Motorola ASTRO SPECTRA Service Manual page 136

9-8
Symptom
Can't Set
Compensation
NOTE: The P501 pins can be probed on the extender cable (see the P501 Extender Cable
February 3, 2003
Table 9-5. Transmitter Troubleshooting Chart (Continued)
Possible Cause
VOCON Board
Command Board
RF Board
diagram on page 10-6 ).
Basic Troubleshooting: Transmitter Troubleshooting
Correction or Test (Measurements
Taken at Room Temperature)
Vary deviation and compensation controls
from maximum to minimum.
With the low frequency source active
(using the appropriate radio programming
Chapter 6: Radio
software–see
Alignment Procedure
) voltage or pin 48
of P501 should vary from <100 mVrms to
>3 mVrms.
With the high frequency source active,
voltage on pin 49 of P501 (ac coupled)
should vary from <100 mVrms to >3
mVrms.
1. All modulation testing should be done
with the radio keyed and 1 Vrms on the
mic high line of the microphone.
Check that normal voice deviation is OK.
Otherwise, go to No Modulation or Bad
Microphone Sensitivity.
2. Set deviation and compensation
controls to maximum.
Voltage on pin 17 of J500 should be > 3 V
p-p.
Voltage @ pin 11 of J500 should be >3 V
p-p.
If not, replace the command board.
If maximum deviation can be set to > 5.0
kHz, but compensation cannot be set,
then replace the RF board.
Otherwise, replace the VCO board.
6881076C20-E