Motorola GP88s

9A-56 Troubleshooting charts
START
No LO?
Tx Carrier?
VCO OK
Check
R260
TRB =
5V? @U241
Pin 19
U241
Pin 10
>1V?
L253 O/C?
Change
L253
Change
U241
AUX 3
High?
Check U201
Pin 2 for 3.2V
U241 Pin 19
=0V
AUX 4
High?
Change
Q261
VCTRL 0V
or 13V?
L243 Open
Circuit?
Change
U241
Change
L243
Change
U201
Check for faulty parts or dry
joints of L271, L273, C370,
C386, R339 & L309
A
A
No
No
Yes
Yes
Yes
No
No
Yes
Yes
Yes
No
Yes
No
No
Yes
Yes
No
No
Check R245 for dry
joint or faulty
No
Troubleshooting Flow Chart for VCO