RE: Computer PSU has very high pitched whine. Is this bad?

["Keith Doxey" <ukha@xxxxxxxxxxx>]

-----Original Message-----
From: UKHA [mailto:mailinglists@xxxxxxx]

> A recently salvaged computer has a PSU which emits a very high pitched
whine
while it's powered up.
> Is this bad? Could it fail? Will it burn my house down, etc?

Very difficult to say because there are many reasons why it could whine.

It could just be a transformer with a noisy core or slightly loose windings
and could work for a very long time.... or....

It could fail :-(
The power supply I used for the KAT5 switcher demoed at Hatfield had a
multi
output switch mode power supply that I had salvaged from something.
Everything appeared fine, all voltages were correct but I did notice that
it
whined slightly. It was in use quite a lot in the week leading upto
Hatfield
and gave no problems whatsoever.

At Hatfield, I got my stand all set up and everything running but after
about an hour the bloody PSU decided it would lose its +12V rail. Luckily I
had a handful of spare wallwarts that I hastily wired into the switcher to
get it back up again but spent the rest of the weekend worrying if the +5V
and -5V rails would also fail. Thankfully it lasted out.

It is unlikely to burn the house down as power supplies have to use
components that fail in a safe manner but if someone has modified it at all
then this may not be the case. If you have any doubts then probably better
to err on the side of caution and get a new one.

Keith