Receiver (Sheet 2 Of 2) - Motorola Professional GP340 Service Manual

3-2
2.0

Receiver (Sheet 2 of 2)

B
Inject RF into J101
IF
signal at
L301?
No
RF
Signal
at T501?
No
RF
Signal at
collector
Q509?
No
RF
Signal at
C504?
No or
weak RF
RF
signal at
C147?
No
Check transmit harmonic filter, antenna
switch and J101
Trace IF signal
Yes
from L301 to U301.
Check for bad
XTAL filter.
Yes
1st LO O/P
310 OK?
Locked?
Yes
Yes
Check filter between
Q509 and T301.
Yes
Check RF amp (Q509)
Stage.
Yes
Check filter between
C147 & C504
No
Check FGU
Check T501, T502,
D501, R507, R508,
R509, C516 and L508
TROUBLESHOOTING CHARTS
U301 drain
Yes
OK?
IF signal
present?
Before replacing
U303, check
U303 voltages;
No
trace IF signal
Yes
Biaising on
U301 OK?
No
Troubleshoot
biasing, AGC
circuits and U301
path.
A