Motorola HT Series Detailed Service Manual page 119

Maintenance: VHF Troubleshooting Charts
8.12.4 Troubleshooting Flow Chart for Receiver, for all models except those with
PCB 8486473Z04 (Sheet 2 of 2)
B
Inject RF into J3501
IF Signal at
C3200?
No
RF Signal
at T3301?
No
RF Signal at
R3313?
No
RF Signal at
C3306?
No or
weak RF
RF Signal at
C3302?
No
Check harmonic filter L3531 & L3532,
C3532 and ant. switches D3521, D3551,
L3551, R3551, C3551, C3552, L3552
Trace IF signal
Yes
from C3200 to
Q3200. Check for
bad XTAL filter.
Yes
No
1st LO O/P
OK?
Locked?
CR3301, R3321, R3322,
Yes
Yes
Check filter between
C3313 & T3301.
Yes
Check RF amp (Q3302)
Stage.
Check filter between
C3302 & C3306; program
Yes
filter to schematic test
freq and check varactor
voltages.
Check FGU
Check T3301, T3302,
R3323
Are varactor
voltages OK?
No
Check U404 voltage and if
U404 can be selected by
MCU before replacing
U404.
Q3200 collec-
Yes
tor OK?
IF signal
present?
Before replacing
U3220, check
U3220 voltages;
No
trace IF signal
Yes
Check for 2.9
VDC
No
Yes
Is R5 present?
No
Check Q3721,
U3701 (pin 48)
voltages and U247
Yes
Check varactor filter.
8-29
path.
A
A