My Lisa 2/10 blinked off unexpectedly the other day, and upon pulling and disassembling the 1.8A power supply, I found that the 3A 250V buss fuse was blown. I replaced it with one of the same spec (as far as I know; does it need a slow-blow?) and put everything back together...it blew immediately as soon as I plugged in the power cable. So I replaced the fuse again, and this time, with the PSU still outside of the Lisa, I plugged in power and it blew again. I tried one more, same thing, then stopped serial-killing fuses...
I am not very skilled with component-level troubleshooting, but I removed the PSU board from the metal case and inspected it for anything obvious. No scorchmarks or bad smells. Everything just looks old.
Are there any usual suspects I could try replacing first? Is there a Lisa expert out there somewhere who might be able to tell me something from a hi-res photo or two?
Thanks,
-- MB
you probably have developed some short somewhere in the ps, if you can find a schematic, you could trace the circut