[Boatanchors] Micamold Paper Caps

[L L bahr]

A few years ago I restored an EF Johnson Viking I.  It had, as I remember, 21 of these micamold caps within it.  Not only were all of them leaky, but they were producing a voltage and acting as a battery.  Apparently moisture in them was reacting to the acid within the capacitor paper insulator and actually produced a voltage while observing it with my VOM in a low voltage mode.

Lee, w0vt
Houston
(no charge for consultations lasting less then 30 seconds)





----- 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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