Vintage HiFi Audio Forum

Repair / Help Forum => Repair / Help => Topic started by: Slim-Shaddy on November 11, 2011, 03:39:28 PM

Title: Kaboom
Post by: Slim-Shaddy on November 11, 2011, 03:39:28 PM
In case you were wondering, this is what it looks like when a cap explodes in an amp...
Title: Re: Kaboom
Post by: tinpan on November 11, 2011, 03:52:02 PM
Oh that sucks...what amp was it?
Title: Re: Kaboom
Post by: Slim-Shaddy on November 11, 2011, 03:54:08 PM
Onkyo M-508
Title: Re: Kaboom
Post by: MacGeek on November 11, 2011, 05:33:14 PM
I have certainly heard of bad caps, but what couses one to explode?
Title: Re: Kaboom
Post by: SunnyDaze on November 11, 2011, 06:05:08 PM
Ah man, sorry to hear this. As soon as I saw this picture on FB, I knew it was an Onkyo 5 series.

I wonder if you got a bad batch of caps?
Title: Re: Kaboom
Post by: Slim-Shaddy on November 11, 2011, 06:05:34 PM
From what I've read online it seems the most likely cause is reversed polarity.
Title: Re: Kaboom
Post by: SunnyDaze on November 11, 2011, 06:07:07 PM
PS - If you part it out, I'm interested in a meter & glass.
Title: Re: Kaboom
Post by: Slim-Shaddy on November 11, 2011, 06:09:58 PM
Quote from: SunnyDaze on November 11, 2011, 06:07:07 PM
PS - If you part it out, I'm interested in a meter & glass.

It will be taken back to the shop for repair. If it's too far gone, I'll let you know.
Title: Re: Kaboom
Post by: OCCD on November 11, 2011, 06:41:53 PM
I have seen this before!!!   :o
Title: Re: Kaboom
Post by: OCCD on November 11, 2011, 06:43:34 PM
Quote from: Shape-shifter on November 11, 2011, 06:05:34 PM
From what I've read online it seems the most likely cause is reversed polarity.

Negative, reversed polarity would have been instant boom.
Title: Re: Kaboom
Post by: Slim-Shaddy on November 11, 2011, 06:47:21 PM
Do you think it was unable to leak? Swelled up and popped?
Title: Re: Kaboom
Post by: SunnyDaze on November 11, 2011, 07:11:59 PM
If it WAS polarity, which I'm not saying it was, but, IF, then it would have blown right away. I think. If I remember right, when you reverse the polarity, the dielectric pretty much vanishes and all of the high current flows right through the electrolyte material. That vaporizes the electrolyte and pressure builds, then KA-POW... but it happens fast.

I could be wrong. My brain is filled with bong resin and statistical methods, so my physics might be way off in left field.
Title: Re: Kaboom
Post by: SunnyDaze on November 11, 2011, 08:30:16 PM
Note to self: Never work on your Stax cans. Or the energizer.  ;D
Title: Re: Kaboom
Post by: OldiesButGoodies on November 12, 2011, 10:34:23 AM
fake chinese cap and overvoltage?

http://www.flickr.com/photos/linux-works/2618014599/# (http://www.flickr.com/photos/linux-works/2618014599/#)
Title: Re: Kaboom
Post by: Falcon on November 12, 2011, 11:22:40 PM
Wow, that sucks!!  >:( >:(