I tried that old capacitor trick and smoked my receiver

Some guy on a forum swore you could jump-start old electrolytic caps by briefly connecting them to a 9V battery. I mean, it sounded sketchy but I figured what the heck, my Pioneer receiver from 1979 was already not working. Hit that cap for maybe 3 seconds and it popped, leaked black stuff everywhere. Took me 4 hours cleaning electrolyte off the board with vinegar and q-tips. Now I gotta replace like 8 caps plus the board traces that got eaten. Has anyone else been burned by this bad advice or was I just doing it wrong?

2 comments

2 Comments

taylor_patel24d ago

1979 Pioneer receivers have 44 year old caps that were already dried out and probably failing. You did exactly what you shouldn't do with a 9V battery on a cap that old. Thats way too much voltage for most electrolytic caps in that era. Most of those old caps are rated for 6.3V or 10V at most on the signal path. You basically forced 9V into something that could barely handle half that. The black goo is just the electrolyte boiling out from the heat and pressure. The real trick isn't to zap them with a battery, its to slowly reform them over hours with a bench supply set to the correct voltage through a resistor. Sorry you wrecked your board but thats on you for not checking the voltage rating first.

terryrobinson24d ago

Oof, yeah, that's a rough lesson. Live and learn, but ouch.