I am thrilled to find your post as I have the same problem with a 800 MHz DVI powerbook; the video is scrambled and the mouse is a confused blocky pattern. As you found, it appears to be only a video issue - if I log in via VNC or screen sharing the video still comes up scrambled.

Can you post an update? Did your fix hold? Also, I would appreciate if you could post some pictures showing the repair process in more detail!

Thanks for the great discovery,