Lostgallifreyan wrote in
:

DaveC wrote in
:

What was the existing cap?

DaveC wrote in
:
It's a Mallory FP119A.

Any clear indications as to why or how it failed?

No. Guesses: Old age? Heat?



Old age isn't a mechanism. Heat could well be right. Also accelerated
loss of electrolyte. Did the cap look like it had burst from inside
earlier than any final appearance of internal gubbins? Another
possibility is the voltage it saw. When you say 110 volts, you mean the
mains, right? If so it will be rectified and that cap will be seeing the
peak value, not the RMS, so around 125V when under no load, so you
really do need it to have a higher voltage rating than that.

Btw, I know that that cap ought not to be unloaded to the point where the
voltage gets to full height in that system, but best assume it will, so if
the load fails the cap remains safe and you get no bad future comeback. I've
seen an amplifier that had an internal fire resulting from a cap failure. It
shocked me. Very very messy scene. I wasn't given to me for repair, I didn't
even get much salvage out of it.