Motorola GP88s

9B-54 Troubleshooting Charts
START
No LO?
Tx Carrier?
VCO OK
Check
R3829
TRB = 3.2V?
U3801
Pin 10
>1V?
L3831,
L3832,
L3833
O/C?
Change
L3831, L3832
Change
U3801
AUX 3 at
U3701
High?
Check U3701
Pin 2 for 3.2V
U3801
Pin 19
=0V
AUX 3 at
U3701
Low?
Change
U3801
VCTRL
0V or
13V?
L3821,
L3822,
L3823 Open
Circuit?
Change
U3801
Change
L3821,
L3822,
L3823,L3825
Change
U3701
Check for faulty parts or dry
joints of L3812 C3806,
R3806, R3802 & L3801
A
A
No
No
Yes
Yes
Yes
No
No
Yes
Yes
Yes
No
Yes
No
No
Yes
Yes
No
No
Check R3811,
L3811 for dry joint
or faulty
No
Troubleshooting Flow Chart for VCO
Yes