Motorola 6864115B62-C - 1.0 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2)

Chapter 3
TROUBLESHOOTING CHARTS
1.0 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2)
Bad SINAD
Bad 20dB Quieting
No Recovered Audio
START
Audio at
pin 8 of
U3101 ?
Check Controller
(in the case of no audio)
OR ELSE go to “B”
Yes
No
Spray or inject 44.85MHz
into XTAL Filter FL3101
Audio heard ?
B
Yes
No
Check 2nd LO
(44.395MHz) at C3135
LO present ?
B
Yes
Check voltages on
U3101
Biasing OK ?
No
No
A
Yes
Check Q3102 bias
for faults
Replace Q3102
Go to B
Yes
No
Check circuitry
around U3101.
Replace
U3101 if defect
Check circuitry around Y3101
Replace Y3101 if defect
Voltages
OK?