Garbled pixels - cable is fine

So, after cleaning up some corrosion issues around the power input and making sure the shielding was back on, my snes now shows corrupted/garbled pixel tiles all over the screen with any game I’ve tried. Sound appears to be ok, but the image is all garbled for some reason. I’ve switched out the multi-out cable, but it doesn’t appear to make a difference.

I don’t see any corrosion on the board anywhere, nor do I see any issues with the chip slot. I’m not even sure where to do a continuity to test various chips/connections as I’m not sure where this issue could be.

The top image is from Mario Paint, the bottom is from Revolution x. The sound from both appears to be ok.