Motorola Pro Series Elite - Troubleshooting Flow Chart for Receiver (Sheet 2 of 2)

3-12 VHF Troubleshooting Charts
IF Signal at
C3200?
No
RF Signal at
T3301?
RF Signal at
R3313?
No
RF Signal at
C3306?
No
RF Signal at
C3302?
No or
Check harmonic filter L3531 & L3532, C3532 and ant.
switches D3521, D3551, L3551, R3551, C3551, C3552,
L3552
Check filter between C3302 &
C3306; program filter to schematic
test freq and check
varactor voltages.
Inject RF into J3501
Are varactor volt-
ages OK?
No
Yes
Check RF amp (Q3302) Stage.
Check filter between C3313 &
T3301.
Yes
Check T3301, T3302, CR3301,
R3321, R3322, R3323
Yes
1st LO O/P OK?
Locked?
Yes
Check FGU
Yes
Trace IF signal from
C3200 to Q3200. Check
for bad XTAL filter.
No
Yes
Q3200 collector
OK?
IF signal present?
Before replacing
U3220, check U3220
voltages; trace IF sig-
nal path.
Yes
Check for 2.9 VDC
Is R5 present?
Check Q3721, U3701 (pin 48)
voltages and U247
No
No
No
Check U404 voltage and if U404 can
be selected by MCU before replacing
U404.
Check varactor filter.
No
Yes
Yes
Yes
A
A
B
weak RF
Troubleshooting Flow Chart for Receiver (Sheet 2 of 2)