Motorola GM640 Service Information - Page 27
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Troubleshooting Flow Chart for 25W Transmitter (Sheet 1 of 3)
Troubleshooting Flow Chart for 25W Transmitter (Sheet 3 of 3
2.2
Check Components
between ASFIC and
Q4441 before
replacing Q4441
ASFIC
YES
U0221 Pin 6
1-4V DC?
NO
Check Bias Tuning
before replacing ASFIC
U0221
Check Final PA Stage
Supply
Voltage
Bias 2 DC
0V
Voltage at
TP4406?
1-4V
NO
RF Voltage
at TP4401
>100mV?
YES
NO
RF Voltage
U4401 Pin 6
>3V?
YES
NO
RF Voltage
Q4421 Gate
>1V?
YES
RF Voltage
NO
Q4441 Gate
>4V?
YES
Check Components
between Q4441 &
Antenna Connector
)
Replace Q4441
Check FGU (U4301)
Check Components
between
TP4401 &C4417
Check Components
between
C4417 & Q4421
Check Components
between
Q4421 & Q4441
3-5