Troubleshooting Charts:
RX RF Failure
5-41
RX RF Failure – Page 8
9
Clock
Synthesizer
Measure tuning
voltage (Vt) at
R608
CLK_SSI_RX
Vt = 3 Vdc?
10
Vt = 0 Vdc?
10
Remove SH2, inspect
clock oscillator circuit
at U601-19,20
Visual
examination
Replace Varactor
VR601
Repair
Defects
No
No
No
Yes
Yes
Yes
No
10
Remove SH2,
inspect
components
Visual
examination
OK?
Check level shifters, U603 and U604 by
checking signal amplitudes using an
oscilloscope at R616, R617, R618. R616
and R617 belong to U603 and R618 belongs
to U604. Note: These resistors are not
placed. You will be probing the pads.
Repair
defects
No
Yes
Yes
Is the input side
pad of R616, R617
& R618 = 3 V?
Is the output side
pad of R616, R617
& R618 = 1.875 V?
Replace
Abacus,
U601
Replace level
shifters, either
U603, U604 or both.
Replace
Abacus,
U601
No
Yes
No
Yes
Note:
RF Test frequency used:
VHF: 154.275MHz
UHF1: 424.975MHz
UHF2: 485.075MHz
700: 769.0625MHz
800: 860.0625MHz
900: 938.0625MHz
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 APX 2000
Page 1: ...APXTM TWO WAY RADIOS APX 1000 APX 2000 APX 4000 APX 4000Li DETAILED SERVICE MANUAL ...
Page 4: ......
Page 6: ...iv Document History Notes ...
Page 8: ...Notes vi Commercial Warranty ...
Page 10: ...Notes ...
Page 22: ...xiv List of Figures Notes ...
Page 226: ...6 64 Troubleshooting Waveforms LF CW on Spectrum Analyzer Notes ...
Page 688: ...Index 4 Index Notes ...
Page 690: ...ii Notes ...
Page 700: ...xvi List of Figures Notes ...
Page 806: ...5 50 Troubleshooting Charts PA Failure Notes ...
Page 1008: ...8 178 Schematics Boards Overlays and Parts Lists Transceiver RF Boards UHF2 84012621001 Notes ...
Page 1062: ...8 234 Schematics Boards Overlays and Parts Lists Keypad Board M2 and M3 PC000261A01 Notes ...
Page 1064: ...ii Notes ...
Page 1068: ...Notes A 4 EMEA Warranty Service and Technical Support Further Assistance From Motorola ...
Page 1090: ...Glossary 10 Glossary Notes ...
Page 1094: ...Index 4 Index Notes ...
Page 1095: ......