Broken Mac Accelerator

Ethan Dicks ethan.dicks at gmail.com
Sat Sep 9 23:48:04 CDT 2006


On 9/10/06, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> >
> > So what I want to know is how the thing functioned at all without the =
> > cap (burnt carbon acted as a capacitor in some way)? and what caused it =
>
> That cap[acitor was probably a tantalum electrolytic (this being the type
> normally known for  exploding in this manner) and was probably a supply
> decoupuling capacitor.

> > to stop working.
>
> Now that I don't know, but it may have nothing to do with that capacitor.

Perhaps there was some PCB damage under the exploded cap?  We had
a tantalum cap (16uF?) blow on a COMBOARD that was installed in a
crowded BA-11... it looked like someone shot the board with a .22.  The
boards on either side were damaged as well, but not perforated.

Since the OP described blackening, perhaps it might be worth a few
minutes to gently remove the residue (95% Isopropyl (1,2-propanol?)) and
a soft toothbrush should get most of the crud off - then check the traces
and see if there's any visible damage.

Even if that's not where the problem is, a gentle cleaning should hurt
anything.

-ethan



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