My A500 died in a cloud of blue smoke when a power supply went bad back in 1994ish. Completely dead. Nothing.
Mysteriously, a few days later, it started working again for no explainable reason. It still works today. :-?
My Amstrad CPC 464 still works like a champ, along with my A1200 and my Atari 2600 (although I have two others that don't).
I've also got two dead ZX Spectrums that both gave up a few years ago. I've been meaning to replace them, but Speccy emulation works so well.