LG CK57 Service Manual page 45

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 TRAY OPEN / CLOSE MOTOR among
them.
4-3. TRAY OPEN / CLOSE MOTOR
4-3-1. Solution
Please check and replace IC400, IC401 on MAIN board.
4-3-2. How to troubleshoot (Countermeasure)
1) Check MOT_OPEN & MOT_CLOSE signals from Pin P4, L4 of IC500 to IC400.
 If no signal, check VDD_CORE and DVCC_3.3V to IC401.
2) Check LOAD± from IC400 to CN401 for driving the tray open / close motor. It is about 3.85 Vp-p.
 If no signal, check M_5V to IC400. If it has any trouble, replace it with a new one.
3) Check if the FFC cable is solidly connected between CN401 and MD.
4) Check the MD.
 If the tray motor is sort-circuit or has any trouble, it can not open or close the tray.
Please check the function after changing another MD.
4-3-3. Service hint (Any picture / Remark)
MOT_OPEN
CLOSE
LO- TO CN401
LO+ TO CN401
< Waveform for driving
TRAY open / close motor >
ONE POINT REPAIR GUIDE
MOT_CLOSE : pin6 to IC500 MOT_CLOSE : pin6 to IC500
MOT_OPEN : pin7 to CN401 MOT_OPEN : pin7 to CN401
LOAD+ : pin9 to CN401(pin4) LOAD+ : pin9 to CN401(pin4)
LOAD- : pin10 to CN401(pin2) LOAD- : pin10 to CN401(pin2)
< MAIN
board top < MAIN board bottom view >
view >
3-8
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IC400 IC400
Only for training and service purposes.