Blown capacitor

butchbass · 1122

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Offline butchbass

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on: August 15, 2017, 05:32:56 AM
I was investigating a malfunction in one of the speakers we use for our PA at church, an EV ZX1-90. I discovered an 18 uf capacitor blown and I mean blown. One end had become separated from the cap and the internals had become the externals. The crossover has two fuses but neither one were blown. The cap is rated at 100vdc. Should I look for something else or just replace the cap?
The speaker coils check out ok.

Butch Gross
Stereomour II/  Blumenstein Orcas, Dungenes/Schiit Bifrost Multibit/Amarra


Offline Paul Joppa

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Reply #1 on: August 15, 2017, 07:22:29 AM
I found a picture, which shows it's a non-polar electrolytic cap. The question is, why did it blow? 100v peak would be 600 watts, so unless the amp is insanely powerful, an over-voltage seems unlikely. Is it old? Is the amp stable?

You can replace it, with either the same thing or possibly a more reliable film cap and/or a higher voltage rating. But if you don't know why it blew, you can't be sure the problem won't recur.

http://reconingspeakers.com/product/electro-voice-zx1-90-crossover/

Paul Joppa


Offline butchbass

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Reply #2 on: August 16, 2017, 07:06:24 AM
Thanks for the feedback. The speaker is about 6 years old and only used on Sunday but it is stored in an unheated/uncooled sea van so maybe the temperature extremes have affected it. The amp  is 300 watts into 8 ohms so I don't see that as an issue. I will just replace the cap and monitor for future issues.

Butch Gross
Stereomour II/  Blumenstein Orcas, Dungenes/Schiit Bifrost Multibit/Amarra


Offline Doc B.

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Reply #3 on: August 16, 2017, 10:16:12 AM
It probably just dried out and shorted.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.