[ksarul]

Classic symptom of a bad video RAM chip. These are soldered to the main board, so if you are not handy with a soldering iron, you might be better off trying to get another console. The video RAM chips are relatively cheap (about $1 a pop), but there are 8 of them in there, all in a long row on the left half of the motherboard (they are TMS4116s). One of them is dead, so you have a bit stuck and that is what's garbling your display data. This is actually a relatively common problem, as I've fielded questions from about half a dozen folks this year on it.