Spindle Motor - LG TH900 Manual

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 SPINDLE MOTOR among
them.

5-1. SPINDLE MOTOR

5-1-1. Solution
Replace IC400 on MAIN board.
5-1-2. How to troubleshoot (Countermeasure)
1) Check the SPDO signal from pin16 of IC401.
  If no signal, check DVCC_3.3V and DV 3.3V (RF) and X400.
2) Check the SPIN+ & SPIN- from IC400 to CN401 for driving SPINDLE motor. It is about 3.6 Vp-p.
  If no signal, check M_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.
5-1-3. Service hint (Any picture/ Remark)
< Waveform of SP- & SP+
for driving SPINDLE motor >
ONE POINT REPAIR GUIDE
< MAIN board top view >
3-9
SP+: pin18 SP+: pin18
SP-: pin19 SP-: pin19
IC400 IC400