![Motorola GM338 Service Manual Download Page 467](http://html.mh-extra.com/html/motorola/gm338/gm338_service-manual_245920467.webp)
Troubleshooting Flow Chart for VCO
3-5
4.0
Troubleshooting Flow Chart for VCO
Are Q5332
Base at 0.7V
Collector at 4.5V
Emitter at 110mV
Are Q5301
Base at 2.4V
Collector at 4.5V
Emitter at 1.7V
Are Q5311
Base = 1.9V
Collector = 4.5V
Emitter = 1.3V
Low or no RF Signal
at TP5003
Visual check
of board
OK?
35mV DC at
U5301 Pin 19
NO
YES
Replace Q5301
at base of Q5332
NO
NO
NO
NO
YES
YES
YES
YES
Low or no RF Signal
at input to PA
4.8V DC at
U5301 Pin 19
Is RF available
at U5401
YES
YES
YES
YES
NO
NO
NO
NO
NO
Audio =180mVrms
at “-” S
ide of
4.5VDC
at CR5321
If C5321 and R5321 are OK,
then replace CR5321
Replace C5322
Replace C5325
NO
NO
YES
YES
TX VCO
RX VCO
Correct
Problem
Visual check
of board
OK?
Check runner
between U5201 Pin 2
and U5301 Pin 19
Is RF available
If all parts from U5301 Pin 8
to Base of Q5332 are OK,
replace U5301
If all parts associated
with the pins are OK,
replace Q5332
If all parts from collector
of Q5332 to TP5003 are
OK, Replace U5301
Power OK but
no modulation
If all parts from U5301 Pin 10
U5401 Pin 16 are OK,
replace U5301
Replace
Q5311
YES
YES
Make sure Synthesizer is
working correctly and runner
between U5201 Pin 28 and
U5301 Pin 14 & 18 are OK
4.5V DC
OK ?
OK?
OK?
C5325
at U5301 Pin 14 & 18
4.5V DC
OK ?
at U5301 Pin 14 &18
NO
Pin 16
If R5361 and
L5361 are OK,
replace U5301
Summary of Contents for GM338
Page 1: ...GM328 GM338 GM398 Mobile Radios Detailed Service Manual 6804112J18 E December 2003 ...
Page 4: ...THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 6: ...THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 7: ...GM328 GM338 GM398 Mobile Radios Service Maintainability Issue December 2003 ...
Page 14: ...vi THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 16: ...viii THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 20: ...1 4 Radio Model Information THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 32: ...2 12 Notes For All Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 35: ...GM328 GM338 GM398 Mobile Radios Controlhead Service Information Issue December 2003 ...
Page 42: ...1 4 GM398 Model GCN6115_ THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 56: ...2 14 Controlhead Model for GM398 THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 70: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 88: ...4 20 Controlhead GM398 PCB 8486178B03 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 89: ...GM328 GM338 GM398 Mobile Radios Controller Service Information Issue December 2003 ...
Page 114: ...2 2 Controller Troubleshooting Chart THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 140: ...3 26 Controller T7 T9 Schematic Diagrams THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 141: ...GM328 GM338 GM398 Mobile Radios VHF 136 174MHz Service Information Issue December 2003 ...
Page 148: ...1 4 Technical Specifications THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 158: ...2 10 VHF 136 174 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 166: ...3 8 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 168: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 186: ...4 20 VHF 1 25W PCBs Schematics Parts Lists THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 187: ...GM328 GM338 GM398 Mobile Radios UHF 403 470MHz Service Information Issue December 2003 ...
Page 204: ...2 10 UHF 403 470 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 212: ...3 8 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 214: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 235: ...GM328 GM338 GM398 Mobile Radios UHF Band 2 450 527MHz Service Information Issue December 2003 ...
Page 252: ...2 10 UHF 450 527 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 260: ...3 8 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 262: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 274: ...4 14 UHF Band 2 1 25W PCBs Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 275: ...GM338 GM398 Mobile Radios Low Band Service Information Issue December 2003 ...
Page 280: ...iv THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 284: ...1 4 Technical Specifications THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 300: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 378: ...4 78 Low Band PCBs Schematics Parts Lists THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 379: ...GM338 Mobile Radios VHF 45W Bipolar 136 174MHz Service Information Issue December 2003 ...
Page 400: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 411: ...GM338 Mobile Radios UHF1 40W Bipolar 403 470MHz Service Information Issue December 2003 ...
Page 426: ...2 10 Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 432: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 434: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 446: ...4 14 UHF 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 447: ...GM338 Mobile Radios UHF2 40W Bipolar 450 520MHz Service Information Issue December 2003 ...
Page 462: ...2 10 Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 468: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 470: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 482: ...4 14 UHF Band 2 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 483: ...GM338 Mobile Radio UHF B1 HIGH POWER LDMOS 403 470MHz Service Information Issue December 2003 ...
Page 498: ...2 10 UHF 403 470 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 506: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 518: ...4 14 UHF 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 534: ...2 10 UHF 450 520 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 540: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 542: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 554: ...4 14 UHF Band 2 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...