Troubleshooting Flow Chart For 40 W Transmitter (Sheet 1 Of 3) - Motorola CM200 Service Manual

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

Check components between
Q100 and RF output,
Antenna Switch D104,
D103, VR102 and Q106
Check power settings, tuning
& components between U103
Pin 3 and ASFIC Pin 6 before
replacing ASFIC
No or too low power when keyed
>4A
Yes
Check PA
Stages
Check 9.3V
No
Regulator
U501
No
Check
Yes
U103
Check forward
START
Current
increase when
keyed?
<500mA
Control
Voltage at
TP150
>4Vdc?
No
Voltage U103
pin 5 =
4.7V?
Yes Check PA
Stages
U103 Pin 3
<1.6Vdc
Yes
U100 Pin 3
>1.8Vdc
No
Power Sense
Circuit
TROUBLESHOOTING CHARTS
>500mA & <4A
Short U100
Pin 3 to
ground
Yes
Voltage at
TP150 rises?
Check Forward
Power Sense
Circuit
No