Service manual

27
Symptom Possible Cause Correction or Test (Measurements Taken at Room Temperature)
No RF Power 1. TX Power Level Check TX power level and frequency programming (from RSS).
Out or Frequency
2. No PTT From With the PTT switch depressed (radio transmitting/keyed), check for INT PTT
Control Top at P901 pin 6 of the control top/PTT flex;
if not there, replace the control top/PTT flex.
3. No Injection To Check LOCK DETECT at pin 13 of the RF board connector;
Power Amplifier if not between 1.0 and 4.5V, replace the RF board.
No Modulation; 1. Programming Check deviation and compensation settings using the RSS.
Distorted 2. Controller With a 1kHz tone at 80mVrms injected at the external microphone, is the
Modulation Board output of the controller board to RF board connector pin 15 distorted?
If so, replace the controller board.
Bad Microphone 1. Check Realign if necessary.
Sensitivity Deviation and
Compensation
2. Microphone Speaking loudly into the microphone, monitor the output voltage (INT MIC)
at the speaker microphone flex connector, P701 pin 4.
If not 2mVrms, replace the speaker/microphone and front shield assembly.
No/Low 1. Check
Signalling Programming
(PL, DPL, MDC) 2. Controller Check for proper modulation at the RF board to controller board
Board connector pin 15; if not there, replace the controller board.
Can’t Set 1. RF Board If maximum deviation can be set to > 5.0kHz, but compensation
Compensation cannot be set, replace the RF board.
Table 18. Transmitter Troubleshooting Chart