hp 6286a supply

This is a constant flamewar in the UK vintage radio magazines... I would be careful shotgunning parts. Firstly that you don't introduce more faults (either by using unsuitable capacitors or mis-connecing them). Secondly that you don't cause problems by changing a capacitor in a timing cirucit and having to re-align things). And of course you do need to be able to trace the fault 'properly' if changing the capacitors doens't fix it. My expeireince with old HP instruments (mostly from their decktop calculators) is that capacitors are not a major source of problems. If I had this PSU in for repair, I'd trace the fault properly first. If I found it was due to defective caps, I probably would change the lot. If it wann't, I might well leave them all alone. That said, there are capacitors I would always change in old equipment. Top of the list (and unlikely to apply to this list) is the coupling capacitor to the grid of an output valve. If that goes leaky, it can mean a burnt-out output valve, a burnt-out rectifier valve, and a burnt-out output transformer. -tony