Troubleshooting Flow Chart For Vco - Motorola GP Series Service Information

Troubleshooting Flow Chart for VCO

5.0 Troubleshooting Flow Chart for VCO
Check R3811,
No
L3811 for dry
joint or faulty
A
U3801
Pin 19 =0V
No
AUX 3 at
U3701
High?
No
Change
U3701
U3801
Pin 10
>1V?
Yes
Yes
L3831,
L3832
L3833
O/C?
No
Change
U3801
Yes
Yes
Change
U3801
Yes
TRB = 3.2V
Change L3831,
L3832
AUX 3 at
U3701
High?
Check U3701
Pin 2 for 3.2V
VCTRL Yes
0V or
13V?
No
Check for faulty parts
or dry joints of L3812,
C3806, R3806,
R3802, & L3801
START
Yes
No LO?
A
No
No
Carrier?
No
VCO OK
Yes
Check
R3829
No
L3821,
Yes
L3822,
L3823,
O/C?
No
Change
U3801
3-7
Tx
Yes
Change
L3821,L3822,
L3823, L3825