What on earth is going on with this SNES?

[AppleQueso]

Picked up an extra SNES recently. Was testing it out and noticed it had some strange graphical issues.

It's easier to just link to videos than describe it in depth, so here it is:
(excuse the awful camera quality)
Super Mario World
Zelda: ALTTP

An interesting note about that Super Mario World vid, it does the same thing on both the standalone cart and the version on SMAS+SMW.

F-Zero goes pretty crazy too, virtually unplayable. Vehicles kinda vanish and appear all over the track at random.

Oddly enough, games like Yoshi's Island have seemingly no problems at all.

So yeah, any clues/ideas?

Personally, I'm guessing the PPU is going south.

[Hobie-wan]

Sounds like a reasonable conclusion. I have one that the screen is a garbled mess sort of like playing dirty NES carts. Carts run fine as does the sound, but everything is Picasso in a blender.

[ApolloBoy]

Bad caps maybe? I had a couple of leaky ones on an SNES I worked on, I think maybe they're just now starting to suffer from it. Most of the caps in the SNES are surface-mount like the ones in the TurboDuo and Game Gear so I wouldn't be surprised if that turned out to be the case.