LG CK57 Service Manual page 44

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.
4-2. SLED MOTOR
4-2-1. Solution
Please check and replace IC400, IC401 on MAIN board.
4-2-2. How to troubleshoot (Countermeasure)
1) Check the SLDO signal from Pin15 of IC401.
 If no signal, check DVCC_3.3V and X400.
2) Check the SLED+ & SLED- from IC400 to CN401 for driving SPINDLE motor. It is about 2.9 Vp-p.
 If no signal, check VDD_CORE and DVCC_3.3V for IC401.
3) Check if the FFC cable is solidly connected between CN401 and MD.
4) Check the MD.
 If the sled motor is sort-circuit or has any trouble, it can not move the pickup module.
Please check the function after changing another MD.
4-2-3. Service hint (Any picture / Remark)
SL- TO CN401
SL+ TO CN401
< Waveform of SLED- & SLED+
for driving SLED motor >
ONE POINT REPAIR GUIDE
SLED- : pin18 SLED- : pin18
to CN401(pin9) to CN401(pin9)
< MAIN
board top < MAIN board bottom view >
view >
3-7
Copyright © 2018 LG Electronics Inc. All rights reserved.
IC400 IC400
SLED+ : pin17 SLED+ : pin17
to CN401(pin7) to CN401(pin7)
Only for training and service purposes.