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9-2
VHF Troubleshooting Tables:
Troubleshooting Table for Synthesizer (VHF)
9.2
Troubleshooting Table for Synthesizer (VHF)
Table 9-2. Troubleshooting Table for Synthesizer (VHF)
Symptom
Possible Causes
Procedure
Corrective Action
Synthesizer Out of
Lock (No RX
Mode)
1. Defective 12.8 MHz
VCTCXO
Verify clock output FL701 pin 3 is
12.8 MHz using high impedance
probe.
Repair/Replace FL701
2. 1/2VCC defective
Verify FL701 pin 1, U502-B pin 5&
U502-D pin 14 voltage is 1.9V.
Troubleshoot: 1/2VCC circuitry
3. No RX-Enable
Verify U101 pin 71 (RX-EN1) is high.
Verify Q304 collector voltage is
approximately 4.7V in RX mode
Check U101 operating
Troubleshoot: Q304 & Q305
circuitry
4. Check PLL-LD port
Verify U101 pin 27 is Low (Normal
Mode)
Verify U101 pin 27 is swept from low
to high (Power Save Mode)
Troubleshoot: PLL circuitry.
Repair/Replace U701
Synthesizer Out of
Lock (No TX Mode)
1. Defective 12.8 MHz
VCTCXO
Verify clock output FL701 pin 3 is
12.8 MHz using high impedance
probe.
Repair/replace FL701
2. 1/2VCC defective
Verify FL701 pin 1, U502-B pin 5 &
U502–D pin 14 voltage is 1.9V.
Troubleshoot: 1/2VCC circuitry
3. No TX-Enable
Verify U101 pin 84(TX-EN1) is high
when PTT is pressed.
Verify Q407 collector voltage is
approximately 4.7V when PTT is
pressed (TX-EN2).
Check U101 operating
Check U101-pin 85 is high/
Replace Q407/check LK2 is
short
4. Check PLL-LD port
Verify U101 pin 27 is Low (Normal
Mode)
Verify U101 pin 27 is swept from low
to high (Power Save Mode)
Troubleshoot: PLL circuitry
Repair/Replace U701
Содержание P100 Series
Страница 1: ...P100 Series Portable Radios Detailed Service Manual ...
Страница 2: ......
Страница 8: ...iv Notes ...
Страница 18: ...xiv List of Tables Notes ...
Страница 22: ...xviii Summary of Printed Circuit Boards and Bands Available Notes ...
Страница 30: ...Notes 2 4 Test Equipment Service Aids and Service Tools Service Aids ...
Страница 54: ...7 4 UHF2 Schematic Diagrams Overlays and Parts Lists Speaker and Microphone Schematic Notes ...
Страница 128: ...7 78 Circuit Board Schematic Diagram and Parts List UHF2 435 480 MHz Notes ...
Страница 150: ...7 100 Circuit Board Schematic Diagram and Parts List UHF2 MDC QCII R TTE 435 470 MHz Notes ...
Страница 166: ...10 4 VHF Schematic Diagrams Overlays and Parts Lists Speaker and Microphone Schematic Notes ...
Страница 192: ...10 26 Circuit Board Schematic Diagram and Parts List VHF 136 174 MHz Notes ...
Страница 218: ...10 52 Circuit Board Schematic Diagram and Parts List VHF 136 174 MHz Notes ...
Страница 242: ...10 76 Circuit Board Schematic Diagram and Parts List VHF MDC QCII R TTE 136 174 MHz Notes ...
Страница 258: ...13 4 UHF1 Schematic Diagrams Overlays and Parts Lists Speaker and Microphone Schematic Notes ...
Страница 261: ...Circuit Board Schematic Diagram and Parts List UHF1 403 447 MHz 13 7 Figure 13 5 Transmitter Schematic Diagram ...
Страница 328: ...13 74 Circuit Board Schematic Diagram and Parts List UHF1 MDC QCII R TTE 403 447 MHz Notes ...
Страница 332: ...A 4 Warranty Service Support and Replacement Parts Further Assistance From Motorola Notes ...
Страница 335: ......