Hello,
I am trying to repair a computer power supply, and of course the part
that burnt up is the only one I cannot identify. It is (I think) a
voltage regulator. It is a 3 pin package attached (screwed) to a
largish heat sink. It has the code k1821 on the face, and there is a
logo that looks like an 'F' over either a 'E' or a 'C' like so F
E
I have looked on NTE and chipdocs with no luck. Thanks!

wrote:

Hello,
I am trying to repair a computer power supply, and of course the part
that burnt up is the only one I cannot identify. It is (I think) a
voltage regulator. It is a 3 pin package attached (screwed) to a
largish heat sink. It has the code k1821 on the face, and there is a
logo that looks like an 'F' over either a 'E' or a 'C' like so F
E
I have looked on NTE and chipdocs with no luck. Thanks!

Just get a new one. There is no telling how long it will work after
you fix it. Most PS parts are run at full bore. When a part fails,
it messes up other parts. Do you need an AT or an ATX power supply?
ATX is sold everywhere. "Intel" supplies have a four pin connector
for +12V to the processor. The ones without the four pin connector
are for Celeron or AMD cheaps. (not a misspelling)