Super NES graphics glitches.

[Super-Hampster]

I pulled out my old snes and tried it out. It comes on but it has glitchy graphics. Strangely it looks like the foreground layer such as title screens, the Nintendo logo on bootup, and sgb border renders fine. It plays music and accepts controller input. But, the sprite layer is all glitchy. Also the sgb works just fine. Starfox just plays music on a mostly black screen. I cleaned the cartridge connector already. Anyone ever hear of anything like this? I have a retroduo and a handheld clone so I can still play games but I would still like the real thing.

[MottZilla]

It can probably be fixed but the cause may be hard to pin down. You may just need to open it up and inspect the entire board for damage or failures. I'd say look for any blown fuses or capacitors.

[Super-Hampster]

Yeah. I just ordered some security bits. I'd hate to lose the snes I got new in 1992.

[MottZilla]

If it has never been opened or water damaged or had the wrong power supply plugged in or a power surge while plugged in then it is very likely repairable. Things like power surges/incorrect power input, water damage, and shock from abuse are the main causes of permanent damage problems. Normal use shouldn't create any deadly problems yet.

[Near]

I have a Japanese Super Famicom with damaged OAM (object attribute memory, basically what tells it where sprites go and how to flip them.)

As a result, you don't read back what you wrote to OAM, and sprites get all mixed up and flipped oddly.

Not much can be done about it, the OAM is inside one of the PPU chips.

[Super-Hampster]

That's what I'm afraid of. Something is wrong with the ppu or some video RAM and no replacements are available.

[Super-Hampster]

Gotta be a bad chip somewhere. PPU or RAM or something. Foreground is ok. Background is even ok, but the sprite layer is all screwed up and the Super Gameboy works. No obvious damage to the board. I guess I'll find another motherboard somewhere.