Re: [LAD] [Somewhat OT] Strange failure mode of a PC

On Sunday, July 18, 2010 09:25:27 am Ralf Mardorf did opine:

> On Sun, 2010-07-18 at 11:14 +0200, fons@email-addr-hidden wrote:
> > On Sat, Jul 17, 2010 at 10:56:47PM -0400, Gene Heskett wrote:
> > > Some lubricant obviously made its way in there, and one would have
> > > to assume that the switched current was sufficient to cause a
> > > microscopic arcing, which will in time create a smoke film on the
> > > internals, which is what you were measuring, and which caused the
> > > PSU to think the button was pressed full time. Lubricants are a
> > > good idea only on a circuit that can be called a dry circuit, where
> > > dry=microamp currents at very low voltages.
> >
> > Ah, yes, these plastic things are often lubricated.
> >
> > > Washing it out with acetone was ok, but I would probably have
> > > reached for a can of paint thinning alcohol as it is less likely to
> > > degrade the plastics.
> >
> > I know, but the acetone was all I had available...
> >
> > Ciao,
>
> Fruit acids or pure alcohols are effective and relatively harmless, but
> most effective are products by chemical companies, there are cleaners
> with qualities comparable to penetrating oil, but made to fit to
> electrical properties. Those cleaners will clean, resp. repair and
> protect.
>
True for the most part, but please do not place the common Freon TF in that
category when magnetic media is involved. 15 years ago at the tv station,
I got tired of paying for Freon-TF by the gallon, and cleaning the heads on
all our VCR's 2-4x daily, and tried cleaning one with paint thinner alcohol
from ACE Hardware. I didn't have to clean it again for a week! So I
switched cleaning agents on the spot. And it turned out that Freon-TF was
also much harder on the elastomer parts like pinch rollers. I cut the time
spent cleaning heads and rollers by 90%. Roller replacements went way down
too.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Humor in the Court:
Q.  Doctor, did you say he was shot in the woods?
A.  No, I said he was shot in the lumbar region.
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