Transmitter Troubleshooting; Table 9-4. Transmitter Troubleshooting Chart - Motorola APX 3000 Basic Service Manual

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Basic Troubleshooting: Transmitter Troubleshooting
Symptom
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
No/Low signaling
(PL, DPL, MDC)
Cannot Set Deviation
Balance
Table 9-3. Receiver Troubleshooting Chart (Continued)
Possible Cause
Synthesizer Not On
Frequency
1. Synthesizer Not On
Frequency
2. Antenna Switch/
Connector
3. Receiver Front-
End Tuning
Main 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. Main Board
1. Check Deviation and
Compensation
2. Accessories
1. Programming
2. Main Board
Main Board
Correction or Test
(Measurements at Room Temperature)
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
Reallign if necessary
Send radio to depot
Check programming
Send radio to depot
Send radio to depot
9-3

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