Motorola HT Series

8-38 Maintenance: Low Band Troubleshooting Charts
8.13.3 Troubleshooting Flow Chart for Receiver (Sheet 2 of 2)
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
Ye s
Check RF amp (Q509)
Stage
Check filter between Q509&
T301
Ye s
Check T501, T502, D501,
R507, R508,
R509,C516,L508
Ye s
1st LO O/P
310OK?
Locked?
Ye s
Check FGU
Ye s
Trace IF signal
from L301 to
U301. Check for
bad XTAL filter
No
Ye s
U301 drain OK?
IF signal
present?
Before replacing
U303, check U303
voltages; trace IF
signal path
Ye s
Biasing on
U301 OK?
Troubleshoot
biasing, AGC
circuits and U301
No
No
Ye s
A
B
weak RF