Troubleshooting Flow Chart For 40W Transmitter (Sheet 2 Of 3) - Motorola CM160 Service Information

Troubleshooting Flow Chart for 40W Transmitter (Sheet 1 of 3)

Troubleshooting Flow Chart for 40W Transmitter (Sheet 2 of 3)

2.1
Check Q102,
Q101, R122, R165
Voltage at
U103 Pin
10=8.8V
Check U103 and Resistive
Network at Pin 10 of U103
before replacing U101
Check bias tuning
before replacing
U504
ASFIC
U504
Pin 5 1.64V
Check components be-
tween ASFIC and Q105
before replacing Q105
No or too low power when keyed
at Q101 & Q102
No
DC
<2V
Yes
No
0V
Yes
Check Final PA Stages
Check PA
Stages
DC
No
Voltage
base=0?
Yes
DC
>5V
Voltage
at U103
Pin 8
2 to 5V
Measure DC Voltage at Pin 2 & 3 of U101
Pin 2
No
Voltage
1.6V x Voltage
at Pin 1
3.5V
Yes
Pin 3
No
Voltage
1.66V x Voltage
at Pin 1
Yes
DC
Supply Voltage
Voltage at
PA_CURRENT
line?
2-3V
Check U510
Check resistive network at
Pin 9 and 10 of U103
before replacing U101
Replace U101
Replace U101
Replace Q105
3-5