
Basic Troubleshooting
: Receiver Troubleshooting
8-3
8.3
Receiver Troubleshooting
lists the possible causes of, and corrections for, receiver problems.
Table 8-3. Receiver Troubleshooting Chart
Symptom
Possible Cause
Correction or Test
(Measurements at Room Temperature)
Radio Dead; Display Does Not
Turn On
1. Dead Battery
Replace with charged battery
2. Blown Fuse
Send radio to depot
3. On/Off Switch
4. Regulators
Radio Dead; Display
Turns On
1. Keypad Board
Send radio to depot
2. Main Board
Radio On; Front Display Off
High operating
temperature (above
80
°
C)
Allow radio to return to normal operating
temperature.
No Receive Audio, or Receiver
Does Not Unmute
Programming
1. Check if transmitted signal matches the
receiver configuration (PL, DPL, etc.)
2. Check if radio able to unmute with Monitor
function enabled
Audio Distorted or Not Loud
Enough
Synthesizer Not On
Frequency
Check synthesizer frequency by measuring the
transmitter frequency; realign if off by more than
±1000 Hz
RF Sensitivity Poor
1. Synthesizer Not On
Frequency
Check synthesizer frequency by measuring the
transmitter frequency; realign if off by more than
±1000 Hz
2. Antenna Switch/
Connector
Send radio to depot
3. Receiver Front-
End Tuning
Check RF front-end tuning for optimum sensitivity
using the tuner
Radio Will Not Turn Off
Main Board
Send radio to depot
Summary of Contents for APX 4000
Page 1: ...APXTM TWO WAY RADIOS APX 1000 APX 2000 APX 4000 APX 4000Li BASIC SERVICE MANUAL ...
Page 6: ...Notes iv Commercial Warranty ...
Page 8: ...ii Notes ...
Page 16: ...x Portable Radio Model Numbering System Notes ...
Page 46: ...3 12 Basic Theory of Operation Controller Section Notes ...
Page 60: ...5 12 Performance Checks Transmitter Performance Checks Notes ...
Page 128: ...8 34 Disassembly Reassembly Procedures Ensuring Radio Submergibility Notes ...
Page 142: ...Index 4 Index Notes ...
Page 144: ...ii Notes ...
Page 150: ...viii List of Figures Notes ...
Page 152: ...x Portable Radio Model Numbering System Notes ...
Page 240: ...7 32 Disassembly Reassembly Procedures Ensuring Reliable Splash Protection Notes ...
Page 250: ...9 6 Exploded Views and Parts Lists APX 1000 Back Kit Exploded View Parts List Notes ...
Page 254: ...Index 4 Index Notes ...
Page 255: ...Title Page ASTRO APX 1000 Digital Portable Radios Section 3 900 MHz APX 1000 ...
Page 256: ......
Page 262: ...viii List of Figures Notes ...
Page 264: ...x Portable Radio Model Numbering System Notes ...
Page 278: ...3 8 Basic Theory of Operation Controller Section Notes ...
Page 336: ...7 32 Disassembly Reassembly Procedures Ensuring Reliable Splash Protection Notes ...
Page 346: ...9 6 Exploded Views and Parts Lists APX 1000 Back Kit Exploded View Parts List Notes ...
Page 350: ...Index 4 Index Notes ...
Page 352: ...ii Notes ...
Page 360: ...x Portable Radio Model Numbering System Notes ...
Page 400: ...5 12 Performance Checks Transmitter Performance Checks Notes ...
Page 428: ...6 28 Radio Alignment Procedures Performance Testing Notes ...
Page 434: ...7 6 Encryption Erase an Encryption Key Notes ...
Page 478: ...8 44 Disassembly Reassembly Procedures Ensuring Radio Submergibility Notes ...
Page 490: ...ii Notes ...
Page 492: ...A 2 Accessories Notes ...
Page 496: ...Notes B 4 EMEA Warranty Service and Technical Support Further Assistance From Motorola ...
Page 520: ...Glossary 12 Glossary Notes ...
Page 524: ...Index 4 Index Notes ...
Page 525: ......