Finicky power problems

[Chip Roberts]

So it all started last Saturday; MP1's plugged into my Furman which plugs into a wall socket, pretty standard deal.  I get to the venue, plug the rack in and the MP1 doesn't power on, but everything else in the rack does.
I take it home, plug the Furman into ANOTHER Furman on my backup rack and everything powers on fine; weird.
I get to rehearsal last night, plug my rack into the wall and the MP1 doesn't power on again.
Any clue what's happening?

[MarshallJMP]

Could be a wall voltage problem, if the voltage is too low it won't start. But it could also be a bad diode or a worn cap.

[rnolan]

Have you tried it without the Furman, maybe your main one has issues ? (not that there's much inside them, particularly for the money they cost).
Though to get you by, maybe swap the Furmans (as your backup seems to work).