Motorola GM338

Troubleshooting Flow Chart for 25W Transmitter 3-5
2.2 Troubleshooting Flow Chart for 25W Transmitter (Sheet 3 of 3)
Check Final PA Stage
NO
0V
1-4V
Bias 2 DC
Voltage at
TP4406?
YES
RF Voltage
at TP4401
>100mV?
YES
RF Voltage
U4401 Pin 6
>3V?
Supply
Replace Q4441
Check FGU (U4301)
NO
Check Components
between
TP4401 &C4417
NO
YES
ASFIC
U0221 Pin 6
1-4V DC?
Check Bias Tuning
before replacing ASFIC
U0221
Check Components
between ASFIC and
Q4441 before
replacing Q4441
YES
RF Voltage
Q4421 Gate
>1V?
NO
Check Components
between
C4417 & Q4421
YES
RF Voltage
Q4441 Gate
>4V?
NO
Check Components
between
Q4421 & Q4441
Check Components
between Q4441 &
Antenna Connector
Voltage