LG LPA-735 Service Manual page 22

3. RF/Servo Circuit
A.
Put disc in.
YES
Disc ID is correct?
YES
Does spindle rotate.
YES
Replace IC(5U1)
YES
D
NO
Laser off
NO
Proper RFL signal on
MT1389?
Check the RFL connection
between 2J3 and MT1389.
NO
Proper DMSO signal on
MT1389
Check the cable connection
between spindle and main PCBA.
3-15
NO
YES
NO
YES
Check the related circuit on
MT1389 RFL signal .
Check DMSO related circuit
on MT1389.