Welp either the other old power supply I swapped out failed in the same manner (after working yesterday) with the system locking with loading the background or the PPC is faulty...
Will have to do more testing... Sigh...
Maybe some solder joints on the PPC are failing.
Heat up the PPC area a bit (to allow for the joints to expand and improve conductivity where possibly fractured) and see if the PPC comes back to life (only to disappear again when the area has cooled off).
Only heat up the PPC chip, do not expose the CPLDs between the two odd-spaced SIMM sockets to excess heat (PPC can be replaced, CPLDs cannot unless taken from a donor CS PPC card).
If it comes back to life this way, you can probably get away with it by having the PPC chip reballed, although it might be wiser to have it replaced with an altogether new (and faster :-) ) chip.
