Chapter 3 Troubleshooting Charts - Motorola CDM Series Detailed Service Manual

Chapter 3
TROUBLESHOOTING CHARTS
1.0 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2)
B
B
Check circuitry
around U3101.
Replace
U3101 if defect
START
Bad SINAD
Bad 20dB Quieting
No Recovered Audio
Audio at
Yes
pin 8 of
U3101?
No
Spray or inject 44.85MHz
into XTAL Filter FL3101
Yes
Audio heard?
No
Check 2nd LO
(44.395MHz) at C3135
Yes
LO present?
No
Check voltages on
U3101
No
Yes
Voltages
OK?
Check Controller
(in the case of no audio)
OR ELSE go to "B"
Check Q3102 bias
No
Biasing OK?
Replace Q3102
Check circuitry around Y3101.
Replace Y3101 if defect
Section 8: 3-1
A
for faults
Yes
Go to B
6881091C63-F