Motorola CDM Series Detailed Service Manual page 507

Troubleshooting Flow Chart for 40W Transmitter
2.0 Troubleshooting Flow Chart for 40W Transmitter
No
Is Q4573
OK?
Change
Yes
Q4573
Yes
Check voltage
on pin 4 U4501
Check R4422-5
No
and go back to top
No
Check voltage
on pin 5 U4501
Troubleshoot
ASFIC
Yes
No
Check voltage
on TP4531
Change
PCIC
Yes
Check R4409 &
R4473 and go back
to top
Change Q4441
START
No power
No
Is Vctrl
there?
Change Q44
No
Check Q4431
gate(open)
and drain resistances
Yes (11kohm)
tances
Is Q4441 OK?
No
Is voltage drop
across
R4497 >4.5V?
Change U4401
Yes
No
Check
MOSBIAS_
Yes
Check
PCIC_MOSBIAS_
Yes
Are D4471 &
D4472 OK?
Yes
Yes Check Q4421
gate(open)
and drain resistances
(11kohm)
No
Yes
Is drive from VCO
>+4dBm?
No
Section 9: 3-3
Check
ASFIC
No Check
PCIC
No
Change
D4471 &
D4472
No
Change Q4421
Troubleshoot
VCO
Yes
Do visual check
on all components
6881091C63-F