LG DP271, DP271B, LPA-837 Service Manual page 23

MAIN ELECTRICAL TROUBLESHOOTING GUIDE
D
YES
Focus on OK.
YES
Track on OK.
YES
Disc is play?
YES
E
Proper
NO
signals on A, B, C, D
of MT1389
Proper FEO signal
on MT1389.
Check IC(U401)
NO
Proper FEO signal
on MT1389.
Properly TRSO signal
on MT1389.
T+ & T-
output properly.
Check cable connection on
pick-up head.
NO
Check RF signal waveform.
3-16
NO
YES
NO
YES
NO
YES
NO
YES
YES
YES
Check connections between
MT1389 and pick-up head.
Check the related circuit
on MT1389 FEO sugnal.
Check the related circuit
on MT1389
Check the TRSO connection
on MT1389 and motor dirver.
Check the tracking control
amp circuit on motor driver.