I had this happen with a Pismo. The ATI Rage chip came loose causing the screen to get garbled. Applying pressure to the bottom would make it better. When I got the logic board out, I noticed even the little heat sink had popped off. I thought maybe the sink came off first, causing it to get hot and subsequently weaken the solder joints.

A mislabeled eBay auction and $14 dollars (shipped) later, I was back in business. This was in 2003!

I bought the Pismo in this condition and ended up with a complete setup (battery, power adapter, discs, DVD-ROM, etc) for $400, in 2003.