Motorola HT1250-LS+ - Page 55

Maintenance 4-19
START
Is RX
LO signal
present?
Tx Carrier?
VCO OK
Check R655
& Q603
Is TRB
(U600 Pin 19)
5V in TX
Mode?
Is U600
Pin 10
>1V?
L253 O/C?
Change
L253
RF signal
at U600
Pin 10?
AUX 3
High in TX
Mode?
Check U201
Pin 2 for 3.2V
TRB
(U600-19)
0V in RX
Mode?
AUX 4
High?
Change
Q603
V ctrl 0V
or 13V?
FL600,
CR600-1
etc. OK?
RF Signal
at U600
Pin8?
Repair/replace
components
Change
U201
A
A
No
No
Ye s
Ye s
Ye s
No
No
Ye s
No
Ye s
No
Ye s
No
No
Ye s
No
Ye s
Check R605 &
L606 for dry joint or
faulty connection.
No
T
roubleshooting Flow Chart for VCO
Change
U600
No
Troubleshoot Q601 and
associated circuitry
Ye s
No
Change
U600
Troubleshoot Q600
& associatd circuitry
Ye s
Ye s
Ye s