Motorola GP338

Troubleshooting charts 6E-27
IF Signal at
L301?
No
RF Signal at
T501?
RF Signal
at collector
Q509?
No
RF Signal at
C504?
No
RF Signal at
C147?
No or
Check transmit harmonic filter, antenna
switch and J101
Check filter between
C147 & C504
Inject RF into J101
No
Yes
Check RF amp (Q509)
Stage.
Check filter between
Q509& T301.
Yes
Check T501, T502,
D501, R507, R508,
R509,C516,L508
Yes
1st LO O/P
310OK?
Locked?
Yes
Check FGU
Yes
Trace IF signal
from L301 to
U301. Check for
badXTALfilter.
No
Yes
U301 drain
OK?
IF signal
present?
Beforereplacing
U303, check
U303 voltages;
trace IF signal
path.
Yes
Biaising on
U301 OK?
Troubleshoot
biasing, AGC
circuits and U301
No
No
Yes
A
B
weak RF
Troubleshooting Flow Chart for Receiver (Sheet 2 of 2)