"Phil Nelson" wrote in message
...
Yes, the flat molded micas are starting to show their age.
Although generally more reliable than paper, I have found
some bad ones in recent 1940s TV projects.

When in doubt, check 'em!

I read somewhere else that the plastic casing in Black
Beauties, etc., developed microscopic cracks and admitted
water vapor over the years, causing the same problems as
in paper caps.

Phil Nelson
That may be, they certainly develop very large cracks
sometimes. I've disected a few BBs. The capacitor itself was
distorted, oddly flattened rather than being tubular.
Perhaps they were wound this way or perhaps some sort of
differential shrinkage of the encapsulation pushed them out
of shape. They were _supposed_ to be very long life, low
leakage, deluxe capacitors and are generally found in high
quality equipment.


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Richard Knoppow
Los Angeles, CA, USA