On 2012-03-28, at 7:23 PM, Bob K6UJ wrote:
> I had one blow years ago, It blew the white debri all over the inside of the
> amp and
> scared the &*%$#%$ out of me. I was lucky and only the cap went. My wife
> came running in and wondered what the hell happened, she was not impressed :-)
> I decided to change all of them with new ones, hihi.
>
> Anyone else have them blow and can share with us ?
>
Hi Bob,
Back in about 1977 when I built my first linear amplifier & associated 1.5 KV
power supply, I employed a collection of similar-looking (and very cheap!)
surplus electrolytic capacitors that I bought from a mail order surplus
outfit...
In those simpler days I had no idea of the necessity of "healing", or
re-forming electrolytic capacitors gradually BEFORE use, & so simply applied
full voltage to the string of them right out of the box, & basically "...let
'er go".
Each cap was an aluminum can type, with a wax plug at the bottom---the caps
were mounted on a drilled piece of breadboard, with the wax caps (i.e. the
bottoms of the cans) pointed upward...and for the initial testing purpose I had
the top cover of the power supply off.
Well, within a second, or two, of applying B+ to the filter, I heard what can
only be described as a shriek from a roman candle---and it grew in intensity.
Suddenly a heard a spraying sound, whereupon I immediately killed the power...
Sure enough, the wax cap from one of the electrolytics had "popped", &
electrolyte had spewed upward like lava from an erupting volcano, and actually
stuck to the ceiling of my shack!
After that experience I brushed-up on the "...care & feeding of electrolytics",
& to this day NEVER install ANY h.v. electrolytic cap without first going
through the re-forming process with it...
~73~ de Eddy VE3CUI - VE3XZ
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