Troubleshooting Flow Chart For 40W Transmitter - Motorola GM328 Service Manual

Troubleshooting Flow Chart for 40W Transmitter

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