5-36
Troubleshooting Charts:
RX RF Failure
RX RF Failure – Page 10
Check Mixer:
Remove shield, SH2. Check
the polarity of T506 and check
to see that all pins are
grounded. Visually inspect
windings.
Is the polarity
correct and all
pins are
gounded?
13
Remove shield, SH2.
Measure the LO power
going into the mixer,
U507, at the output side
of R525.
Is the LO power
around -3dBm?
Remove shield, SH1.
Check the polarity of T507
and check to see that all pins
are grounded. Visually
inspect windings.
Is the polarity
correct and all
pins are
gounded?
Replace
T506
Replace
T507
No
Yes
Yes
No
Remove shields, SH1 &
SH11. Measure IF level at
XTAL filter and compute
XTAL filter loss, non
ground side of C515 and
non ground side of C644.
Loss:
700: < 6dB?
800: < 6dB?
UHF1/UHF2/VHF:
<5dB?
No problem
found.
12
No
Yes
8
Yes
8
Check FGU
and replace
U507 if
needed.
No
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.
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: ......