LG CM8440 Series - Page 32

3-11
ONE POINT REPAIR GUIDE
5. NO OPERATION OF MD (DRIVING THE SERVO MOTORS)
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
Please check and replace IC407, IC408 on MAIN board.
5-1-2. How to troubleshoot (Countermeasure)
1) Check the SPDO signal from Pin16 of IC407.
 If no signal, check 3.3 V(RF) and X400.
2) Check the SP- & SP+ from IC408 to CN405 for driving SPINDLE motor. It is about 3.6 Vp-p.
 If no signal, check +1.8 V and +5 V for IC408.
3) Check if the FFC cable is solidly connected between CN405 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)
pj[W_
zwR
zwT
zwR
w]GGju[W\
zwT
_GGju[W\
< Waveform of SP- & SP+
for driving SPINDLE motor >
< Signal check point >