LG CM5660 Service Manual page 27

5. NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD disc
if the servo motors in MD don't work. This step is for checking the SLED MOTOR among them.
5-2. SLED MOTOR
5-2-1. Solution
Please check and replace IC400 on MAIN board.
5-2-2. How to troubleshoot (Countermeasure)
1) Check the SLDO signal from pin15 of IC401.
  If no signal, check DVCC_3.3V and DV_3.3V (RF) and X400.
2) Check the SPED+ & SLED- from IC400 to CN401 for driving SPINDLE motor. It is about 2.9 Vp-p.
  If no signal, check M_5V for IC400.
3) Check if the FFC cable is solidly connected between CN401 and MD.
4) Check the MD.
  If the SPINDLE motor is sort-circuit or has any trouble, it can not rotate CD discs.
Please check the function after changing another MD.
5-2-3. Service hint (Any picture/ Remark)
SP+
SP-
< Waveform of SLED- & SLED+
for driving SLED motor >
ONE POINT REPAIR GUIDE
3-10
SLED+ (TP422) SLED+ (TP422)
SLED- (TP424) SLED- (TP424)
< MAIN board bottom view >