My Lisa 2/10 no longer powers up. No response anywhere when power button is depressed. Is it ok to power up the PS on the bench without anything connected (no load) to it?
No response may be due to problems other than the PSU.
Try removing the I/O Board and reassembling (without it); most Lisa's will power up immediately if power is connected and the I/O board is missing. If it does power up, then the problem is likely on the I/O Board. If it does not, then checking the PSU outside the Lisa would be a good step.
The PSU won't just start up outside the Lisa when plugged in.
You'll need a test fixture that:
Connects +5 sense to +5.
Has a modest load on +12 and +5.
Has a switch or jumper to connect +5 Standby to ON
(I'll add some details shortly.)
HTH