How tough is a capacitor?

[digi2t]

Been working on an Echodrive clone of late. I finally fired it up last night, and my expected plate voltage of around 150v was actually 280v. I played around with it for about 20 minutes or so before realizing that I incorrectly configured the transformer.

Anyway, my electros are rated at 220v, and the film caps at 250v and 275v. I haven't noticed and bulging or discoloration, but I was wondering if there might be potential damage that's not visible to the eye when caps are pushed past their ratings?

[Slowpoke101]

The film caps are probably OK as the over-voltage was not very high and not for very long. Film caps can usually handle a brief 15% over-voltage condition with no problems. But the electros are a different story. They really don't like going too far over their maximum recommended voltage. The electrolyte starts to boil and pressure starts to build and then we get the usual familiar catastrophic failure. You may have gotten away with the over voltage. Did the electros get warm or hot?
I would recommend replacing them as a precaution anyway. I usually replace old high voltage electros when restoring equipment as it prevents problems and surprises later on.

[anotherjim]

Overvoltage is one stress, and high temperature is another. Sometimes it doesn't fail until you get both.

[digi2t]

Did the electros get warm or hot?
I would recommend replacing them as a precaution anyway. I usually replace old high voltage electros when restoring equipment as it prevents problems and surprises later on.

I thought about putting a finger on them... just for a moment, but then thought better. With my luck, it would have probably blown it's top the moment I touched it. Just close inspection, no bulging whatsoever. No wrinkled wrapper either. Look perfectly normal. As you state though, there's only two of them, so I can swap them out, just to be on the safe side.