Motorola GM338

Troubleshooting Flow Chart for 40W Transmitter 3-3
2.0 Troubleshooting Flow Chart for 40W Transmitter
Q5441 gate (63kohm)
and drain resistances
(15kohm)
Check
No
Yes
Is drive from VCO
>+4dBm?
Is voltage
drop across R5497
between 1V and 0.7V
when Tx power
= 44W?
No
No
Q5421 gate (12kohm)
and drain resistances
(15kohm)
Check
No
PCIC_MOSBIAS_1
Check
No
No
Change
Q5473
START
No power
Is Vctrl
there?
Is Q5473
OK?
Check voltage
n pin 4, U5501
Check voltage
on pin 5, U5501
Check R5422-5
and go back to top
Troubleshoot
ASFIC
Change
PCIC
Check R5409 and
R5473 and go back
to top
Check
MOSBIAS_2/
MOSBIAS_3
Check
ASFIC
Are D5471 &
D5472 OK?
Change
D5471 &
D5472
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Check
PCIC
Yes
Change Q5421
Change Q5441
Change U5401
Yes
Do visual check
on all components
No
Troubleshoot
VCO
Check voltage
on TP5531
Check if Pressure
Pad closes S5440
Yes