Motorola GM328

3-1
Section 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 C1129.
LO present?
B
Yes
Check volt-
ages on
U1103. OK?
Biasing OK?
No
No
A
Yes
Check Q1106 bias
for faults.
Replace Q1106.
Go to B
Yes
No
Check cir-
cuitry around
U1103.
Replace
U1103 if
defect.
Check circuitry around Y1101.
Replace Y1101 if defect.