Troubleshooting Flow Chart For 25W Transmitter - Motorola GM328 Service Manual

Troubleshooting Flow Chart for 25W Transmitter

2.0 Troubleshooting Flow Chart for 25W Transmitter (Sheet 1 of 3)
Check Components between
Q5441 and RF Output,
Antenna Switch
D5471,D5472,Q5472,
VR3471,Q3471
Check PA Stages
Check 9.3 V Regulator
U0641
Replace PCIC U5501
If U5201 Pin 2 is high,
replace PCIC
U5501,otherwise
check controller and
FGU
Check Power Setting,
Tuning & Components
between PCIC Pin 5
and ASFIC (U0221)
Pin 4 before replacing
ASFIC
Replace PCIC U5501
START
No or too low Power when keyed
Check if Pressure Pad closes S5440
Current
>500mA & <4A
>4A
increase
when
keyed?
<500mA
Control Volt-
YES
age at
TP5402
>1V
NO
NO
PCIC U5501
Pin 14 9.3V
DC?
YES
NO
PCIC U5501
Pin 16 >4V
DC
YES
NO
TP5404
9.1V DC
YES
NO
PCIC U5501
Pin 5 > 1V
DC?
YES
YES
TP5403
>0.5V DC?
NO
Check Forward Power
Sense Circuit (D5451)
NO
Check PA Stages
Check Forward Power
Sense Circuit (D5451)
3-3
Short TP5403 to
Ground
Voltage at
TP5402
rises?
YES