"Marky P" wrote in message
...

Basically, there was a severe buzzing noise on the output and the
fault was traced to the PSU supply not being stable.

Is it a linear, or switch-mode? How many output rails are there? does the
instability affect them all, or only one or two?

The caps were
replaced

All of them?

and the problem was rectified. Well, within a couple of
months the fault is back,

So probably not capacitors then, unless it's the ones that got missed last
time. (Is the fault *exactly* the same?) Maybe the instability is the result
of a broken PCB track, dry joint or poor connection somewhere that makes
contact when it wants too, and the "cure" last time was due to the physical
handling of the PSU causing this to make contact again, for a while.

and instead of paying silly prices to one of
the very few tape machine repair guys around, my mate wanted me to fix
it if I could find the faulty caps. The last repair cost £500. The
tape machine is a Saturn Soundcraft, and aparently there is only one
person in the country who can repair them (he lives in Bury St.
Edmunds).

Unlikely. Unless the machine was designed on Saturn (or in Bury St Ed) any
competent repair technician ought to be able repair it.

David.