Motorola ASTRO SPECTRA Service Manual page 135

Basic Troubleshooting: Transmitter Troubleshooting
Symptom
Bad
Microphone
Sensitivity
No/Low
signaling (PL,
DPL, Trunking,
MDC)
6881076C20-E
Table 9-5. Transmitter Troubleshooting Chart (Continued)
Possible Cause
Check Deviation and
Compensation
Microphone
Command Board
VOCON Board
Command Board
VCO Board
Check Programming
Correction or Test (Measurements
Taken at Room Temperature)
Retune, if necessary.
Speak loudly into the microphone while
monitoring the microphone line (pin 6 of
P502).
If it is not >80 mVrms, then replace the
microphone.
With 80 mVrms on the mic high line, check
pin 39 of P501.
If not >100 mVrms (ac coupled), replace
the command board.
With 80 mVrms on the mic high line, check
pin 49 of P501.
If not >100 mVrms (ac coupled), replace
the VOCON board.
With 80 mVrms on the mic high line,
monitor the VCO mod line (pin 11 on
J500). Voltage should be >200 mVrms.
If not, replace the command board.
If correct voltage was found on pin 11 of
J500, replace the VCO board.
Reprogram codeplug.
9-7
February 3, 2003