I installed an Apple V Mod on this very new console and it immediately started to show sounds and video problems even at the start up xbox logo. I think somehow the video and sound driver IC got damaged cause even after I took the mod ic off I'm still getting this problem, there a very loud high pitch tone on the audio and the video is not perfect. I took an a very close inspection on the pcb for possible solder drops, shorted pins or broken traces and found none, the board is still very nice and clean.
Yeap, I have the machine at home and I'm using my xbox's cables and there is no change. To me it looks like an electronic problem, maybe somebady can tell me which IC I should replace and where I can get it.
Never mind, I found the problem. After looking real hard on the board, I found a very small drop of solder between pins on one of the IC's. I removed it and reinstalled the ModChip ok.