051040010 0.1UF C381 3101051030020 0.01UF...
  • Page 292 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description C415 3101051010030 100PF C416 3101051010030 100PF C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF 3101050100030 C420 3101051010030 100PF C421 3101052210010 220PF C422 3101051040010 0.1UF C423 3101052210010 220PF C424 3101052210010...
  • Page 293 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C454 3101051010030 100PF C455 3101051010030 100PF C456 3101051010030 100PF 3101052210010 220PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467 3101051010030 100PF C468 3101051010030 100PF C469 3101051010030 100PF C470...
  • Page 294 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description C518 3101051010030 100PF C519 3101071060010 10UF 3101052210010 220PF C520 3101071060010 10UF 3101052290020 2.2PF 3101063690000 3.6PF 3101050600010 3101051030020 0.01UF 3101051200020 12PF 3101052210010 220PF 3101054710010 470PF 3101051000020 10PF C6100 3101061050020 C6102 3101054710010...
  • Page 295 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C6133 3101050300000 C6134 3101053300000 33PF C6135 3101053300000 33PF C6136 3101053300000 33PF C6137 3101053300000 33PF c6138 3101055600000 56PF C6139 3101053300000 33PF C6140 3101053300000 33PF C6141 3101053300000 33PF C6142 3101053300000 33PF c6143...
  • Page 296 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description C6179 3101051040010 0.1UF C6180 3101051040010 0.1UF C6185 3101061050020 C6190 3101061050020 C6193 3101061040010 0.1UF C6194 3212106689000 6.8nH 3101050100030 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3110071040000 0.1UF 3101051040010 0.1UF 3110071040000...
  • Page 297 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C729 3101051040010 0.1UF C730 3101052200010 22PF C731 3101050600010 C732 3101052200010 22PF C733 3101051040010 0.1UF C734 3101053000010 30PF C735 3101051040010 0.1UF C736 3101051030020 0.01UF C737 3101051040010 0.1UF C738 3101051010030 100PF C739...
  • Page 298 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description C802 3101063320000 3300PF C803 3101063300000 33PF C804 3101092260010 22UF C807 3101081060010 10UF C808 3101062210000 220PF C809 3101062210000 220PF C810 3101073000000 30PF C811 3101054710010 470PF C812 3101080500010 C814 3101061800000 18PF 0Ω...
  • Page 299 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C848 3101061510000 150PF 3101051040010 0.1UF C850 3101054710010 470PF C851 3101080100010 C852 3101066800000 68PF C853 3101062210000 220PF C854 3101061040010 0.1UF C855 3101072700000 27PF C856 3101080300010 C857 3101062200010 22PF 3101051040010 0.1UF C861...
  • Page 300 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description C897 3101052210010 220PF C898 3101052210010 220PF C899 3101051210000 120PF 3101052290020 2.2PF 3101051010030 100PF C900 3101061050020 C901 3101061050020 C902 3101062200010 22PF C905 3101061050020 C906 3101061050020 C907 3101061040010 0.1UF C908 3101061050020 C909...
  • Page 301 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C935 3101061040010 0.1UF C936 3101061040010 0.1UF C937 3101054710010 470PF 3110071040000 0.1UF C940 3101066800000 68PF C941 3101051540000 0.15UF C942 3101061040010 0.1UF C943 3101062700010 27PF C944 3101054710010 470PF C945 3101054710010 470PF C946...
  • Page 302 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description D102 3304010100220 Varactor D105 3304010100220 Varactor D106 3304010100220 Varactor D107 3304010100220 Varactor D108 3304010100220 Varactor D109 3304010100220 Varactor D110 3304010100220 Varactor D111 3304010100220 Varactor D112 3304010100220 Varactor D113 3304010100220 Varactor...
  • Page 303 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description D6100 3303060300010 Switching diode D6101 3304010101100 Varactor D6102 3304010101100 Varactor D6103 3304010101100 Varactor D6104 3304010101100 Varactor D6105 3399990000260 Rectifier diode D6106 3699019000000 Mixer IC D701 3304060300050 Varactor D702 3304060300010 Varactor...
  • Page 304 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description L116 3217607471000 470nH L117 3217607471000 470nH L118 3217607471000 470nH L121 3217607471000 470nH L122 3210306150000 15nH L123 3210306150000 15nH L124 3237199080000 Air-core coil 8nH L126 3214307270010 27nH L127 3217607471000 470nH L128...
  • Page 305 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description L403 3221506300000 Bead L404 3221506300000 Bead L405 3221506300000 Bead L406 3221506300000 Bead L407 3221506300000 Bead L408 3221506300000 Bead L409 3221506300000 Bead L410 3221506300000 Bead L411 3221506300000 Bead L412 3221506300000 Bead...
  • Page 306 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 3221506601000 Bead L701 3221506601000 Bead L702 3221506601000 Bead L703 3221506601000 Bead L704 3213212103000 10uH L705 3213212103000 10uH L706 3221506601000 Bead L707 3221506601000 Bead L708 3217107221010 220nH L709 3221506601000 Bead L710...
  • Page 307 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 0Ω L823 3001060000000 L824 3221506601000 Bead L825 3221506601000 Bead L826 3101061600000 16PF L827 3212106390000 39nH L828 3217112102020 L829 3101068200000 82PF L830 3101068200000 82PF L832 3212106689000 6.8nH L833 3101064700000 47PF 3221506601000...
  • Page 308 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description Q230 3499000000150 Composite transistor Q231 3499000000150 Composite transistor Q232 3499000000150 Composite transistor Q233 3499000000150 Composite transistor Q234 3499000000150 Composite transistor Q235 3499000000150 Composite transistor Q323 3403008000010 Q400 3413001000010 PNP transistor Q401...
  • Page 309 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description Q908 3403008000010 Q909 3403002000010 PNP transistor Q910 3414001000020 NPN transistor Q912 3403008000010 Q913 3403008000010 Q914 3403008000010 Q921 3404999000020 NPN transistor Q922 3403008000010 Q923 3403008000010 47Ω 3001054700000 10Ω R109 3001051000000 100Ω...
  • Page 310 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 20KΩ R155 3001052030000 68Ω R156 3001056800000 R157 3221506601000 Bead 6.8KΩ R158 3001056820000 7.5KΩ R159 3001057520000 100Ω R160 3001051010040 18KΩ R161 3001051830000 33Ω R167 3001053300010 0Ω R171 3001060000000 0Ω...
  • Page 311 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 5.6KΩ R239 3001055620000 0Ω R240 3001050000000 56KΩ R241 3001055630000 0Ω 1000 R242 3001050000000 0Ω 1001 R243 3001050000000 22KΩ 1002 R244 3001052230010 1Ω 1003 R245 3001160100000 22KΩ 1004 R246 3001052230010 100KΩ...
  • Page 312 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 30KΩ 1037 R283 3001053030010 15KΩ 1038 R284 3001051530000 15KΩ 1039 R285 3001051530000 47KΩ 1040 R286 3001054730000 5.6KΩ 1041 R287 3001055620000 47KΩ 1042 R288 3001054730000 0Ω 1043 R289 3001050000000 1KΩ...
  • Page 313 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 10KΩ 1077 R365 3001051030000 10KΩ 1078 R366 3001051030000 33Ω 1079 R367 3001053300010 33Ω 1080 R369 3001053300010 33Ω 1081 R371 3001053300010 10KΩ 1082 R372 3001051030000 0Ω 1083 R374 3001050000000 0Ω...
  • Page 314 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 33Ω 1117 R412 3001053300010 33Ω 1118 R413 3001053300010 10Ω 1119 R414 3001051000000 33Ω 1120 R415 3001053300010 33Ω 1121 R416 3001053300010 33Ω 1122 R420 3001053300010 100Ω 1123 R421 3001051010000 1KΩ...
  • Page 315 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 33Ω 1157 R456 3001053300010 33Ω 1158 R457 3001053300010 100Ω 1159 R458 3001051010000 100Ω 1160 R459 3001051010000 1KΩ 1161 R460 3001051020010 10KΩ 1162 R461 3001051030000 10KΩ 1163 R462 3001051030000 10KΩ...
  • Page 316 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 10KΩ 1197 R501 3001051030000 1KΩ 1198 R502 3001051020000 1KΩ 1199 R503 3001051020000 1KΩ 1200 R504 3001051020000 0Ω 1201 R505 3001050000000 10KΩ 1202 R506 3001051030000 0Ω 1203 R507 3001050000000 0Ω...
  • Page 317 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 0Ω 1237 R542 3001060000000 10KΩ 1238 R543 3001051030000 0Ω 1239 R544 3001050000000 33Ω 1240 R545 3001053300010 470Ω 1241 R546 3001054710000 470Ω 1242 R547 3001054710000 470Ω 1243 R548 3001054710000 470Ω...
  • Page 318 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 100KΩ 1277 R6111 3001051040000 100KΩ 1278 R6112 3001051040000 270KΩ 1279 R6113 3001052740000 33Ω 1280 R6114 3001053300010 100KΩ 1281 R6115 3001051040000 0Ω 1282 R6116 3001060000000 82Ω 1283 R6117 3001078200000 3.3KΩ...
  • Page 319 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 1.8KΩ 1317 R714 3001051820000 33Ω 1318 R715 3001053300010 5.6KΩ 1319 R716 3001055620000 33Ω 1320 R717 3001053300010 510Ω 1321 R718 3001055110000 33Ω 1322 R719 3001053300010 33Ω 1323 R720 3001053300010 33Ω...
  • Page 320 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 47Ω 1357 R830 3001074700000 1KΩ 1358 R831 3001051020000 82Ω 1359 R835 3001068200000 0Ω 1360 R837 3001050000000 33KΩ 1361 R838 3001053330000 3.3KΩ 1362 R839 3001053320000 1363 R840 3101060800010 33KΩ...
  • Page 321 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 56KΩ 1397 R883 3001055630000 10KΩ 1398 R884 3001051030000 10KΩ 1399 R885 3001051030000 220KΩ 1400 R886 3001052240000 820Ω 1401 R887 3001058210000 0Ω 1402 R889 3001050000000 3.3KΩ 1403 R890 3001053320000 3.3KΩ...
  • Page 322 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 51KΩ 1437 R934 3001055130010 4.7KΩ 1438 R937 3001054720000 10KΩ 1439 R938 3001051030000 1KΩ 1440 R939 3001061020010 22KΩ 1441 R940 3001052230010 1KΩ 1442 R941 3001051020010 4.7KΩ 1443 R942 3001054720000 47KΩ...
  • Page 323 UHF2 (450-520MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 10KΩ 1477 R976 3001051030000 1KΩ 1478 R978 3001051020010 10KΩ 1479 R979 3001051030000 10KΩ 1480 R980 3001051030000 100KΩ 1481 R982 3001051040000 0Ω 1482 R983 3001050000000 220Ω 1483 R984 3001052210000 100Ω...
  • Page 324 Service Manual UHF2 (450-520MHz 45W) Information Ref No. Print No. Part No. Description 1517 U909 3608006000000 Power management IC 1518 U910 3609010000170 Reset IC 1519 U914 3605008005070 Operational amplifier 1520 U915 3608015000060 Power management IC 1521 U917 3609006003050 Reset IC 1522 U918 3608015000210...

  • Page 325: Troubleshooting Flow Chart

    UHF2 (450-520MHz 45W) Information Service Manual 11.8 Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (73.35MHz) The second LO is Check Q701.
  • Page 326 Service Manual UHF2 (450-520MHz 45W) Information Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 73.35MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 327 UHF2 (450-520MHz 45W) Information Service Manual Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Control voltage Current is Check U801. is low or high? normal? [1] Check PA, High antenna switch and low-pass TX VCO works circuits.
  • Page 328 Service Manual UHF2 (450-520MHz 45W) Information Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 329 UHF2 (450-520MHz 45W) Information Service Manual FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 330 Service Manual UHF2 (450-520MHz 45W) Information Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 3.6V [3] Check whether the emitter voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 1.8V under normal RX/TX status.

  • Page 331: Uhf3 (350-400Mhz 25W) Information

    UHF3 (350-400MHz 25W) Information Service Manual 12. UHF3 (350-400MHz 25W) Information 12.1 Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 332: Pre-Driver Power Amplifier

    Service Manual UHF3 (350-400MHz 25W) Information signal (enabled by antenna switch), so as to further control the power supply for the whole circuit. 12.1.3 Pre-driver Power Amplifier The pre-driver power amplifier is formed by Q805, with variable gain controlled by voltage VGG. The input matching circuit is composed of C826, L826, L814, C843 and R824.

  • Page 333: Directional Coupler

    UHF3 (350-400MHz 25W) Information Service Manual 12.1.8 Directional Coupler A directional coupler that consists of microstrip directional coupler, D803, D804 and etc, is used to detect both forward and reverse directed power of the transmitter. The forward power is coupled to the diode D803, and the voltage is applied to the power control circuit (U801).

  • Page 334: Receiver Front-End

    Service Manual UHF3 (350-400MHz 25W) Information Figure 12-2 Diagram of Receiver Circuit 12.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (73.35MHz).

  • Page 335: Receiver Back-End

    UHF3 (350-400MHz 25W) Information Service Manual 12.2.2 Receiver Back-end Figure 12-3 Diagram of IF Processor The first IF signal (73.35MHz) output by the IF amplifier goes into IF IC via Pin 47, where the signal is converted to the second IF signal (2.25MHz). Then the un-demodulated digital I/Q signal output from the SSI interface is sent to U302 for demodulation.

  • Page 336: Reference Oscillator

    Service Manual UHF3 (350-400MHz 25W) Information 12.3.2 Reference Oscillator X100 is a 19.2MHz TCXO, and its reference frequency is calibrated by the digital-to-analog converter (U500) for accuracy. 12.3.3 PLL IC The PLL IC (U100) is a fractional frequency divider. The logic IC U101 and U102 work with the PLL IC (U100) to achieve locking.

  • Page 337: Vco

    UHF3 (350-400MHz 25W) Information Service Manual 12.3.4 The VCO is composed of transistors (Q100, Q103, Q106 and Q110), varactors and four Colpitts oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals and the other two VCOs (Q106 and Q110) to receive LO signals. U302 controls the operating frequency of the VCO.

  • Page 338: Pcb View

    12.4 PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 339 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 340 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Top Layer 顶层...
  • Page 341 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 342: Block Diagram

    12.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q100\Q103\Q106\Q110 Q104 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 343 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 344 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL MCSI1 McBSP2 GPIOs TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 345: Schematic Diagram

    12.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 346 MD78X/MD78XG Schematic Diagram (RX Circuit) MD780/780G 原理图（接收电路） L6100 L6100 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6100 C6100 R6100 R6100 C6102 C6102 C6185 C6185 R6101 R6101 470p 470p R6102 R6102 TRANSISTOR TRANSISTOR L6101 L6101 Q6101 Q6101 BLM18PG600SN1 BLM18PG600SN1 TRANSISTOR TRANSISTOR RF_ATTEN C6103 C6103 220p...
  • Page 347 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 0.1u 0.1u 10uF/10V 10uF/10V R570 R570 R542 0 R542 0 C509 C509 C484 C484 1000p 1000p C508 C508 C483 C483 C510 C510 R528 R528 8200p 8200p 0.1u 0.1u...
  • Page 348 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 349 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/16V 10u/16V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 350 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 351 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 352 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 353 MD78X/MD78XG Schematic Diagram (Power Circuit) U900 U900 RP102N331B RP102N331B 3V3D TP4031 TP4031 VOUT TP4032 TP4032 C900 C900 C901 C901 B900 B900 MMBZ6V8ALT1G MMBZ6V8ALT1G D237 D237 U901 U901 C902 C902 D900 D900 TP4035 TP4035 RP102N331B RP102N331B 3V3DP C903 C903 470p/50V 470p/50V...
  • Page 354 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1000p 1000p 0.1u 0.1u C1010 C1010 1000p 1000p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 355 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 Q101 Q101 4V3A EMD22 EMD22 R142 R142 3.3k 3.3k 220p 220p 0.1u 0.1u 470n 470n R145 R145 TX_VCO_H 220p 220p C195 C195 C194 C194 R143 R143 220p 220p 0.1u 0.1u 6.8k 6.8k...
  • Page 356 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 330n 330n 0.01u 0.01u IF-out TP701 TP701 L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702...
  • Page 357 MD78X/MD78XG Schematic Diagram (TX Circuit) C909 C909 C889 C889 C913 C913 C888 C888 C825 C825 C885 C885 L801 L801 W801 W801 C855 C855 47pF 47pF 470p 470p BLM41PG600SN1 BLM41PG600SN1 100p 100p 3300p 3300p 0.018uF 0.018uF 33pF 33pF C916 C916 C930...
  • Page 358 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 359: Parts List

    UHF3 (350-400MHz 25W) Information Service Manual 12.7 Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101051020010 1000PF 3101060900010 C100 3101052210010 220PF C1000 3101052210010 220PF C1001 3101054710010 470PF C1002...
  • Page 360 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C152 3101054090010 C153 3101053900000 39PF C154 3101054700010 47PF C155 3101060900010 C156 3101052210010 220PF C157 3101055600000 56PF C158 3101051800070 18PF C159 3101050500030 3101051000030 10PF C160 3101052210010 220PF C161 3101055600000 56PF C162...
  • Page 361 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 3101052200010 22PF 3101052210010 220PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 0.47uF C238 3101061050020 C239 3101051040010 0.1UF 3101051040010 0.1UF C240...
  • Page 362 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C268 3101064740010 0.47UF C269 3101052210010 220PF 3101050590010 0.5PF C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010 10UF C276 3101051050000 C277 3101061050020...
  • Page 363 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C309 3101051010030 100PF 3101060300010 C310 3101051050000 C311 3101051040010 0.1UF 3101050500010 C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051010030 100PF C330 3101051040010 0.1UF C331 3101081060010 10UF C332 3101051040010 0.1UF...
  • Page 364 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C361 3101051010030 100PF C362 3101058200000 82PF C363 3101058200000 82PF C364 3101053900000 39PF C365 3101058200000 82PF C366 3101051040010 0.1UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF...
  • Page 365 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C413 3101051010030 100PF C414 3101051010030 100PF C415 3101051010030 100PF C416 3101051010030 100PF C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF 3101050100030 C420 3101051010030 100PF C421 3101052210010 220PF C422 3101051040010...
  • Page 366 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C452 3101051010030 100PF C453 3101051010030 100PF C454 3101051010030 100PF C455 3101051010030 100PF C456 3101051010030 100PF 3101052210010 220PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467 3101051010030 100PF C468...
  • Page 367 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C513 3101051020010 1000PF C514 3101051040010 0.1UF C515 3101051040010 0.1UF C516 3101051010030 100PF C517 3101051010030 100PF C518 3101051010030 100PF C519 3101071060010 10UF 3101052210010 220PF C520 3101071060010 10UF 3101051590000 1.5PF 3101060400010 3101051000030...
  • Page 368 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C6125 3101050200010 C6126 3101052790060 2.7PF C6127 3101052790060 2.7PF C6128 3101054710010 470PF C6129 3101051200020 12PF C6130 3101051010030 100PF C6133 3101057590000 7.5PF C6134 3101056800000 68PF C6135 3101056800000 68PF C6136 3101056800000 68PF C6137...
  • Page 369 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C6171 3101051040010 0.1UF 0Ω C6172 3001050000000 C6173 3101051040010 0.1UF C6175 3101051040010 0.1UF 0Ω C6176 3001060000000 C6177 3101051500020 15PF C6178 3101051030020 0.01UF C6179 3101051040010 0.1UF C6180 3101051040010 0.1UF C6185 3101061050020 C6190...
  • Page 370 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C718 3101051050160 C719 3101051050000 3110071040000 0.1UF C720 3101051040010 0.1UF C721 3101051010030 100PF C722 3101051010030 100PF C723 3101051500020 15PF C724 3101051800010 18PF C725 3101051030020 0.01UF C726 3101074750000 4.7UF C727 3101054710010 470PF...
  • Page 371 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C756 3101051040010 0.1UF 3101051010030 100PF C763 3101051010030 100PF C764 3101051010030 100PF C765 3101051010030 100PF C766 3101051010030 100PF C767 3101051010030 100PF C769 3101051010030 100PF 3101051010030 100PF 3110071040000 0.1UF 3101051020010 1000PF 3101054710010...
  • Page 372 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C837 3101080700010 C838 3101080400010 C839 3101065620010 5600PF 3110071040000 0.1UF C840 3101074700000 47PF C841 3101373900000 39pF 0Ω C843 3001060000000 C845 3101062210000 220PF C847 3101061510000 150PF C848 3101061510000 150PF 3101051040010 0.1UF C850...
  • Page 373 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C890 3101052210010 220PF C891 3101051210000 120PF C892 3101062210000 220PF C893 3101081020010 1000pF C894 3101051830000 0.018UF C895 3101052210010 220PF C896 3101052210010 220PF C897 3101052210010 220PF C898 3101052210010 220PF C899 3101051210000 120PF...
  • Page 374 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description C929 3101071060010 10UF 3101051010030 100PF C930 3101061830000 0.018UF C931 3101062700010 27PF C932 3101062250000 2.2UF C933 3101092260010 22UF C934 3101062250000 2.2UF C935 3101061040010 0.1UF C936 3101061040010 0.1UF C937 3101051020010 1000PF 3110071040000...
  • Page 375 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 3101051030020 0.01UF C978 3101051040010 0.1UF 3101051040010 0.1UF C980 3101081060010 10UF C981 3101081060010 10UF 3101052710000 270PF D100 3303990000060 Switching diode D101 3304010100220 Varactor D102 3304010100220 Varactor D105 3304010100220 Varactor D106 3304010100220...
  • Page 376 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description D404 3310240000000 ESD protection diode D405 3310240000000 ESD protection diode D406 3310240000000 ESD protection diode D407 3399040600010 ESD protection diode D408 3399040600010 ESD protection diode D409 3310240000040 ESD protection diode D450 3699037000010...
  • Page 377 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L105 3237199120000 12.5nH 0.29Ω L106 3214307390000 L107 3217607471000 470nH L108 3217607471000 470nH L110 3217607471000 470nH L112 3217607471000 470nH L114 3237199120000 12.5nH 0.27Ω L115 3217607330000 L116 3217607471000 470nH L117 3217607471000 470nH...
  • Page 378 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description L173 3212106120000 12nH 3210306180000 18nH 30Ω L232 3221506300000 L233 3211506101000 100nH L234 3211506101000 100nH L235 3211506101000 100nH L321 3212106390000 39nH 30Ω L322 3221506300000 3217607471000 470nH 30Ω L401 3221506300000 30Ω...
  • Page 379 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L6119 3210306220000 22nH L6120 3210306470000 47nH L6121 3211506101000 100nH L6122 3101061040010 0.1UF L6123 3213306821000 0.82uH L6125 3210406331000 330nH L6126 3101061040010 0.1UF L6216 3210305270000 27nH L6217 3210305270000 27nH 600Ω...
  • Page 380 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description L813 3233099160000 16nH L814 3212106689000 6.8nH 600Ω L815 3221506601000 L816 3233099111000 111nH L817 3233099160000 16nH L819 3233099470000 47nH 1.75Ω L820 3217112102020 600Ω L821 3221506601000 600Ω L822 3221506601000 0Ω...
  • Page 381 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description Q106 3408002000080 NPN transistor Q107 3404006000000 NPN transistor Q108 3403999000000 Composite transistor Q109 3404006000000 NPN transistor Q110 3408002000080 NPN transistor Q111 3401002000990 NPN transistor Q112 3403999000000 Composite transistor Q116 3403999000000 Composite transistor...
  • Page 382 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description Q804 3504990000040 PA MOSFET Q805 3504990000010 PA MOSFET Q810 3403002000000 PNP transistor Q811 3403008000010 Q812 3403008000010 Q813 3403008000010 Q902 3403002000000 PNP transistor Q903 3403008000010 Q905 3499000000150 Composite transistor Q906 3414001000020 NPN transistor...
  • Page 383 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 6.8KΩ R142 3001056820010 R143 3001057520000 7.5KΩ 150Ω R144 3001061510000 100Ω R145 3001051010040 100Ω R146 3001051010040 100Ω R147 3001051010040 100Ω R148 3001051010040 15KΩ R151 3001051530010 36KΩ R152 3001053630000 600Ω...
  • Page 384 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description 10KΩ R202 3001051030000 33Ω R231 3001053300010 33Ω R232 3001053300010 10KΩ 1000 R234 3001051030000 10KΩ 1001 R235 3001051030000 10KΩ 1002 R236 3001051030000 56KΩ 1003 R237 3001055630000 5.6KΩ 1004 R239 3001055620000 56KΩ...
  • Page 385 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 30KΩ 1037 R279 3001053030000 0Ω 1038 R282 3001060000000 30KΩ 1039 R283 3001053030000 15KΩ 1040 R284 3001051530010 15KΩ 1041 R285 3001051530010 47KΩ 1042 R286 3001054730000 5.6KΩ 1043 R287 3001055620000 47KΩ...
  • Page 386 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description 0Ω 1077 R363 3001050000000 0Ω 1078 R364 3001050000000 10KΩ 1079 R365 3001051030000 10KΩ 1080 R366 3001051030000 33Ω 1081 R367 3001053300010 100Ω 1082 R368 3001051010000 33Ω 1083 R369 3001053300010 100Ω...
  • Page 387 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 33Ω 1117 R408 3001053300010 33Ω 1118 R409 3001053300010 100Ω 1119 R410 3001051010040 100Ω 1120 R411 3001051010040 33Ω 1121 R412 3001053300010 33Ω 1122 R413 3001053300010 10Ω 1123 R414 3001051000000 33Ω...
  • Page 388 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description 10KΩ 1157 R452 3001051030000 10KΩ 1158 R453 3001051030000 10KΩ 1159 R454 3001051030000 100KΩ 1160 R455 3001051040000 100Ω 1161 R458 3001051010040 100Ω 1162 R459 3001051010040 1KΩ 1163 R460 3001051020000 10KΩ...
  • Page 389 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 100KΩ 1197 R500 3001051040000 10KΩ 1198 R501 3001051030000 1KΩ 1199 R502 3001051020000 1KΩ 1200 R503 3001051020000 1KΩ 1201 R504 3001051020000 0Ω 1202 R505 3001050000000 1203 R506 3001050000000 0Ω...
  • Page 390 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description 10KΩ 1237 R543 3001051030000 0Ω 1238 R544 3001050000000 33Ω 1239 R545 3001053300010 470Ω 1240 R546 3001054710000 470Ω 1241 R547 3001054710000 470Ω 1242 R548 3001054710000 470Ω 1243 R549 3001054710000 470Ω...
  • Page 391 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1.2KΩ 1277 R6110 3001051220000 100KΩ 1278 R6111 3001051040000 100KΩ 1279 R6112 3001051040000 270KΩ 1280 R6113 3001052740000 33Ω 1281 R6114 3001053300010 100KΩ 1282 R6115 3001051040000 0Ω 1283 R6116 3001060000000 82Ω...
  • Page 392 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description 100KΩ 1317 R713 3001051040000 1.8KΩ 1318 R714 3001051820000 33Ω 1319 R715 3001053300010 5.6KΩ 1320 R716 3001055620000 33Ω 1321 R717 3001053300010 510Ω 1322 R718 3001055110000 33Ω 1323 R719 3001053300010 33Ω...
  • Page 393 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 0Ω 1357 R837 3001050000000 33KΩ 1358 R838 3001053330000 3.3KΩ 1359 R839 3001053320000 33KΩ 1360 R841 3001053330000 12KΩ 1361 R842 3001051230000 5.6KΩ 1362 R843 3001065620000 3.6KΩ 1363 R844 3001063620000 20KΩ...
  • Page 394 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description 820Ω 1397 R887 3001058210000 0Ω 1398 R889 3001050000000 3.3KΩ 1399 R890 3001053320000 3.3KΩ 1400 R891 3001053320000 1401 R892 3001058230000 82KΩ 0Ω 1402 R894 3001050000000 56KΩ 1403 R895 3001055630000 470KΩ...
  • Page 395 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1KΩ 1437 R947 3001051020000 100Ω 1438 R948 3001051010040 47KΩ 1439 R949 3001054730000 10KΩ 1440 R950 3001051030000 1.5KΩ) 1441 R951 3001051520010 24KΩ 1442 R952 3001062430000 10Ω 1443 R953 3001061000000 1KΩ...
  • Page 396 Service Manual UHF3 (350-400MHz 25W) Information Ref No. Print No. Part No. Description 1477 T6101 3244599189000 Transmission coil 1478 U100 3604019000000 PLL IC 1479 U101 3616059000000 Switch IC 1480 U102 3616059000000 Switch IC 1481 U201 3602042000000 Audio amplifier 1482 U231 3613010000000 Baseband processor 1483...
  • Page 397 UHF3 (350-400MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1517 X302 3701019250040 TCXO 1518 X375 3701327610060 Crystal 1519 Z6100 3802733540030 Crystal filter 1520 41MD7801000H0...

  • Page 398: Troubleshooting Flow Chart

    Service Manual UHF3 (350-400MHz 25W) Information 12.8 Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (73.35MHz) The second LO is Check Q701.
  • Page 399 UHF3 (350-400MHz 25W) Information Service Manual Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 73.35MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 400 Service Manual UHF3 (350-400MHz 25W) Information Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Control voltage Current is Check U801. is low or high? normal? [1] Check PA, High antenna switch and low-pass TX VCO works circuits.
  • Page 401 UHF3 (350-400MHz 25W) Information Service Manual Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 402 Service Manual UHF3 (350-400MHz 25W) Information FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 403 UHF3 (350-400MHz 25W) Information Service Manual Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 3.6V [3] Check whether the emitter voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 1.8V under normal RX/TX status.

  • Page 404: Uhf3 (350-400Mhz 45W) Information

    Service Manual UHF3 (350-400MHz 45W) Information 13. UHF3 (350-400MHz 45W) Information 13.1 Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 405: Pre-Driver Power Amplifier

    UHF3 (350-400MHz 45W) Information Service Manual 13.1.3 Pre-driver Power Amplifier The pre-driver power amplifier is formed by Q805, with variable gain controlled by voltage VGG. The input matching circuit is composed of C826, L826, L814, C843 and R824. 13.1.4 Driver Power Amplifier The driver power amplifier is formed by Q804, with variable gain controlled by voltage VGG.

  • Page 406: Directional Coupler

    Service Manual UHF3 (350-400MHz 45W) Information 13.1.8 Directional Coupler A directional coupler that consists of microstrip directional coupler, D803, D804 and etc, is used to detect both forward and reverse directed power of the transmitter. The forward power is coupled to the diode D803, and the voltage is applied to the power control circuit (U801).

  • Page 407: Receiver Front-End

    UHF3 (350-400MHz 45W) Information Service Manual Figure 13-2 Diagram of Receiver Circuit 13.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (73.35MHz).

  • Page 408: Receiver Back-End

    Service Manual UHF3 (350-400MHz 45W) Information 13.2.2 Receiver Back-end Figure 13-3 Diagram of IF Processor The first IF signal (73.35MHz) output by the IF amplifier goes into IF IC via Pin 47, where the signal is converted to the second IF signal (2.25MHz). Then the un-demodulated digital I/Q signal output from the SSI interface is sent to U302 for demodulation.

  • Page 409: Reference Oscillator

    UHF3 (350-400MHz 45W) Information Service Manual 13.3.2 Reference Oscillator X100 is a 19.2MHz TCXO, and its reference frequency is calibrated by the digital-to-analog converter (U500) for accuracy. 13.3.3 PLL IC The PLL IC (U100) is a fractional frequency divider. The logic IC U101 and U102 work with the PLL IC (U100) to achieve locking.

  • Page 410: Vco

    Service Manual UHF3 (350-400MHz 45W) Information 13.3.4 The VCO is composed of transistors (Q100, Q103, Q106 and Q110), varactors and four Colpitts oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals and the other two VCOs (Q106 and Q110) to receive LO signals. U302 controls the operating frequency of the VCO.

  • Page 411: Pcb View

    13.4 PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 412 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 413 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Top Layer 顶层...
  • Page 414 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 415: Block Diagram

    13.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q100\Q103\Q106\Q110 Q104 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 416 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 417 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL MCSI1 McBSP2 GPIOs TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 418: Schematic Diagram

    13.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 419 MD78X/MD78XG Schematic Diagram (RX Circuit) MD780/780G 原理图（接收电路） L6100 L6100 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6100 C6100 R6100 R6100 C6102 C6102 C6185 C6185 R6101 R6101 470p 470p R6102 R6102 TRANSISTOR TRANSISTOR L6101 L6101 Q6101 Q6101 BLM18PG600SN1 BLM18PG600SN1 TRANSISTOR TRANSISTOR RF_ATTEN C6103 C6103 220p...
  • Page 420 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 0.1u 0.1u 10uF/10V 10uF/10V R570 R570 R542 0 R542 0 C509 C509 C484 C484 1000p 1000p C508 C508 C483 C483 C510 C510 R528 R528 8200p 8200p 0.1u 0.1u...
  • Page 421 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 422 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/16V 10u/16V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 423 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 424 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 425 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 426 MD78X/MD78XG Schematic Diagram (Power Circuit) U900 U900 RP102N331B RP102N331B 3V3D TP4031 TP4031 VOUT TP4032 TP4032 C900 C900 C901 C901 B900 B900 MMBZ6V8ALT1G MMBZ6V8ALT1G D237 D237 U901 U901 C902 C902 D900 D900 TP4035 TP4035 RP102N331B RP102N331B 3V3DP C903 C903 470p/50V 470p/50V...
  • Page 427 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1000p 1000p 0.1u 0.1u C1010 C1010 1000p 1000p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 428 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 Q101 Q101 4V3A EMD22 EMD22 R142 R142 3.3k 3.3k 220p 220p 0.1u 0.1u 470n 470n R145 R145 TX_VCO_H 220p 220p C195 C195 C194 C194 R143 R143 220p 220p 0.1u 0.1u 6.8k 6.8k...
  • Page 429 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 330n 330n 0.01u 0.01u IF-out TP701 TP701 L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702...
  • Page 430 MD78X/MD78XG Schematic Diagram (TX Circuit) C909 C909 C889 C889 C913 C913 C888 C888 C825 C825 C885 C885 L801 L801 W801 W801 C855 C855 47pF 47pF 470p 470p BLM41PG600SN1 BLM41PG600SN1 100p 100p 3300p 3300p 0.018uF 0.018uF 33pF 33pF C916 C916 C930...
  • Page 431 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 432: Parts List

    Service Manual UHF3 (350-400MHz 45W) Information 13.7 Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101051020010 1000PF 3101060900010 C100 3101052210010 220PF C1000 3101052210010 220PF C1001 3101054710010 470PF C1002...
  • Page 433 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C152 3101054090010 C153 3101053900000 39PF C154 3101054700010 47PF C155 3101060900010 C156 3101052210010 220PF C157 3101055600000 56PF C158 3101051800070 18PF C159 3101050500030 3101051000030 10PF C160 3101052210010 220PF C161 3101055600000 56PF C162...
  • Page 434 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 3101052200010 22PF 3101052210010 220PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 0.47uF C238 3101061050020 C239 3101051040010 0.1UF 3101051040010 0.1UF C240...
  • Page 435 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C268 3101064740010 Chip capacitor C269 3101052210010 220PF 3101050590010 0.5PF C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010 10UF C276 3101051050000 C277...
  • Page 436 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description C309 3101051010030 100PF 3101060300010 C310 3101051050000 C311 3101051040010 0.1UF 3101050500010 C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051010030 100PF C334 3101051040010 0.1UF C335 3101051010030 100PF C336 3101051040010 0.1UF...
  • Page 437 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C365 3101058200000 82PF C366 3101051040010 0.1UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF C380 3101051040010 0.1UF C381 3101051030020 0.01UF C382 3101051040010 0.1UF C383 3101051040010 0.1UF...
  • Page 438 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF 3101050100030 C420 3101051010030 100PF C421 3101052210010 220PF C422 3101051040010 0.1UF C423 3101052210010 220PF C424 3101052210010 220PF C425 3101052210010 220PF C426 3101051010030...
  • Page 439 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C456 3101051010030 100PF 3101052210010 220PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467 3101051010030 100PF C468 3101051010030 100PF C469 3101051010030 100PF C470 3101051010030 100PF C471 3101051040010 0.1UF C472...
  • Page 440 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description C517 3101051010030 100PF C518 3101051010030 100PF C519 3101071060010 10UF 3101052210010 220PF C520 3101071060010 10UF 3101051590000 1.5PF 3101060400010 3101051000030 10PF 3101051030020 0.01UF 3101051200020 12PF 3101052210010 220PF 3101051020010 1000PF 3101051800010 18PF C6100...
  • Page 441 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C6129 3101051200020 12PF C6130 3101051010030 100PF C6133 3101057590000 7.5PF C6134 3101056800000 68PF C6135 3101056800000 68PF C6136 3101056800000 68PF C6137 3101056800000 68PF C6138 3101056800000 68PF C6139 3101056800000 68PF C6140 3101056800000 68PF...
  • Page 442 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 0Ω C6176 3001060000000 C6177 3101051500020 15PF C6178 3101051030020 0.01UF C6179 3101051040010 0.1UF C6180 3101051040010 0.1UF C6185 3101061050020 C6190 3101061050020 C6193 3101061040010 0.1UF 3101050100030 C6244 3101051000030 10PF C6245 3101050200010 C6246 3101050600010...
  • Page 443 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C721 3101051010030 100PF C722 3101051010030 100PF C723 3101051500020 15PF C724 3101051800010 18PF C725 3101051030020 0.01UF C726 3101074750000 4.7UF C727 3101054710010 470PF C728 3101051020010 1000PF C729 3101051040010 0.1UF C730 3101052200010 22PF...
  • Page 444 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description C765 3101051010030 100PF C766 3101051010030 100PF C767 3101051010030 100PF C769 3101051010030 100PF 3101051010030 100PF 3110071040000 0.1UF 3101051020010 1000PF 3101054710010 470PF 3101051030020 0.01UF C801 3101081020010 1000pF C802 3101063320000 3300PF C803 3101063300000...
  • Page 445 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C835 3101080600010 C836 3101080400010 C837 3101080700010 C838 3101080400010 C839 3101068210000 820PF 3110071040000 0.1UF C840 3101063900000 39PF C841 3101371200000 12pF C842 3101081200010 12pF 0Ω C843 3001060000000 C845 3101062210000 220PF C847 3101061510000...
  • Page 446 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description C885 3101082700010 Chip capacitor C887 3101061020040 1000PF C888 3101063300000 33PF C889 3101062200010 22PF 3101051040010 0.1UF C890 3101052210010 220PF C891 3101051210000 120PF C892 3101062210000 220PF C893 3101084710010 470pF C894 3101051830000 0.018UF...
  • Page 447 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description C925 3101061050020 C926 3101071060010 10UF C927 3101061040010 0.1UF C928 3101081060010 10UF C929 3101071060010 10UF 3101051010030 100PF C930 3101061830000 0.018UF C931 3101062700010 Chip capacitor C932 3101062250000 2.2UF C933 3101092260010 22UF C934...
  • Page 448 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description C966 3101061050020 C967 3101051040010 0.1UF C968 3101051040010 0.1UF C969 3101051040010 0.1UF 3101051030020 0.01UF C978 3101051040010 0.1UF 3101051040010 0.1UF C980 3101081060010 10UF C981 3101081060010 10UF 3101052710000 270PF D100 3303990000060 Switching diode D101...
  • Page 449 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description D240 3310240000000 ESD protection diode D241 3302031100010 Zener diode D402 3310240000000 ESD protection diode D403 3310240000000 ESD protection diode D404 3310240000000 ESD protection diode D405 3310240000000 ESD protection diode D406 3310240000000 ESD protection diode...
  • Page 450 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description J400 5201020100110 Board-to-board connector J404 5206040200010 FFC connector 3213212332000 3.3uH L103 3217607471000 470nH L105 3237199120000 12.5nH L106 3214307390000 39nH L107 3217607471000 470nH L108 3217607471000 470nH L110 3217607471000 470nH L112 3217607471000...
  • Page 451 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description L167 3210306270000 27nH L168 3210306270000 27nH L169 3210306560000 56nH L171 3210306150000 15nH L173 3212106120000 12nH 3210306180000 18nH 30Ω L232 3221506300000 L233 3211506101000 100nH L234 3211506101000 100nH L235 3211506101000 100nH 3217607471000...
  • Page 452 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description L6117 3210306220000 22nH L6118 3210306220000 22nH L6119 3210306220000 22nH L6120 3210306470000 47nH L6121 3211506101000 100nH L6122 3101061040010 0.1UF L6123 3213306821000 0.82uH L6125 3210406331000 330nH L6126 3101061040010 0.1UF L6216 3210305270000 Multi-layer chip inductor...
  • Page 453 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description L810 3233099160000 16nH L811 3215006100010 10nH L813 3233099160000 16nH L814 3212106689000 6.8nH 600Ω L815 3221506601000 L816 3233099111000 Air-core coil L817 3233099160000 16nH L819 3233099470000 47nH 1.75Ω L820 3217112102020 600Ω...
  • Page 454 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description Q104 3403003000060 NPN transistor Q105 3403999000000 Composite transistor Q106 3408002000080 NPN transistor Q107 3404006000000 NPN transistor Q108 3403999000000 Composite transistor Q109 3404006000000 NPN transistor Q110 3408002000080 NPN transistor Q111 3401002000990 NPN transistor...
  • Page 455 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description Q801 3404999000000 NPN transistor Q802 3601017000000 RF PA module Q803 3601017000000 RF PA module Q804 3504990000040 Q805 3504990000010 PA MOSFET Q810 3403002000000 PNP transistor Q811 3403008000010 Q812 3403008000010 Q813 3403008000010...
  • Page 456 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 100Ω R139 3001051010040 100Ω R140 3001051010040 47Ω R141 3001054700000 6.8KΩ R142 3001056820010 7.5KΩ R143 3001057520000 100Ω R144 3001051010040 100Ω R145 3001051010040 100Ω R146 3001051010040 100Ω R147 3001051010040 100Ω...
  • Page 457 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 15KΩ R198 3001051530010 120KΩ R199 3001051240000 0Ω 3001060000000 10KΩ 1000 R202 3001051030000 33Ω 1001 R231 3001053300010 33Ω 1002 R232 3001053300010 10KΩ 1003 R234 3001051030000 10KΩ 1004 R235 3001051030000 10KΩ...
  • Page 458 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 100KΩ 1037 R276 3001051040000 47KΩ 1038 R277 3001054730000 100Ω 1039 R278 3001051010040 30KΩ 1040 R279 3001053030000 0Ω 1041 R282 3001060000000 30KΩ 1042 R283 3001053030000 15KΩ 1043 R284 3001051530010 15KΩ...
  • Page 459 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 1077 R360 3221505121000 Bead 15KΩ 1078 R361 3001051530010 15KΩ 1079 R362 3001051530010 33Ω 1080 R367 3001053300010 33Ω 1081 R369 3001053300010 33Ω 1082 R371 3001053300010 10KΩ 1083 R372 3001051030000 0Ω...
  • Page 460 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 100Ω 1117 R411 3001051010040 33Ω 1118 R412 3001053300010 33Ω 1119 R413 3001053300010 10Ω 1120 R414 3001051000000 33Ω 1121 R415 3001053300010 33Ω 1122 R416 3001053300010 33Ω 1123 R420 3001053300010 100Ω...
  • Page 461 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 100Ω 1157 R458 3001051010040 100Ω 1158 R459 3001051010040 1KΩ 1159 R460 3001051020000 10KΩ 1160 R461 3001051030000 10KΩ 1161 R462 3001051030000 10KΩ 1162 R463 3001051030000 10KΩ 1163 R464 3001051030000 10KΩ...
  • Page 462 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 1KΩ 1197 R504 3001051020000 0Ω 1198 R505 3001050000000 0Ω 1199 R506 3001050000000 10KΩ 1200 R507 3001051030000 10KΩ 1201 R509 3001051030000 10KΩ 1202 R510 3001051030000 4.7KΩ 1203 R511 3001054720000 10KΩ...
  • Page 463 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 470Ω 1237 R547 3001054710000 470Ω 1238 R548 3001054710000 470Ω 1239 R549 3001054710000 470Ω 1240 R550 3001054710000 470Ω 1241 R551 3001054710000 33Ω 1242 R552 3001053300010 33Ω 1243 R553 3001053300010 1KΩ...
  • Page 464 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 33Ω 1277 R6114 3001053300010 100KΩ 1278 R6115 3001051040000 0Ω 1279 R6116 3001060000000 82Ω 1280 R6117 3001068200000 3.9KΩ 1281 R6118 3001053920010 1.2KΩ 1282 R6119 3001051220000 51Ω 1283 R6120 3001055100010 18Ω...
  • Page 465 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 33Ω 1317 R717 3001053300010 510Ω 1318 R718 3001055110000 33Ω 1319 R719 3001053300010 33Ω 1320 R720 3001053300010 33Ω 1321 R721 3001053300010 0Ω 1322 R724 3001060000000 33Ω 1323 R725 3001053300010 47KΩ...
  • Page 466 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 33KΩ 1357 R838 3001053330000 3.3KΩ 1358 R839 3001053320000 1359 R840 3101060600010 33KΩ 1360 R841 3001053330000 12KΩ 1361 R842 3001051230000 5.6KΩ 1362 R843 3001065620000 10KΩ 1363 R844 3001061030000 20KΩ...
  • Page 467 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 0Ω 1397 R889 3001050000000 3.3KΩ 1398 R890 3001053320000 3.3KΩ 1399 R891 3001053320000 82KΩ 1400 R892 3001058230000 0Ω 1401 R894 3001050000000 56KΩ 1402 R895 3001055630000 1403 R897 3001054740010 Chip resistor 1404 R898...
  • Page 468 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 1KΩ 1437 R947 3001051020000 100Ω 1438 R948 3001051010040 47KΩ 1439 R949 3001054730000 10KΩ 1440 R950 3001051030000 1.5KΩ 1441 R951 3001051520010 24KΩ 1442 R952 3001062430000 10Ω 1443 R953 3001061000000 1KΩ...
  • Page 469 UHF3 (350-400MHz 45W) Information Service Manual Ref No. Print No. Part No. Description 1477 T6101 3244599189000 Transmission coil 1478 U100 3604019000000 PLL IC 1479 U101 3616059000000 Switch IC 1480 U102 3616059000000 Switch IC 1481 U201 3602042000000 Audio amplifier 1482 U231 3613010000000 Baseband processor 1483...
  • Page 470 Service Manual UHF3 (350-400MHz 45W) Information Ref No. Print No. Part No. Description 1517 41MD7801000H0...

  • Page 471: Troubleshooting Flow Chart

    UHF3 (350-400MHz 45W) Information Service Manual 13.8 Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (73.35MHz) The second LO is Check Q701.
  • Page 472 Service Manual UHF3 (350-400MHz 45W) Information Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 73.35MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 473 UHF3 (350-400MHz 45W) Information Service Manual Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Control voltage Current is Check U801. is low or high? normal? [1] Check PA, High antenna switch and low-pass TX VCO works circuits.
  • Page 474 Service Manual UHF3 (350-400MHz 45W) Information Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 475 UHF3 (350-400MHz 45W) Information Service Manual FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 476 Service Manual UHF3 (350-400MHz 45W) Information Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 3.6V [3] Check whether the emitter voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 1.8V under normal RX/TX status.

  • Page 477: Vhf (136-174Mhz 25W) Information

    VHF (136-174MHz 25W) Information Service Manual 14. VHF (136-174MHz 25W) Information 14.1 Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 478: Driver Power Amplifier

    Service Manual VHF (136-174MHz 25W) Information 14.1.3 Driver Power Amplifier The driver power amplifier is formed by Q804, with variable gain controlled by voltage VGG. The maximum output power is 34.5dBm, and the maximum variable gain is 15dB. 14.1.4 Final Power Amplifier The final power amplifier consists of Q802 and Q803, with the maximum output power of 48.5dBm, and the maximum variable gain of 14dB.

  • Page 479: Output Power Control

    VHF (136-174MHz 25W) Information Service Manual The directional coupler can adjust the TX power and detect the VSWR load. The reverse power is coupled to D804. The voltage is applied to U802 and then feeds into APC for detection. 14.1.8 Output Power Control The TX power is controlled by U801.

  • Page 480: Receiver Front-End

    Service Manual VHF (136-174MHz 25W) Information Figure 14-2 Diagram of Receiver Circuit 14.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (44.85MHz).

  • Page 481: Receiver Back-End

    VHF (136-174MHz 25W) Information Service Manual 14.2.2 Receiver Back-end Figure 14-3 Diagram of IF Processor The first IF signal (44.85MHz) output by the IF amplifier goes into IF IC via Pin 47, where the signal is converted to the second IF signal (2.25MHz). Then the un-demodulated digital I/Q signal output from the SSI interface is sent to U302 for demodulation.

  • Page 482: Reference Oscillator

    Service Manual VHF (136-174MHz 25W) Information 14.3.2 Reference Oscillator X100 is a 19.2MHz TCXO, and its reference frequency is calibrated by the digital-to-analog converter (U500) for accuracy. 14.3.3 PLL IC The PLL IC (U100) is a fractional frequency divider. The logic IC U101 and U102 work with the PLL IC (U100) to achieve locking.

  • Page 483: Vco

    VHF (136-174MHz 25W) Information Service Manual 14.3.4 The VCO is composed of transistors (Q100, Q103, Q106 and Q110), varactors and four Colpitts oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals and the other two VCOs (Q106 and Q110) to receive LO signals. U302 controls the operating frequency of the VCO.

  • Page 484: Pcb View

    14.4 PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 485 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 486 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Top Layer 顶层...
  • Page 487 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 488: Block Diagram

    14.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q104 Q100\Q103\Q106\Q110 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 489 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 490 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL McBSP2 GPIOs MCSI1 TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 491: Schematic Diagram

    14.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 492 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 R572 R572 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 4.7k 4.7k 0.1u 0.1u 10uF/10V 10uF/10V R542 0 R542 0 R573 R573 R570 R570 5.1k 5.1k 5.6k 5.6k C509 C509 C508 C508 C510 C510 R528 R528 0.1u...
  • Page 493 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 494 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/10V 10u/10V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 495 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 496 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 497 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 498 MD78X/MD78XG Schematic Diagram (Power Circuit) TP4031 TP4031 TP4032 TP4032 U900 U900 B900 B900 RP102N331B RP102N331B R901 R901 3V3D VOUT C900 C900 C901 C901 C902 C902 D900 D900 C903 C903 470p/50V 470p/50V MMBZ6V8ALT1G MMBZ6V8ALT1G 470uF/25V 470uF/25V MR2835SKG MR2835SKG D237 D237 B901...
  • Page 499 MD78X/MD78XG Schematic Diagram (TX Circuit) C983 C983 C985 C985 C973 C973 C972 C972 C974 C974 C971 C971 C984 C984 R878 R878 C986 C986 C970 C970 C975 C975 C976 C976 C977 C977 C982 C982 L812 L812 220p 220p 180p 180p 120p...
  • Page 500 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1500p 1500p 0.1u 0.1u C1010 C1010 1500p 1500p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 501 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 R185 R185 5VA_FGU Q117 Q117 EMD22 EMD22 R142 R142 D127 D127 1500p 1500p 0.1u 0.1u Q101 Q101 3.3k 3.3k EMD22 EMD22 4V3A DAN222 DAN222 680n 680n TX_VCO_H R145 R145 1500p 1500p...
  • Page 502 MD78X/MD78XG Schematic Diagram (RX Circuit) L6200 L6200 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6243 C6243 R6201 R6201 0.1uF 0.1uF C6202 C6202 C6100 C6100 R6100 R6100 470p 470p TRANSISTOR TRANSISTOR Q6201 Q6201 L6101 L6101 R6202 R6202 BLM18PG600SN1 BLM18PG600SN1 UMT1N UMT1N RF_ATTEN C6103 C6103 220p...
  • Page 503 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 0.01u 0.01u TP701 TP701 IF-out L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702 601S 601S...
  • Page 504 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 505: Parts List

    VHF (136-174MHz 25W) Information Service Manual 14.7 Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101051520000 1500PF 3101061300000 13PF C100 3101051520000 1500PF C1000 3101052210010 220PF C1001 3101051520000 1500PF...
  • Page 506 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description C150 3101051520000 1500PF C151 3101061100010 11PF C152 3101050900000 C153 3101053900000 39PF C154 3101053300000 33PF C155 3101061600000 16PF C156 3101051520000 1500PF C157 3101051510000 150PF C158 3101053300000 33PF C159 3101051000020 10PF 3101052400010...
  • Page 507 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 3101051520000 1500PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 0.47uF C238 3101061050020 C239 3101051040010 0.1UF 3101051040010 0.1UF C240 3101051040010 0.1UF...
  • Page 508 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description C269 3101052210010 220PF 3101050100030 C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010 10UF C276 3101051050000 C277 3101061050020 C278 3101061050020 C279 3101061050020...
  • Page 509 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C310 3101051050000 C311 3101051040010 0.1UF 3101051500080 15PF C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051500080 15PF C330 3101051040010 0.1UF C331 3101081060010 10UF C332 3101051040010 0.1UF C333 3101081060010 10UF...
  • Page 510 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description C362 3101058200000 82PF C363 3101058200000 82PF C364 3101053900000 39PF C365 3101058200000 82PF C366 3101051040010 0.1UF C367 3104071060070 10UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF...
  • Page 511 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C411 3101051010030 100PF C412 3101051010030 100PF C413 3101051010030 100PF C414 3101051010030 100PF C415 3101051010030 100PF C416 3101051010030 100PF C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF C420 3101051010030 100PF...
  • Page 512 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description C451 3101051010030 100PF C452 3101051010030 100PF C453 3101051010030 100PF C454 3101051010030 100PF C455 3101051010030 100PF C456 3101051010030 100PF 3101051520000 1500PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467...
  • Page 513 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C517 3101051010030 100PF C518 3101051010030 100PF C519 3104071060070 10UF 3101051520000 1500PF C520 3104071060070 10UF 3101051500080 15PF 3101051000020 10PF 3101060300010 3101051520000 1500PF 3101051030020 0.01UF 3101052000020 20PF 3101051520000 1500PF 3101051520000 1500PF C6042...
  • Page 514 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description C6152 3101050500010 C6153 3101050400010 C6154 3101050600010 C6155 3101051030020 0.01UF C6157 3101061010010 100PF 0Ω C6158 3001060000000 C6159 3101052210010 220PF C6160 3101054700010 47PF C6161 3101052000020 20PF C6162 3101051500080 15PF C6163 3101050700010 C6164...
  • Page 515 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C6218 3101050200010 C6221 3101050200010 0Ω C6222 3001050000000 C6223 3101051000030 10PF C6224 3101055600000 56PF C6225 3101051000030 10PF C6226 3101051000030 10PF C6228 3101051520000 1500PF C6230 3101051500080 15PF C6231 3101056800000 68PF C6232 3101056800000...
  • Page 516 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description C710 3101051020010 1000PF C712 3101051040010 0.1UF C713 3101053330000 0.033UF C714 3101051000030 10PF C715 3101063340000 0.33UF C716 3101061810010 180PF C717 3101054710010 470PF C718 3101051050160 C719 3101051050000 3110071040000 0.1UF C720 3101051040010 0.1UF...
  • Page 517 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C749 3101053900000 39PF 3101051020010 1000PF C750 3101071050020 C751 3101051000030 10PF C752 3101074750000 4.7UF C754 3101061050020 C755 3104071060070 10UF C756 3101051040010 0.1UF 3101051010030 100PF C763 3101051010030 100PF C764 3101051010030 100PF C765...
  • Page 518 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 3101051040010 0.1UF C830 3101372000000 20pF C833 3101081000010 10pF C8330 3101376800000 68pF C836 3101081200010 12pF C837 3101372400000 24pF C838 3101080700010 C839 3101071830000 0.018UF 3110071040000 0.1UF C841 3101373900000 39pF C843 3212106829000 8.2nH...
  • Page 519 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C883 3101052210010 220PF C885 3101084710010 470pF C886 3101064720000 4700PF C887 3101062210000 220PF C888 3101068200000 82PF C889 3101061020000 1000PF 3101051040010 0.1UF C890 3101052210010 220PF C891 3101051210000 120PF C892 3101062210000 220PF C893...
  • Page 520 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description C922 3101055600000 56PF C923 3101061050020 C924 3101061050020 C925 3101061050020 C926 3101071060010 10UF C927 3101061040010 0.1UF C928 3101081060010 10UF C929 3104071060070 10UF 3101051020010 1000PF C930 3101061020000 1000PF C931 3101065610000 560PF C932...
  • Page 521 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description C960 3101061800000 18PF C962 3101051050000 C963 3101061040010 0.1UF C965 3101062250000 2.2UF C966 3101061050020 C967 3101051040010 0.1UF C968 3101051040010 0.1UF C969 3101051040010 0.1UF 3101051030020 0.01UF C970 3101063910000 390PF C971 3101061010010 100PF...
  • Page 522 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description D108 3304010100220 Varactor D109 3304010100220 Varactor D110 3304010100220 Varactor D111 3304010100220 Varactor D112 3304010100220 Varactor D113 3304010100220 Varactor D116 3304010100220 Varactor D117 3304010100220 Varactor D121 3304010100220 Varactor D122 3304010100220 Varactor...
  • Page 523 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description D6106 3699019000000 Mixer IC D6201 3304010100390 Varactor D6202 3304010100390 Varactor D6203 3311990000060 Schottky barrier diode D701 3304060300050 Varactor D702 3304060300010 Varactor D801 3303210100000 Switching diode D802 3303210100000 Switching diode D803 3303030300000...
  • Page 524 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description L118 3217607681000 680nH L121 3217107102000 L124 3237110220000 Air-core coil 22NH L126 3214307151000 150nH L127 3217607681000 680nH L129 3217607681000 680nH L131 3221506601000 Bead L132 3210406331000 330nH L133 3217607681000 680nH L134 3217107102000...
  • Page 525 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L407 3221506300000 Bead L408 3221506300000 Bead L409 3221506300000 Bead L410 3221506300000 Bead L411 3221506300000 Bead L412 3221506300000 Bead 0Ω L413 3005060000010 0Ω L414 3001050000000 0Ω L415 3001050000000 0Ω...
  • Page 526 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description L6122 3101061040010 0.1UF L6123 3213306821000 0.82uH L6125 3210406471000 470nH L6200 3211506101000 Bead L6202 3210306561010 560nH L6203 3210106560000 56nH L6210 3210306330000 33nH L6213 3210305560000 56nH L6216 3210305560000 56nH 3221506601000 Bead L701...
  • Page 527 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description L814 3212106470000 47nH L815 3221506601000 Bead L816 3233099111000 Air-core coil 111nH L817 3233099400010 Air-core coil 40nH L818 3221513600000 Bead L819 3233099470000 Air-core coil 47nH L820 3233099470000 Air-core coil 47nH L821 3221506601000 Bead...
  • Page 528 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description Q106 3408002000080 NPN transistor Q107 3404006000000 NPN transistor Q108 3403999000000 Composite transistor Q109 3404006000000 NPN transistor Q110 3408002000080 NPN transistor Q111 3401002000990 NPN transistor Q112 3403999000000 Composite transistor Q116 3403999000000 Composite transistor...
  • Page 529 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description Q805 3504990000010 PA MOSFET Q810 3403002000000 PNP transistor Q811 3403008000010 Q812 3403008000010 Q813 3403008000010 Q902 3403002000000 PNP transistor Q903 3403008000010 Q905 3499000000150 Composite transistor Q906 3414001000020 NPN transistor Q908 3403008000010 Q909...
  • Page 530 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 8.2KΩ R143 3001058220000 150Ω R144 3001061510000 100Ω R145 3001051010040 100Ω 1000 R146 3001051010040 100Ω 1001 R147 3001051010040 100Ω 1002 R148 3001051010040 15KΩ 1003 R151 3001051530010 47KΩ 1004 R152 3001054730000 1005...
  • Page 531 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 10KΩ 1037 R202 3001051030000 33Ω 1038 R231 3001053300010 33Ω 1039 R232 3001053300010 10KΩ 1040 R234 3001051030000 10KΩ 1041 R235 3001051030000 10KΩ 1042 R236 3001051030000 56KΩ 1043 R237 3001055630000 5.6KΩ...
  • Page 532 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 30KΩ 1077 R279 3001053030000 1KΩ 1078 R280 3001051020000 0Ω 1079 R282 3001060000000 1080 R283 3001053030000 30KΩ 15KΩ 1081 R284 3001051530010 15KΩ 1082 R285 3001051530010 47KΩ 1083 R286 3001054730000 5.6KΩ...
  • Page 533 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1117 R360 3221505121000 Bead 15KΩ 1118 R361 3001051530010 15KΩ 1119 R362 3001051530010 0Ω 1120 R363 3001050000000 0Ω 1121 R364 3001050000000 10KΩ 1122 R365 3001051030000 10KΩ 1123 R366 3001051030000 33Ω...
  • Page 534 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 100Ω 1157 R404 3001051010040 0Ω 1158 R405 3001060000000 100Ω 1159 R406 3001051010040 33Ω 1160 R407 3001053300010 33Ω 1161 R408 3001053300010 33Ω 1162 R409 3001053300010 100Ω 1163 R410 3001051010040 100Ω...
  • Page 535 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 1.5KΩ 1197 R449 3001061520000 2.7KΩ 1198 R450 3001072720010 10KΩ 1199 R451 3001051030000 10KΩ 1200 R452 3001051030000 10KΩ 1201 R453 3001051030000 10KΩ 1202 R454 3001051030000 100KΩ 1203 R455 3001051040000 33Ω...
  • Page 536 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 33Ω 1237 R495 3001053300010 4.7KΩ 1238 R496 3001054720000 33Ω 1239 R498 3001053300010 4.7KΩ 1240 R499 3001054720000 0Ω 1241 3001050000000 100KΩ 1242 R500 3001051040000 1243 R501 3001051030000 10KΩ 1KΩ...
  • Page 537 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 0Ω 1277 R536 3001050000000 10KΩ 1278 R538 3001051030000 10KΩ 1279 R539 3001051030000 10KΩ 1280 R540 3001051030000 10KΩ 1281 R541 3001051030000 10KΩ 1282 R543 3001051030000 0Ω 1283 R544 3001050000000 33Ω...
  • Page 538 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 10KΩ 1317 R6035 3001051030000 1KΩ 1318 R6049 3001051020000 1KΩ 1319 R6050 3001051020000 10KΩ 1320 R6051 3001051030000 1KΩ 1321 R6052 3001051020000 10KΩ 1322 R6053 3001051030000 510Ω 1323 R6100 3001055110000 680Ω...
  • Page 539 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 470Ω 1357 R6208 3001054710000 4.7KΩ 1358 R6209 3001054720000 1.2KΩ 1359 R6211 3001051220000 100KΩ 1360 R6212 3001051040000 100KΩ 1361 R6213 3001051040000 0Ω 1362 R6214 3001050000000 0Ω 1363 R6215 3001050000000 51Ω...
  • Page 540 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 0Ω 1397 R822 3001060000000 10Ω 1398 R823 3001061000000 10Ω 1399 R823 3001061000000 1400 R824 3101064710000 470PF 33Ω 1401 R825 3001113300000 12Ω 1402 R826 3001061200010 12Ω 1403 R828 3001061200010 200Ω...
  • Page 541 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 43KΩ 1437 R876 3001054330000 47KΩ 1438 R877 3001054730000 10Ω 1439 R878 3001081000000 4.7KΩ 1440 R880 3001074720010 4.7KΩ 1441 R881 3001074720010 180KΩ 1442 R882 3001051840010 13KΩ 1443 R883 3001051330000 18KΩ...
  • Page 542 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 4.7KΩ 1477 R925 3001064720000 100Ω 1478 R929 3001051010040 15KΩ 1479 R930 3001051530010 47KΩ 1480 R931 3001054730000 4.7KΩ 1481 R932 3001064720000 220Ω 1482 R933 3001052210000 51KΩ 1483 R934 3001055130010 4.7KΩ...
  • Page 543 VHF (136-174MHz 25W) Information Service Manual Ref No. Print No. Part No. Description 2.74kΩ 1517 R971 3099052741000 2.2KΩ 1518 R972 3001062220000 1KΩ 1519 R974 3001061020010 20KΩ 1520 R975 3001052030000 10KΩ 1521 R976 3001051030000 1KΩ 1522 R978 3001051020000 10KΩ 1523 R979 3001051030000 10KΩ...
  • Page 544 Service Manual VHF (136-174MHz 25W) Information Ref No. Print No. Part No. Description 1557 U804 3605008005070 Operational amplifier 1558 U900 3608006000000 Power management IC 1559 U901 3608006000000 Power management IC 1560 U902 3608053000010 Power management IC 1561 U903 3608015000170 Power management IC 1562 U905 3608015000060...

  • Page 545: Troubleshooting Flow Chart

    VHF (136-174MHz 25W) Information Service Manual 14.8 Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (44.85MHz) The second LO is Check Q701.
  • Page 546 Service Manual VHF (136-174MHz 25W) Information Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 44.85MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 547 VHF (136-174MHz 25W) Information Service Manual Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Current is Control voltage is Check U801. normal? [1] low or high?[2] Check PA, High antenna switch, and low-pass TX VCO works circuits.
  • Page 548 Service Manual VHF (136-174MHz 25W) Information Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 549 VHF (136-174MHz 25W) Information Service Manual FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 550 Service Manual VHF (136-174MHz 25W) Information Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer or the communication test set. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 4.3V [3] Check whether the emitter-base voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 0.7V under normal RX/TX status.

  • Page 551: Vhf (136-174Mhz 50W) Information

    VHF (136-174MHz 50W) Information Service Manual 15. VHF (136-174MHz 50W) Information 15.1 Transmitter Circuit The transmitter circuit is composed of power amplifier circuit and power control circuit. The former is used to amplify the VCO signal to the desired output power level, while the latter can keep the output power at the desired level, so as to protect the power amplifier from damage caused by over heat, antenna mismatch, and out-of-range voltage (over voltage or under voltage may result in damage to Q801, Q805, Q804, Q802 and Q803).

  • Page 552: Final Power Amplifier

    Service Manual VHF (136-174MHz 50W) Information maximum output power is 34.5dBm, and the maximum variable gain is 15dB. 15.1.4 Final Power Amplifier The final power amplifier consists of Q802 and Q803, with the maximum output power of 48.5dBm, and the maximum variable gain of 14dB. The input matching circuit is composed of C815, C839, R804, R806, R807, R813, R818 and R861, while the power combining circuit is composed of C820, C8330, C833, C831, C819, C812, C841 and C842.

  • Page 553: Output Power Control

    VHF (136-174MHz 50W) Information Service Manual 15.1.8 Output Power Control The TX power is controlled by U801. The forward power is applied to the directional coupler, to output a voltage that can represent the forward power. The voltage together with the preset voltage feeds to U801 to output a voltage VGG, which can control both gate voltage and gain of Q804 and Q805, ensuring a constant power output.

  • Page 554: Receiver Front-End

    Service Manual VHF (136-174MHz 50W) Information 15.2.1 Receiver Front-end RF signals feed to the low-pass filter to remove out-of-band signals, and are applied to the two-stage electrically tunable band-pass filter to get useful signals. After passing through the RF band-pass filter and LNA (Q6102), the RF signals together with the first LO signal feed to the mixer for the first frequency conversion, to generate the first IF signal (44.85MHz).

  • Page 555: Frequency Generation Unit (Fgu)

    VHF (136-174MHz 50W) Information Service Manual the LC resonance loop (D702, L715 and C745). DSP (U302) gets the audio signal from IF IC (U701). Then this signal goes through U302 to output data signal, which is sent to U231 and PIN44 (SSI_DI) for digital-to-analog conversion. Finally, the output analog audio signal will be subjected to gain control, and then fed to the speaker.

  • Page 556: Vco

    Service Manual VHF (136-174MHz 50W) Information Figure 15-4 Diagram of PLL IC The 19.2MHz frequency generated by the reference oscillator (X100) goes into the PLL IC (U100) for division, generating the reference frequency. Meanwhile, the frequency generated by VCO goes into PLL IC (U100) for frequency division.

  • Page 557: Figure 15-5 Diagram Of Vco

    VHF (136-174MHz 50W) Information Service Manual Figure 15-5 Diagram of VCO...

  • Page 558: Pcb View

    15.4 PCB View MD78X/MD78XG PCB View (Front Panel) Top Layer...
  • Page 559 MD78X/MD78XG PCB View (Front Panel) Bottom Layer...
  • Page 560 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Top Layer 顶层...
  • Page 561 MD78X/MD78XG PCB View (Main Board) MD780/MD780G PCB 元件位置图（主板） Bottom Layer 底层...

  • Page 562: Block Diagram

    15.5 Block Diagram MD78X/MD78XG Block Diagram (Power Section) Auto baterry Voltage Q802\Q803\U201 13.6 Q804\Q805 9V3A 9V1A Q920\Q921\U914 Q801 Q801 Q6102 9V1A Q902 Q6103 U6000 U703 Q6105 U701 U702 U701 U915 4V3A Q104 Q100\Q103\Q106\Q110 U100 U918 3V3A X100 U905 U500 ON\OFF KEY PWB...
  • Page 563 MD78X/MD78XG Block Diagram (RF Section) High Temperature Protection 9V1A_TX Gain:10 dB Gain:15 dB Gain:11dB Tx/Rx Gain:16 dB Gain:-6 dB Switch Tx_PORT Microstrip Attenuator Match Match Match Matcher Microstrip Dual Q804 Harmonic Q805 Q801 Rx_PORT Directional Coupler Filter PreDriver Driver Firststage Switch s Power 9.1V...
  • Page 564 MD78X/MD78XG Block Diagram (BB Section) IF processor RF Unit BB Schematic Block Diagram TX RX CTL McBSP2 GPIOs MCSI1 TEMP_DET Audio Codec Nor FLASH and pSRAM Headset McBSP1 FLASH: 8Mx16 Driver datax16 pSRAM:2Mx16 TMS320C55x BELL Driver Speed:96MHz(max) Mobile SDRAM McBSP3...

  • Page 565: Schematic Diagram

    15.6 Schematic Diagram MD78X/MD78XG Schematic Diagram (Audio Circuit) R245 R245 EXT_SPKR+ R253 R253 EXT_SPKR- R293 R293 SPKR1+ R294 R294 SPKR1- L232 L232 9d3V BLM18PG300SN1 BLM18PG300SN1 C232 C232 C233 C233 0.1u 0.1u C285 C285 C284 C284 0.1u 0.1u C234 C234 C235...
  • Page 566 MD78X/MD78XG Schematic Diagram (DAC Circuit) L500 L500 R572 R572 BLM18PG600SN1 BLM18PG600SN1 C471 C471 C405 C405 4.7k 4.7k 0.1u 0.1u 10uF/10V 10uF/10V R542 0 R542 0 R573 R573 R570 R570 5.1k 5.1k 5.6k 5.6k C509 C509 C508 C508 C510 C510 R528 R528 0.1u...
  • Page 567 MD78X/MD78XG Schematic Diagram (Memory Circuit) F_D0 R487 R487 F_D0_LCD F_D1 R489 R489 F_D1_LCD F_D2 R490 R490 F_D2_LCD F_D3 R492 R492 F_D3_LCD F_D4 R515 R515 F_D4_LCD F_D5 R516 R516 F_D5_LCD F_D6 R517 R517 F_D6_LCD F_D7 R518 R518 F_D7_LCD R519 R519 /OE_LCD...
  • Page 568 MD78X/MD78XG Schematic Diagram (OMAP Circuit) 19.2_OMAP 3V3A R414 R414 R419 R419 C338 C338 C336 C336 C401 C401 0.1u 0.1u 10u/10V 10u/10V 1000p 1000p TP309 TP309 C364 39p C364 39p X302 X302 TP377 TP377 L151 L151 C337 C337 R426 R426 C375...
  • Page 569 MD78X/MD78XG Schematic Diagram (OMAP & GPS Circuit) 3V3D TP326 TP326 R323 R323 R325 R325 U302B U302B OMAP OMAP 3V3D MPUIO2/SPIF.CS1/UWIRE.CS1 LCD.P0 U322 U322 R357 R357 98_PE R329 R329 R330 R330 MPUIO4/SPIF.CS2/UWIRE.CS2/LED2 LCD.P1 R327 R327 DVDD_IO SLC/SPC I2C_SCL 98_PC MPUIO1/SPIF.SCK LCD.P2...
  • Page 570 MD78X/MD78XG Schematic Diagram (Peripheral Interface Circuit) 3V3D C482 C482 C481 C481 C409 C409 C410 C410 C411 C411 C412 C412 C413 C413 C414 C414 C415 C415 C416 C416 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p 100p J400...
  • Page 571 MD78X/MD78XG Schematic Diagram (40-Pin Interface Circuit) SPK+ SPK+ 3V3D C468 C468 C439 C439 C438 C438 C441 C441 C440 C440 C435 C435 C420 C420 C419 C419 USB_VBUS R494 R494 R555 R555 100p 100p 0.47u 0.47u 0.47u 0.47u 100p 100p 100p 100p...
  • Page 572 MD78X/MD78XG Schematic Diagram (Power Circuit) TP4031 TP4031 TP4032 TP4032 U900 U900 B900 B900 RP102N331B RP102N331B R901 R901 3V3D VOUT C900 C900 C901 C901 C902 C902 D900 D900 C903 C903 470p/50V 470p/50V MMBZ6V8ALT1G MMBZ6V8ALT1G 470uF/25V 470uF/25V MR2835SKG MR2835SKG D237 D237 B901...
  • Page 573 MD78X/MD78XG Schematic Diagram (TX Circuit) C983 C983 C985 C985 C973 C973 C972 C972 C974 C974 C971 C971 C984 C984 R878 R878 C986 C986 C970 C970 C975 C975 C976 C976 C977 C977 C982 C982 L812 L812 220p 220p 180p 180p 120p...
  • Page 574 MD78X/MD78XG Schematic Diagram (PLL Circuit) 5VA_FGU L156 L156 R175 R175 3.3UH 3.3UH C1009 C1009 1500p 1500p 0.1u 0.1u C1010 C1010 1500p 1500p 1u/16V 1u/16V 3V3A_FGU 601SN1 601SN1 601SN1 601SN1 0.01U 0.01U 0.1u 0.1u 601SN1 601SN1 C121 C121 100p 100p 0.1u 0.1u...
  • Page 575 MD78X/MD78XG Schematic Diagram (VCO Circuit) R153 R153 601SN1 601SN1 R185 R185 5VA_FGU Q117 Q117 EMD22 EMD22 R142 R142 D127 D127 1500p 1500p 0.1u 0.1u Q101 Q101 3.3k 3.3k EMD22 EMD22 4V3A DAN222 DAN222 680n 680n TX_VCO_H R145 R145 1500p 1500p...
  • Page 576 MD78X/MD78XG Schematic Diagram (RX Circuit) L6200 L6200 BLM18PG600SN1 BLM18PG600SN1 9V1A_RX C6243 C6243 R6201 R6201 0.1uF 0.1uF C6202 C6202 C6100 C6100 R6100 R6100 470p 470p TRANSISTOR TRANSISTOR Q6201 Q6201 L6101 L6101 R6202 R6202 BLM18PG600SN1 BLM18PG600SN1 UMT1N UMT1N RF_ATTEN C6103 C6103 220p...
  • Page 577 MD78X/MD78XG Schematic Diagram (IF Circuit) TP703 TP703 TP702 TP702 TP704 TP704 C701 C701 C703 C703 2FLO 2FLO 0.01u 0.01u TP701 TP701 IF-out L716 L716 C743 C743 TEST POINT TEST POINT C702 C702 0.01u 0.01u L701 L701 L702 L702 601S 601S...
  • Page 578 MD78X/MD78XG Schematic Diagram (Front Panel) 3V3A TP10 TP10 TP11 TP11 TP12 TP12 TP13 TP13 TP14 TP14 TP15 TP15 TP16 TP16 TP17 TP17 MMBZ6V8ALT1G MMBZ6V8ALT1G 100pf 100pf MENU 100pf 100pf 0.1uf 0.1uf DOWN EMI FILTER EMI FILTER UART2_RXD LOGIC IC LOGIC IC...

  • Page 579: Parts List

    VHF (136-174MHz 50W) Information Service Manual 15.7 Parts List MD78X/MD78XG Main Board Ref No. Print No. Part No. Description 6201928000000 VCO shielding cover 6202010000000 APC shielding cover 3101051520000 1500PF 3101061300000 13PF C100 3101051520000 1500PF C1000 3101052210010 220PF C1001 3101051520000 1500PF...
  • Page 580 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C150 3101051520000 1500PF C151 3101061100010 11PF C152 3101050900000 C153 3101053900000 39PF C154 3101053300000 33PF C155 3101061600000 16PF C156 3101051520000 1500PF C157 3101051510000 150PF C158 3101053300000 33PF C159 3101051000020 10PF 3101052400010...
  • Page 581 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 3101051520000 1500PF C232 3101051040010 0.1UF C233 3101051040010 0.1UF C234 3101081060010 10UF C235 3101051030020 0.01UF C236 3101051040010 0.1UF C237 3101054740020 0.47uF C238 3101061050020 C239 3101051040010 0.1UF 3101051040010 0.1UF C240 3101051040010 0.1UF...
  • Page 582 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C269 3101052210010 220PF 3101050100030 C270 3101052210010 220PF C271 3101052210010 220PF C272 3101052210010 220PF C273 3101052210010 220PF C274 3101051040010 0.1UF C275 3101071060010 10UF C276 3101051050000 C277 3101061050020 C278 3101061050020 C279 3101061050020...
  • Page 583 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description C310 3101051050000 C311 3101051040010 0.1UF 3101051500080 15PF C325 3101051040010 0.1UF C326 3101051010030 100PF C329 3101051040010 0.1UF 3101051500080 15PF C330 3101051040010 0.1UF C331 3101081060010 10UF C332 3101051040010 0.1UF C333 3101081060010 10UF...
  • Page 584 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C362 3101058200000 82PF C363 3101058200000 82PF C364 3101053900000 39PF C365 3101058200000 82PF C366 3101051040010 0.1UF C367 3104071060070 10UF C375 3101051200020 12PF C376 3101051200020 12PF C378 3101051010030 100PF C379 3101051040010 0.1UF...
  • Page 585 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description C411 3101051010030 100PF C412 3101051010030 100PF C413 3101051010030 100PF C414 3101051010030 100PF C415 3101051010030 100PF C416 3101051010030 100PF C417 3101051010030 100PF C418 3101051010030 100PF C419 3101051010030 100PF C420 3101051010030 100PF...
  • Page 586 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C451 3101051010030 100PF C452 3101051010030 100PF C453 3101051010030 100PF C454 3101051010030 100PF C455 3101051010030 100PF C456 3101051010030 100PF 3101051520000 1500PF C463 3101051010030 100PF C465 3101051010030 100PF C466 3101051010030 100PF C467...
  • Page 587 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description C517 3101051010030 100PF C518 3101051010030 100PF C519 3104071060070 10UF 3101051520000 1500PF C520 3104071060070 10UF 3101051500080 15PF 3101051000020 10PF 3101060300010 3101051520000 1500PF 3101051030020 0.01UF 3101052000020 20PF 3101051520000 1500PF 3101051520000 1500PF C6042...
  • Page 588 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C6152 3101050500010 C6153 3101050400010 C6154 3101050600010 C6155 3101051030020 0.01UF C6157 3101061010010 100PF 0Ω C6158 3001060000000 C6159 3101052210010 220PF C6160 3101054700010 47PF C6161 3101052000020 20PF C6162 3101051500080 15PF C6163 3101050700010 C6164...
  • Page 589 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description C6218 3101050200010 C6221 3101050200010 0Ω C6222 3001050000000 C6223 3101051000030 10PF C6224 3101055600000 56PF C6225 3101051000030 10PF C6226 3101051000030 10PF C6228 3101051520000 1500PF C6230 3101051500080 15PF C6231 3101056800000 68PF C6232 3101056800000...
  • Page 590 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C710 3101051020010 1000PF C712 3101051040010 0.1UF C713 3101053330000 0.033UF C714 3101051000030 10PF C715 3101063340000 0.33UF C716 3101061810010 180PF C717 3101054710010 470PF C718 3101051050160 C719 3101051050000 3110071040000 0.1UF C720 3101051040010 0.1UF...
  • Page 591 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description C749 3101053900000 39PF 3101051020010 1000PF C750 3101071050020 C751 3101051000030 10PF C752 3101074750000 4.7UF C754 3101061050020 C755 3104071060070 10UF C756 3101051040010 0.1UF 3101051010030 100PF C763 3101051010030 100PF C764 3101051010030 100PF C765...
  • Page 592 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C824 3101081800010 18pF C825 3101061010010 100PF C827 3101081020010 1000pF C829 3101061040010 0.1UF 3101051040010 0.1UF C830 3101372000000 20pF C831 3101376800000 68pF C833 3101376800000 68pF C8330 3101081200010 12pF C835 3101081800010 18pF C836...
  • Page 593 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description C868 3101061040010 0.1UF 3101051040010 0.1UF C870 3101371010000 100pF C873 3101061020000 1000PF C875 3101051510000 150PF C877 3101062730000 0.027UF C878 3101062210000 220PF C879 3101082700010 27pF 3110071040000 0.1UF C880 3101066830000 0.068UF C883 3101052210010...
  • Page 594 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C912 3101072250030 2.2UF C913 3101061040030 0.1UF C914 3101104760000 47UF C915 3101082260020 22UF C916 3101063320000 3300PF C917 3104071060070 10UF C918 3101052200010 22PF C919 3101072260000 22UF C920 3101062250000 2.2UF C921 3101052210010 220PF...
  • Page 595 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description C952 3101061030010 0.01UF C953 3101061020000 1000PF C954 3101062710000 270PF C955 3101051040010 0.1UF C956 3101081060010 10UF C957 3101081060010 10UF C958 3101051040010 0.1UF C959 3101061010010 100PF 3101051520000 1500PF C960 3101061800000 18PF C962...
  • Page 596 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description C994 3101058200000 82PF C996 3101061040010 0.1UF C997 3101051810010 180p D100 3303990000060 Switching diode D101 3304010100220 Varactor D102 3304010100220 Varactor D105 3304010100220 Varactor D106 3304010100220 Varactor D107 3304010100220 Varactor D108 3304010100220...
  • Page 597 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description D408 3399040600010 ESD protection diode D409 3310240000040 ESD protection diode D450 3699037000010 USB IC D6009 3303990000060 Switching diode D601 3307110100080 D6010 3303990000060 Switching diode D6014 3303990000060 Switching diode D6015 3303990000060 Switching diode...
  • Page 598 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description L105 3211256000000 56nH L106 3214307181000 180nH L107 3217607681000 680nH L108 3217607681000 680nH L110 3217107102000 L112 3217607681000 680nH L114 3211256000000 56nH L115 3217107121000 120nH L116 3217607681000 680nH L117 3217607681000 680nH L118...
  • Page 599 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description L235 3211506101000 Bead L321 3212106390000 39nH L322 3221506300000 Bead 3217607681000 680nH L401 3221506300000 Bead L402 3221506300000 Bead L403 3221506300000 Bead L404 3221506300000 Bead L405 3221506300000 Bead L406 3221506300000 Bead L407...
  • Page 600 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description L6040 3217106569000 5.6nH L6101 3211506101000 Bead L6114 3211506101000 Bead L6115 3211506101000 Bead L6116 3210306470000 47nH L6117 3210306390000 39nH L6118 3210306220000 22nH L6119 3210306330000 33nH L6120 3210306470000 47nH L6121 3211506101000 Bead...
  • Page 601 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description L802 3221513600000 Bead L803 3221513600000 Bead L804 3233099270000 27nH L805 3210306101000 100nH L806 3213306102000 L807 3210406331000 330nH L808 3233099220000 22nH L809 3233099400010 40nH L810 3233099400010 40nH L811 3210306470000 47nH L812...
  • Page 602 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description L913 3221506300000 Bead L916 3221513600000 Bead L917 3221513600000 Bead L930 3241799103000 10uH L931 3213099472000 4.7uH L940 3221513600000 Bead 3503020000030 N-MOSFET Q100 3408002000080 NPN transistor Q101 3403999000000 Composite transistor Q102 3401002000990 NPN transistor...
  • Page 603 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description Q411 3414999000000 Q412 3414999000000 Q413 3403008000010 Q6100 3499000000150 Composite transistor Q6103 3404999000000 NPN transistor Q6104 3404006000000 NPN transistor Q6105 3404006000000 NPN transistor Q6201 3403014000020 Composite transistor Q6202 3404999000000 NPN transistor Q701...
  • Page 604 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 18Ω R122 3001051800000 51Ω R123 3001055100010 82KΩ R128 3001058230000 270Ω 1000 R129 3001052710000 120Ω 1001 R130 3001051210010 3.3KΩ 1002 R131 3001053320010 3.3KΩ 1003 R132 3001053320000 270Ω 1004 R135 3001052710000 1005...
  • Page 605 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 1KΩ 1037 R181 3001051020000 1KΩ 1038 R183 3001051020000 1039 R186 3221506601000 Bead 10Ω 1040 R187 3001061000000 0Ω 1041 R188 3001050000000 100Ω 1042 R190 3001051010040 150Ω 1043 R192 3001061510000 8.2KΩ...
  • Page 606 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 1KΩ 1077 R264 3001051020000 1.8KΩ 1078 R265 3001051820000 47KΩ 1079 R266 3001054730000 1KΩ 1080 R267 3001051020000 100KΩ 1081 R268 3001051040000 100KΩ 1082 R269 3001051040000 47KΩ 1083 R270 3001054730000 100Ω...
  • Page 607 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 100Ω 1117 R338 3001051010040 100Ω 1118 R339 3001051010040 100Ω 1119 R346 3001051010040 33Ω 1120 R347 3001053300010 0Ω 1121 R348 3001050000000 33Ω 1122 R349 3001053300010 33Ω 1123 R350 3001053300010 10KΩ...
  • Page 608 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 33Ω 1157 R387 3001053300010 10Ω 1158 R388 3001051000000 10KΩ 1159 R390 3001051030000 10KΩ 1160 R391 3001051030000 10KΩ 1161 R392 3001051030000 10KΩ 1162 R393 3001051030000 10KΩ 1163 R394 3001051030000 4.7KΩ...
  • Page 609 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 33Ω 1197 R432 3001053300010 33Ω 1198 R433 3001053300010 100Ω 1199 R434 3001051010040 4.7KΩ 1200 R435 3001054720000 4.7KΩ 1201 R436 3001054720000 4.7KΩ 1202 R437 3001054720000 10KΩ 1203 R438 3001051030000 100Ω...
  • Page 610 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 33Ω 1237 R474 3001053300010 10KΩ 1238 R476 3001051030000 1KΩ 1239 R477 3001051020000 33Ω 1240 R479 3001053300010 10KΩ 1241 R481 3001051030000 10KΩ 1242 R482 3001051030000 10KΩ 1243 R483 3001051030000 33Ω...
  • Page 611 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 33Ω 1277 R521 3001053300010 33Ω 1278 R522 3001053300010 33Ω 1279 R523 3001053300010 33Ω 1280 R524 3001053300010 33Ω 1281 R525 3001053300010 33Ω 1282 R526 3001053300010 33Ω 1283 R527 3001053300010 68KΩ...
  • Page 612 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 33KΩ 1317 R563 3001053330000 0Ω 1318 R564 3001050000000 0Ω 1319 R565 3001050000000 0Ω 1320 R566 3001050000000 0Ω 1321 R567 3001050000000 1322 R568 3001055120030 5.1K 1KΩ 1323 R569 3001051020000 1324 R570...
  • Page 613 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 51Ω 1357 R6132 3001055100010 330Ω 1358 R6133 3001053310000 1359 R6134 3001053030000 30KΩ 4.7KΩ 1360 R6135 3001054720000 20KΩ 1361 R6136 3001052030000 30KΩ 1362 R6137 3001053030000 0Ω 1363 R6138 3001060000000 56KΩ...
  • Page 614 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 33Ω 1397 R721 3001053300010 0Ω 1398 R724 3001060000000 33Ω 1399 R725 3001053300010 47KΩ 1400 R727 3001064730000 47KΩ 1401 R728 3001064730000 0Ω 1402 R729 3001050000000 0Ω 1403 R731 3001050000000 12KΩ...
  • Page 615 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 18KΩ 1437 R844 3001061830010 18KΩ 1438 R845 3001061830010 1.5KΩ 1439 R846 3001061520000 47KΩ 1440 R847 3001054730000 2.2KΩ 1441 R849 3001052220010 470Ω 1442 R853 3001064710000 56KΩ 1443 R854 3001055630000 100Ω...
  • Page 616 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 13KΩ 1477 R896 3001051330000 150Ω 1478 R897 3001061510000 36Ω 1479 R898 3001063600010 150Ω 1480 R899 3001061510000 12Ω 1481 R900 3001061200010 470KΩ 1482 R902 3001054740010 470KΩ 1483 R903 3001054740010 470KΩ...
  • Page 617 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 1KΩ 1517 R947 3001051020000 100Ω 1518 R948 3001051010040 47KΩ 1519 R949 3001054730000 1520 R950 3001051030000 10KΩ 1.5KΩ 1521 R951 3001051520010 24KΩ 1522 R952 3001062430000 10Ω 1523 R953 3001061000000 1KΩ...
  • Page 618 Service Manual VHF (136-174MHz 50W) Information Ref No. Print No. Part No. Description 1557 T6101 3244599189000 Transmission coil 1558 U100 3604019000000 PLL IC 1559 U101 3616059000000 Switch IC 1560 U102 3616059000000 Switch IC 1561 U201 3602042000000 Audio amplifier 1562 U231 3613010000000 Baseband processor 1563...
  • Page 619 VHF (136-174MHz 50W) Information Service Manual Ref No. Print No. Part No. Description 1597 X302 3701019250040 TCXO 1598 X375 3701327610060 12.5pF 1599 Z6100 3802448540040 Crystal filter 1600 41MD7801001D0...

  • Page 620: Troubleshooting Flow Chart

    Service Manual VHF (136-174MHz 50W) Information 15.8 Troubleshooting Flow Chart Receiver Circuit No receive Q920 (9V3A) Check the power- outputs normally? on circuit. Normal signal Q902 (9V1A) Replace the front output from front pan- outputs normally? panel. el? [1] Check Q902 and IF signal (44.85MHz) The second LO is Check Q701.
  • Page 621 VHF (136-174MHz 50W) Information Service Manual Description of Normal Situations: [1] During sensitivity test, use a communication test set to demodulate the audio signal (TP4012 and TP4016). If the signal is demodulated normally, it is concluded that the front panel is defective. [2] Use the communication test set to input a 44.85MHz IF signal at the mixer, and see whether it can be processed normally afterwards.
  • Page 622 Service Manual VHF (136-174MHz 50W) Information Transmitter Circuit No Power Output Power supply Check the power works normally? circuit. Current is Control voltage is Check U801. normal? [1] low or high?[2] Check PA, High antenna switch, and low-pass TX VCO works circuits.
  • Page 623 VHF (136-174MHz 50W) Information Service Manual Description of Normal Situations: [1] The current in analog mode is above 6A under 45W power supply and above 1A under 5W. However, in digital mode, the current will be reduced by 50%. [2] The APC voltage should be above 2V at TP811. [3] Check whether there is an appropriate TX LO signal at TP803.
  • Page 624 Service Manual VHF (136-174MHz 50W) Information FGU Check U915 (5VA) and Replace U915 U918 (3V3A) work at and U918. normal voltage? Q104 (4V3A) works Replace Q104. at normal voltage? Q108, Q112, Q106, Q110, Replace Q106, Q110, Q101 and Q105 work Q100 and Q103 work VCO oscillates? [1] Q100 and Q103.
  • Page 625 VHF (136-174MHz 50W) Information Service Manual Description of Normal Situations: [1] Detect the oscillation frequency of RX TP123 and TX TP111 using a spectrum analyzer or the communication test set. [2] Check whether switches (Q108, Q112, Q101 and Q105) are turned on and output 4.3V [3] Check whether the emitter-base voltage of the four transistors (Q106, Q110, Q100 and Q103) is about 0.7V under normal RX/TX status.

  • Page 626: Disassembly And Assembly

    Service Manual Disassembly and Assembly 16. Disassembly and Assembly 16.1 Disassembly Turn off the radio and remove the power cord and antenna. Step 1 Loosen the three screws to remove the front panel. Then remove the FFC. Step 2 Detach the volume control knob and loosen the four screws. Then remove the PCB from the Step 3 control panel.

  • Page 627: Assembly

    Disassembly and Assembly Service Manual Loosen the eleven screws to remove the upper shield cover. Step 5 Loosen the screw fixing the antenna connector and two screws fixing the PA module. Then take Step 6 the PCB out. 16.2 Assembly To assemble the radio, perform the above steps in a reverse way.
  • Page 628 Service Manual Disassembly and Assembly Fix the radio bracket with four or six self-tapping screws (black, 4.8X20). Step 2 Fasten the two adjustment screws, each of which has a silicone rubber pad. Step 3 Connect the palm microphone to the radio (via front-panel connector).When the palm Step 4 microphone is not in use, hang it on the microphone hanger.

  • Page 629: Exploded View

    Exploded View Service Manual 17. Exploded View 10 11 12 13 14 15 16 17 18 19 20...
  • Page 630 Service Manual Exploded View Part No. Description Qty. 6300109000000 Aluminum chassis 7500358000000 Heat sink pad 6100492101000 Waterproof ring for front case 4210090000200 Signal cable 5208010100010 Connector (male) 10Pin 6001079000000 Light-guide plate for keys 7300048000000 Metal dome 6100408001000 Waterproof ring for microphone jack 6100488000000 P+R front panel keys 6201893000000...
  • Page 631 Exploded View Service Manual Part No. Description Qty. 7500344000000 PORON pad 5130000000040 TFT LCD 2.0" TFT 6001078000000 LCD bracket 5202002100270 Board-to-wire connector 7207003700000 6100334000000 O-ring for encoder switch 4399030000020 Rotary switch 41078001000F0 PCB for control panel 6100533101000 Waterproof ring for aluminum chassis 6300126000000 Aluminum upper cover 7103015000000...
  • Page 632 Service Manual Exploded View Part No. Description Qty. 5205002100110 Power socket (male) 3103994770150 Electrolytic capacitor 7212002500000 6100531100000 Waterproof ring for antenna connector 4401000009000 BNC RF connector 6100494000000 Soft stopple for GPS antenna connector 7500159000100 Thermal conductive silicone rubber 7500357000000 Heat sink pad 6100574100000 O_ring 7500344000000...

  • Page 633: Packing Guide

    Packing Guide Service Manual 18. Packing Guide...

  • Page 634: Specifications

    Service Manual Specifications 19. Specifications General UHF1: 400-470MHz UHF2: 450-520MHz Frequencies UHF3: 350-400MHz VHF: 136-174MHz Channel Capacity 1024 Zone Capacity 64 (each with a maximum of 16 channels) Channel Spacing 12.5KHz/ 20KHz/25KHz Operating Voltage 13.6V±15% Standby <0.6A Receive <2.0A Current <5A Drain Transmit...
  • Page 635 Specifications Service Manual UHF1 (400-470MHz): 5-45W UHF2 (450-520MHz): 5-45W High Power UHF3 (350-400MHz): 5-45W VHF (136-174MHz): 5-50W 11K0F3E@12.5KHz FM Modulation 14K0F3E@20KHz 16K0F3E@25KHz 12.5KHz Data Only: 7K60FXD 4FSK Digital Modulation 12.5kHz Data & Voice: 7K60FXW -36dBm<1GHz Conducted/Radiated Emission -30dBm>1GHz ±2.5KHz@12.5KHz Modulation Limiting ±4.0KHz@20KHz ±5.0KHz@25KHz -40dB@12.5KHz...
  • Page 636 Service Manual Specifications 0.3μV /BER5% Digital Adjacent Channel Selectivity 65dB@12.5 KHz /75dB@20/25KHz TIA-603 60dB@12.5KHz /70dB@25KHz/20KHz ETSI Intermodulation 75dB@12.5/20/25KHz TIA-603 70dB@12.5/20/25KHz ETSI Spurious Response Rejection 75dB@12.5/20/25KHz TIA-603 70dB@12.5/20/25KHz ETSI Blocking 90dB TIA-603 84dB ETSI -40dB@12.5kHz Hum and Noise -43dB@20kHz -45dB@25kHz Internal (@20 ohm load) Rated Audio Power Output External (@8 ohm load) 7.5W...
  • Page 637 Specifications Service Manual IEC 61000-4-2 (level 4) ±8kV (contact) ±15kV (air) American Military Standard MIL-STD-810 C/D/E/F Dust & Water Intrusion IP54 Standard Humidity Per MIL-STD-810 C/D/E/F Standard Shock & Vibration Per MIL-STD-810 C/D/E/F Standard GPS (for MD78XG only) Accuracy specs are for long-term tracking (95th percentile values>5 satellites visible at a nominal -130dBm signal strength).
  • Page 638 Hytera Communications Corp., Ltd. 201 Hytera Corp., Ltd. All Rights Reserved. Address: HYT Tower, Hi-Tech Industrial Park North, Beihuan RD., Nanshan District, Shenzhen, China Postcode: 518057 http://www.hytera.com 1616300000170 201 - L06773...

This manual is also suitable for:

Md78xg

Table of Contents

Save PDF