Motorola 6864115B62-C

Troubleshooting Flow Chart for Receiver 3-3
Troubleshooting Flow Chart for Receiver (Sheet 2 of 2)
Check for detailed mixer.
Is
9V3 present
?
RF
Signal at
pin 3 of
U1051
?
RF
Signal at
C1002
?
RF
Signal at
C1013
?
IF
Signal at
pin 2 of
U1051
?
No
RF
Signal at
C1017
?
No
No
No or
Check harmonic filters J1401
and ant.switch
Check preselector
and RF amp.
Inject RF into J1401
No
Yes
Check RF amp (Q1001)
Stage.
Check filter between
C1017 & mixer U1051
Yes
Yes
1st
LO level OK?
Locked
?
Yes
Check FGU
Yes
Trace IF signal
from C1036 to
Q1106. Check for
bad XTAL filter.
No
Yes
IF
signal at
Q1106
collector
?
Before replacing
U1103, check
U1103 voltages.
Yes
Check Supply Voltage
circuitry. Check U0681,
U3211 and U0641.
No
No
Yes
A
B
weak RF