LG CM8440 Series Service Manual page 31

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.
4-5. DSP IC (IC501)
4-5-1. Solution
Please check and replace IC501(MLC3730) on MAIN board.
4-5-2. 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).
4-5-3. Service hint (Any picture / Remark)
R546
IC501
< Signal check point >
ONE POINT REPAIR GUIDE
3-10
R594
PGPB12
(Yellow)
R598
PAD19
(Green)
R597
PAD20
(Pink)
< Signal waveform >