Motorola CDM1250 - Troubleshooting Charts; 1.0 Troubleshooting Flow Chart for Receiver

Section 7: 3-1
6881091C63-F
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 U1103?
Check Controller (in the case of no audio).
Or else go to “B”
Yes
No
Spray or inject 10.7MHz
into XTAL Filter FL1102.
Audio heard?
B
Yes
No
Check 2nd LO
(10.245MHz) at
LO present?
B
Yes
Check
voltages on
U1103. OK?
Biasing OK?
No
No
A
Yes
Check Q1106 bias
for faults.
Replace Q1106.
Go to B
Yes
No
Check
circuitry
around
U1103.
Replace
U1103 if
Check circuitry around Y1101.
Replace Y1101 if defect.