Transmitter Troubleshooting - Motorola APX 7000 Basic Service Manual

Basic Troubleshooting: Transmitter Troubleshooting
Symptom
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
9.4

Transmitter Troubleshooting

Table 9-4 lists the possible causes of, and corrections for, transmitter problems.
Symptom
No RF Power Out
No Modulation;
Distorted Modulation
Bad Microphone Sensitivity
Table 9-3. Receiver Troubleshooting Chart (Continued)
Possible Cause
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
Table 9-4. Transmitter Troubleshooting Chart
Possible Cause
1. TX Power Level or Frequency
2. No Injection To Power
Amplifier
3. Antenna Switch/Connector
1. Programming
2. VOCON Board
1. Check Deviation and
Compensation
2. Microphone
Correction or Test
(Measurements at Room Temperature)
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
Correction or Test (Measurements
Taken at Room Temperature)
Check TX power level and frequency
programming (from tuner)
Send radio to depot
Check deviation and compensation
settings using the tuner
Send radio to depot
Realign if necessary
Send radio to depot
Sec 2: 9-3