LG CMS9540F 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 >