A "fake" electrolytic!
I’ve heard stories over the years of “fake” axial electrolytic caps being sold on eBay, or even reputable places like Ted Weber Speakers. They can usually be spotted by a double crimp, and or rubber plugs on both sides, rather than the negative side being metal.
Well, I finally spotted one myself in a locally made hand-wired Fender Champ clone I had in just for a general once-over.
The cap was branded ELON - 20uf @ 500VDC, was crimped on both the plus and minus ends, and had a rubber stopper on both ends.
In the amp, it was is in parallel with an old 40uf 450VDC can cap section. Also, it wasn't actually soldered down! The lead was just wrapped around a few times. Ohhhh dear.
I decided to risk paying to replace the part myself for the chance to cut open that ELON. Well, I was vindicated.
Like a Russian doll, there was an itty bitty little radial leaded cap inside, with an extension leg soldered on, and wrapped up under the shrink wrap! The little tiny cap was marked "20uf 500V". I'll say.
Word on the street is, that these caps are salvaged from disposable cameras, then they have the new leads soldered on with a new wrap, that falsely identifies them as a different rating, then they're stuffed into the axial body. Seems like a lot of effort to me...
I'm guessing if this thing actually had 500V on it, it would curl up and smoke just like the Wicked Witch of the West.
I should note that I measured the cap with my Fluke 115 capacitance metre, and it measured at exactly 21uf. Not so bad!
Peeling the onion back one more layer reveals the TRUE cap inside: a radial Rubycon 22uf @ 400V!