1. Manuals
  2. Brands
  3. Motorola Manuals
  4. Radio
  5. GM328
  6. Service manual

Motorola GM328 Service Manual

Hide thumbs Also See for GM328:
1
2
3
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
Table of Contents

Advertisement

Quick Links

GM328/GM338/GM398
Mobile Radios
Detailed Service Manual
6804112J18-E
December, 2003

Advertisement

Table of Contents

Troubleshooting

loading

Related Manuals for Motorola GM328

Summary of Contents for Motorola GM328

  • Page 1 GM328/GM338/GM398 Mobile Radios Detailed Service Manual 6804112J18-E December, 2003...
  • Page 2 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola prod-...
  • Page 3 The following major changes have been implemented in this manual since the previous edition: Edition Description Date 6804112J18-O Initial edition 6804112J18-E Added Document History section. Dec. 2003 Changed to latest Safety Information (Feb. 2002) Added GM328 model information to VHF, UHF1 and UHF2 bands.
  • Page 4 THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 5 GM328/GM338/GM398 Mobile Radios Detailed Service Manual Contents Section 1 Service Maintainability Section 2 Controlhead Service Information Section 3 Controller Service Information Section 4 VHF Service Information Section 5 UHF Band 1 Service Information Section 6 UHF Band 2 Service Information...
  • Page 6 THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 7 GM328/GM338/GM398 Mobile Radios Service Maintainability Issue: December, 2003...
  • Page 8 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...

  • Page 9: Safety Information

    These recommended RF exposure levels include substantial margins of protection. All Motorola 2-way radios are designed, manufactured, and tested to ensure they meet government- established RF exposure levels. In addition, manufacturers also recommend specific operating instructions to users of 2-way radios.
  • Page 10 Compliance with RF Exposure Standard Your Motorola two-way radio is designed and tested to comply with a number of national and international standards and guidelines (listed below) regarding human exposure to radio frequency electromagnetic energy. This radio complies with the IEEE and ICNIRP exposure limits for occupational/controlled RF exposure environment at duty factors of up to 50% talk–50% listen and...

  • Page 11: Approved Accessories

    40 to 110 watts 3 feet (90 centimeters) NOTE:If you are not sure of the rated power of your radio, contact your Motorola representative or dealer and supply the radio model number found on the radio model label. If you cannot determine the rated power out, then assure 3-feet separation from the body of the vehicle.
  • Page 12 Compliance and Control Guidelines and Operating Instructions for Mobile Two-Way Radios Installed as Fixed Site Stations If mobile radio equipment is installed at a fixed location and operated as a control station or as a fixed unit, the antenna installation must comply with the following requirements in order to ensure optimal performance and compliance with the RF energy exposure limits in the standards and guidelines listed on page ii: •...

  • Page 13: Operational Warnings

    Operational Warnings For Vehicles With An Air Bag Do not mount or place a mobile radio in the area over an air bag or in the air bag deployment area. Air bags inflate with great force. If a radio is placed in the air bag deployment area and the air bag inflates, the radio may be propelled with great force and cause serious injury to occupants of the vehicle.
  • Page 14 THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 15: Table Of Contents

    2.0 Warranty and Service Support................1-1 2.1 Warranty Period and Return Instructions ............1-1 2.2 After Warranty Period ..................1-1 2.3 Piece Parts Availability ...................1-2 2.4 Technical Support...................1-2 2.5 Further Assistance From Motorola ..............1-2 3.0 Radio Model Information..................1-3 Section 2 Maintenance 1.0 Introduction ......................2-1 2.0 Preventive Maintenance ..................2-1...
  • Page 16 viii THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 17: Scope Of Manual

    In instances where the product is covered under a “return for replacement” or “return for repair” warranty, a check of the product should be performed prior to shipping the unit back to Motorola. This is to ensure that the product has been correctly programmed or has not been subjected to damage outside the terms of the warranty.

  • Page 18: Piece Parts Availability

    Aftermarket Division (AAD). If no part number is assigned, the part is not normally available from Motorola. If the part number is appended with an asterisk, the part is serviceable by Motorola Depot only. If a parts list is not included, this generally means that no user-serviceable parts are available for that kit or assembly.

  • Page 19: Radio Model Information

    Table 1-1 Radio Model Number (Example: AZM25KHF9AA5) Type of Model Freq. Power Physical Channel Feature Protocol Unit Series Band Level Packages Spacing Level 1-25W GM328 Program- Conventional GM328 (136- mable 174MHz) UHF1 25-60W GM338 GM338 (403- 470MHz) UHF2 GM398 GM398 (450-...
  • Page 20 Radio Model Information THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 21: Maintenance

    Section 2 MAINTENANCE Introduction This chapter of the manual describes: preventive maintenance • safe handling of CMOS devices • repair procedures and techniques • Preventive Maintenance The radios do not require a scheduled preventive maintenance program; however, periodic visual inspection and cleaning is recommended. Inspection Check that the external surfaces of the radio are clean, and that all external controls and switches are functional.

  • Page 22: Safe Handling Of Cmos And Ldmos

    When damaged parts are replaced, identical parts should be used. If the identical replacement component is not locally available, check the parts list for the proper Motorola part number and order the component from the nearest Motorola Communications parts center listed in the “Piece Parts”...
  • Page 23 General Repair Procedures and Techniques Chip Components Use either the RLN4062 Hot-Air Repair Station or the Motorola 0180381B45 Repair Station for chip component replacement. When using the 0180381B45 Repair Station, select the TJ-65 mini- thermojet hand piece. On either unit, adjust the temperature control to 370 °C (700 °F), and adjust the airflow to a minimum setting.
  • Page 24 General Repair Procedures and Techniques Shields Removing and replacing shields will be done with the R1070 station with the temperature control set to approximately 215°C (415°F) [230°C (445°F) maximum]. To remove the shield: • Place the circuit board in the R1070 circuit board holder. Select the proper heat focus head and attach it to the heater chimney.

  • Page 25: Notes For All Schematics And Circuit Boards

    1. Unless otherwise stated, resistances are in Ohms (K = 1000), and capacitances are in picofarads (pF) or microfarads (µF). 2. DC voltages are measured from point indicated to chassis ground using a Motorola DC multimeter or equivalent. Transmitter measurements should be made with a 1.2 µH choke in series with the voltage probe to prevent circuit loading.
  • Page 26 Notes For All Schematics and Circuit Boards BL KP RED Red Keypad Back Light Control BL LCD GREEN Green Display Back Light Control BL LCD RED Red Display Back Light Control BL RED Red Back Light Control BOOT CNTRL Bootstrap Mode Enable Signal BOOT MODE Boot Mode Select BOOT PWR ON...
  • Page 27 Notes For All Schematics and Circuit Boards EXP1 CS Expansion Board Chip Select 1 EXP2 CS Expansion Board Chip Select 2 EXT KP COL External Keypad Matrix Column Signal EXT KP ROW External Keypad Matrix Row Signal EXT MIC External (from Accessory Connector) Microphone Input EXT SWB+ External Switched 13.2V Supply Voltage F1200...
  • Page 28 Notes For All Schematics and Circuit Boards INT KP ROW Internal Keypad Matrix Row Signal INT MIC Internal (from Control Head) Microphone Input INT SWB Internal Switched 13.2V Supply Voltage INT SWB+ Internal Switched 13.2V Supply Voltage Interrupt Request from Control Head K9V1 9.1V in Transmit Mode KEYPAD ID...
  • Page 29 Notes For All Schematics and Circuit Boards ON OFF SENSE (Controller) Service Request Line from Control Head OPT CS Option Board Chip Select OPT PTT PTT from Option Board PA PWR SET ASFIC Output Voltage to set the Transmitter Power PA SWB Switches Supply Voltage for PA Current Control Circuitry PA SUPVLTG...
  • Page 30 2-10 Notes For All Schematics and Circuit Boards SQ DET Squelch Detect Signal µP Clock Signal TEMP SENSE Temperature Sense Line for LCD TEMPSENSE Temperature Sense Line from PA to µP TX/RX VCO Switch Signal TX AUD RTN Option Board Output to Transmit Audio Path TX AUD SND Microphone Audio to Option Board TXINJ...
  • Page 31 Notes For All Schematics and Circuit Boards 2-11 Voltage Super Filtered (5V) VSTBY 5V Supply for µP when the Radio is switched off 4-LAYER CIRCUIT BOARD DETAIL VIEWING COPPER STEPS IN PROPER LAYER SEQUENCE SIDE 1 LAYER 1 (L1) LAYER 2 (L2) INNER LAYERS LAYER 3 (L3) LAYER 4 (L4)
  • Page 32 2-12 Notes For All Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 33: Service Aids

    Table 3-1 lists the service aids recommended for working on the radio. While all of these items are available from Motorola, most are standard workshop equipment items, and any equivalent item capable of the same performance may be substituted for the item listed.

  • Page 34: Test Equipment

    Test Equipment Test Equipment Table 3-2 lists test equipment required to service the radio and other two-way radios. Table 3-2 Recommended Test Equipment Motorola Part Description Characteristics Application Number R2600_NT Comms System Analyzer This monitor will sub- Frequency/deviation (non MPT)
  • Page 35 GM328/GM338/GM398 Mobile Radios Controlhead Service Information Issue: December, 2003...
  • Page 36 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 37 Table of Contents Section 1 overview 1.0 GM328 Model (GCN6112_) .................1-1 2.0 GM338 Model (GCN6114_) .................1-2 3.0 GM398 Model (GCN6115_) .................1-3 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 Controlhead Model for GM328................2-1 2.1 Power Supplies....................2-1 2.2 Power On / Off....................2-1 2.3 Microprocessor Circuit..................2-2...
  • Page 38 Controlhead PCBs / Schematics / Parts lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 2.0 Controlhead GM328 - PCB 8486146B07 / Schematics........4-3 Controlhead GM328 - PCB 8486146B07 .............. 4-3 Controlhead GM328 - Schematic Sheet 1 of 2............4-4 Controlhead GM328 - Schematic Sheet 2 of 2............

  • Page 39: Gm328 Model (Gcn6112_)

    Light Emitting Diodes (LED) to inform the user about the radio status. To control the LED’s and to communicate with the host radio the control head uses the Motorola 68HC11E9 microprocessor.

  • Page 40: Gm338 Model (Gcn6114_)

    14 character Liquid Crystal Display (LCD) for alpha - numerical information e.g. channel number or call address name. To control the LED’s and the LCD, and to communicate with the host radio the control head uses the Motorola 68HC11E9 microprocessor.

  • Page 41: Gm398 Model (Gcn6115_)

    Liquid Crystal Display (LCD) with 21 pre - defined symbols and a 32*96 dot matrix for graphical or alpha - numerical information e.g. channel number, select code, call address name. To control the LEDs and the LCD, and to communicate with the host radio the control head uses the Motorola 68HC11K4 microprocessor.
  • Page 42 GM398 Model (GCN6115_) THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 43: Theory Of Operation

    Light Emitting Diodes (LED) to inform the user about the radio status. To control the LED’s and to communicate with the host radio the control- head uses the Motorola 68HC11E9 microprocessor. Power Supplies The power supply to the controlhead is taken from the host radio’s FLT A+ voltage via connector...

  • Page 44: Microprocessor Circuit

    Controlhead Model for GM328 Microprocessor Circuit The controlhead uses the Motorola 68HC11E9 microprocessor (µP) (U0831) to control the LED’s and to communicate with the host radio. RAM and ROM are contained within the microprocessor itself. The microprocessor generates it’s clock using the oscillator inside the microprocessor along with a 8 MHz ceramic resonator (U0833) and R0920.

  • Page 45: Keypad Keys

    Controlhead Model for GM328 Keypad Keys The controlhead keypad is a 6-key keypad. All keys are configured as 2 analogue lines read by µP pins 13 and 15 . The voltage on the analogue lines varies between 0 volts and +5 volts depending on which key has been pressed.

  • Page 46: Speaker

    14 character Liquid Crystal Display (LCD) for alpha - numerical information e.g. channel number or call address name. To control the LEDs and the LCD, and to communicate with the host radio the controlhead uses the Motorola 68HC11E9 microprocessor. Power Supplies The power supply to the controlhead is taken from the host radio’s FLT A+ voltage via connector...

  • Page 47: Microprocessor Circuit

    µP will switch the radio off. Microprocessor Circuit The controlhead uses the Motorola 68HC11E9 microprocessor (µP) (U0831) to control the LEDs and the LCD and to communicate with the host radio. RAM and ROM are contained within the microprocessor itself.

  • Page 48: Keypad Keys

    Controlhead Model for GM338 When the controlhead µP wants to communicate to the host radio, the µP brings request line CH REQUEST to a logic “0” via µP pin 62. This switches on Q0823, which pulls line ON OFF CONTROL high through diode D0821. A low to high transition on this line informs the radio, that the controlhead requires service.

  • Page 49: Liquid Crystal Display (Lcd)

    Controlhead Model for GM338 Liquid Crystal Display (LCD) The LCD H0971 uses the display driver U0971. The display is a single layer super twist nematic (STN) LCD display. It has 14 characters with a 5*8 dot matrix for displaying alpha - numerical information and a line with 21 pre - defined icons above the dot matrix The driver contains a data interface to the µP, an LCD segment driver, an LCD power circuit, an oscillator, data RAM and control logic.

  • Page 50: Speaker

    Controlhead Model for GM338 Line PTT IRDEC (J0811-6) is used to key up the radio’s transmitter. While the PTT button on a connected microphone is released, line PTT IRDEC is pulled to +5 volts level by R0843. Transistor Q0843 is switched on and causes a low at µP port PA2. When the PTT button is pressed, signal PTT IRDEC is pulled to ground level.

  • Page 51: Controlhead Model For Gm398

    - numerical information e.g. channel number, select code, call address name. To control the LEDs and the LCD, and to communicate with the host radio the controlhead uses the Motorola 68HC11K4 microprocessor. Power Supplies The power supply to the controlhead is taken from the host radio’s FLT A+ voltage via connector J0801 pin 3.

  • Page 52: Microprocessor Circuit

    U0861 via line 5 SOURCE and transistor Q0866 and the controlhead’s microprocessor starts execution. Microprocessor Circuit The controlhead uses the Motorola 68HC11K4 microprocessor (µP) (U0871) to control the LEDs and the LCD and to communicate with the host radio. RAM and ROM are contained within the microprocessor itself.

  • Page 53: Keypad Keys

    Controlhead Model for GM398 2-11 When the controlhead µP wants to communicate to the host radio, the µP brings request line CH REQUEST to a logic “0” via µP pin 8. This switches on Q0852, which pulls line ON OFF CONTROL high through diode D0852.

  • Page 54: Liquid Crystal Display (Lcd)

    2-12 Controlhead Model for GM398 The back light for the LCD module uses a similar circuitry. The only differences are that µP port PH2 controls the back light brightness and that the LEDs are located on the LCD module which is connected via J0821.

  • Page 55: Speaker (Remote Mount Configuration Only)

    Controlhead Model for GM398 2-13 Line PTT IRDEC (J0811-6) is used to key up the radio’s transmitter. While the PTT button on a connected microphone is released, line PTT IRDEC is pulled to +5 volts level by R0880. Transistor Q0871 is switched on and causes a low at µP port PA2. When the PTT button is pressed, signal PTT IRDEC is pulled to ground level.
  • Page 56 2-14 Controlhead Model for GM398 THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 57: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Controlhead GM328 Troubleshooting Flow Chart On/Off Radio cannot be switched on via ON/OFF/Volume Knob Check / Replace R0823 Pin TAB R0822 / VR0822 / = 5V ? D0822 Press and hold On/Off/Volume Knob R0823 Pin TAB1...

  • Page 58: Microprocessor

    Controlhead GM328 Troubleshooting Flow Chart Microprocessor Power Up Alert Tone is OK but volume knob does not operate and no indicator is on EXTAL Check / Replace U0831 Pin 31 R0831 / U0833 / U0831 = 8.00 MHz ? RESET...

  • Page 59: Controlhead Gm338 Troubleshooting Flow Chart

    Controlhead GM338 Troubleshooting Flow Chart Controlhead GM338 Troubleshooting Flow Chart On/Off Radio cannot be switched on via ON/OFF/Volume Knob Check / Replace R0823 Pin TAB R0822 / VR0822 / = 5V ? D0822 / C0822 Press and hold On/Off/Volume Knob R0823 Pin TAB1 Check / Replace when pressed...

  • Page 60: Microprocessor

    Controlhead GM338 Troubleshooting Flow Chart Microprocessor Power Up Alert Tone is OK but volume knob does not operate and no indicator is on EXTAL Check / Replace U0831 Pin 31 R0831 / U0833 / U0831 = 8.00 MHz ? RESET Check / Replace TP0833 C0833 / R0832 / U0831...

  • Page 61: Display

    Controlhead GM338 Troubleshooting Flow Chart Display Power Up Alert Tone is OK, volume knob does operate, indicator/backlight is on but nothing on display V5 (against 5V) TP0973 between Check LCD Assembly -6V and -7V ? Activity on Check for shortage Address &...

  • Page 62: Backlight

    Controlhead GM338 Troubleshooting Flow Chart Backlight Power Up Alert Tone is OK, volume knob does operate, indicator/display is on but no backlight U0831 Pin 58 Check for shortage is toggling ? U0831 Base of Check / Replace Q0934 R0847 / C0843 / R0943 >...

  • Page 63: Controlhead Gm398 Troubleshooting Flow Chart

    Controlhead GM398 Troubleshooting Flow Chart Controlhead GM398 Troubleshooting Flow Chart On/Off Radio can not be switched on via ON/OFF/Volume Knob R0854 Check / Replace Pin TAB R0855 / VR0855 / D0855 = 5V? C0856 Press and hold On/Off/ Volume Knob R0854 Pin TAB1 Check / Replace...

  • Page 64: Microprocessor

    Controlhead GM398 Troubleshooting Flow Chart Microprocessor Power Up Alert Tone is audible on external speaker but volume knob does not operate and no indicators are on TP0876 =5V ? U0871 TP0866 Pin 73 EXTAL = 8 MHz = 0V Check / Replace Check / Replace R0866 / C0866 / R0873 / U0873 /...

  • Page 65: Microprocessor (Cont.)

    Controlhead GM398 Troubleshooting Flow Chart Microprocessor (cont.) Measure with scope while rotating Volume Pot Data Signal Check on J0801 Radio Controller Pin 5 BUS+ Data Signal Check / Replace on TP0877 R0888 / R0889 SCI_RX Data Signal Check / Replace on TP0878 U0871 SCI_TX...

  • Page 66: Display

    3-10 Controlhead GM398 Troubleshooting Flow Chart Display Power Up Alert Tone is audible, volume knob does operate, indicator/backlight is on but nothing is seen on the display. TP0973 Voltage Sense Check / Replace between LCD Module 2V and 2.4V Activity on Address &...

  • Page 67: Keypad Backlight

    Controlhead GM398 Troubleshooting Flow Chart 3-11 Keypad Backlight Power Up Alert Tone is audible, volume knob does operate, display is on but no keypad backlight. Check for shortage U0871 Pin 25 U0871 is toggling ? Check / Replace Base of Q0943 R0945 / C0943 / R0947 >...

  • Page 68: Display Backlight

    3-12 Controlhead GM398 Troubleshooting Flow Chart Display Backlight Power Up Alert Tone is audible, volume knob does operate, display is on but no display backlight. Check for shortage U0871 Pin 24 U0871 is toggling ? Check / Replace Base of Q0963 R0965 / C0963 / R0967 >...

  • Page 69: Allocation Of Schematics And Circuit Boards

    Section 4 CONTROLHEAD PCBS / SCHEMATICS / PARTS LISTS Allocation of Schematics and Circuit Boards Table 4-1 Controlhead Diagrams and Parts Lists PCB : Controlhead GM328 Page 4-3 8486146B07 Main Board Top Side Page 4-3 8486146B07 Main Board Bottom Side...
  • Page 70 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 89: December

    GM328/GM338/GM398 Mobile Radios Controller Service Information Issue: December, 2003...
  • Page 90 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 91 Table of Contents Section 1 Theory of Operation 1.0 Controller Circuits ....................1-1 1.1 Overview......................1-1 1.2 General......................1-1 1.3 Radio Power Distribution ................1-2 1.4 Electronic ON/OFF ..................1-4 1.5 Emergency .....................1-4 1.6 Mechanical ON/OFF..................1-5 1.7 Ignition ......................1-5 1.8 Microprocessor Clock Synthesizer ..............1-5 1.9 Serial Peripheral Interface (SPI)..............1-6 1.10 SBEP Serial Interface..................1-7 1.11 General Purpose Input/Output................1-7 1.12 Normal Microprocessor Operation..............1-8...
  • Page 92 Section 3 Controller Schematics / Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............3-1 1.1 Controller Circuits ................... 3-1 1.2 Voice Storage Facility..................3-1 2.0 Controller T5 / Schematic Diagrams..............3-3 Controller T5 Schematic Diagram - Controller Overall ........... 3-3 Controller T5 Schematic Diagram - Supply Voltage ..........

  • Page 93: Theory Of Operation

    MUX ICs, the On/Off circuit, and general purpose Input/Output circuitry. The controller uses the Motorola 68HC11FL0 microprocessor (U0101). In addition to the microprocessor, the controller has 3 external memory devices. The 3 memory devices consist of a 32KByte SRAM (U0122), a 512KByte FLASH EEPROM (U0121), and a 16KByte EEPROM (U0111).

  • Page 94: Radio Power Distribution

    Controller Circuits External To Synthesizer Microphone Internal Microphone 16.8 MHz Reference Clock Audio/Signalling from Synthesizer Architecture External Speaker Recovered Audio Audio ASFIC_CMP Internal from Synthesizer Speaker Section (5V_RF) µP Clock To RF Section SCI to Accessory & Controlhead Digital Connector Architecture HC11FL0 EEPROM...
  • Page 95 Controller Circuits Transistor Q0681 and resistors R0681 / R0682 divide the regulated 9.3V down to about 6 volts. This voltage supplies the 5V regulator, located on the RF section. By reducing the supply voltage of the regulator, the power dissipation is divided between the RF section and the controller section. The voltage VSTBY, which is derived directly from the supply voltage by components R0621 and VR0621, is used to buffer the internal RAM.

  • Page 96: Electronic On/Off

    Controller Circuits Electronic ON/OFF The radio has circuitry which allows radio software and/or external triggers to turn the radio on or off without direct user action. For example, automatic turn on when ignition is sensed and off when ignition is off. Q0661 is used to provide INT SW B+ to the various radio circuits and to enable the voltage regulators via transistor Q0641.

  • Page 97: Mechanical On/Off

    Controller Circuits Mechanical ON/OFF This refers to the typical On/Off/Volume knob, located on the controlhead, and which turns the radio on and off. If the radio is turned off and the On/Off/Volume knob is pressed, line ON OFF CONTROL (J0401 pin 11) goes high and switches the radio’s voltage regulators on as long as the button is pressed.

  • Page 98: Serial Peripheral Interface (Spi)

    Controller Circuits The ASFIC CMP synthesizer loop uses C0245, C0246 and R0241 to set the switching time and jitter of the clock output. If the synthesizer cannot generate the required clock frequency it will switch back to its default 3.6864MHz output. Because the ASFIC CMP synthesizer and the µP system will not operate without the 16.8 MHz reference clock it (and the voltage regulators) should be checked first in debugging the system.

  • Page 99: Sbep Serial Interface

    Controller Circuits 1.10 SBEP Serial Interface The SBEP serial interface allows the radio to communicate with the Customer Programming Software (CPS), or the Universal Tuner via the Radio Interface Box (RIB). This interface connects to the microphone connector via controlhead connector (J0401-8) and to the accessory connector J0501-17 and comprises BUS+.

  • Page 100: Normal Microprocessor Operation

    Controller Circuits 1.12 Normal Microprocessor Operation For this radio, the µP is configured to operate in one of two modes, expanded and bootstrap. In expanded mode the µP uses external memory devices to operate, whereas in bootstrap operation the µP uses only its internal memory. In normal operation of the radio the µP is operating in expanded mode as described below.
  • Page 101 Controller Circuits There are 8 analogue to digital converter ports (A/D) on U0101. They are labelled within the device block as PE0-PE7. These lines sense the voltage level ranging from 0 to 5V of the input line and convert that level to a number ranging from 0 to 255 which can be read by the software to take appropriate action.

  • Page 102: Flash Electronically Erasable Programmable Memory(Flash Eeprom)1-10

    1-10 Controller Circuits 1.13 FLASH Electronically Erasable Programmable Memory(FLASH EEPROM) The 512KByte FLASH EEPROM (U0121) contains the radio’s operating software. This software is common to all open architecture radios within a given model type. For example Trunking radios may have a different version of software in the FLASH EEPROM than a non Trunking radio. This is, as opposed to the codeplug information stored in EEPROM (U0111) which could be different from one user to another in the same company.

  • Page 103: Controller Board Audio And Signalling Circuits

    Controller Board Audio and Signalling Circuits 1-11 Controller Board Audio and Signalling Circuits General - Audio Signalling Filter IC with Compander (ASFIC CMP) The ASFIC CMP (U0221) used in the controller has 4 functions; 1) RX/TX audio shaping, i.e. filtering, amplification, attenuation 2) RX/TX signalling, PL/DPL/HST/MDC/MPT 3) Squelch detection 4) Microprocessor clock signal generation (see Microprocessor Clock Synthesizer Description).
  • Page 104 1-12 Controller Board Audio and Signalling Circuits 2.2.1 Mic/Data Input Path The radio supports 2 distinct microphone paths known as internal (from controlhead) and external mic (from accessory connector J0501-2) and an auxiliary path (FLAT TX AUDIO, from accessory connector J0501-5). The microphones used for the radio require a DC biasing voltage provided by a resistive network.
  • Page 105 Controller Board Audio and Signalling Circuits 1-13 The ASFIC has an internal AGC that can control the gain in the mic audio path. The AGC can be disabled / enabled by the µP. Another feature that can be enabled or disabled in the ASFIC is the VOX.

  • Page 106: Transmit Signalling Circuits

    1-14 Controller Board Audio and Signalling Circuits Transmit Signalling Circuits Refer to 1-4 for reference for the following sections. SUMMER 5-3-2 STATE HIGH SPEED ENCODER CLOCK IN SPLATTER (HSIO) FILTER DTMF MICRO ENCODER CONTROLLER U0101 ASFIC_CMP U0221 LOW SPEED ENCODER SUMMER CLOCK IN (LSIO)
  • Page 107 Controller Board Audio and Signalling Circuits 1-15 This drives a tone generator inside U0221 which generates a staircase approximation to a PL sine wave or DPL data pattern. This internal waveform is then low-pass filtered and summed with voice or data. The resulting summed waveform then appears on U0221-40 (MOD IN), where it is sent to the RF board as previously described for transmit audio.

  • Page 108: Receive Audio Circuits

    1-16 Controller Board Audio and Signalling Circuits Receive Audio Circuits Refer to 1-5 for reference for the following sections. ACCESSORY CONNECTOR FLT/FLAT RX AUDIO J0501 AUDIO SPKR + EXTERNAL SPKR - U0271 SPEAKER SPKR+ SPKR- CONTROLHEAD CONNECTOR INTERNAL SPEAKER J0401 HANDSET AUDIO URX OUT...
  • Page 109 Controller Board Audio and Signalling Circuits 1-17 SQ DET is used to determine all audio mute / unmute decisions except for Conventional Scan. In this case CH ACT is a pre-indicator as it occurs slightly faster than SQ DET. 2.4.2 Audio Processing and Digital Volume Control The receiver audio signal enters the controller section from the IF IC on DISC AUDIO.
  • Page 110 1-18 Controller Board Audio and Signalling Circuits If the voltage is between 3.3 and 6.4V, the device will be active but has its input (U0273-1/9) off. This is a mute condition which is used to prevent an audio pop when the PA is enabled. The SPK+ and SPK- outputs of the audio PA have a DC bias which varies proportionately with FLT A+ (U0271-7).

  • Page 111: Receive Signalling Circuits

    Controller Board Audio and Signalling Circuits 1-19 Receive Signalling Circuits Refer to 1-6 for reference for the following sections. DATA FILTER HSIO LIMITER AND DEEMPHASIS MICRO CONTROLLER DISC DET AUDIO ASFIC_CMP U0101 DISCRIMINATOR AUDIO U0221 FROM RF SECTION LSIO (IF IC) FILTER LIMITER PLCAP2...

  • Page 112: Voice Storage (Optional)

    1-20 Controller Board Audio and Signalling Circuits The output of the generator is summed into the audio chain just after the RX audio de-emphasis block. Inside U0221 the tone is amplified and filtered, then passed through the 8-bit digital volume attenuator, which is typically loaded with a special value for alert tone audio.

  • Page 113: Troubleshooting Charts

    Section 2 TROUBLESHOOTING CHARTS Controller Troubleshooting Chart Controller Check Press PTT. No RF Output Before replacing Power. Power Up Not able to MCU, check SPI Alert Tone program Audio AUDIO clock, SPI data, J0501 RF Board ICs at Audio PA and RF IC select Audio at Pin (U0271)
  • Page 114 Controller Troubleshooting Chart THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 115 Section 3 CONTROLLER SCHEMATICS / PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits This Chapter shows the Schematics and the Parts Lists for the Controller circuits. Voice Storage Facility The Voice Storage is fitted on all MPT radios GM338/GM398 as standard. The schematics, component layout and parts list for these circuits are shown in this chapter.
  • Page 116 Allocation of Schematics and Circuit Boards Table 3-3 Controller T9 Diagrams and Parts Lists Controller T9 used on PCB : T9 on 8485670Z03 UHF B1, 1-25W SCHEMATICS Controller Overall Page 3-12 Supply Voltage Page 3-13 Audio Page 3-14 Page 3-16 Microprocessor Page 3-18 Voice Storage (if fitted)
  • Page 141 GM328/GM338/GM398 Mobile Radios VHF (136-174MHz) Service Information Issue: December, 2003...
  • Page 142 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 143 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM328/GM338/GM398 Model Chart ..............1-1 2.0 Technical Specifications ..................1-2 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 VHF (136-174 MHz) Receiver................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and High Intermediate Frequency (IF)..........2-2...
  • Page 144 Section 4 VHF PCBs/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 VHF 1-25W PCBs / Schematics / Parts Lists ............4-3 VHF (136-174 MHz) 1-25W 8486172B06 Top Side ..........4-3 VHF (136-174 MHz) 1-25W 8486172B06 Bottom Side......... 4-4 VHF (136-174 MHz) Power Amplifier 1-25W............

  • Page 145: Model Chart And Technical Specifications

    GM328 136-174 MHz 1-25W AZM25KHF9AA5 GM338 136-174 MHz 1-25W AZM25KHN9AA8 GM398 136-174 MHz 1-25W Item Description GCN6112_ GM328 Control Head Direct Mount GCN6114_ GM338 Control Head Direct Mount GCN6115_ GM398 Control Head Direct Mount IMUD6010_ Tanapa WM 136-174 MHz 1-25W IMUD6023_...

  • Page 146: Technical Specifications

    59mm x 179mm x 198mm (25 - 45W) (add 9mm for Volume Knob) Dimensions: H x W x D (mm) Depth excluding knobs GM398 72mm x 185mm x 188mm (add 7mm for Volume Knob) Weight GM328/GM338 1400 g Weight GM398 1500 g Sealing: Withstands rain testing per...
  • Page 147 Technical Specifications Transmitter 136-174 *Frequencies - Full Bandsplit Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.5 ppm (-30°C to +60°C, +25° Ref.) Power 1-25W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...
  • Page 148 Technical Specifications THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 149: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the VHF circuits in the radio. For details of the theory of operation and troubleshooting for the the associated Controller circuits refer to the Controller Section of this manual. VHF (136-174 MHz) Receiver Receiver Front-End The receiver is able to cover the VHF range from 136 to 174 MHz.

  • Page 150: Front-End Band-Pass Filters & Pre-Amplifier

    VHF (136-174 MHz) Receiver There are two 2-pole 44.85 MHz crystal filters in the high-IF section and 2 pairs of 455 kHz ceramic filters in the low-IF section to provide the required adjacent channel selectivity. The correct pair of ceramic filters for 12.5 or 25kHz channel spacing is selected via control line BWSELECT. The second IF at 455 kHz is mixed, amplified and demodulated in the IF IC.

  • Page 151: Low Intermediate Frequency (If) And Receiver Back End

    VHF (136-174 MHz) Transmitter Power Amplifier (PA) 25 W Low Intermediate Frequency (IF) and Receiver Back End The 44.85 MHz high-IF signal from the second IF amplifier feeds the IF IC (U3101) at pin 1. Within the IF IC, the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator (2nd LO) to produce the low-IF signal at 455 kHz.

  • Page 152: First Power Controlled Stage

    VHF (136-174 MHz) Transmitter Power Amplifier (PA) 25 W First Power Controlled Stage The first stage (U3401) is a 20dB gain integrated circuit containing two LDMOS FET amplifier stages. It amplifies the RF signal from the VCO (TXINJ). The output power of stage U3401 is controlled by a DC voltage applied to pin 1 from the op-amp U3402-1, pin 1.

  • Page 153: Directional Coupler

    VHF (136-174 MHz) Transmitter Power Amplifier (PA) 25 W Directional Coupler The directional coupler is a microstrip printed circuit, which couples a small amount of the forward power delivered by Q3441. The coupled signal is rectified by D3451. The DC voltage is proportional to the RF output power and feeds the RFIN port of the PCIC (U3501 pin 1).

  • Page 154: Vhf (136-174 Mhz) Frequency Synthesis

    VHF (136-174 MHz) Frequency Synthesis VHF (136-174 MHz) Frequency Synthesis The frequency synthesizer subsystem consists of the reference oscillator (Y3261 or Y3263), the Low Voltage Fractional-N synthesizer (LVFRAC-N, U3201), and the voltage-controlled oscillators and buffer amplifiers (U3301, Q3301-2 and associated circuitry). Reference Oscillator The reference oscillator (Y3263) contains a temperature compensated crystal oscillator with a frequency of 16.8 MHz.

  • Page 155: Voltage Controlled Oscillator (Vco)

    VHF (136-174 MHz) Frequency Synthesis A voltage of 5V applied to the super filter input (U3201 pin 30) supplies an output voltage of 4.5 VDC (VSF) at pin 28. It supplies the VCO, VCO modulation bias circuit (via R3363) and the synthesizer charge pump resistor network (R3251, R3252).

  • Page 156: Synthesizer Operation

    VHF (136-174 MHz) Frequency Synthesis The VCOBIC together with the Fractional-N synthesizer (U3201) generates the required frequencies in both the transmit and receive modes. The TRB line (U3301 pin 19) determines which tank circuits and internal buffers are to be enabled. A high level on TRB enables the TX tank and TX output (pin 10), and a low enables the RX tank and RX output (pin 8).
  • Page 157 VHF (136-174 MHz) Frequency Synthesis In order to modulate the PLL, the two spot modulation method is utilized. Via U3201 pin 10 (MODIN), the audio signal is applied to both the A/D converter (low frequency path) as well as the balance attenuator (high frequency path).
  • Page 158 2-10 VHF (136-174 MHz) Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 159: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...

  • Page 160: Troubleshooting Flow Chart For Receiver

    Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J3401 Trace IF signal from C3035 to Q3101. IF Signal at Check for bad XTAL IF signal at Q3102 C3035? filter collector? Before replacing U3101, check U3101 voltages RF Signal at...
  • Page 161 Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 1 of 3) START No or too low Power when keyed Check if Pressure Pad closes S3440 Check Components between Current Q3441 and RF Output, >500mA & <4A >4A increase Antenna Switch...
  • Page 162 Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 2 of 3) Check PA Stages No or too low Power when keyed DC Voltage If U3201 Pin 2 is high, at U3501 replace PCIC Pin 23 =0? Check Resistive Net- >6 <2V...

  • Page 163: Troubleshooting Flow Chart For 25W Transmitter

    Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 3 of 3 Check Final PA Stage Supply Voltage Bias 2 DC Voltage at Replace Q3441 TP3406? 1-4V Check Components ASFIC RF Voltage between ASFIC and U0221 Pin 6 Check FGU (U3301) at TP3401 Q3441 before...

  • Page 164: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer 5V at Check 5V U3201 pins 5, Start Regulator 20, 34 & 36 U3211, R3211 Visual Correct check of the Problem Board OK? Is 16.8MHz 16.8MHz Replace Signal at signal at U3201 Is U3201 U3201 Pin...

  • Page 165: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP3001 Visual check Visual check Correct of board of board Problem Make sure U3211 is working correctly and runner 5V DC at U3301...
  • Page 166 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 167 Section 4 VHF PCBS/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The VHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the VHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 168 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 170 C0341 C3505...
  • Page 179 C3233...
  • Page 187 GM328/GM338/GM398 Mobile Radios UHF (403-470MHz) Service Information Issue: December, 2003...
  • Page 188 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 189 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM328/GM338/GM398 Model Chart ..............1-1 2.0 Technical Specifications ..................1-2 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 UHF (403-470 MHz) Receiver ................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and High Intermediate Frequency (IF)..........2-2...
  • Page 190 Section 4 UHF PCB/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 UHF 1-25W PCBs / Schematics / Parts Lists ............4-3 UHF (403-470 MHz) 1-25W 8485670Z02 Top Side ..........4-3 UHF (403-470 MHz) 1-25W 8485670Z02 Bottom Side......... 4-4 UHF (403-470 MHz) Power Amplifier 1 - 25W ............

  • Page 191: Model Chart And Technical Specifications

    GM328 403-470 MHz 1-25W AZM25RHF9AA5 GM338 403-470 MHz 1-25W AZM25RHN9AA8 GM398 403-470 MHz 1-25W Item Description GCN6112_ GM328 Control Head Direct Mount GCN6114_ GM338 Control Head Direct Mount GCN6115_ GM398 Control Head Direct Mount IMUE6021_ Tanapa WM 403-470 MHz 1-25W IMUE6039_...

  • Page 192: Technical Specifications

    59mm x 179mm x 198mm (25 - 45W) (add 9mm for Volume Knob) Dimensions: H x W x D (mm) Depth excluding knobs GM398 72mm x 185mm x 188mm (add 8mm for Volume Knob) Weight: GM328/GM338 1400 g Weight: GM398 1500 g Sealing: Withstands rain testing per...
  • Page 193 Technical Specifications Transmitter *Frequencies - Full Bandsplit UHF 403-470 MHz Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.0 ppm (-30°C to +60°C, +25° Ref.) Power 1-25W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...
  • Page 194 Technical Specifications Receiver Audio Response (300 - 3000Hz @ 20/25kHz) +1 to -3 dB (300 - 2550Hz @12.5kHz) -57 dBm <1 GHz Conducted Spurious Emission (ETS) -47 dBm >1 GHz *Availability subject to the laws and regulations of individual countries.

  • Page 195: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the UHF circuits in the radio. For details of the theory of operation and troubleshooting for the the associated Controller circuits refer to the Controller Section of this manual. UHF (403-470 MHz) Receiver Receiver Front-End The receiver is able to cover the UHF range from 403 to 470 MHz.

  • Page 196: Front-End Band-Pass Filters & Pre-Amplifier

    UHF (403-470 MHz) Receiver There are two 2-pole 44.85 MHz crystal filters in the high-IF section and 2 pairs of 455 kHz ceramic filters in the low-IF section to provide the required adjacent channel selectivity .The correct pair of ceramic filters for 12.5 or 25KHz channel spacing is selected via control line BWSELECT. The second IF at 455 kHz is mixed, amplified and demodulated in the IF IC.

  • Page 197: Low Intermediate Frequency (If) And Receiver Back End

    UHF (403-470 MHz) Transmitter Power Amplifier (PA) 25 W Low Intermediate Frequency (IF) and Receiver Back End The 44.85 high IF signal from the second IF amplifier feeds the IF IC (U3101) at pin1. Within the IF IC the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator (2nd LO) to produce the low IF signal at 455 kHz.

  • Page 198: First Power Controlled Stage

    UHF (403-470 MHz) Transmitter Power Amplifier (PA) 25 W First Power Controlled Stage The first stage (U4401) is a 20dB gain integrated circuit containing two LDMOS FET amplifier stages. It amplifies the RF signal from the VCO (TXINJ). The output power of stage U4401 is controlled by a DC voltage applied to pin 1 from the op-amp U4402-1, pin 1.

  • Page 199: Directional Coupler

    UHF (403-470 MHz) Transmitter Power Amplifier (PA) 25 W Directional Coupler The directional coupler is a microstrip printed circuit, which couples a small amount of the forward power delivered by Q4441. The coupled signal is rectified by D4451. The DC voltage is proportional to the RF output power and feeds the RFIN port of the PCIC (U4501 pin 1).
  • Page 200 UHF (403-470 MHz) Frequency Synthesis U4502 is a temperature-sensing device, which monitors the circuit board temperature in the vicinity of the transmitter driver and final devices, and provides a DC voltage to the PCIC (TEMP, pin 30) proportional to temperature. If the DC voltage produced exceeds the set threshold in the PCIC, the transmitter output power will be reduced so as to reduce the transmitter temperature.

  • Page 201: Uhf (403-470 Mhz) Frequency Synthesis

    UHF (403-470 MHz) Frequency Synthesis Fractional-N Synthesizer The LVFRAC-N synthesizer IC (U4201) consists of a pre-scaler, a programmable loop divider, control divider logic, a phase detector, a charge pump, an A/D converter for low frequency digital modulation, a balance attenuator to balance the high frequency analogue modulation and low frequency digital modulation, a 13V positive voltage multiplier, a serial interface for control, and finally a super filter for the regulated 5 volts.
  • Page 202 UHF (403-470 MHz) Frequency Synthesis Voltage Controlled Oscillator (VCO) The Voltage Controlled Oscillator (VCO) consists of the VCO/Buffer IC (VCOBIC, U4301), the TX and RX tank circuits, the external RX buffer stages, and the modulation circuitry. AUX3 (U4201 Pin 2) U4201 Pin 32 Prescaler Out TRB IN...

  • Page 203: Synthesizer Operation

    UHF (403-470 MHz) Frequency Synthesis The external RX buffers (Q4332) are enabled by a high at U4201 pin 3 (AUX4) via transistor switch Q4333. In TX mode the modulation signal (VCOMOD) from the LVFRAC-N synthesizer IC (U4201 pin41) is applied modulation circuitry CR4321, R4321, R4322 and C4324, which modulates the TX VCO frequency via coupling capacitor C4321.
  • Page 204 2-10 UHF (403-470 MHz) Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 205: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...

  • Page 206: Troubleshooting Flow Chart For Receiver

    Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J4401 Trace IF signal from C3101 to IF Signal at signal at Q3102 Q3101. Check for C3101? collector? bad XTAL filter. Before replacing U3101, check U3101 voltages.

  • Page 207: Troubleshooting Flow Chart For 25W Transmitter

    Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 1 of 3) START No or too low Power when keyed Check if Pressure Pad closes S5440 Check Components between Current Q4441 and RF Output, >500mA & <4A >4A increase Antenna Switch...
  • Page 208 Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 2 of 3) Check PA Stages No or too low Power when keyed DC Voltage If U4201 Pin 2 is high, at U4501 replace PCIC Pin 23 =0? Check Resistive Net- >6 Voltage at...
  • Page 209 Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 3 of 3 Check Final PA Stage Supply Voltage Bias 2 DC Voltage at Replace Q4441 TP4406? 1-4V Check Components ASFIC RF Voltage between ASFIC and U0221 Pin 6 Check FGU (U4301) at TP4401 Q4441 before...

  • Page 210: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Start Check 5V at U4201 Regulator pins 5, 20, 34 U4211 & 36 Visual Correct check of the Problem Board Check D4201, C4202, C4203, & C4206 16.8MHz 16.8MHz Replace U4201 Pin 47 signal at Signal at U4201 at pin 6 of...

  • Page 211: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP4003 Visual check Visual check Correct of board of board Problem Make sure Synthesizer is 4.5V DC 4.5V DC...
  • Page 212 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 213 Section 4 UHF PCB/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The UHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the UHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 214 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 215 UHF 1-25W PCBs / Schematics / Parts Lists UHF 1-25W PCBs / Schematics / Parts Lists J0451 R4221 C0251 R0257 R4222 C4210 C4221 C0256 C4225 C3145 R4224 L4221 R4223 C0211 C4289 L4201 C4216 C4230 C0212 R0256 C4213 Y3102 C4236 FL3114 R3145 U0251 R0252...
  • Page 216 UHF 1-25W PCBs / Schematics / Parts Lists C3146 C3152 TP4202 D4261 C4262 R0208 C4263 R4203 C4207 C4203 C0205 C3147 R4262 C4241 C0267 TP4201 R4201 R0265 C0255 J0401 R3152 R3146 C4202 R0412 R0441 R0267 R4241 C0492 R0266 R3147 C3151 R4204 C0265 D4201 C0254...
  • Page 225 TOP METAL TOP METAL...
  • Page 235 GM328/GM338/GM398 Mobile Radios UHF Band 2 (450-527MHz) Service Information Issue: December, 2003...
  • Page 236 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 237 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM328/GM338/GM398 Model Chart ..............1-1 2.0 Technical Specifications ..................1-2 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 UHF (450-527 MHz) Receiver ................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and High Intermediate Frequency (IF)..........2-2...
  • Page 238 Section 4 UHF PCB/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 UHF Band 2 1-25W PCBs / Schematics / Parts List..........4-3 UHF Band 2 (450-527 MHz) 1-25W 8485671Z03 Top Side........4-3 UHF Band 2 (450-527 MHz) 1-25W 8485671Z03 Bottom Side ......

  • Page 239: Model Chart And Technical Specifications

    GM328 450-527 MHz 1-25W AZM25SHF9AA5 GM338 450-527 MHz 1-25W AZM25SHN9AA8 GM398 450-527 MHz 1-25W Item Description GCN6112_ GM328 Control Head Direct Mount GCN6114_ GM338 Control Head Direct Mount GCN6115_ GM398 Control Head Direct Mount IMUE6022_ Tanapa WM 450-527 MHz 1-25W IMUE6043...

  • Page 240: Technical Specifications

    59mm x 179mm x 198mm (25 - 45W) (add 9mm for Volume Knob) Dimensions: H x W x D (mm) Depth excluding knobs GM398 72mm x 185mm x 188mm (add 8mm for Volume Knob) Weight GM328/GM338 1400 g Weight GM398 1500 g Sealing: Withstands rain testing per...
  • Page 241 Technical Specifications Transmitter *Frequencies - Full Bandsplit UHF 450-527 MHz Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.0 ppm (-30°C to +60°C, +25° Ref.) Power 1-25W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...
  • Page 242 Technical Specifications Receiver Audio Response (300 - 3000Hz @ 20/25kHz) +1 to -3 dB (300 - 2550Hz @12.5kHz) -57 dBm <1 GHz Conducted Spurious Emission (ETS) -47 dBm >1 GHz *Availability subject to the laws and regulations of individual countries.

  • Page 243: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the UHF circuits in the radio. For details of the theory of operation and troubleshooting for the the associated Controller circuits refer to the Controller Section of this manual. UHF (450-527 MHz) Receiver Receiver Front-End The receiver is able to cover the UHF range from 450 to 527 MHz.

  • Page 244: Front-End Band-Pass Filters & Pre-Amplifier

    UHF (450-527 MHz) Receiver There are two 2-pole 44.85 MHz crystal filters in the high-IF section and 2 pairs of 455 kHz ceramic filters in the low-IF section to provide the required adjacent channel selectivity .The correct pair of ceramic filters for 12.5 or 25 kHz channel spacing is selected via control line BWSELECT. The second IF at 455 kHz is mixed, amplified and demodulated in the IF IC.

  • Page 245: Low Intermediate Frequency (If) And Receiver Back End

    UHF (450-527 MHz) Transmitter Power Amplifier (PA) 25 W Low Intermediate Frequency (IF) and Receiver Back End The 44.85 high IF signal from the second IF amplifier feeds the IF IC (U3101) at pin1. Within the IF IC the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator (2nd LO) to produce the low IF signal at 455 kHz.

  • Page 246: First Power Controlled Stage

    UHF (450-527 MHz) Transmitter Power Amplifier (PA) 25 W First Power Controlled Stage The first stage (U5401) is a 20dB gain integrated circuit containing two LDMOS FET amplifier stages. It amplifies the RF signal from the VCO (TXINJ). The output power of stage U5401 is controlled by a DC voltage applied to pin 1 from the op-amp U5402-1, pin 1.

  • Page 247: Directional Coupler

    UHF (450-527 MHz) Transmitter Power Amplifier (PA) 25 W Directional Coupler The directional coupler is a microstrip printed circuit, which couples a small amount of the forward power delivered by Q5441. The coupled signal is rectified by D5451. The DC voltage is proportional to the RF output power and feeds the RFIN port of the PCIC (U5501 pin 1).

  • Page 248: Uhf (450-527 Mhz) Frequency Synthesis

    UHF (450-527 MHz) Frequency Synthesis U5502 is a temperature-sensing device, which monitors the circuit board temperature in the vicinity of the transmitter driver and final devices, and provides a DC voltage to the PCIC (TEMP, pin 30) proportional to temperature. If the DC voltage produced exceeds the set threshold in the PCIC, the transmitter output power will be reduced so as to reduce the transmitter temperature.

  • Page 249: Reference Oscillator

    UHF (450-527 MHz) Frequency Synthesis Fractional-N Synthesizer The LVFRAC-N synthesizer IC (U5201) consists of a pre-scaler, a programmable loop divider, control divider logic, a phase detector, a charge pump, an A/D converter for low frequency digital modulation, a balance attenuator to balance the high frequency analogue modulation and low frequency digital modulation, a 13V positive voltage multiplier, a serial interface for control, and finally a super filter for the regulated 5 volts.

  • Page 250: Voltage Controlled Oscillator (Vco)

    UHF (450-527 MHz) Frequency Synthesis Voltage Controlled Oscillator (VCO) The Voltage Controlled Oscillator (VCO) consists of the VCO/Buffer IC (VCOBIC, U5301), the TX and RX tank circuits, the external RX buffer stages, and the modulation circuitry. AUX3 (U5201 Pin 2) U5201 Pin 32 Prescaler Out TRB IN...

  • Page 251: Synthesizer Operation

    UHF (450-527 MHz) Frequency Synthesis The external RX buffers (Q5332) are enabled by a high at U5201 pin 3 (AUX4) via transistor switch Q5333. In TX mode the modulation signal (VCOMOD) from the LVFRAC-N synthesizer IC (U5201 pin41) is applied modulation circuitry CR5321, R5321, R5322 and C5324, which modulates the TX VCO frequency via coupling capacitor C5321.
  • Page 252 2-10 UHF (450-527 MHz) Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 253: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...

  • Page 254: Troubleshooting Flow Chart For Receiver

    Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J5401 Trace IF signal from C3101 to IF Signal at signal at Q3102 Q3101. Check for C3101? collector? bad XTAL filter. Before replacing U3101, check U3101 voltages.

  • Page 255: Troubleshooting Flow Chart For 25W Transmitter

    Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 1 of 3) START No or too low Power when keyed Check if Pressure Pad closes S5440 Check Components between Current Q5441 and RF Output, >500mA & <4A >4A increase Antenna Switch...
  • Page 256 Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 2 of 3) Check PA Stages No or too low Power when keyed DC Voltage If U5201 Pin 2 is high, at U5501 replace PCIC Pin 23 =0? Check Resistive Net- >6 Voltage at...
  • Page 257 Troubleshooting Flow Chart for 25W Transmitter Troubleshooting Flow Chart for 25W Transmitter (Sheet 3 of 3 Check Final PA Stage Supply Voltage Bias 2 DC Voltage at Replace Q5441 TP5406? 1-4V Check Components ASFIC RF Voltage between ASFIC and U0221 Pin 6 Check FGU (U5301) at TP5401 Q5441 before...

  • Page 258: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Start Check 5V at U5201 Regulator pins 5, 20, 34 U5211 & 36 Visual Correct check of the Problem Board Check D5201, C5202, C5203, & C5206 16.8MHz 16.8MHz Replace U5201 Pin 47 signal at Signal at U5201 at pin 6 of...

  • Page 259: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP5003 Visual check Visual check Correct of board of board Problem Make sure Synthesizer is 4.5V DC 4.5V DC...
  • Page 260 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 261 Section 4 UHF PCB/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The UHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the UHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 262 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 264 R 0 1 R 0 1 1 7...
  • Page 275 GM338/GM398 Mobile Radios Low Band Service Information Issue: December, 2003...
  • Page 276 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 277 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM338 Model Chart.....................1-1 2.0 Technical Specifications ..................1-2 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 Low Band Receiver....................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters and Pre-Amplifier ..........2-2 2.3 First Mixer and High Intermediate Frequency (IF)..........2-2 2.4 High Intermediate Frequency (IF) and Blanker Switches .......2-2 2.5 Low Intermediate Frequency (IF) and Receiver Back End......2-3...
  • Page 278 Section 4 Low Band PCBs/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 Low Band PCBs / Schematics / Parts Lists ............4-3 Low Band Range 1 (29.7-36.0 MHz) 8486206B06 Top Side ......... 4-3 Low Band Range 1 (29.7-36.0 MHz) 8486206B06 Bottom Side ......
  • Page 279 Low Band Range 1/2/3 - IF sheet 1 of 2 (for PC Boards 8486206B06, 8486207B05 & 8486908Z02) ....................4-38 Low Band Range 1/2/3 - IF sheet 2 of 2 (for PC Boards 8486206B06, 8486207B05 & 8486908Z02) ....................4-39 Low Band Range 1/2/3 - IF sheet 1 of 2 (for PC Boards 8486206B08, 8486207B07 & 8486908Z04) ....................4-40 Low Band Range 1/2/3 - IF sheet 2 of 2 (for PC Boards 8486206B08, 8486207B07 &...
  • Page 280 THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 281: Model Chart And Technical Specifications

    Section 1 MODEL CHART AND TECHNICAL SPECIFICATIONS GM338 Model Chart GM Series, Low Band Model Description AZM25BKF9AA5 GM338 29.7-36.0 MHz 40-60W AZM25CKF9AA5 GM338 36.0-42.0 MHz 40-60W AZM25DKF9AA5 GM338 42.0-50.0 MHz 40-60W Item Description X GCN6114_ Preferred Control Head Direct Mount IMUB6000_ Tanapa WM 29.7-36.0 MHz 40-60W IMUB6001_...

  • Page 282: Technical Specifications

    Technical Specifications Technical Specifications Data is specified for +25°C unless otherwise stated. General Specifications Channel Capacity GM338 Power Supply 13.2Vdc (10.8 - 15.6Vdc) Dimensions: H x W x D (mm) Depth excluding knobs GM338 60mm x 179mm x 250mm (45 - 60W) Weight GM338 2064 g Sealing:...
  • Page 283 Technical Specifications Transmitter Low Band Low Band 1 29.7-36.0 MHz *Frequencies - Full Bandsplit Low Band 2 36.0-42.0 MHz Low Band 3 42.0-50.0 MHz Channel Spacing 12.5/20/30 kHz Frequency Stability ±5 ppm (-30°C to +60°C, +25° Ref.) Power 40-60W ±2.5 @ 12.5 kHz Modulation Limiting ±5.0 @ 20/30 kHz -40 dB @ 12.5kHz...
  • Page 284 Technical Specifications THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 285: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the Low Band circuits in the radio. For details of the theory of operation and troubleshooting for the the associated Controller circuits refer to the Controller Section of this manual. Low Band Receiver Receiver Front-End The low band receiver, shown in Figure 2-1, is bandsplit into three ranges depending on radio...

  • Page 286: Front-End Band-Pass Filters And Pre-Amplifier

    Low Band Receiver There are two 2-pole 10.7 MHz crystal filters in the high-IF section and two switched pairs of 455 kHz ceramic filters in the low-IF section to provide the required adjacent channel selectivity.The second IF at 455 kHz is mixed, amplified and demodulated in the IF IC. The processing of the demodulated audio signal is performed by an audio processing IC located in the controller section.

  • Page 287: Low Intermediate Frequency (If) And Receiver Back End

    Low Band Receiver presented to the high-Q crystal filter FL1102, would cause ringing of the filter response, stretching an otherwise narrow impulse into a long and audible output waveform. Therefore, source follower stage Q1104 isolates the blanker switches from the crystal filters, providing a consistent source impedance via matching network L1106, L1107 and associated components.

  • Page 288: Transmitter Power Amplifier (Pa) 60 W

    Transmitter Power Amplifier (PA) 60 W AGC input pin 5 of U1601, reducing its gain and therefore the amount of noise pulses which are detected and processed. Transmitter Power Amplifier (PA) 60 W The radio’s 60W power amplifier (PA), shown in Figure 2-2, is a three-stage amplifier used to amplify the output from the VCO to the radio transmit level.

  • Page 289: Driver Stage

    Transmitter Power Amplifier (PA) 60 W Driver Stage The next stage is an LDMOS device (Q1401) providing a gain of 13dB. This device requires a positive gate bias and a quiescent current flow for proper operation. The voltage of the line MOSBIAS_1 is set during transmit mode by the PCIC pin 24, and fed to the gate of Q1401 via resistors R1402, R1447, R1449, R1458, R1459, and R1463.

  • Page 290: Power Control

    Transmitter Power Amplifier (PA) 60 W Power Control The transmitter uses the Power Control IC (PCIC, U1503) to control the power output of the radio. A differential DC amplifier U1502-1 compares the voltage drop across current-measuring resistor R1409, which is proportional to the transmitter final stage DC current, with the voltage drop across resistors R1508 and R1535, which is proportional to the current through transistor Q1503.

  • Page 291: Frequency Synthesis

    Frequency Synthesis Frequency Synthesis The frequency synthesizer subsystem, shown in Figure 2-3, consists of the reference oscillator crystal (Y1201), the Low Voltage Fractional-N synthesizer (LVFRAC-N, U1201), and the receive and transmit VCOs and buffers (Q1303 through Q1308 and associated components). LOCK LOCK (U0101 PIN 56) DATA (U0101 PIN 100)

  • Page 292: Voltage Controlled Oscillator (Vco) And Buffers

    Frequency Synthesis of 13 volts DC. U1201 pins 15 and 14 This multiplier is driven by two 1.05 MHz clock signals from (VMULTI1 and VMULTI2) which are 180 degree out of phase. Output LOCK (U1201-4) provides information about the lock status of the synthesizer loop. A high level at this output indicates a stable loop.

  • Page 293: Synthesizer Operation

    Frequency Synthesis The VCOs, together with Fractional-N synthesizer U1201, generates the required frequencies for transmit and receive modes. The TRB line (U1201, pin 2) determines which VCO/buffer circuit is to be enabled. A high level on TRB will turn on the transistors in U1378 to turn on via R1376, applying the 8.3 volt VSF source to the receiver VCO and first buffer.
  • Page 294 2-10 Frequency Synthesis To reduce synthesizer lock time when new frequency data has been loaded into the synthesizer the magnitude of the loop current is increased by enabling the IADAPT (U1201-45) for a certain software programmable time (Adapt Mode). The adapt mode timer is started by a low to high transient of the CSX line.

  • Page 295: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Audio at pin 8 Check Controller (in the case of no audio). of U1103? Or else go to “B” Spray or inject 10.7MHz into XTAL Filter FL1102.
  • Page 296 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J1401 Trace IF signal from IF Signal at IF signal at C1036 to Q1106. pin 2 of Q1106 collec- Check for bad U1051 tor?

  • Page 297: Troubleshooting Flow Chart For Transmitter

    Troubleshooting Flow Chart for Transmitter Troubleshooting Flow Chart for Transmitter START No or Low Power Out Check Pressure Pad Safefy and/or Switch Switch Circuitry > 1 A < 1 A DC Voltage @Drains of CURRENT Q1402 & Q1403 Look for <<18V pp short on RF @...

  • Page 298: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Check 5V Reg- 5V at U1201 ulator U1250, L1201 Start pins 5, 13, 20, & R1201 24 & 36 Visual Check D3201, C3203, Correct check of the C3205, & C3206 Problem Board OK? Is 16.8MHz...

  • Page 299: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO RX VCO TX VCO LOW OR NO RF SIGNAL LOW OR NO RF SIGNAL AT INPUT TO PA AT U1051 VISUAL CHECK VISUAL CHECK CORRECT OF BOARD OF BOARD PROBLEM MAKE SURE SYNTHESIZER IS WORKING CORRECTLY AND 8.5V DC AT...
  • Page 300 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 301 Section 4 LOW BAND PCBS/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The Low Band circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the Low Band circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 302 Allocation of Schematics and Circuit Boards Table 4-3 Low Band Range 3 (42-50MHz) Diagrams and Parts Lists PCB : 848608Z02 Main Board Top Side Page 4-7 848608Z02 Main Board Bottom Side Page 4-8 SCHEMATICS Power Amplifier 40 - 60W Page 4-19 Page 4-20 Voltage Controlled Oscillator Page 4-14...
  • Page 305 C1253...
  • Page 379 GM338 Mobile Radios VHF 45W Bipolar (136-174MHz) Service Information Issue: December, 2003...
  • Page 380 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 381 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM338 Model Chart.....................1-1 2.0 Technical Specifications ..................1-1 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 VHF (136-174 MHz) Receiver................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and 1st Intermediate Frequency (IF) ..........2-2 2.4 2nd Intermediate Frequency (IF) and Receiver Back End ......2-3 3.0 Transmitter Power Amplifier (PA) 45 W ...............2-3...
  • Page 382 Section 4 VHF PCB/Schematics/Parts List 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 VHF 25-45W PCB / Schematics / Parts List ............4-3 VHF (136-174 MHz) 25-45W 8486140B13 Top Side ..........4-3 VHF (136-174 MHz) 25-45W 8486140B13 Bottom Side........4-4 VHF (136-174 MHz) Power Amplifier 25-45W............

  • Page 383: Model Chart And Technical Specifications

    Section 1 MODEL CHART AND TECHNICAL SPECIFICATIONS GM338 Model Chart GM Series, VHF 136-174 MHz Model Description AZM25KKF9AA5 GM338 136-174 MHz 25-45W Item Description GCN6114_ GM338 Control Head Direct Mount IMUD6011_ Tanapa WM 136-174 MHz 25-45W RAD4198_ BNC 136-144 MHz, 1/4 Wave Roof Mount RAD4199_ BNC 146-150.8 MHz, 1/4 Wave Roof Mount RAD4200_...
  • Page 384 Technical Specifications Transmitter 136-174 *Frequencies - Full Bandsplit Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.5 ppm (-30°C to +60°C, +25° Ref.) Power 25-45W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...

  • Page 385: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the VHF circuits in the radio. For details of the theory of operation and troubleshooting for the the associated Controller circuits refer to the Controller Section of this manual. VHF (136-174 MHz) Receiver Receiver Front-End The receiver is able to cover the VHF range from 136 to 174 MHz.

  • Page 386: Front-End Band-Pass Filters & Pre-Amplifier

    VHF (136-174 MHz) Receiver There are two 2-pole 44.85 MHz crystal filters in the 1st IF section and 2 pairs of 455 kHz ceramic filters in the 2nd IF section to provide the required adjacent channel selectivity. The correct pair of ceramic filters for 12.5 or 25kHz channel spacing is selected via control line BWSELECT.

  • Page 387: 2Nd Intermediate Frequency (If) And Receiver Back End

    Transmitter Power Amplifier (PA) 45 W 2nd Intermediate Frequency (IF) and Receiver Back End The 44.85 MHz 1st IF signal from the second IF amplifier feeds the IF IC (U3101) at pin1. Within the IF IC, the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator (2nd LO) to produce the 2nd IF signal at 455 kHz.

  • Page 388: Power Controlled Stage

    Transmitter Power Amplifier (PA) 45 W Power Controlled Stage The first stage (U3401) is a 20 dB gain integrated circuit containing two LDMOS FET amplifier stages. It amplifies the RF signal from the VCO (TXINJ). The output power of stage U3401 is controlled by a dc voltage applied to pin 1 from the power control circuit (U3501 pin 4, with transistors Q3501 and Q3502 providing current gain and level-shifting).

  • Page 389: Antenna Switch

    Transmitter Power Amplifier (PA) 45 W Antenna Switch The antenna switch consists of two PIN diodes, D3471 and D3472. In the receive mode, both diodes are off. Signals applied at the antenna jack J3401 are routed, via the harmonic filter, through network L3472, C3474 and C3475, to the receiver input.

  • Page 390: Frequency Synthesis

    Frequency Synthesis Frequency Synthesis The frequency synthesizer subsystem consists of the reference oscillator (Y3261 or Y3262), the Low Voltage Fractional-N synthesizer (LVFRAC-N, U3201), and the voltage-controlled oscillators and buffer amplifiers (U3301, Q3301-2 and associated circuits). Reference Oscillator The reference oscillator (Y3262) contains a temperature compensated crystal oscillator with a frequency of 16.8 MHz.
  • Page 391 Frequency Synthesis A voltage of 5V applied to the super filter input (U3201 pin 30) supplies an output voltage of 4.5 Vdc (VSF) at pin 28. It supplies the VCO, VCO modulation bias circuit (via R3363) and the synthesizer charge pump resistor network (R3251, R3252). The synthesizer supply voltage is provided by the 5V regulator U3211.
  • Page 392 Frequency Synthesis The VCOBIC together with the Fractional-N synthesizer (U3201) generates the required frequencies in both the transmit and receive modes. The TRB line (U3301, pin 19) determines which tank circuits and internal buffers are to be enabled. A high level on TRB enables the TX tank and TX output (pin 10), and a low enables the RX tank and RX output (pin 8).
  • Page 393 Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...
  • Page 394 Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J3401 Trace IF signal from C3035 to Q3101. IF Signal at Check for bad XTAL IF signal at Q3102 C3035? filter collector? Before replacing U3101, check U3101 voltages RF Signal at...
  • Page 395 Troubleshooting Flow Chart for 45W Transmitter Troubleshooting Flow Chart for 45W Transmitter (Sheet 1 of 2) START No or too low Power when keyed Current in- Check Components between >500mA & <5A >5A crease when Q3441 and RF Output, Antenna keyed? Switch D3471,D3472 <500mA...
  • Page 396 Troubleshooting Flow Chart for 45W Transmitter Troubleshooting Flow Chart for 45W Transmitter (Sheet 2 of 2) Check PA Stages No or too low Power when keyed Pin 3 Voltage 0.51 Check Voltage at Pin 2 & 3 of U3401 Replace U3401 * Voltage at Pin 1? Pin 2...
  • Page 397 Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer 5V at Check 5V U3201 pins 5, Start Regulator 20, 34 & 36 U3211, R3211 Visual Correct check of the Problem Board OK? Is 16.8MHz 16.8MHz Replace Signal at signal at U3201 Is U3201 U3201 Pin...
  • Page 398 Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP3001 Visual check Visual check Correct of board of board Problem Make sure U3211 is working correctly and runner 5V DC at U3301...
  • Page 399 Section 4 VHF PCB/SCHEMATICS/PARTS LIST Allocation of Schematics and Circuit Boards Controller Circuits The VHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the VHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 400 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 401 C3009 C0652...
  • Page 411 GM338 Mobile Radios UHF1 40W Bipolar (403-470MHz) Service Information Issue: December, 2003...
  • Page 412 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 413 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM338 Model Chart.....................1-1 2.0 Technical Specifications ..................1-1 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 UHF (403-470 MHz) Receiver ................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and 1st Intermediate Frequency (IF) ..........2-2 2.4 2nd Intermediate Frequency (IF) and Receiver Back End ......2-3 3.0 Transmitter Power Amplifier (PA) 40 W ...............2-3...
  • Page 414 Section 4 UHF PCB/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 UHF 25-40W PCB / Schematics / Parts List ............4-3 UHF (403-470 MHz) 25-40W 8480643Z06 Top Side ..........4-3 UHF (403-470 MHz) 25-40W 8480643Z06 Bottom Side........4-4 UHF (403-470 MHz) Power Amplifier 25-40W ............
  • Page 415 Section 1 MODEL CHART AND TECHNICAL SPECIFICATIONS GM338 Model Chart GM Series, UHF Band 1, 403-470 MHz Model Description AZM25RKF9AA5 GM338 403-470 MHz 25-40W Conv Pref (Bipolar) Item Description GCN6114_ GM338 Control Head Direct Mount IMUE6012_ Tanapa WM 403-470 MHz 25-40W RAE4151_ BNC 403-430 MHz, Wave Roof Mount...
  • Page 416 Technical Specifications Transmitter *Frequencies - Full Bandsplit UHF 403-470 MHz Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.0 ppm (-30°C to +60°C, +25° Ref.) Power 25-40W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...
  • Page 417 Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the UHF circuits in the radio. For details of the theory of operation and troubleshooting for the the associated Controller circuits refer to the Controller Section of this manual. UHF (403-470 MHz) Receiver Receiver Front-End The receiver is able to cover the UHF range from 403 to 470 MHz.
  • Page 418 UHF (403-470 MHz) Receiver The 2-pole 44.85 MHz crystal filters in the 1st IF section and two pairs of 455 kHz ceramic filters in the 2nd IF section provide the required adjacent channel selectivity. The correct pair of ceramic filters for 12.5 or 25 kHz channel spacing is selected via control line BWSELECT. The 2nd IF at 455 kHz is mixed, amplified, and demodulated in the IF IC.
  • Page 419 Transmitter Power Amplifier (PA) 40 W 2nd Intermediate Frequency (IF) and Receiver Back End The 44.85 MHz 1st IF signal from the second IF amplifier feeds the IF IC (U3101) at pin1. Within the IF IC the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator (2nd LO) to produce the low IF signal at 455 kHz.
  • Page 420 Transmitter Power Amplifier (PA) 40 W Power Controlled Stage The first stage (U4401) amplifies the RF signal from the VCO (TXINJ) and controls the output power of the PA. The output power of the transistor U4401 is controlled by a voltage control line feed from the PCIC pin4(U4501).
  • Page 421 Transmitter Power Amplifier (PA) 40 W Bi-Directional Coupler The Bi-directional coupler is a microstrip printed circuit, which couples a small amount of the forward and reverse power of the RF power from Q4441. The coupled signal is rectified to an output power proportional dc voltage by the diodes D4451 &...
  • Page 422 Frequency Synthesis The PCIC provides a dc output voltage at pin 4 (INT) and applied as CNTLVLTG to the power-adjust input pin of the first transmitter stage U4401. This adjusts the transmitter power output to the intended value. Variations in forward or reflected transmitter power cause the dc voltage at pin 1 to change, and the PCIC adjusts the control voltage above or below its nominal value to raise or lower output power.

  • Page 423: Reference Oscillator

    Frequency Synthesis Fractional-N Synthesizer The LVFRAC-N synthesizer IC (U4201) consists of a pre-scaler, a programmable loop divider, control divider logic, a phase detector, a charge pump, an A/D converter for low frequency digital modulation, a balanced attenuator to balance the high frequency analog modulation and low frequency digital modulation, a 13V positive voltage multiplier, a serial interface for control, and finally a super filter for the regulated 5 volts.

  • Page 424: Voltage Controlled Oscillator (Vco)

    Frequency Synthesis Voltage Controlled Oscillator (VCO) The Voltage Controlled Oscillator (VCO) consists of the VCO buffer IC (VCOBIC, U4301), the TX and RX tank circuits, the external RX buffer stages, and the modulation circuits. The VCOBIC together with Fractional-N synthesizer (U4201) generates the required frequencies in both transmit and receive modes.

  • Page 425: Synthesizer Operation

    Frequency Synthesis Synthesizer Operation The complete synthesizer subsystem comprises mainly of a low voltage FRAC-N (LVFRACN) IC, Reference Oscillator (crystal oscillator with temperature compensation), charge pump circuits, loop filter circuits, and dc supply. The output signal (PRESC_OUT) of the VCOBIC (U4301, pin12) is fed to of U4201, pin 32 (PREIN) via a low pass filter (C4229,L4225,C4226) which attenuates harmonics and provides correct level to close the synthesizer loop.
  • Page 426 2-10 Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 427: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...
  • Page 428 Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J4401 Trace IF signal from C3101 to IF Signal at signal at Q3102 Q3101. Check for C3101? collector? bad XTAL filter. Before replacing U3101, check U3101 voltages.

  • Page 429: Troubleshooting Flow Chart For 45W Transmitter

    Troubleshooting Flow Chart for 40W Transmitter Troubleshooting Flow Chart for 40W Transmitter START No power Is Vctrl Is Q4573 Check Check there? MOSBIAS_2 ASFIC Change Q4573 Check voltage Check on pin 4 U4501 Check PCIC PCIC_MOSBIAS_1 Check R4422-5 and go back to top Check voltage Are D4471 &...

  • Page 430: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Check 5V 5V at U4201 Start Regulator pins 5, 20, 34 & U4211 Visual Check D4201, C4202, Correct check of the C4203, & C4206 Problem Board OK? Is 16.8MHz 16.8MHz Is U4201 Pin 47 at pin 6 of Replace...

  • Page 431: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP4003 Visual check Visual check Correct of board of board Problem Make sure Synthesizer is 4.5V DC 4.5V DC...
  • Page 432 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 433 Section 4 UHF PCB/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The UHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the UHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 434 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 447 GM338 Mobile Radios UHF2 40W Bipolar (450-520MHz) Service Information Issue: December, 2003...
  • Page 448 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 449 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM338 Model Chart.....................1-1 2.0 Technical Specifications ..................1-1 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 UHF (450-520 MHz) Receiver ................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and High Intermediate Frequency (IF)..........2-2 2.4 Low Intermediate Frequency (IF) and Receiver Back End......2-3 3.0 Transmitter Power Amplifier (PA) 40W ..............2-3...
  • Page 450 Section 4 UHF PCB/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 UHF Band 2 25-40W PCB / Schematics / Parts List ........... 4-3 UHF Band 2 (450-520 MHz) 40W 8480645Z04 Top Side........4-3 UHF Band 2 (450-520 MHz) 40W 8480645Z04 Bottom Side........

  • Page 451: Model Chart And Technical Specifications

    Section 1 MODEL CHART AND TECHNICAL SPECIFICATIONS GM338 Model Chart GM Series, UHF Band 2, 450-520 MHz Model Description AZM25SKF9AA5 GM338 450-520 MHz 25-40W Item Description GCN6114_ GM338 Control Head Direct Mount IMUE6019_ Tanapa WM 450-520 MHz 25-40W RAE4155_ BNC 470-512 MHz, 1/4 Wave Roof Mount RAE4156_ BNC 470-494 MHz, 3.5 Gain Roof Mount RAE4157_...
  • Page 452 Technical Specifications Transmitter *Frequencies - Full Bandsplit UHF 450-520 MHz Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.0 ppm (-30°C to +60°C, +25° Ref.) Power 25-40W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...

  • Page 453: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the UHF circuits in the radio. For details of the theory of operation and troubleshooting for the associated Controller circuits refer to the Controller Section of this manual. UHF (450-520 MHz) Receiver Receiver Front-End The UHF receiver, shown in Figure 2-1, is able to cover the UHF range from 450 to 520 MHz.

  • Page 454: Front-End Band-Pass Filters & Pre-Amplifier

    UHF (450-520 MHz) Receiver The two 2-pole 44.85 MHz crystal filters in the high-IF section and two pairs of 455 kHz ceramic filters in the low-IF section provide the required adjacent channel selectivity .The correct pair of ceramic filters for 12.5 or 25KHz channel spacing is selected via control line BWSELECT. The second IF at 455 kHz is mixed, amplified, and demodulated in the IF IC.

  • Page 455: Transmitter Power Amplifier (Pa) 40W

    Transmitter Power Amplifier (PA) 40W Low Intermediate Frequency (IF) and Receiver Back End The 44.85 MHz first IF signal from the second IF amplifier feeds the IF IC (U3101) at pin1. Within the IF IC the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator to produce a low IF signal of 455 kHz.

  • Page 456: Power Controlled Stage

    Transmitter Power Amplifier (PA) 40W Power Controlled Stage The first stage (U5401) amplifies the RF signal from the VCO (TXINJ) and controls the output power of the PA. The output power of the transistor U5401 is controlled by a voltage control line feed from the PCIC (U5501, pin 4).

  • Page 457: Antenna Switch

    Transmitter Power Amplifier (PA) 40W Antenna Switch The antenna switch utilizes the existing dc feed (A+) to the last stage device (Q5441). Basic operation is to have both PIN diodes (D5471 and D5472) turned on during key-up by forward biasing them. This is achieved by pulling down the voltage at the cathode end of D5472 to around 11.8V (0.7V drop across each diode).

  • Page 458: Frequency Synthesis

    Frequency Synthesis Frequency Synthesis The synthesizer, shown in Figure 2-3, consists of a reference oscillator (Y5261 or Y5262), low voltage LVFRAC-N synthesizer (U5201), and a voltage controlled oscillator (VCO). Reference Oscillator The reference oscillator (Y5262) contains a temperature compensated crystal oscillator with a frequency of 16.8 MHz.
  • Page 459 Frequency Synthesis LOCK LOCK (U0101 PIN 56) DATA (U0101 PIN 100) DATA FREFOUT FREF (U0221 PIN 34) CLOCK (U0101 PIN 1) 6, 22, 33, 44 CSX (U0101 PIN 2) STEERING LINE MODIN MOD IN (U0221 PIN 40) 2-POLE IOUT 13, 30 LOOP IADAPT VCC, DC5V...

  • Page 460: Voltage Controlled Oscillator (Vco)

    Frequency Synthesis Voltage Controlled Oscillator (VCO) The voltage controlled oscillator (VCO), shown in Figure 2-4, consists of a VCO buffer IC (VCOBIC, U5301), TX and RX tank circuits, external RX buffer stages, and modulation circuits. The VCOBIC together with Fractional-N synthesizer (U5201) generates the required frequencies in both transmit and receive modes.

  • Page 461: Synthesizer Operation

    Frequency Synthesis The external RX buffers (Q5332) are enabled by a high at U5201, pin 3 (AUX4) via transistor switch Q5333. In TX mode, the modulation signal (VCOMOD) from the LVFRAC-N synthesizer IC (U5201, pin 41) is applied to the modulation circuits CR5321, R5321, R5322, and C5324. These modulate the TX VCO frequency via coupling capacitor C5321.
  • Page 462 2-10 Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 463: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...
  • Page 464 Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J5401 Trace IF signal from C3101 to IF Signal at signal at Q3102 Q3101. Check for C3101? collector? bad XTAL filter. Before replacing U3101, check U3101 voltages.

  • Page 465: Troubleshooting Flow Chart For 40W Transmitter

    Troubleshooting Flow Chart for 40W Transmitter Troubleshooting Flow Chart for 40W Transmitter START No power Is Vctrl Check Is Q5573 Check there? MOSBIAS_2 ASFIC Change Q4573 Check voltage Check Check n U5501, pin 4 PCIC_MOSBIAS_1 PCIC Check R5422-5 and go back to top Check voltage on U5501, pin 5 Are D5471 &...

  • Page 466: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Start Check 5V at U5201 Regulator pins 5, 20, 34 U5211 & 36 Visual Correct check of the Problem Board Check D5201, C5202, C5203, & C5206 16.8MHz 16.8MHz Replace U5201 Pin 47 signal at Signal at U5201 at pin 6 of...

  • Page 467: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP5003 Visual check Visual check Correct of board of board Problem Make sure Synthesizer is 4.5V DC 4.5V DC...
  • Page 468 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 469 Section 4 UHF PCB/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The UHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the UHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 470 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 471 SH5301 L5403...
  • Page 483 GM338 Mobile Radio UHF B1 HIGH POWER LDMOS (403-470MHz) Service Information Issue: December, 2003...
  • Page 484 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 485 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM338 Model Chart.....................1-1 2.0 Technical Specifications ..................1-1 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 UHF (403-470 MHz) Receiver ................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and High Intermediate Frequency (IF)..........2-2 2.4 Low Intermediate Frequency (IF) and Receiver Back End......2-3 3.0 UHF (403-470 MHz) Transmitter Power Amplifier (PA) 40 W......2-3...
  • Page 486 Section 4 UHF PCB/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 UHF 25-40W PCB / Schematics / Parts List ............4-3 UHF (403-470 MHz) 25-40W 8486127Z01 Top Side ..........4-3 UHF (403-470 MHz) 25-40W 8486127Z01 Bottom Side........4-4 UHF (403-470 MHz) Power Amplifier 25-40W ............

  • Page 487: Model Chart And Technical Specifications

    Section 1 MODEL CHART AND TECHNICAL SPECIFICATIONS GM338 Model Chart GM Series, UHF Band 1, 403-470 MHz Mode Description AZM25RKF9AA5 GM338 403-470 MHz 25-40W Conv Pref (LDMOS) Item Description GCN6114_ GM338 Control Head Direct Mount IMUE6012_ Tanapa WM 403-470 MHz 25-40W RAE4151_ BNC 403-430 MHz, Wave Roof Mount...
  • Page 488 Technical Specifications Transmitter *Frequencies - Full Bandsplit UHF 403-470 MHz Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.0 ppm (-30°C to +60°C, +25° Ref.) Power 25-40W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...

  • Page 489: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the UHF circuits in the radio. For details of the theory of operation and troubleshooting for the the associated Controller circuits refer to the Controller Section of this manual. UHF (403-470 MHz) Receiver Receiver Front-End The receiver is able to cover the UHF range from 403 to 470 MHz.

  • Page 490: Front-End Band-Pass Filters & Pre-Amplifier

    UHF (403-470 MHz) Receiver There are two 2-pole 44.85 MHz crystal filters in the high-IF section and 2 pairs of 455 kHz ceramic filters in the low-IF section to provide the required adjacent channel selectivity .The correct pair of ceramic filters for 12.5 or 25KHz channel spacing is selected via control line BWSELECT. The second IF at 455 kHz is mixed, amplified and demodulated in the IF IC.

  • Page 491: Low Intermediate Frequency (If) And Receiver Back End

    UHF (403-470 MHz) Transmitter Power Amplifier (PA) 40 W Low Intermediate Frequency (IF) and Receiver Back End The 44.85 high IF signal from the second IF amplifier feeds the IF IC (U3101) at pin1. Within the IF IC the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator (2nd LO) to produce the low IF signal at 455 kHz.

  • Page 492: First Power Controlled Stage

    UHF (403-470 MHz) Transmitter Power Amplifier (PA) 40 W First Power Controlled Stage The first stage (U4401) is a 20dB gain integrated circuit containing two LDMOS FET amplifier stages. It amplifies the RF signal from the VCO (TXINJ). The output power of stage U4401 is controlled by a DC voltage applied to pin 1 from Q4473.

  • Page 493: Directional Coupler

    UHF (403-470 MHz) Transmitter Power Amplifier (PA) 40 W Directional Coupler The directional coupler is a microstrip printed circuit, which couples a small amount of the forward power delivered by Q4441. The coupled signal is rectified by D4451. The DC voltage is proportional to the RF output power and feeds the RFIN port of the PCIC (U4501 pin 1).

  • Page 494: Uhf (403-470 Mhz) Frequency Synthesis

    UHF (403-470 MHz) Frequency Synthesis U4502 is a temperature-sensing device, which monitors the circuit board temperature in the vicinity of the transmitter driver and final devices, and provides a DC voltage to the PCIC (TEMP, pin 30) proportional to temperature. If the DC voltage produced exceeds the set threshold in the PCIC, the transmitter output power will be reduced so as to reduce the transmitter temperature.

  • Page 495: Fractional-N Synthesizer

    UHF (403-470 MHz) Frequency Synthesis Fractional-N Synthesizer The LVFRAC-N synthesizer IC (U4201) consists of a pre-scaler, a programmable loop divider, control divider logic, a phase detector, a charge pump, an A/D converter for low frequency digital modulation, a balance attenuator to balance the high frequency analogue modulation and low frequency digital modulation, a 13V positive voltage multiplier, a serial interface for control, and finally a super filter for the regulated 5 volts.

  • Page 496: Voltage Controlled Oscillator (Vco)

    UHF (403-470 MHz) Frequency Synthesis Voltage Controlled Oscillator (VCO) The Voltage Controlled Oscillator (VCO) consists of the VCO/Buffer IC (VCOBIC, U4301), the TX and RX tank circuits, the external RX buffer stages, and the modulation circuitry. AUX3 (U4201 Pin 2) U4201 Pin 32 Prescaler Out TRB IN...

  • Page 497: Synthesizer Operation

    UHF (403-470 MHz) Frequency Synthesis The external RX buffers (Q4332) are enabled by a high at U4201 pin 3 (AUX4) via transistor switch Q4333. In TX mode the modulation signal (VCOMOD) from the LVFRAC-N synthesizer IC (U4201 pin41) is applied modulation circuitry CR4321, R4321, R4322 and C4324, which modulates the TX VCO frequency via coupling capacitor C4321.
  • Page 498 2-10 UHF (403-470 MHz) Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 499: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...
  • Page 500 Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J4401 Trace IF signal from C3101 to IF Signal at signal at Q3102 Q3101. Check for C3101? collector? bad XTAL filter. Before replacing U3101, check U3101 voltages.

  • Page 501: Troubleshooting Flow Chart For 40W Transmitter

    Troubleshooting Flow Chart for 40W Transmitter Troubleshooting Flow Chart for 40W Transmitter (Sheet 1 of 2) START No or too low Power when keyed Check if Pressure Pad closes S5440 Put in pressure pad Check Components between Current Q4441 and RF Output, >500mA &...
  • Page 502 Troubleshooting Flow Chart for 40W Transmitter Troubleshooting Flow Chart for 40W Transmitter (Sheet 2 of 2) Check PA Stages Check Check MOSBIAS_2/ ASFIC MOSBIAS_3 Check Check PCIC_MOS PCIC BIAS_1 Change D4471 & Are D4471 & D4472 D4472 OK? Change Q4441 Check Q4441 Check Q4421 gate (63kohm)

  • Page 503: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Start Check 5V at U4201 Regulator pins 5, 20, 34 U4211 & 36 Visual Correct check of the Problem Board Check D4201, C4202, C4203, & C4206 16.8MHz 16.8MHz Replace U4201 Pin 47 signal at Signal at U4201 at pin 6 of...

  • Page 504: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP4003 Visual check Visual check Correct of board of board Problem Make sure Synthesizer is 4.5V DC 4.5V DC...
  • Page 505 Section 4 UHF PCB/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The UHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the UHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 506 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 507 R3132 C3137 L4006 C4441 R0682...
  • Page 508 T P 0 6 6 1...
  • Page 519 GM338 Mobile Radios UHF B2 HIGH POWER LDMOS (450-520 MHz) Service Information Issue: December, 2003...
  • Page 520 Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola...
  • Page 521 Table of Contents Section 1 Model Chart and Technical Specifications 1.0 GM338 Model Chart.....................1-1 2.0 Technical Specifications ..................1-1 Section 2 Theory of Operation 1.0 Introduction ......................2-1 2.0 UHF (450-520 MHz) Receiver ................2-1 2.1 Receiver Front-End ..................2-1 2.2 Front-End Band-Pass Filters & Pre-Amplifier ..........2-2 2.3 First Mixer and High Intermediate Frequency (IF)..........2-2 2.4 Low Intermediate Frequency (IF) and Receiver Back End......2-3 3.0 UHF (450-520 MHz) Transmitter Power Amplifier (PA) 40W.......2-3...
  • Page 522 Section 4 UHF PCB/Schematics/Parts Lists 1.0 Allocation of Schematics and Circuit Boards ............4-1 1.1 Controller Circuits ................... 4-1 2.0 UHF Band 2 25-40W PCB / Schematics / Parts List ........... 4-3 UHF Band 2 (450-520 MHz) 40W 8486250Z02 Top Side........4-3 UHF Band 2 (450-520 MHz) 40W 8486250Z02 Bottom Side........

  • Page 523: Model Chart And Technical Specifications

    Section 1 MODEL CHART AND TECHNICAL SPECIFICATIONS GM338 Model Chart GM Series, UHF Band 2, 450-520 MHz Model Description AZM25SKF9AA5 GM338 450-520 MHz 25-40W (LDMOS) Item Description GCN6114_ GM338 Control Head Direct Mount IMUE6019_ Tanapa WM 450-520 MHz 25-40W RAE4155_ BNC 470-512 MHz, 1/4 Wave Roof Mount RAE4156_ BNC 470-494 MHz, 3.5 Gain Roof Mount...
  • Page 524 Technical Specifications Transmitter *Frequencies - Full Bandsplit UHF 450-520 MHz Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.0 ppm (-30°C to +60°C, +25° Ref.) Power 25-40W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz -40 dB @ 12.5kHz FM Hum &...

  • Page 525: Theory Of Operation

    Section 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the UHF circuits in the radio. For details of the theory of operation and troubleshooting for the associated Controller circuits refer to the Controller Section of this manual. UHF (450-520 MHz) Receiver Receiver Front-End The UHF receiver, shown in Figure 2-1, is able to cover the UHF range from 450 to 520 MHz.

  • Page 526: Front-End Band-Pass Filters & Pre-Amplifier

    UHF (450-520 MHz) Receiver The two 2-pole 44.85 MHz crystal filters in the high-IF section and two pairs of 455 kHz ceramic filters in the low-IF section provide the required adjacent channel selectivity .The correct pair of ceramic filters for 12.5 or 25KHz channel spacing is selected via control line BWSELECT. The second IF at 455 kHz is mixed, amplified, and demodulated in the IF IC.

  • Page 527: Low Intermediate Frequency (If) And Receiver Back End

    UHF (450-520 MHz) Transmitter Power Amplifier (PA) 40W Low Intermediate Frequency (IF) and Receiver Back End The 44.85 MHz first IF signal from the second IF amplifier feeds the IF IC (U3101) at pin1. Within the IF IC the 44.85 MHz high IF signal mixes with the 44.395 MHz second local oscillator to produce a low IF signal of 455 kHz.

  • Page 528: First Power Controlled Stage

    UHF (450-520 MHz) Transmitter Power Amplifier (PA) 40W First Power Controlled Stage The first stage (U5401) is a 20dB gain integrated circuit containing two LDMOS FET amplifier stages. It amplifies the RF signal from the VCO (TXINJ). The output power of stage U5401 is controlled by a DC voltage applied to pin 1 from Q5473.

  • Page 529: Antenna Switch

    UHF (450-520 MHz) Transmitter Power Amplifier (PA) 40W Antenna Switch The antenna switch consists of two PIN diodes, D5471 and D5472. In the receive mode, both diodes are off. Signals applied at the antenna jack J5401 are routed, via the harmonic filter, through network L5472, C5474 and C5475, to the receiver input.

  • Page 530: Uhf (450-520 Mhz) Frequency Synthesis

    UHF (450-520 MHz) Frequency Synthesis UHF (450-520 MHz) Frequency Synthesis The synthesizer subsystem shown in Figure 2-3, consists of the reference oscillator (Y5261 or Y5262), the Low Voltage Fractional-N synthesizer (LVFRAC-N, U5201), and the Voltage Controlled Oscillator (VCO). Reference Oscillator The reference oscillator (Y5262) contains a temperature compensated crystal oscillator with a frequency of 16.8 MHz.
  • Page 531 UHF (450-520 MHz) Frequency Synthesis LOCK LOCK (U0101 PIN 56) DATA (U0101 PIN 100) DATA FREFOUT FREF (U0221 PIN 34) CLOCK (U0101 PIN 1) 6, 22, 33, 44 CSX (U0101 PIN 2) STEERING LINE MODIN MOD IN (U0221 PIN 40) 2-POLE IOUT 13, 30...

  • Page 532: Voltage Controlled Oscillator (Vco)

    UHF (450-520 MHz) Frequency Synthesis Voltage Controlled Oscillator (VCO) The voltage controlled oscillator (VCO), shown in Figure 2-4, consists of a VCO buffer IC (VCOBIC, U5301), TX and RX tank circuits, external RX buffer stages, and modulation circuits. The VCOBIC together with Fractional-N synthesizer (U5201) generates the required frequencies in both transmit and receive modes.

  • Page 533: Synthesizer Operation

    UHF (450-520 MHz) Frequency Synthesis The external RX buffers (Q5332) are enabled by a high at U5201, pin 3 (AUX4) via transistor switch Q5333. In TX mode, the modulation signal (VCOMOD) from the LVFRAC-N synthesizer IC (U5201, pin 41) is applied to the modulation circuits CR5321, R5321, R5322, and C5324. These modulate the TX VCO frequency via coupling capacitor C5321.
  • Page 534 2-10 UHF (450-520 MHz) Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK...

  • Page 535: Troubleshooting Charts

    Section 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at (in the case of no audio) pin 8 of OR ELSE go to “B” U3101 ? Spray or inject 44.85MHz into XTAL Filter FL3101...
  • Page 536 Troubleshooting Flow Chart for Receiver Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J5401 Trace IF signal from C3101 to IF Signal at signal at Q3102 Q3101. Check for C3101? collector? bad XTAL filter. Before replacing U3101, check U3101 voltages.

  • Page 537: Troubleshooting Flow Chart For 40W Transmitter

    Troubleshooting Flow Chart for 40W Transmitter Troubleshooting Flow Chart for 40W Transmitter START No power Check if Pressure Pad closes S5440 Check Check Is Vctrl MOSBIAS_2/ Is Q5473 ASFIC there? MOSBIAS_3 Change Q5473 Check voltage Check Check n pin 4, U5501 PCIC_MOSBIAS_1 PCIC Check R5422-5...

  • Page 538: Troubleshooting Flow Chart For Synthesizer

    Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Start Check 5V at U5201 Regulator pins 5, 20, 34 U5211 & 36 Visual Correct check of the Problem Board Check D5201, C5202, C5203, & C5206 16.8MHz 16.8MHz Replace U5201 Pin 47 signal at Signal at U5201 at pin 6 of...

  • Page 539: Troubleshooting Flow Chart For Vco

    Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO Low or no RF Signal Low or no RF Signal TX VCO RX VCO at input to PA at TP5003 Visual check Visual check Correct of board of board Problem Make sure Synthesizer is 4.5V DC 4.5V DC...
  • Page 540 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 541 Section 4 UHF PCB/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The UHF circuits are contained on the Printed Circuit Board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the UHF circuits only, refer to the Controller section for details of the related Controller circuits .
  • Page 542 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK...
  • Page 544 C 0 2 7 5...
  • Page 555 Service Manuals need to be updated accordingly. If you wish to be informed of these updates, kindly fill in and fax us your details. Fax to: 6-04-6124944 The Technical Publications Coordinator, Media and Communications, R&D Department, Motorola Penang. Your Details Name/Contact Person: Company Name: Address: Telephone No.: Fax No.:...
  • Page 556 Kindly take a few moments to provide feedback on this manual. Thank you for your cooperation. Fax to: 6-04-6124944 The Technical Publications Coordinator, Media and Communications, R&D Department, Motorola Penang. 1. Please check all the appropriate boxes: Disassembly Pro- cedures Alignment...

This manual is also suitable for:

Gm398Gm338

Table of Contents