LG CJ87 Service Manual page 58

ELECTRICAL TROUBLESHOOTING GUIDE
3. NO AUDIO CHECK
CD FUNCTION
Can
disc insert?
YES
Disc reading OK?
YES
IC401 pin34 ~ 36
I2S output signal OK?
YES
IC501 pin N1, N2, N4
I2S input signal OK?
YES
A
NO
LOAD +, - OK?
Is motor impedance
about 12 Ω?
NO
OPU driving
(Focusing & Tracking) OK?
Check OPU.
(Pick-up module)
IC401
NO
RF & Servo signal
OK?
NO
Check IC501.
3-29
NO
YES
NO
NO
NO
NO
YES
Is Motor_open/ close OK?
(IC400 pin6, 7)
YES
Check IC501.
Check loading motor.
Check IC400.
NO
Focusing/
Tracking/ Sled signal
OK?
YES
MON_MPD(CN400 pin22)
About 180 mV?
Check FFC cable
to CN400, CN401.