LG GCC-4241N Service Manual page 48

Tracking Servo is unstable.
Tracking Error Check.
Is Focus Servo stable?
OK
Is DiscMotor Servo stable?
OK
Is Track Error normal?
IC201(100)
OK
Is OFTR signal normal?
TL109
OK
Is Track Drivel normal?
TL315
OK
1)Check Soldering of PG101.
2) Check voltage of TL331(5V).
3) Check voltage of TL327(2.2V).
4) Check insertion or damage of
Main FPC.
OK
Replace Unit Mecha and
Execute LD Calibration.
50
NG
Go to "Focus Servo is unstable".
NG
Go to "Disc Motor Servo is
unstable".
NG
Is Pick Up Signal normal?
PG101(22,23,25-30)
1)Check Soldering of PG101.
2) Check voltage of TL331(5V).
3) Check voltage of TL327(2.2V).
4) Check insertion or damage of
Main FPC.
Replace Unit Mecha and
Execute LD Calibration.
NG
Check Capacitor C101.
NG
Is Track Drivel normal?
IC201(179).
Replace IC201.
OK
NG
OK
OK
OK
NG
Check Dumping Reg. RA102,
RA103, RA104.
OK
1)Check Soldering of IC101.
2) Check voltage of 5V.
3) Check voltage of Vhalf.
OK
Replace IC101.
Check soldering of IC101.
OK
Replace IC101.
Check LPF (R251, C251).