I never knew an little used machine could accumulate so much dust.
It's been stripped, cleaned, had anything that could be reseated reseated, the PSU has been checked, capacitors inspected (no leaky or bulging ones found yet).
All in all it was in OK shape apart from the dust, a scarily large amount of which was in the PPC card's heatsink.
I have since managed to get it booted, though it refused to do so until I flashed the PPC card.
I wonder just how many years are left in the old girl now :-/