LG RH188S Service Manual page 69

Track Servo is unstable
Is TE signal
output normal in Focusing
ON and Tracking OFF?
(LIC121 pin 24*)
YES
Is there TDRV
signal output in Tracking ON?
(LIC201 pin66)
YES
Check the Drive IC(LIC301) and
P/U referring to "Focus Actuator
operating is abnormal".
NO Is PICK UP
(E, F, G, H) output normal?
(LPM101 pin 8, 5, 9, 4)
YES
Replace the LIC121.
NO
Replace the LIC201.
4-8
NO
Check the PICK UP FFC.
Replace the PICK UP.
* LIC121 pin24 is MOUT1(FEP Monitor1).
After disc recognition action, Monitor port
is off. So, please check TE signal during
disc recognition.