In a previous thread, I mentioned the problems I encountered with two recently acquired Power Macs (Dead Acquisitions: 8200, 9500 -- http://www.applefritter.com/node/6474). After further testing, I've concluded that both the 8200 and 9500 boards are dead, as is the 9500 psu, but the 8200 psu seems sound.
The third Mac in this bundle is a 7100 and, like the other two, it had been stored in a damp garage. I left it for a week or so to acclimatise indoors and cleaned the obvious filth off the motherboard, case and internals. It was surprisingly interesting for a 7100: lots of RAM, a 2GB disk, unusual Formac graphics card, ISDN card.
The 7100 worked fine for a couple of hours so I wiped the disk in preparation to install a clean operating system. During the reinstallation, I encountered system freezes and bus errors. So I wiped the disk again, assuming that the Mac OS installer didn't get on with the disk formatting tools and tried different system versions etc.
Then the power supply went bang. Literally. That explains the system freezes...
The moral of this story is that old computers don't like being stored in damp sheds and attics. Look after your old Macs and protect them whenever you put them in storage. When you acquire Macs that have been stored badly, handle them with caution and don't be surprised when things don't work.
Phil
I always remove the batteries from anything I'm going to store outside.
to me with a 5400 PowerMac. I found it outside. It worked for about 2 weeks and the I heard a humming getting louder and louder, then the PSU blew out the back of the Computer and set the curtains on fire. Needless to say that there was a hole the size of my fist (and mine is pretty big) in the back of the case. I am guessing that one of the monsterous Capacitor was swelling and finally blew. There was yellow gunk everywhere inside it. It also caused a surge big enough to destroy every thing including the keyboard and Mouse, the floppy drive was the only thing salvagable.
I was at my toystore (here) and found a Kaypro 4 luggable. I plugged it in, hit the powerswich and *POOF* a cloud of putrid magic smoke blows outta the power supply. I pulled the power plug from the outlet, then turned the switch back off. I didn't buy the sucker, but it would have been a nice find, but for that nasty event...