23 Feb
2009
23 Feb
'09
10:29 a.m.
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.
So even though I was one of the first people on this list to suggest
reforming old capacitors, I have basically completely reversed my view
on the issue. Now, if the machine is not super old, I will just pretty
much plug in the machine and let it power up. Even if something does
fail, most of the machines I deal with have enough built in protection
that they will just shut down safely.
By the way - counterfeit components are nothing new to the industry.
For example, there were rashes of fake tubes in the 1920s and 50s.
--
Will