I've never seen a SNES stop working...or an N64...I once had a GC where the SD video was blown out from a power surge (but even then D Video still worked). Maybe you can use a PS2 AV port? Those things are laying dead all over the place.
kept the nicest looking one for myself... Only to find that one of the controller ports is bad. So for now, my main SNES unit is terribly yellowed/browned and has large cracks across the top.
I haven't picked up SNES systems for like a decade now, but I've probably encounter 20 - 30 that did not work one way or another.