Motorola HT1250-LS+ Service Manual page 55

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