Receiver Troubleshooting - Motorola APX 5000 Service Manual

Basic Troubleshooting: Receiver Troubleshooting
9.3

Receiver Troubleshooting

Table 9-3 lists the possible causes of, and corrections for, receiver problems.
Symptom
Radio Dead; Display Does Not
Turn On
Radio Dead; Display
Turns On
Radio On; Front Display Off
No Receive Audio, or Receiver
Does Not Unmute
Audio Distorted or Not Loud
Enough
RF Sensitivity Poor
Radio Will Not Turn Off
Table 9-3. Receiver Troubleshooting Chart
Possible Cause
1. Dead Battery
2. Blown Fuse
3. On/Off Switch
4. Regulators
1. VOCON Board
2. RF Board
3. Expansion Board
High operating
temperature (above
°
80 C)
Programming
Synthesizer Not On
Frequency
1. Synthesizer Not On
Frequency
2. Antenna Switch/
Connector
3. Receiver Front-
End Tuning
VOCON Board
Correction or Test
(Measurements at Room Temperature)
Replace with charged battery
Send radio to depot
Send radio to depot
Allow radio to return to normal operating
temperature.
1. Check if transmitted signal matches the
receiver configuration (PL, DPL, etc.)
2. Check if radio able to unmute with monitor
function enabled
Check synthesizer frequency by measuring the
transmitter frequency; realign if off by more than
±1000 Hz
Check synthesizer frequency by measuring the
transmitter frequency; realign if off by more than
±1000 Hz
Send radio to depot
Check RF front-end tuning for optimum sensitivity
using the tuner
Send radio to depot
Sec 1: 9-3