5-40
Troubleshooting Charts:
VCO Failure
VCO Failure – Page 3 (7/800MHz)
2
Control
voltage at
At Tx 764-776MHz, Rx 851-870MHz, is
R3018 high?
or
At Tx 851-870MHz, Rx 764-776MHz, is
R3052 high?
or
At Tx 794-824MHz, is R3019 high?
Yes
No
At Tx 764-776MHz, Rx 851-870MHz, is
Vdc at Q3038 4.55V?
or
At Tx 851-870MHz, Rx 764-776MHz, is
Vdc at Q3062 4.55V?
or
At Tx 794-824MHz,
Yes
Yes
At Tx 764-776MHz, Rx 851-870MHz, check and
visual inspect VR3010, VR3003, VR3012,
VR3013, C3014, C3015, C3022, C3023, Y3020.
At Tx 851-870MHz, Rx 764-776MHz, check and
visual inspect VR3048, VR3017, VR3020,
VR3021, C3050, C3051, C3054, C3055, Y3053.
At Tx 794-824MHz, check and visual inspect
VR3011,VR3004, VR3014, VR3015, C3016,
C3017, C3024, C3025, Y3021
Replace U702
Is Vdc at C742 5V,
Vdc at C726,
C734, C737
Is Vdc at Y701
pin 4 2.775V?
16.8MHz at
pin 3 of Y701
16.8MHz at
L753?
Yes
Yes
Yes
Yes
2.775Vdc at
pin 4 of D722?
10.8Vdc at
pin 2 of D723?
No
Yes
Yes
Check D722,
D723, C716
Take continuity
check of traces to
No
No
No
No
No
Check 2.775V and
5V supply
Check 2.775V
supply
Replace Y701
and/or C736
Check and visual
inspect U746
circuitry. Fault
found?
No
Yes
Replace the
suspected
No
No
Summary of Contents for Astro APX 3000
Page 1: ...APXTM TWO WAY RADIOS APX 3000 DETAILED SERVICE MANUAL ...
Page 2: ......
Page 4: ...Notes ...
Page 6: ...vi Document History Notes ...
Page 10: ...x Table of Contents Notes ...
Page 12: ...xii List of Tables Notes ...
Page 18: ...xviii List of Figures Notes ...
Page 22: ...xxii CommercialWarranty Notes ...
Page 46: ...3 20 Theory of Operation Main Board Notes ...
Page 84: ...3 58 Theory of Operation Bluetooth Notes ...
Page 208: ...6 64 Troubleshooting Waveforms LF CW on Spectrum Analyzer Notes ...
Page 222: ...7 14 Troubleshooting Tables List of Board and IC Signals Notes ...
Page 282: ...8 60 Schematics Boards Overlays and Parts Lists Main Board Block UHF1 84012513001_A Notes ...
Page 390: ...8 168 Schematics Boards Overlays and Parts Lists Main Board Block VHF 84012512001_A Notes ...
Page 456: ...9 8 Debugging Fixture Powering up Covert Board Notes ...
Page 468: ...Glossary 10 Glossary Notes ...
Page 472: ...Index 4 Index Notes ...
Page 473: ......