Motorola Commercial CM Series - Troubleshooting Flow Chart for Receiver RF (Sheet 1 of 2)

3-2 TROUBLESHOOTING CHARTS
1.0 Troubleshooting Flow Chart for Receiver RF (Sheet 1 of 2)
Problem in 12 KHz and
25 KHz channel spacing
9V on
R310 (LNA)
OK
?
Check
RX_EN
No
Go to
DC Section
Yes
RX_EN
ON ?
No
Check Q306, Q300
and U403
Yes
START
LOC_DIST
ON
?
Check Q304, D305
and U403
LO
POWER
OK ?
Go to SYN
Section
Yes
Yes
No
No
Go
to A
3 V
to U301
Okay ?
No
Check
LOC_DIST
Go to
DC Section
Yes
Check D301-304
Replace IF Filters( FL304, FL301
If problem in 25 KHz spacing
Check
TPI
Check 5V
on R337 (UHF),
R336 (VHF)
5V
(IF AMP)
OK ?
Go to
DC Section
Yes
No
Check 3V
on R339
No (Either 12.5kHz or 25kHz channel spacing problem)
Yes