Electrolytic cap "protection"

From: Tothwolf <tothwolf_at_concentric.net>
Date: Mon Feb 10 13:16:00 2003

On Mon, 10 Feb 2003, Dwight K. Elvey wrote:

> > Awhile ago there was a thread about electrolytic capacitors popping
> > and then destroying the motherboard they are on. One of the ideas was
> > to replace them before they go.
> >
> > Now I was wondering about another idea... Would it be okay to encase
> > the capacitor in silicone gel? Then when the capacitor pops, it
> > wouldn't spread its electrolyte all over the motherboard.
> >
> > But would this cause other problems with heat or something? Would it
> > further shorten the life of the capacitor?
>
> There isn't much you could cover it with that would stop a cap from
> blowing. The pressures can get to several thousand PSI if there isn't a
> relief someplace. Wrapping several layers of paper towel around them
> might be better. This would at least keep the mess from the PCB.
> There was an article about some bad capacitors made in the last few
> years. According to the story, someone stole a formula for the
> electrolyte and the formula was missing some key ingredient ( most
> likely a depolarizer ). The caps made this way would out gas and
> rupture.

Why not just cover the cap with heat-shrink tubing? I've seen this done
quite a bit in high end switching power supplies. They often have about
3/8-1/2" extra sticking up from the top of the cap.

-Toth
Received on Mon Feb 10 2003 - 13:16:00 GMT