"Scott Dorsey" wrote in message
...
Mark wrote:
I have obtained some surplus linear regulated power supplies. The
date code for the electrolytic caps in the filter section are late
1993. I've not powered these
supplies up. I know that these caps have a limited life. These caps
are also
harder to come by due to the proliferation of switch mode power
supplies and
their lower values. Any ideas/suggestions to minimize stress to these
caps
or even rejuvinate, if possible, these caps. I'm aware of inrush
current at
supply turn on and I plan to minimize that. Any other ideas or
suggestions???

You have three choices:

1. Bring the things up slowly, on a variac. This allows the capacitors
to slowly reform.

2. Bring the things up for a while with a 60W light bulb in series, then
apply full power. Same basic principle, if you don't have a variac,
but
slower.

3. Apply full power. If any caps blow, they were marginal and should have
been replaced anyway.

I tend to be a fan of method #3, but I can understand the arguments in
favor
of the first two. But caps that are only a decade old? Don't sweat it.
--scott



Many manufacturers of aluminum electrolytic caps recommend they be reformed
after 18 months of storage, others say 2 years, and others say 3 years.