I once had an A1200 I thought was dead. To make sure, I pumped 24VDC through it and it was...:lol:
Actually, my A600 stopped working for no apparent reason, but there is no physical damage I can see. At the same time, it doesnt draw any current so perhaps it is something repairable.
My first A1200 was indeed victim to a dodgy PC PSU that sent a rather large voltage spike through it, probably much higher than 24V ;-)
My second A1200 has stood the test of time. It was towered for a while, then I got a new mobo from eyetech and put the old one away for safe keeping - its now up and running in my recently cobbled together A1200D :-)
Several friends all owned Big Box amigas and they have all had endless problems with them. Personally I think the 1200 was the most reliable machine ever made...