24 Feb
2009
24 Feb
'09
2:17 a.m.
On Feb 23, 2009, at 1:29 PM, William Donzelli wrote:
Yup:
http://deep-blue.ro/tmp/chinese%20capacitor.jpg
Frightening, isn't it?
Not to
mention cheapness in commodity equipment and counterfeit
components.
In fact I'd bet real money that these issues are the culprits far
more
often than high frequency and high current. There are components
available
that are designed to withstand such things, and they're quite good.
Yes, there was a rash of ultra cheap counterfeit capacitors a while
back, and the problem is still not solved. 
I would worry more about
them than any caps in a MicroVAX. Those 70s and 80s era caps are
pretty good, and I have only very rarely seen ones go bad (and yes, I
have dealt with piles of them). I would also say that most of the
failures are due not to age and (lack of) reforming issues, but to
seals that leak and let in contaminants. No amount of careful powering
up will repair a capacitor with a bad seal. I am tempted to research
this a little more, talking to capacitor guys and digging up the
reports the military industry has done on the issue, but I fear the
results I find will fall on deaf ears on this list.
Not these ears! Research away; I'm interested. We're not ALL
curmudgeons.
-Dave
--
Dave McGuire
Port Charlotte, FL