LG OM4560 Service Manual page 23

4. 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 SPINDLE MOTOR among them.
4-1. SPINDLE MOTOR
4-1-1. Solution
Please check and replace IC400, IC401 on MAIN board.
4-1-2. How to troubleshoot (Countermeasure)
1) Check the SPDO signal from pin24 of IC401.
  If no signal, check 3.3 V(RF) and X400.
2) Check the SPIN- & SPIN+ from IC401 to CN401 for driving SPINDLE motor. It is about 3.6 Vp-p.
  If no signal, check +1.8 V and +5 V 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.
4-1-3. Service hint (Any picture/ Remark)
< Waveform of SP- & SP+
for driving SPINDLE motor >
ONE POINT REPAIR GUIDE
< Signal check point >
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