Troubleshooting Charts:
RX RF Failure
5-35
RX RF Failure – Page 9
11
Measure control
voltage at TP603
Fvco too low?
7/800/ UHF1
UHF2/ VHF:
<107.4 MHz
TP603 = 5 Vdc?
TP603= 0 Vdc?
10
10
Remove Abacus
2nd LO shield,
SH4, and inspect
second LO VCO.
Visual
examination
Repair defects
Replace
Varactor
VR602
No
No
Yes
No
Yes
Yes
No
Yes
12
Remove IF filter shield,
SH1. Check IF filter and
LC matching networks.
Visual
inspection
OK?
Repair
Defects
Replace IF
filter, FL502.
No
Yes
Note: RF Test frequency used:
UHF1: 424.975MHz
UHF2: 485.075MHz
VHF: 154.275MHz
700: 769.0625MHz
800: 860.0625MHz
Measured with a High Frequency Probe for relative comparisons and troubleshooting
only. Actual S21 gain or loss may differ if the test point is not 50 ohms.
TP603 (Vdc)
TP601 (MHz) Fvco
0.00
102.70
1.33
107.40
3.89
111.90
5.00
112.75
(For reference only)
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: ......