Shorted or high-leakage electrolytic caps are usually expected when
resurrecting vintage electronic gear. I don't know if drawing a direct
parallel to HV amplifier supplies is appropriate or not, but a 180uf,
450V polarized cap can be (for example) found in both cases. In one case
perhaps by itself, another case in series with others using equalizing
resistors.
Also -
I don't have 40+ years of field experience yet, but when my homebrew
4-400(s) PS and my L4B PS 'banged' at different times, shorted caps were
found in both. I assumed they were the cause of the failure - perhaps
secondary damage instead? I haven't had a correctly-spec'd oil-filled
cap fail yet so don't have any failure data - except for plain old oil
leaks. (which probably don't count)
Every time my most basic assumptions are challenged on this list, I wish
once more I hadn't given up smoking...
Jim, N7CXI
Danny Pease wrote:
> I have experienced several new electrolytics that shorted and besides the
> mess, they have a nasty fishy smell!
>
> NG9R
>
>
>
> I have seen shorted oil filled capacitors and boy do they make a mess when
> they puke their oil.
>
> 73,
> Gerald K5GW
>
>
>
>
> In a message dated 2/11/2010 12:00:51 P.M. Central Standard Time,
> dezrat1242@yahoo.com writes:
>
> ORIGINAL MESSAGE:
>
> On Thu, 11 Feb 2010 12:16:44 -0500, "Paul Christensen" <w9ac@arrl.net>
> wrote:
>
>> 2) series R between the rectifier and filter C for
>> rectifier preservation during a C short;
>
> REPLY:
>
> Has anyone actually experienced a shorted filter C? Open C is far more
> common, in my experience.
>
> In more than 50 years of electronics I have never seen a shorted
> aluminum electrolytic cap. I have replaced hundreds if not thousands
> of open ones and I have seen shorted tantalums on many occasions, but
> that's all. I am sure it must happen but it seems to be exceedingly
> rare.
>
> 73, Bill W6WRT
> _______________________________________________
>
>
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