Ti Powerbook G4 video loss...what can it be?

[EHUnlucky7x9@ao]

I've got a Ti Powerbook G4 and it keeps having a loss video feed. I've had this PB for a while and I've changed the LVDS cable...still has video problems. I changed the LCD...still has the probelms.. i check the wires....no cuts or anything. I don't understand what's up with this thing. It seems to be good if i push down on the left speaker area... what on the logic board or on the heatsink assembly deals with the video on the left side of the keyboard? I have been trying to pinpoint this for sometime now and those are the last two things that need to be addressed. I've placed this logic board in another Ti-book and it works perfect. No video problems. What is underneath the left side of the speaker? If anyone has any information...please help. Thank you!