I bought a SNES about a year ago on Ebay, have played it every once in awhile, and it seemed to play fine. The other day, a handful of my SNES games had a purple-green swirl pattern on the screen. Is this a console problem or a problem with the handful of carts? Most of my carts display fine, and the ones that don't are mostly ex-rental carts. I don't have another console to test them. Has anyone else had this occur with their SNES?