Powers on but no audio or video output at all?

After years of service, suddenly my old N64 won't output audio or video. It powers on, but there is no output whatsoever, with or without a game in. I tried on multiple TVs with multiple output cables. I haven't tried multiple power supplies, but that doesn't seem to be the problem. Is my N64 fried? Can it be fixed? What should I do with it?