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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
2.4 Low Intermediate Frequency (IF) and Receiver Back End.............................2-3
3.0 VHF (136-174 MHz) Transmitter Power Amplifier (PA) 25 W..............................2-3
3.1 First Power Controlled Stage..........................................................................2-4
3.2 Power Controlled Driver Stage .......................................................................2-4
3.3 Final Stage .....................................................................................................2-4
3.4 Directional Coupler .........................................................................................2-5
3.5 Antenna Switch...............................................................................................2-5
3.6 Harmonic Filter ...............................................................................................2-5
3.7 Power Control.................................................................................................2-5
4.0 VHF (136-174 MHz) Frequency Synthesis ..........................................................2-6
4.1 Reference Oscillator .......................................................................................2-6
4.2 Fractional-N Synthesizer ................................................................................2-6
4.3 Voltage Controlled Oscillator (VCO)...............................................................2-7
4.4 Synthesizer Operation ....................................................................................2-8
Section 3
Troubleshooting Charts
1.0 Troubleshooting Flow Chart for Receiver ............................................................3-1
2.0 Troubleshooting Flow Chart for 25W Transmitter ................................................3-3
3.0 Troubleshooting Flow Chart for Synthesizer........................................................3-6
4.0 Troubleshooting Flow Chart for VCO...................................................................3-7
Summary of Contents for GM338
Page 1: ...GM328 GM338 GM398 Mobile Radios Detailed Service Manual 6804112J18 E December 2003 ...
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Page 7: ...GM328 GM338 GM398 Mobile Radios Service Maintainability Issue December 2003 ...
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Page 20: ...1 4 Radio Model Information THIS PAGE INTENTIONALLY LEFT BLANK ...
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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 ...
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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 ...
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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 ...
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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 ...
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Page 235: ...GM328 GM338 GM398 Mobile Radios UHF Band 2 450 527MHz Service Information Issue December 2003 ...
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Page 275: ...GM338 GM398 Mobile Radios Low Band Service Information Issue December 2003 ...
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Page 284: ...1 4 Technical Specifications THIS PAGE INTENTIONALLY LEFT BLANK ...
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Page 379: ...GM338 Mobile Radios VHF 45W Bipolar 136 174MHz Service Information Issue December 2003 ...
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Page 411: ...GM338 Mobile Radios UHF1 40W Bipolar 403 470MHz Service Information Issue December 2003 ...
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Page 447: ...GM338 Mobile Radios UHF2 40W Bipolar 450 520MHz Service Information Issue December 2003 ...
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Page 483: ...GM338 Mobile Radio UHF B1 HIGH POWER LDMOS 403 470MHz Service Information Issue December 2003 ...
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