FWIW, you might also want to consider getting a BlueSCSI v2 and a high-endurance SD card to go along with it!
-- thorpej
The machine is a Quadra 630, with a date stamp of Feb 28 1995. I haven't opened the case, though I noticed corrosion on the bottom plate.
Replacing capacitors is probably beyond my skills. Once it's open on a bench I'll take photos for expert opinion gathering.
Thanks all for the info!