Motorola CDM Series Detailed Service Manual page 576

Section 11: 3-4
Troubleshooting Flow Chart for 45 W Transmitter (Sheet 2 of 3)
2.1
Check S3440,
R3442 and R3443
6881091C63-F
No power or low power when keyed
DC
NO
voltage at
U3402-1 pin
3 = 8.8V?
YES
Measure DC voltage at pin 2 & 3 of U3401
Check Q3442 and
resistive network at
U3402-1 pin 3
before replacing
U3401
Troubleshooting Flow Chart for 45 W Transmitter
Check PA stages
NO
DC voltage
If U3201 pin 2 is high,
at U3501
pin 23 =0?
YES
>6
<2V
DC voltage
network at pins 2 & 3 of
at U3402-1
pin 1?
2-6
Pin 2 volt-
NO
age 0.62 *
voltage at
pin 1?
YES
Pin 3 voltage NO
0.51 *
voltage at
pin 1?
YES
ELSE
DC voltage at
TP3408?
2-6V
Check final PA stage
replace PCIC
Check resistive
U3402-1 before
replacing U3401
Replace U3401
Replace U3401
Retune MOSBIAS_1