Motorola GP338 Plus - Troubleshooting Flow Chart for Receiver (Sheet 1

5D-32 Troubleshooting charts
Bad SINAD
Bad 20dB Quieting
No Recovered Audio
START
Audio at pin 27
of U301?
Check Controller
Yes
No
Spray of inject 1st IF into
XTAL Filter
IF Freq: 45.1MHz
Audio heard?
B
Yes
No
Check 2nd LO Control
Voltage at C363
VCO locked?
B
Yes
16.8 MHz
check at pin 22
U301?
Activity on
U301 sel pin?
Check FGU
No
No
A
A
Yes
Check Q320 bias cir-
cuitry for faults.
Rotate Freq. Knob
Check controller.
Before replacing U301, check 2nd VCO
Q320. Check VCO O/P level, C351,
C352.
Yes
No
Troubleshooting Flow Chart for Receiver (Sheet 1 of 2)