Geforce 4 Repairs

Well My old ti4600 finally crapped out I'm getting white vertical bars at boot up and then nothing. I've hear the the ti4200 were having the psod (pink screen of death) caused by bad capicitors. I know that other people have had problems with the 4400/4600 (white bars).

Does anyone actually know for a fact what is causing the white bars?

Is it a memory problem or a capacitor problem.
Its junk and i can't RMA it.
I'd like to take a crack at fixing it.

Any PRO info would be appreciated.