Troubleshooting Flow Chart For Receiver Rf (Sheet 1 Of 2) - Motorola CM140 Service Information

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Troubleshooting Flow Chart for Receiver RF (Sheet 1 of 2)

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