Motorola CDM1250 Service Manual

Troubleshooting Flow Chart for 40 W Transmitter Section 10: 3-3
6881091C63-F
2.0 Troubleshooting Flow Chart for 40 W Transmitter
No
Is Q5441 OK?
Yes
Is drive from VCO
>+4dBm?
No
Is voltage drop across
R5497 >4.5V?
No
Check Q5431 gate(open)
and drain resistances
(11kohm)
No
Check Q5421 gate(open)
and drain resistances
(11kohm)
No
PCIC_MOSBIAS_1
Check
No
No
Change
Q4573
START
No power
Is Vctrl
there?
Is Q557
3
OK?
Check voltage
o
n U5501, pin 4
Check voltage
on U5501, pin 5
Check R5422-5
and go back to top
Troubleshoot
ASFIC
Change
PCIC
Check R5409 and
R5473 and go back
to top
Check
MOSBIAS_2
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 Q5431
Yes
Change U540
1
Yes
D
o v
i
sua
l
c
h
ec
k
on all components
No
Change Q5441
Troubleshoot
VCO
Check voltage
on TP5531

Motorola CDM1250 Specifications

General

Display	Alphanumeric
IP Rating	IP54
Frequency Range	VHF: 136-174 MHz, UHF: 403-470 MHz
Signaling	PL, DPL, MDC1200, Quick Call II
Operating Temperature	-22°F to +140°F (-30°C to +60°C)
Power Output	VHF: 1-25W; UHF: 1-25W