Motorola Professional GP340 - Receiver (Sheet 2 of 2)

3-2 TROUBLESHOOTING CHARTS
2.0 Receiver (Sheet 2 of 2)
RF
Signal at
collector
Q509?
IF
signal at
L301?
No
RF
Signal
at T501?
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 and T301.
Yes
Check T501, T502,
D501, R507, R508,
R509, C516 and L508
Yes
1st LO O/P
310 OK?
Locked?
Yes
Check FGU
Yes
Trace IF signal
from L301 to U301.
Check for bad
XTAL filter.
No
Yes
U301 drain
OK?
IF signal
present?
Before replacing
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