Motorola GP344 - Page 167

TROUBLESHOOTING CHARTS 2-5
IF Signal
at L3200?
No
RF
Signal at
T3301?
RF
Signal at
R3313?
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; pro-
gram filter to schematic
test freq and check
varactor voltages.
Inject RF into J3501
Are varactor
voltages 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 L3200 to
Q3200. Check for
bad XTAL filter.
No
Yes
Q3200
collector OK?
IF signal
present?
Before replacing
U3220, check
U3220 volt-
ages; trace IF
signal 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
RF
Signal at
C3306?
Figure 2-4 Troubleshooting Chart for Receiver (PCB 8415533H02) (Sheet 2 of 2)