Service manual

3-10 UHF Troubleshooting Charts
Bad SINAD
Bad 20dB Quieting
No Recovered Audio
START
Audio at pin
27 of U301?
Check Controller
Yes
No
Induce or 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
circuitry 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)