Chapter 3 Troubleshooting Charts; Troubleshooting Flow Chart For Receiver (Sheet 1 Of 2); Troubleshooting Flow Chart For Receiver (Sheet 2 Of 2) - Motorola GP Series Service Manual

1.0

Troubleshooting Flow Chart for Receiver (Sheet 1 of 2)

A
START
Bad SINAD
Bad 20dB Quieting
No Recovered Audio
A
udio
at pin 27 of
U351?
No
Spray of inject 1st IF into
XTAL Filter
IF Freq: 109.65MHz
Yes
Audio
B
heard?
No
Check 2nd LO Control Voltage at C365
Yes
VCO
B
locked?
No
16.8 MHz
Yes
at pin 22 U351
?
No
Check FGU
TROUBLESHOOTING CHARTS
Yes
Check Controller
Before replacing U351, check 2nd
VCO Q350. Check VCO O/P level,
Chapter 3
A
Check Q350 bias
circuitry for faults.
Rotate Freq. Knob
Activity
No
on U351
pin19
?
Yes
Check controller
C385, C387.