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Section 12: 3-6
Troubleshooting Flow Chart for VCO
4.0
Troubleshooting Flow Chart for VCO
Are Q4332
Base at 0.7V
Collector at 4.5V
Emitter at 110mV
Are Q4301
Base at 2.4V
Collector at 4.5V
Emitter at 1.7V
Are U4301 Pins
13 at 4.4V
15 at 1.1V
10 at 4.5V
16 at 1.9V
Low or no RF Signal
at TP4003
Visual check
of board
OK?
35mV DC at
U4301 Pin 19
NO
YES
Replace Q4301
at base of Q4332
NO
NO
NO
NO
YES
YES
YES
YES
Low or no RF Signal
at input to PA
4.8V DC at
U4301 Pin 19
Is RF available
at C4402
YES
YES
YES
YES
NO
NO
NO
NO
NO
Audio =180mVrms
at “-” S
ide of
4.5VDC
at CR4321
If C4321 and R4321 are OK,
then replace CR4321
Replace C4322
Replace C4325
NO
NO
YES
YES
If parts between
R4402 & U4301 Pin10
are OK, replace U4301
TX VCO
RX VCO
Correct
Problem
Visual check
of board
OK?
Check runner
between U4201 Pin 2
and U4301 Pin 19
Is RF available
If all parts from U4301 Pin 8
to Base of Q4332 are OK,
replace U4301
If all parts associated
with the pins are OK,
replace Q4332
If all parts from collector
of Q4332 to TP4003 are
OK, Replace Q4332
Power OK but
no modulation
Check parts from
R4402 to U4401 Pin16
If all parts
associated
with the pins
are OK,
replace U4301
YES
YES
Make sure Synthesizer is
working correctly and runner
between U4201 Pin 28 and
U4301 Pin 14 & 18 are OK
4.5V DC
OK?
OK?
OK?
C4325
at U4301 Pin 14 & 18
4.5V DC
OK?
at U4301 Pin 14 &18
NO
Summary of Contents for PRO Series
Page 1: ...CDM Series and PRO Series Two Way Mobile Radios Detailed Service Manual 6881091C63 F ...
Page 4: ...Notes ...
Page 6: ...Notes ...
Page 8: ...Section 1 ii 6881091C63 F Notes ...
Page 12: ...Section 1 1 4 Radio Model Information 6881091C63 F Notes ...
Page 22: ...Section 1 2 10 Notes For All Schematics and Circuit Boards 6881091C63 F Notes ...
Page 46: ...Section 2 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 78: ...Section 3 1 20 Controller Board Audio and Signaling Circuits Section 6881091C63 F Notes ...
Page 80: ...Section 3 2 2 Troubleshooting Flow Chart for Controller 6881091C63 F Notes ...
Page 84: ...Section 3 3 4 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 146: ...Section 3 3 66 Controller T6 T7 Schematics and Parts Lists 8471235L06 Notes 6881091C63 F ...
Page 152: ...Section 4 1 4 Technical Specifications 6881091C63 F Notes ...
Page 168: ...Section 4 3 8 Troubleshooting Flow Chart for VCO 6881091C63 F Notes ...
Page 172: ...Section 4 4 4 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 232: ...Section 5 1 4 Technical Specifications 6881091C63 F Notes ...
Page 242: ...Section 5 2 10 UHF Band 1 403 470 MHz 1 25 W Frequency Synthesis 6881091C63 F Notes ...
Page 296: ...Section 6 1 4 Technical Specifications 6881091C63 F Notes ...
Page 306: ...Section 6 2 10 UHF Band 2 450 512 527 MHz 1 25 W Frequency Synthesis 6881091C63 F Notes ...
Page 316: ...Section 6 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 352: ...Section 7 3 6 Troubleshooting Flow Chart for VCO 6881091C63 F Notes ...
Page 356: ...Section 7 4 4 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 458: ...Section 8 1 4 Technical Specifications Section 6881091C63 F Notes ...
Page 474: ...Section 8 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 496: ...Section 9 1 4 Technical Specifications Section 6881091C63 F Notes ...
Page 512: ...Section 9 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 530: ...Section 10 1 4 Technical Specifications Section 6881091C63 F Notes ...
Page 546: ...Section 10 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 564: ...Section 11 1 4 Technical Specifications 6881091C63 F Notes ...
Page 580: ...Section 11 3 8 Troubleshooting Flow Chart for VCO 6881091C63 F Notes ...
Page 582: ...Section 11 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 608: ...Section 12 1 4 Technical Specifications 6881091C63 F Notes ...
Page 624: ...Section 12 3 8 Troubleshooting Flow Chart for PassPort 6881091C63 F Notes ...
Page 626: ...Section 12 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 654: ...Section 13 1 4 Technical Specifications 6881091C63 F Notes ...
Page 672: ...Section 13 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...