[Jedi Master Thrash]

I just got Pocky & Rocky for the SNES. The character sprites where all weird, cropped, moved, compressed.

I tried everything, but eventually tracked it down to the use of an s-video cable.

Now the weird thing is that I had tried to rule that out by using an old fasioned NES style RF adapter. But it turns out that as long as the s-video cable end of the a/v adapter is plugged in to something, even if you are actually viewing the video over the RF port instead, the sprites in the game are messed up!

What in the world could cause that?

So in order to play I just have to unplug the s-video end from the av cable, to make sure only the composite video end is connected.

[Chilly Willy]

The only thing I can think of is power - the svideo cable puts too much load on the video chip, causing it to freak out under certain circumstances. Nothing else would make any sense... it's not like the svideo cable is an INPUT. Maybe a combination of the load from the svideo out and the cart... if you have a SNES flash cart, you might try that game from the flash cart.

[ExCyber]

Yeah, I'd guess that the S-Video jack is somehow pulling too much current out of an amplifier, making a voltage rail sag and screwing up the sprite chip (it is a physically separate chip in most SNES models I think). Maybe there's a short in the jack, or maybe the amp in question is just fried?

[Jedi Master Thrash]

I tested several other sprite-heavy games (final fight 3, battlemaniacs, etc) and none of them have this issue. I'd never noticed it before with other games.

[Chilly Willy]

Jedi Master Thrash, on 15 December 2011 - 09:15 PM, said:

I tested several other sprite-heavy games (final fight 3, battlemaniacs, etc) and none of them have this issue. I'd never noticed it before with other games.

It wouldn't be a SOFTWARE issue or you'd see it with everything. It's likely a HARDWARE issue that affects that one cart - that cart maybe pulls a little more current than other carts for some reason, and that combined with the extra current pull of the svideo cable is just enough to affect the VDP. That would be my guess on the matter based on the observations relayed.