Re: Dell BIOS
On Mon, 16 Jan 2017 14:53:33 -0600
"Martin McCormick" <martin.m@suddenlink.net> wrote:
> Felix Miata <mrmazda@earthlink.net> writes:
> > What models are they? If of approximately 2002 to 2007 vintage,
> > they could be victims of the bad capacitor plague:
> >
> > http://en.wikipedia.org/wiki/Capacitor_plague
>
> Interesting article. These dells could possibly be in
> that group as one has a BIOS date of August 1, 2001 and another
> is July 12, 2000. Both are Dell desktops so they could possibly
> be in that group. By the way, very few electronic malfunctions
> are quite as spectacular as an electrolytic capacitor that
> develops a sudden and catastrophic internal short.
>
> It sounds like the caps discussed in the article have a
> safety valve in the form of the vent but nothing short of high
> explosives equals an electrolytic filter cap popping.
>
> It sounds like a firecracker and throws more aluminum
> foil shrapnel than one could think would fit in the case.
>
> I had one about the size of a thumb blow up on me once
> and I could still find pieces of plastic and foil 6 months later.
>
> Thanks for the link to the article.
>
It doesn't have the whole story. I've seen thousands (literally: some
television cameras I have repaired contained over 100 dodgy capacitors)
of surface-mount aluminium electrolytics leaking. The electrolyte used
in these [Japanese] capacitors was obviously very conductive, but it
also dissolved copper. There was literally no limit to the types of
fault caused by some tracks disappearing and some being bridged
together.
The mention of 'amine' rings a bell, when hot this electrolyte smelled
of fish, so the quick way to distinguish between harmless flux left on
a PCB after manufacture, and the brownish electrolyte, was to touch a
soldering iron to it. Evil stuff.
--
Joe
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