Troubleshooting Flow Chart For Vco - Motorola HT Series Service Manual

Maintenance: VHF Troubleshooting Charts

8.12.9 Troubleshooting Flow Chart for VCO

No
Check R3811,
L3811 for faulty
parts and dry joints
Change
U3801
No
L3831,
Yes
L3832,
L3833 L3831, L3832
O/C?
Yes
Yes
Pin 10
TRB = 3.2V?
>1V?
Check U3701
Pin 2 for 3.2V
A
Yes
Pin 19
=0V
Check for faulty parts or dry
No
joints of L3812 C3806,
R3806, R3802 and L3801
AUX 3
Low?
No
Yes
Change
U3801
Change
No
No
Yes
AUX 3
High?
No
L3823, and L243
V ctrl 0V
or 13V?
Yes
No
Change
U3701
START
No LO?
No
Tx Carrier?
Yes
VCO OK
Check
R3829
Change
L3821, L3822,
Yes
L3821,
L3822,
L3823 Open
No
Circuit?
8-35
Yes
A
Change
U3801