Jerome,
Is this on your PC or on your PDP-11? If it was on the PC, just toss
the powersupply. It's not worth the effort.
I disagree for at least 2 reasons.
Firstly, whatever machine it's from, you want to be sure that the old PSU
was faulty so that you know you've fixed the problem by replacing it.
THis is particularly important for intermittant faults!
Secondly, the old AT-style PC PSUs seem to be very hard to find over here
now. They are certainly worth fixing, since most of the time all they
need is new capacitors...
-tony