Troubleshooting Charts:
PA Failure
5-49
PA Failure – Page 4 (ALC)
Remove SH15 and measure
PA control voltage at
U901 for VHF,
U1601 for UHF1/UHF2 and
U1001 for 700/800 MHz
pin 4
5
VC_OFFSET low,
remove SH6
Is U901/U1601/U1001/
Pin 1 about 2.5V?
Replace U901/U1601/U1001
Yes
Is U1202 Pin 5 about
2.3+/-0.2V?
Replace U1202
Yes
No
Is U1251 Pin 1
about 2.3+/-0.2V?
Replace U1251
Yes
No
Is U1282 Pin 6
about 2.3+/-0.2V?
Replace U1282
Yes
No
Is U1269 Pin 3
about 2.3+/-0.2V?
Yes
No
Is U1269 Pin 1
ANA_CTRL_ISET
about 5V?
U1269 is a smaller picker. If Pin 1 measured voltage was
lower than Pin 3, Pin 1 voltage will be picked as V-control
and caused no or low V_control to bias PA, resulting no
or low TX power
Yes
MAKO Ramp is working fine
Is U1253 Pin 1
about 2.3+/-0.2V?
No
Replace U1253
Yes
Is U1201 Pin 1
about 5V at DAC 4095?
No
Replace R1244
Yes
No
Replace U1201
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: ......