Motorola CDM1250 Service Manual

Troubleshooting Flow Chart for 40W Transmitter Section 9: 3-3
6881091C63-F
2.0 Troubleshooting Flow Chart for 40W Transmitter
No
Is Q4441 OK?
Yes
Is drive from VCO
>+4dBm?
No
Is voltage drop
R4497 >4.5V?
across
No
and drain resistances
(11kohm)
tances
No
Check Q4421
and drain resistances
(11kohm)
gate(open)
No
Check
PCIC_MOSBIAS
_
No
No
Change
Q4573
START
No power
Is Vctrl
there?
Is Q457
3
OK?
Check voltage
on pin 4 U450
1
Check voltage
on pin 5 U4501
Check R4422-5
and go back to top
Troubleshoot
ASFIC
Check voltag
e
on TP4531
Change
PCIC
Check R4409 &
R4473 and go back
to top
Check
MOSBIAS
_
Check
ASFIC
Are D4471
&
D4472 OK?
Change
D4471
&
D4472
NoNo No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Check
PCIC
Yes
Change Q4421
Change Q44
Yes
Change U440
1
Yes
D
o v
i
sua
l
c
h
ec
k
on all components
No
Change Q4441
Troubleshoot
VCO
Check Q4431
gate(open)

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