SNES produces white screen with flickering black lines when powered up, buzzing sound

[SpoDaddy]

Whether or not there is a cartridge inserted it creates the same white screen with flickering black lines moving across it and a faint buzzing sound through the speakers. I've opened it up and cleaned the cartridge slot by putting a credit card inside a cloth that I dampened with rubbing alcohol and then inserting it in and out of the slot, cleaned the cartridges, checked the a/v plug with an N64; I can't seem to figure out what the problem is. The SNES was working the last time I used it a few years ago, and it's just been sitting on a shelf since then.

Any ideas on what the problem could be?

[Guntz]

I think replacing the power supply (wall wart, AC Adapter) wouldn't be a bad place to start. Better to eliminate the simple things like you were doing rather than assume this component has died or that mobo trace has cracked...

[SpoDaddy]

Is there a cheap SNES-compatible AC adapter out there, or perhaps an AC adapter for another console that works with the SNES?