LG CM9750 Service Manual page 32

NO BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order (HELLO  VOL XX 
CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
8-5. DSP (IC501)
8-5-1. Solution
Please check and replace IC501 on MAIN board.
8-5-2. How to troubleshoot (Countermeasure)
1)After check them by Previous pages about NO Booting, if the set is still no booting,
  Check soldering status of IC501.
2) If below bootstrap waveform doesn't come out, then replace IC501(DSP IC).
8-5-3. Service hint (Any picture / Remark)
IC501 IC501
< MAIN board top view >
ONE POINT REPAIR GUIDE
3-13
R594
PGPB12
(Yellow)
R598
PAD19
(Green)
R597
PAD20
(Pink)
< Bootstrap waveform >