Motorola HT Series Detailed Service Manual page 147

Maintenance: 900 MHz Troubleshooting Charts
8.17.6 Troubleshooting Flow Chart for Receiver (for PCB No. 8471203M01)
(Sheet 2 of 2)
B
Inject RF into J101
IF Signal at
L305?
No
RF Signal at
pin 8 of U301?
No
RF Signal at
C302?
No or
weak RF
RF Signal at
C300?
No or
weak RF
RF Signal at
C316?
No
Check harmonic filter L104 & L105 and
antenna switch CR101, CR102 and
associated components.
Trace IF signal from
Yes
L305 to Q350.
Check for bad XTAL
Yes
1st LO O/P
OK?
Locked?
Yes
Yes
Check filter FL301 and
associated circuitry
Yes
Check RF amp Q302 Stage
Yes
Check filter FL300 &
associated circuitry.
filter.
No
Check FGU
Check U301, C323 and
R320.
Q350 collector
Yes
OK?
IF signal present?
Before replacing
U350, check U350
voltages; trace IF
signal path.
No
Yes
Check for 3.0VDC
@ Q350-C
No
Yes
Is 5V supply
present?
No
Check U202.
8-57
A
A