[Boatanchors] Micamold Paper Caps

[David C. Hallam]

The audiophools love black beauties.  When ever you replace any black 
beauties, keep the leads a long as possible and sell them on eBay.  
Leaky capacitors enhance and beautify sound

David
KW4DH

On 7/5/2013 7:48 PM, WA5CAB at cs.com wrote:
> My experience (50+ years of it) is all with military sets.  What I've found
> about vintage capacitors in general, including Micamoild and any brand of
> oil filled paper, is that they may all be good, they may all be bad, or a few
> are bad and the rest good.  My SOP is to test first.  If about the first
> three or four of a specific package type and value are bad, I assume that all
> like that are bad.  But not necessarily all like that except for being a
> different value.
>
> Except for Sprague BB's.  The US military realised by about 1960 that there
> was a problem with them and started issuing MWO's or T.O.'s to replace them
> wholesale, no testing required.
>
> I have only seen so far one receiver (a BC-342) where every capacitor in it
> (except the air variables) was bad.  But where there is one, there are
> probably more.  So I'm not saying that anyone who found another such set is
> wrong.  Just that anyone who (except with BB's) arbitrarily replaced all in a
> set without checking first was probably wrong.
>
> Robert Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
> In a message dated 07/05/2013 15:12:58 PM Central Daylight Time,
> pulsarxp at embarqmail.com writes:
>> ----- Original Message -----
>>       Micamold made paper caps in flat packages that look
>> like mica caps.  I replaced a bunch in an RCA AR-88 recently
>> and saved them.  I tested them using an Eico 950B capacitor
>> checker out of curiousity and found all were very leaky.
>> They were much leakier than the oil filled bathtub paper
>> caps out of the same receiver even though the seals had
>> disintegrated on them letting the oil leak out. I dissected
>> a couple of the Micamold caps. They appear to be the same
>> sort of plastic impregnated paper as used in the Black
>> Beauty caps but do not show the same mechanical distortion
>> as in the BBs.  In any case, any Micamold paper caps should
>> be tossed. I have read these are bad guys but wanted to
>> confirm it. I did.  In comparison modern film caps do not
>> exhibit any detectable leakage on this tester.
>>
>>
>> --
>> Richard Knoppow
>> Los Angeles
>> WB6KBL
>> dickburk at ix.netcom.com
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