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Motorola HT Series Detailed Service Manual

Professional series two-way portable radios
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See also: Detailed Service Manual , Service Manual

REVISION CHANGE:

This manual revision contains theories of operation, schematics, board layouts, and troubleshooting
flowcharts for Professional Series radios with the following boards installed:
UHF (403 - 470 MHz) Main Board
UHF Band 2 (450 - 527 MHz) Main Board
VHF (136 - 174 MHz) Main Board
* Indicates parts that cannot be ordered.
Use the information provided in this manual revision to supplement your Professional Series Two-Way
Portable Radios Detailed Service Manual, Motorola publication part number 6881088C46-E.
NOTE: Radio model charts and specifications information can be found in the appropriate Basic Service
Manual for the radio model you are servicing.
HT1250
Basic Service Manual
© Motorola, Inc. 2003
8000 West Sunrise Boulevard
Fort Lauderdale, Florida 33322
®
Publication Title
•
LS Professional Series Two-Way Radio
MANUAL REVISION
HT Series, MTX Series, PRO Series
Professional Series
Two-Way Portable Radios
Detailed Service Manual
PCB No. 8486458Z02*
PCB No. 8486686Z01*
PCB No. 8486473Z03*
Part number
6864110R15
*FMR2045A-2*
6881088C46-E
FMR-2045A-2
12-26-03

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  • Page 1: Revision Change

    * Indicates parts that cannot be ordered. Use the information provided in this manual revision to supplement your Professional Series Two-Way Portable Radios Detailed Service Manual, Motorola publication part number 6881088C46-E. NOTE: Radio model charts and specifications information can be found in the appropriate Basic Service Manual for the radio model you are servicing.

  • Page 2: Fmr-2045A

    This page intentionally left blank. December 26, 2003 FMR-2045A-2...

  • Page 3: Table Of Contents

    Table of Contents REVISION CHANGE: ..........................1 Chapter 1 UHF Theory of Operation ................7 Transmitter............................7 1.1.1 General ..........................7 1.1.2 Power Amplifier........................7 1.1.3 Antenna Switch........................8 1.1.4 Harmonic Filter ........................8 1.1.5 Antenna Matching Network....................8 1.1.6 Power Control Integrated Circuit (PCIC)................
  • Page 4 Table of Contents Notes For All Schematics and Circuit Boards ................. 45 Circuit Board/Schematic Diagrams and Parts List ................47 Chapter 6 UHF Band 2 Troubleshooting Charts ............61 Troubleshooting Flow Chart for Controller ..................61 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2)..............62 Troubleshooting Flow Chart for Receiver (Sheet 2 of 2)..............
  • Page 5 Table of Contents List of Figures Transmitter Block Diagram ........................7 UHF Receiver Block Diagram ......................9 Frequency Generation Unit Block Diagram ..................10 Synthesizer Block Diagram ........................ 11 VCO Block Diagram ........................... 12 UHF (403-470MHz) Main Board Top Side PCB No. 8486458Z02............. 17 UHF (403-470MHz) Main Board Bottom Side PCB No.
  • Page 6 Table of Contents This page intentionally left blank. 12/26/03 FMR-2045A-2...

  • Page 7: Chapter 1 Uhf Theory Of Operation

    UHF Theory of Operation: Transmitter Chapter 1 UHF Theory of Operation Transmitter P C I C Antenna Vcontrol Vcontrol Jack Antenna Switch/ From VCO PA - Fi n a l Harmonic Filter/ Driver Sta g e Matching Network Figure 1-1. Transmitter Block Diagram 1.1.1 General (Refer to...

  • Page 8: Antenna Switch

    UHF Theory of Operation: Transmitter 1.1.3 Antenna Switch The antenna switch circuit consists of two PIN diodes (CR101 and CR102), a pi network (C107, L104 and C106), and two current limiting resistors (R101, R170). In the transmit mode, B+ at PCIC (U102) pin 23 will go low and turn on Q111 where a B+ bias is applied to the antenna switch circuit to bias the diodes “on.”...

  • Page 9: Receiver

    UHF Theory of Operation: Receiver Receiver Antenna Pin Diode Varactor Varactor Antenna Crystal RF Amp Mixer IF Amp Tuned Filter Tuned Filter Switch RF Jack Filter First LO from VCO Control Voltage from ASFIC U301 Demodulator Limiter Recovered Audio RSSI 455kHz 455kHz Filter...

  • Page 10: Receiver Back-End

    UHF Theory of Operation: Frequency Generation Circuitry The output of the post-RF amplifier filter which is connected to the passive double balanced mixer consists of T301, T302 and CR306. Matching of the filter to the mixer is provided by C381. After mixing with the first LO signal from the voltage controlled oscillator (VCO) using low side injection, the RF signal is down-converted to the 44.85 MHz IF signal.

  • Page 11: Synthesizer

    UHF Theory of Operation: Synthesizer The Frequency Generation Circuitry is composed of two main ICs: • Fractional-N synthesizer (U201) • VCO/Buffer IC (U241) Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally would require additional circuitry. The synthesizer block diagram illustrates the interconnect and support circuitry used in the region.

  • Page 12: Voltage-Controlled Oscillator (Vco)

    UHF Theory of Operation: Voltage-Controlled Oscillator (VCO) The loop filter which consist of C231, C232, C233, R231, R232 and R233 provides the necessary dc steering voltage for the VCO and determines the amount of noise and spur passing through. In achieving fast locking for the synthesizer, an internal adapt charge pump provides higher current at pin 45 of U201 to put synthesizer within the lock range.
  • Page 13 UHF Theory of Operation: Voltage-Controlled Oscillator (VCO) The VCOBIC (U241) in conjunction with the Fractional-N synthesizer (U201) generates RF in both the receive and the transmit modes of operation. The TRB line (U241 pin 19) determines which oscillator and buffer will be enabled. A sample of the RF signal from the enabled oscillator is routed from U241 pin 12, through a low pass filter, to the prescaler input (U201 pin 32).
  • Page 14 UHF Theory of Operation: Voltage-Controlled Oscillator (VCO) This page intentionally left blank. December 26, 2003 FMR-2045A-2...

  • Page 15: Chapter 2 Uhf Circuit Board Layouts, Schematic Diagrams And Parts List

    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 16 UHF Circuit Board Layouts, Schematic Diagrams and Parts List: Notes for All Schematics and Circuit Boards This page intentionally left blank. December 26, 2003 FMR-2045A-2...

  • Page 17: Circuit Board/Schematic Diagrams And Parts List

    Circuit Board/Schematic Diagrams and Parts List Circuit Board/Schematic Diagrams and Parts List PB501 PB504 PB502 PB503 C521 R410 E407 E409 R437 SH323 R418 C505 VR440 C338 FL302 B503 B504 FL201 R507 FL301 FL304 C325 C349 VR501 U405 FL303 U406 C432 Y301 TP201 J400...

  • Page 18: Uhf (403-470Mhz) Main Board Bottom Side Pcb No. 8486458Z02

    Circuit Board/Schematic Diagrams and Parts List VR441 C522 VR444 C436 C523 VR442 VR506 C437 R376 SH322 E404 E405 L505 C355 C334 E406 C358 R373 R426 C350 E403 R374 C383 R359 R368 S502 L332 R372 R366 L331 C359 U303 R378 U248 B501 E402 R371...

  • Page 19: Uhf Controls And Switches Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List RADIO_CODE BATTERY_CONTACT L505 B501 UNSWB+ 390nH BATT_CODE DATA 1 NEG BATT+ S502 3 POS F501 SWITCH BATT- CONN_J MECH_SWB+ LI_ION B503 TAB2 CR501 B504 VR506 VR439 C503 C502 6.8V TAB1 100pF 0.47uF R507 6.8V C505 VR501 100pF...

  • Page 20: Uhf Receiver Front-End Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List DACRx C322 82pF R342 100K L310 150nH C315 R308 C314 R310 R305 100pF 0.1uF R304 C380 R309 .01uF CR306 L304 C321 180nH 100pF T301 C306 XFMR C309 R306 C308 100pF R307 100pF 100K 100K C312 C318 C310...

  • Page 21: Uhf Receiver Back-End Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List U302-1 R345 R360 TC7W04F FL303 C352 CFWC455E 0.1uF 1 IN U302-3 TC7W04F U302-4 PWR_GND R355 100K BW_SEL U302-2 CR312 R321 TC7W04F R324 FL304 C362 CFWC455G 0.1uF OUT 2 R361 CR313 R350 R358 3.3K 2.4K C329 C357 0.1uF...

  • Page 22: Uhf Synthesizer Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List U210 U211 TC7ST04FU C296 C257 TC7ST04FU C265 0.1uF 100pF 3 GND C258 .01uF U247 ADP3300 C259 SWB+ .01uF (SOURCE) CR201 C291 3 K3 10uF C294 C293 4V_3.3V L202 U248 100pF 0.47uF 2 K2 A2 5 LP2980 2.2uH L203...

  • Page 23: Uhf Voltage Controlled Oscillator Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List C281 R245 100pF R242 L243 C250 C286 RESONATOR C276 C285 7.5pF 0.1uF 2.2uF 100pF C246 L281 R241 L273 100pF 390nH 33nH C242 7.5pF C272 C273 0.1uF C243 L242 L271 R244 7.5pF 220nH 68nH RX_INJ C245 2.4pF TX_INJ...

  • Page 24: Uhf Harmonic Filter Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List ANT_BIAS SH100 C108 100pF L105 SHIELD 390nH TX_OUT HF SHIELD CR101 L102 L101 L104 19.61nH 19.61nH 19.61nH RX_IN CR102 C101 C106 C102 C103 C104 C107 100pF 6.2pF 10pF 6.2pF 4.7pF 3.3pF R170 C175 20pF RF_JACK R101 ZMY0130486-A...

  • Page 25: Uhf Transmitter Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List E101 R102 BEAD 0.075 UNSWB+ L107 C114 C123 33.47nH 100pF 10uF C172 0.1uF C109 L106 UNSWB+ 100pF 7.66nH Microstrip Microstrip X_OUT R106 R172 Q110 C121 C160 L112 R175 L109 L108 100pF 100pF 22nH Microstrip 4.22nH C111 C112...
  • Page 26 Circuit Board/Schematic Diagrams and Parts List UHF Radio Parts List Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Part No. Part No. Part No. Circuit Motorola Description C171 2113743N50 100pF C264 2113743N50 100pF C338 NOT PLACED Part No. C172...
  • Page 27 Circuit Board/Schematic Diagrams and Parts List Circuit Motorola Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Description Part No. Part No. Part No. Part No. C420 2113743L41 10000pF C495 2113743N50 100pF E403 2480640Z01 Ferrite bead L303 2462587V26 22nH C421 2113928N01 0.1uF...
  • Page 28 Circuit Board/Schematic Diagrams and Parts List Circuit Motorola Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Description Part No. Part No. Part No. Part No. R111 0662057M33 R320 NOT PLACED R413 0662057M01 R506 0662057N15 R112 0662057M61 R321 0662057N13 R414...
  • Page 29 VR460 4802245J73 ZENER DIODE-6.8V VR501 4813830A18 6.8V ZENER VR506 4802245J73 ZENER DIODE-6.8V Y300 4802245J84 Xtal Oscillator 33.395MHz Y301 9186145B02 455kHz Ceramic Discriminator 1485777Z01 INSULATOR (KAPTON) 8486458Z01 UHF B1 main PC board * Motorola Depot Servicing only FMR-2045A-2 December 26, 2003...

  • Page 30: Controller Asfic/On_Off Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List 4V_3.3V R405 R402 TP410 SWB+ Q400 Vddd TP406 BATT_CODE UNSWB+ Vddd 800 MHz only C405 C401 C400 R401 0.1uF .01uF 100pF R406 R427 2.7K C403 U400 10uF LP2951ACMM-3.3 CR412 Vdda C402 R407 OUTPUT INPUT INT_EXT_Vdd A1 4 0.1uF...

  • Page 31: Chapter 3 Uhf Troubleshooting Charts

    UHF Troubleshooting Charts: Troubleshooting Flow Chart for Controller Chapter 3 UHF Troubleshooting Charts Troubleshooting Flow Chart for Controller MCU Check Press PTT. Red LED does not Before replacing light up Not able to Power Up MCU, check SPI Audio program RF AUDIO Alert Tone clock, SPI data,...

  • Page 32: Troubleshooting Flow Chart For Receiver (Sheet 1 Of 2)

    UHF Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at pin 8 of U301? Spray or inject 1st IF 44.85 MHz into XTAL Filter Check Q302 bias...

  • Page 33: Troubleshooting Flow Chart For Receiver (Sheet 2 Of 2)

    UHF Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J101 Trace IF signal Q302 collec- from L311 to IF Signal at tor OK? Q302. Check for L311? IF signal bad XTAL filter.

  • Page 34: Troubleshooting Flow Chart For Transmitter

    UHF Troubleshooting Charts: Troubleshooting Flow Chart for Transmitter Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Check Q111 Bias for Ant switch Is Control Volt- Check PCIC Is Current age High or Low High Check Drive to Module 1.

  • Page 35: Troubleshooting Flow Chart For Synthesizer

    UHF Troubleshooting Charts: Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Check U248, 3.3V at U201 Start L201 & L202 pins 5, 20, 34 & 36 Visual Correct Check CR201, check of the U210, U211, C258, Problem Board OK? C259 &...

  • Page 36: Troubleshooting Flow Chart For Vco

    UHF Troubleshooting Charts: Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO START Change U241 No LO? Change L253 O/C? L253 Pin 10 TRB = 5V? Tx Carrier? >1V? VCO OK Check R245 for dry joint or faulty AUX 3 Check High? R260...

  • Page 37: Chapter 4 Uhf Band 2 Theory Of Operation

    UHF Band 2 Theory of Operation: Transmitter Chapter 4 UHF Band 2 Theory of Operation Transmitter P CI C Antenna Vcontrol Vcontrol Jack Antenna Switch/ From VCO PA-Final Harmonic Filter/ Driver Stage Matching Network Figure 4-1. Transmitter Block Diagram 4.1.1 General (Refer to Figure...

  • Page 38: Antenna Switch

    UHF Band 2 Theory of Operation: Transmitter 4.1.3 Antenna Switch The antenna switch circuit consists of two PIN diodes (CR101 and CR102), a pi network (C107, L104 and C106), and two current limiting resistors (R101, R170). In the transmit mode, B+ at PCIC (U102) pin 23 will go low and turn on Q111 where a B+ bias is applied to the antenna switch circuit to bias the diodes "on."...

  • Page 39: Receiver

    UHF Band 2 Theory of Operation: Receiver Receiver Antenna Pin Diode Varactor Varactor Antenna Crystal RF Amp Mixer IF Amp Tuned Filter Tuned Filter Switch RF Jack Filter First LO from VCO Control Voltage from ASFIC U301 Demodulator Limiter Recovered Audio RSSI 455kHz 455kHz...

  • Page 40: Receiver Back-End

    UHF Band 2 Theory of Operation: Frequency Generation Circuitry The output of the post-RF amplifier filter which is connected to the passive double balanced mixer consists of T301, T302, and CR306. Matching of the filter to the mixer is provided by C381. After mixing with the first LO signal from the voltage controlled oscillator (VCO) using low side injection, the RF signal is down-converted to the 44.85 MHz IF signal.

  • Page 41: Synthesizer

    UHF Band 2 Theory of Operation: Synthesizer The Frequency Generation Circuitry is composed of two main ICs: • Fractional-N synthesizer (U201) • VCO/Buffer IC (U241) Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally would require additional circuitry.

  • Page 42: Voltage-Controlled Oscillator (Vco)

    UHF Band 2 Theory of Operation: Voltage-Controlled Oscillator (VCO) The loop filter, which consists of C231, C232, C233, R231, R232, and R233, provides the necessary DC steering voltage for the VCO and determines the amount of noise and spur passing through. In achieving fast locking for the synthesizer, an internal adapt charge pump provides higher current at pin 45 of U201 to put the synthesizer within the lock range.
  • Page 43 UHF Band 2 Theory of Operation: Voltage-Controlled Oscillator (VCO) The VCOBIC (U241), in conjunction with the Fractional-N synthesizer (U201), generates RF in both the receive and the transmit modes of operation. The TRB line (U241 pin 19) determines which oscillator and buffer will be enabled. A sample of the RF signal from the enabled oscillator is routed from U241 pin 12, through a low pass filter, to the prescaler input (U201 pin 32).
  • Page 44 UHF Band 2 Theory of Operation: Voltage-Controlled Oscillator (VCO) This page intentionally left blank. December 26, 2003 FMR-2045A-2...

  • Page 45: Chapter 5 Uhf Band 2 Cb Layouts, Schematic Diagrams, And Parts List

    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 46 UHF Band 2 CB Layouts, Schematic Diagrams, and Parts List: Notes For All Schematics and Circuit Boards This page intentionally left blank. December 26, 2003 FMR-2045A-2...

  • Page 47: Circuit Board/Schematic Diagrams And Parts List

    Circuit Board/Schematic Diagrams and Parts List Circuit Board/Schematic Diagrams and Parts List R410 C521 E407 E409 R437 C338 FL302 C325 C349 VR501 U405 TP201 J400 R506 SH201 C324 C220 Q505 L311 R355 R505 SH323 L203 C426 C425 U247 C512 C513 C260 Q502 C352...

  • Page 48: Uhf Band 2 (450-527 Mhz) Main Board Bottom Side Pcb No. 8486686Z01

    Circuit Board/Schematic Diagrams and Parts List VR444 C522 VR442 C523 R376 E404 C437 L505 C334 E406 R373 C350 S502 R359 R372 C383 R366 R374 R368 R371 R378 C359 C327 R370 C390 R375 E401 C348 L325 Q302 R312 R344 C279 R377 R415 R311 C525...
  • Page 49 Circuit Board/Schematic Diagrams and Parts List RADIO_CODE BATTERY_CONTACT L505 UNSWB+ B501 390nH BATT_CODE DATA BATT+ F501 S502 BATT- CONN_J SWITCH MECH_SWB+ LI_ION B503 TAB2 B504 VR506 VR439 C503 C502 TAB1 CR501 6.8V 100pF 0.47uF R507 C505 6.8V VR501 100pF Vdda PB501 SWITCH VR440...
  • Page 50 Circuit Board/Schematic Diagrams and Parts List DACRx C322 82pF R342 100K L310 150nH C315 R308 R310 R305 C314 100pF 0.1uF R304 C380 R309 .01uF L304 C321 CR306 180nH 100pF C306 T301 XFMR C309 C308 R307 100pF R306 100pF 100K 100K C312 C310 C316...
  • Page 51 Circuit Board/Schematic Diagrams and Parts List U302-1 TC7W04F C352 R345 R360 0.1uF FL303 U302-4 CFWC455E U302-3 PWR_GND TC7W04F OUT 2 R355 100K U302-2 TC7W04F BW_SEL C362 CR312 R321 R324 CR313 FL304 0.1uF 120K CFWC455G OUT 2 R361 R350 R358 C329 0.1uF C357 0.1uF...

  • Page 52: Uhf Band 2 Synthesizer Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List U211 TC7ST04FU U210 TC7ST04FU C296 C265 C257 0.1uF 100pF C258 .01uF U247 ADP3300 C259 SWB+ .01uF (SOURCE) CR201 C291 0.47uF C294 C293 4V_3.3V 100pF L202 0.47uF U248 2.2uH L203 LP2980 C277 C278 2.2uH 100pF 2.2uF C229 C230...

  • Page 53: Uhf Band 2 Voltage Controlled Oscillator Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List C281 R245 100pF R242 C250 L243 C276 C286 C285 4.3pF 2.2uF 0.1uF 100pF RESONATOR C246 L273 R241 L281 100pF 18nH 390nH C242 4.3pF C272 1.1pF C273 0.1uF C243 L242 L271 R244 4.3pF 22nH 27nH RX_INJ C245 2.7pF...

  • Page 54: Uhf Band 2 Harmonic Filter Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List ANT_BIAS SH100 C108 SHIELD L105 100pF 390nH TX_OUT HF SHIELD CR101 L104 L101 L102 12.39nH 12.39nH 12.39nH RX_IN CR102 C101 C102 C103 C104 C106 C107 100pF 6.2pF 13pF 6.2pF 4.7pF 3.3pF C188 R170 36pF RF_JACK R101 Figure 5-8.

  • Page 55: Uhf Band 2 Transmitter Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List E101 BEAD R102 UNSWB+ L107 C123 33.47nH 10uF C114 100pF C172 0.1uF C109 L106 UNSWB+ 100pF 7.66nH TX_OUT R106 Microstrip Microstrip Q110 R172 C160 L112 L108 R191 C121 R175 56pF 4.22nH 100pF 390nH Microstrip C118 100pF C111...
  • Page 56 Circuit Board/Schematic Diagrams and Parts List UHF Band 2 Radio Parts List Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Part No. Part No. Part No. Circuit Motorola C169 2113743N09 C257 2113743N50 100pF C325 2109445U26 9.1pF Description Part No.
  • Page 57 Circuit Board/Schematic Diagrams and Parts List Circuit Motorola Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Description Part No. Part No. Part No. Part No. C409 2113743M24 0.1uF C481 2113928N01 0.1uF CR501 4880107R01 Rectifier L273 2462587V32 68nH C410 2113928N01 0.1uF...
  • Page 58 Circuit Board/Schematic Diagrams and Parts List Circuit Motorola Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Description Part No. Part No. Part No. Part No. R107 NOT PLACED R311 0662057N11 R407 0662057N19 R498 0662057M98 R108 0662057M92 5.6K R312 0662057M90 4.7K...
  • Page 59 Y301 9186145B02 455kHz Ceramic Discriminator *8486686Z01 UHF B2 Main PC Board * Motorola Depot Servicing only ** Not Field Serviceable Note: Tolerance Capacitor - 5% unless specified otherwise Inductor - 10% unless specified otherwise Resistor - 5% unless specified otherwise...

  • Page 60: Controller Asfic/On_Off Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List 4V_3.3V R405 R402 TP410 SWB+ Q400 Vddd BATT_CODE TP406 Vddd UNSWB+ C405 100pF C400 800MHz only R401 C401 .01uF R406 R427 0.1uF 2.7K C403 U400 LP2951ACMM-3.3 10uF CR412 Vdda INPUT C402 OUTPUT R407 FEEDBACK 0.1uF ERROR INT_EXT_Vdd...

  • Page 61: Chapter 6 Uhf Band 2 Troubleshooting Charts

    UHF Band 2 Troubleshooting Charts: Troubleshooting Flow Chart for Controller Chapter 6 UHF Band 2 Troubleshooting Charts Troubleshooting Flow Chart for Controller MCU Check Press PTT. Red LED does not Before replacing light up Not able to pro- Power Up MCU, check SPI gram RF Board Audio at...

  • Page 62: Troubleshooting Flow Chart For Receiver (Sheet 1 Of 2)

    UHF Band 2 Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at pin 8 of U301? Spray or inject 1st IF 44.85 MHz into XTAL Filter...

  • Page 63: Troubleshooting Flow Chart For Receiver (Sheet 2 Of 2)

    UHF Band 2 Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J101 Trace IF signal Q302 collec- from L311 to IF Signal at tor OK? Q302.

  • Page 64: Troubleshooting Flow Chart For Transmitter

    UHF Band 2 Troubleshooting Charts: Troubleshooting Flow Chart for Transmitter Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Check Q111 Bias for Ant switch Is Control Volt- Check PCIC Is Current age High or Low High Check Drive to Module 1.

  • Page 65: Troubleshooting Flow Chart For Synthesizer

    UHF Band 2 Troubleshooting Charts: Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Check U248, 3.3V at U201 Start L201 & L202 pins 5, 20, 34 & Visual Check CR201, U210, Correct check of the U211, C258, C259 & Problem Board OK? C228...

  • Page 66: Troubleshooting Flow Chart For Vco

    UHF Band 2 Troubleshooting Charts: Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO START Change U241 No LO? Change L253 O/C? L253 Pin 10 TRB = 5V? Tx Carrier? >1V? VCO OK Check R245 for dry joint or faulty AUX 3 Check High?

  • Page 67: Chapter 7 Vhf Theory Of Operation

    Chapter 7 VHF Theory of Operation Transmitter P CI C Antenna Vcontrol Vcontrol Jack Antenna Switch/ From VCO Harmonic Filter/ Driver Final Stage Matching Network Figure 7-1. Transmitter Block Diagram 7.1.1 General (Refer to Figure 7-1.) The VHF transmitter contains five basic circuits: •...

  • Page 68: Antenna Switch

    VHF Theory of Operation: Transmitter 7.1.3 Antenna Switch The antenna switch circuit consists of two PIN diodes (D3521 and D3551), a pi network (C3531, L3551 and C3550), and three current limiting resistors (R3571, R3572, R3573). In the transmit mode, B+ at PCIC (U3502) pin 23 will go low and turn on Q3561 where a B+ bias is applied to the antenna switch circuit to bias the diodes “on.”...

  • Page 69: Receiver

    VHF Theory of Operation: Receiver Receiver Antenna Pin Diode Varactor Varactor Antenna Crystal RF Amp Mixer IF Amp Tuned Filter Tuned Filter Switch RF Jack Filter First LO from VCO Control Voltage from ASFIC U3220 Demodulator Limiter Recovered Audio RSSI 455kHz 455kHz Filter...

  • Page 70: Receiver Back-End

    VHF Theory of Operation: Receiver The output of the post-RF amplifier filter is connected to the passive double balanced mixer which consists of T3301, T3302 and CR3301. Matching of the filter to the mixer is provided by C3317, C3318 and L3308. After mixing with the first LO signal from the voltage controlled oscillator (VCO) using high side injection, the RF signal is down-converted to the 44.85 MHz IF signal.

  • Page 71: Frequency Generation Circuitry

    VHF Theory of Operation: Frequency Generation Circuitry Radio signal strength indicator, RSSI, a voltage signal, is used to drive Q3301 to saturation i.e. turned on. RSSI is produced by U3220 and is proportional to the gain of the RF amplifier and the input power to the radio.

  • Page 72: Synthesizer

    VHF Theory of Operation: Synthesizer Synthesizer (Refer to the VHF Synthesizer Schematic Diagram on page 82.) The Fractional-N Synthesizer uses a 16.8MHz crystal (Y3761) to provide a reference for the system. The LVFractN IC (U3701) further divides this to 2.1MHz, 2.225 MHz, and 2.4 MHz as reference frequencies.

  • Page 73: Voltage-Controlled Oscillator (Vco)

    VHF Theory of Operation: Voltage-Controlled Oscillator (VCO) Voltage-Controlled Oscillator (VCO) (Refer to the VHF Voltage-Controlled Oscillator Schematic Diagram on page 83.) AUX3 (U3701 Pin2) U3701 Pin 32 Prescaler Out TRB_IN Pin 20 Pin 19 Pin 12 Pin7 Rx-SW TX/RX/BS Tx-SW Pin13 Switching Network LO RF INJECTION...
  • Page 74 VHF Theory of Operation: Voltage-Controlled Oscillator (VCO) The RF section of the VCOBIC(U3801) is operated at 4.54 V (VSF), while the control section of the VCOBIC and Fractional-N synthesizer (U3701) is operated at 3.3V. The operation logic is shown in Table 7-1.

  • Page 75: Chapter 8 Vhf Circuit Board Layouts, Schematic Diagrams And Parts List

    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 multime- ter or equivalent. Transmitter measurements should be made with a 1.2 µH choke in series with the voltage probe to prevent circuit loading.
  • Page 76 VHF Circuit Board Layouts, Schematic Diagrams and Parts List: Notes For All Schematics and Circuit Boards This Page Intentionally Left Blank December 26, 2003 FMR-2045A-2...

  • Page 77: Circuit Board/Schematic Diagrams And Parts List

    Circuit Board/Schematic Diagrams and Parts List Circuit Board/Schematic Diagrams and Parts List VR444 VR440 PB503 PB502 PB501 PB504 C523 R410 E407 E409 C521 R437 C522 SH3203 R418 C3202 Y3205 Y3761 C3206 Y3204 Y3203 C3278 Y3200 U405 C3225 R3275 TP3702 C432 U406 Y3202 J400...

  • Page 78: Vhf (136-174Mhz) Main Board Bottom Side Pcb No. 8486473Z03

    Circuit Board/Schematic Diagrams and Parts List VR442 R375 R373 VR441 C328 R376 R370 E405 C437 R374 L505 E404 R378 R3209 C3236 U303 C390 D3761 E406 C3763 C359 R3271 R377 R3224 R3222 L3202 R3274 S502 C3279 R414 C3275 E403 L3270 C3215 B501 E402 C3200...

  • Page 79: Vhf Controls And Switches Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List UNSWB+ F501 mgc_comps PB505 S502 MECH_SWB+ SWITCH B501 BATT_CODE EMER TAB2 DATA L505 C535 C502 C503 390nH 100pF 1000pF 1000pF 0.47uF VR506 VR439 TAB1 6.8V CR501 C520 .01uF PB501 SWITCH Vdda LI_ION B503 VR440 C521 6.8V .01uF...

  • Page 80: Vhf Receiver Front-End Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List R5_2_FE R5_3_FE C3320 82pF R3316 C3337 C3309 L3309 0.1uF 0.1uF .022uF 150nH R3321 R3322 UNSWB_PLUS_1_RX UNSWB_PLUS_2_RX UNSWB+ IF_1_FE L3304 C3308 470nH 330pF R3323 C3336 10uF C3307 R3315 100pF C3315 T3301 10pF R3310 C3317 2.7K C3312 C3311 C3313...

  • Page 81: Vhf Receiver Back-End Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List Y3203 R3209 CFWC455E 1 IN R3212 U3221-1 TC7W04F C3225 0.1uF U3221-2 R3276 100K TC7W04F U3221-3 TC7W04F BW_SEL U3221-4 PWR_GND C3208 R3211 R3205 0.1uF Y3204 CFWC455G OUT 2 CR3202 CR3203 R3206 R3208 R3207 C3226 C3238 0.1uF 0.1uF Y3205...

  • Page 82: Vhf Synthesizer Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List U3711 mgc_comps 5V_1_FN 5V_2_FN SWB_PLUS_1_FN (SOURCE) SWB+ C3711 C3715 10uF 470pF L3701 C3713 C3712 390nH 0.1uF 2.2uF 2 K2 C3701 A2 5 .01uF A1 6 R3701 C3702 D3701 .01uF C3710 2.2uF C3703 .01uF BIAS_ADJ C3704 .01uF BIAS_ADJ_1_FN...

  • Page 83: Vhf Voltage Controlled Oscillator Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List Vdda Vdda_3_VCO VSF_1_VCO R5_1_VCO L3813 R3817 R3811 R3802 C3822 C3813 D3821 1000pF C3810 L3811 C3812 R3818 .01uF L3812 C3811 C3830 VCTRL_1_VCO C3825 10pF 100nH 0.1uF C3804 100nH 0.1uF 68pF 15pF VCTRL 0.1uF L3824 C3818 R3828 .022uF R3821...

  • Page 84: Vhf Transmitter Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List RESET UNSWB+ UNSWB+ UNSWB+ UNSWB+ DATA CLK 5V_2_PA RESET_1_PA C3571 470pF BIAS_TUNING C3570 330pF CLK_2_PA R3570 DATA_2_PA Q3561 CSX_2_PA UNSW_LPLUS_3_PA R3569 C3560 5.6K UNSWB_LPLUS_2_PA GND2 BPOS R3561 DATA U3502 H99S-4 TEMP LM50C RSET C3566 F168 5185963A15 100pF...
  • Page 85 Circuit Board/Schematic Diagrams and Parts List VHF Radio Parts List Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Part No. Part No. Part No. Circuit Motorola C3304 2113743N54 150pF C3504 2113743M08 22000pF C3562 2113743L29 3300pF Description Part No. C3305...
  • Page 86 Circuit Board/Schematic Diagrams and Parts List Circuit Motorola Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Description Part No. Part No. Part No. Part No. C3742 2113743L01 220pF C3832 2113743L17 1000pF C436 2113743N34 22pF C492 2113743L09 470pF C3743 2113743L01...
  • Page 87 Circuit Board/Schematic Diagrams and Parts List Circuit Motorola Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Description Part No. Part No. Part No. Part No. D3831 4805649Q13 Varactor Diode L3515 2479990C03 13.85nH PB505 4086470Z01 Tactile Switch R3270 0662057M74 1000...
  • Page 88 Circuit Board/Schematic Diagrams and Parts List Circuit Motorola Circuit Motorola Circuit Motorola Circuit Motorola Description Description Description Description Part No. Part No. Part No. Part No. R3541 0662057N13 R3752 0662057N29 180K R405 0662057M01 R456 0662057M01 R3542 0662057M92 5600 R376 0662057M01...
  • Page 89 16.8 MHZ Crystal Oscillator U3221 5109522E10 Inverter IC U3501 5185130C65 LDMOS Driver IC 8486473Z01 VHF main PC Board U3502 5185765B26 PCIC * Motorola Depot Servicing only U3503 5185963A15 Temperature Sensor U3701 5185130C18 LV FRAC-N IC U3711 5105739X05 5V Regulator U3801 5105750U54...

  • Page 90: Controller Asfic/On_Off Schematic Diagram

    Circuit Board/Schematic Diagrams and Parts List 4V_3.3V R405 R402 SWB+ Vddd Q400 TP406 1 BATT_CODE Vddd UNSWB+ C401 C400 R401 0.1uF .01uF R427 R406 2.7K U400 LP2951ACMM-3.3 C403 10uF OUTPUT C402 INPUT A1 4 R407 0.1uF BATT_DATA_IN ERROR FEEDBACK A2 5 INT_EXT_Vdd SENSE SHUTDOWN...

  • Page 91: Chapter 9 Vhf Troubleshooting Charts

    Chapter 9 VHF Troubleshooting Charts Troubleshooting Flow Chart for Controller MCU Check Press PTT. Red LED does not Before replacing light up Power Up Not able to pro- MCU, check SPI Audio Alert Tone gram RF Board AUDIO clock, SPI data, at Audio PA J403 Audio and RF IC select...

  • Page 92: Troubleshooting Flow Chart For Receiver (Sheet 1 Of 2)

    VHF Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Audio Check Controller at pin 8 of (in the case of no audio) U3220? or else go to “B”...
  • Page 93 VHF Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J3501 Trace IF signal Q3200 from L3200 to Signal at collector OK? Q3200. Check for L3200? IF signal bad XTAL filter.

  • Page 94: Troubleshooting Flow Chart For Transmitter

    VHF Troubleshooting Charts: Troubleshooting Flow Chart for Transmitter Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Check Bias for Ant Q3561 switch Is Control Is Current Check PCIC Voltage high or low? High Check Drive to Module 1.

  • Page 95: Troubleshooting Flow Chart For Synthesizer

    VHF Troubleshooting Charts: Troubleshooting Flow Chart for Synthesizer Troubleshooting Flow Chart for Synthesizer Check U3201, 3.3V at U3701 Start L3731 pins 5, 20, 34 & 36 Visual Check D3701, Correct check of the D3702, U3701, Problem Board OK? C3701 - C3707 16.8MHz Is 16.8MHz Is U3701 Pin 47...

  • Page 96: Troubleshooting Flow Chart For Vco

    VHF Troubleshooting Charts: Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO START Change U3801 L3831, L3832, Change No LO? L3833 L3831, L3832 O/C? Pin 10 TRB = 3.2V? Tx Carrier? >1V? VCO OK Check R3811, L3811 for faulty parts and dry joints AUX 3 Check...

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