[Hallicrafters] postage stamp mica caps

[john]

Barring a megger, you can always hook up a tester with a Variable B+
DC supply and a multimeter in series checking the leakage current. It's nice
to have a current limiting resistor too, in case the cap begins to conduct
heavily. Run it to rated voltage slowly, keeping an eye on the leakage...

Best
John


At 03:23 PM 6/23/02 -0400, JM/CO wrote:
>Informed opinions are of no use in a situation like this. Scientific
>evidence is required. I once made a similar "find", but upon electrical
>inspection, discovered that they were ALL bad. Use a megger. This is the
>only way to check these at their rated voltage. Simple capacitance meters,
>or ohmmeters will not tell the tale. Capacitance measurements should be
>undertaken to see if they are still within tolerance ( probably 20 % ), but
>the use of a megger is the only way to determine if they will still handle
>their rated voltage. When it comes to older capacitors, NEVER assume
>anything.
>Chuck N1LNH
>-----Original Message-----
>From: Kenneth Laine Ketner <ketner at arisbeassociates.com>
>To: baswaplist <baswaplist at foothill.net>; Hallilist
><hallicrafters at mailman.qth.net>
>Date: Saturday, June 22, 2002 6:16 PM
>Subject: [Hallicrafters] postage stamp mica caps
>
>
>A friend just gave me a nice cabinet with a large assortment of molded
>mica caps. Can’t beat the free price. Some of these are labelled 500
>vdc. These are probably fairly recent manufacture, not the old slick
>plastic molded micas from the 1930s. Does anyone have an informed
>opinion on whether these are dependable for re-capping purposes within
>the wvdc range?
>
>--
>
>Ken Ketner
>ARS KA5ELD (Extra Class)
>  Personal Webpage: http://www.wyttynys.net
>  Office Webpage: http://www.pragmaticism.net
>Email:
>home: ketner at arisbeassociates.com
>office: b9oky at ttacs.ttu.edu
>
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>
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