[Hallicrafters] S40 restoration

[Craig Roberts]

Hi Brent,

You'll be getting a lot of messages just like this:

"Replace those black plastic caps. Those are popularly called Black 
Beauties and are simply paper caps encased in plastic. They are 
notoriously unreliable."

In a recently completed restoration of a Hammarlund SP-600, I replaced 
dozens of them.  Every single one was bad.  In the Hallicrafters SX-42 
I'm now finishing, a previous owner or repair person had replaced one of 
the original paper caps with a "new" Black Beauty -- probably in the 
50's or '60's. Sure enough, it was bad -- even though many of the 
original paper caps were still functional (although I replaced them all).

The idea behind the plastic encased design of the Black Beauties was to 
exclude destructive moisture more efficiently than the "crude" beeswax 
covering of earlier paper caps.  Instead, the plastic seems to have 
TRAPPED moisture more efficiently. This, of course, accelerated the 
decay rather than retard it.  As a result, the failure rate of Black 
Beauties is many times that of the supposedly "inferior" devices they 
replaced.

Many years ago, before any of us had access to the shared knowledge 
internet discussion groups afford, I learned about Black Beauties the 
hard way.  The owner  of a radio station for which I worked "willed" me 
several boxes of NOS Black Beauties for use in my little radio 
restoration side business.  I happily installed my new "freebies" into 
several customers' radios without incident. On a subsequent job, 
however, my replacement caps seemed to have made matters worse rather 
than better. When I recieved the radio, it was working "okay". When I 
got done recapping it with my Black Beauties, it didn't work at all.  It 
took sevceral hours to figure out what was going on. Eventually, good 
old "Orange Drops" saved the day. I was then, of course, honor bound to 
recall the several repairs I had just done to make them right, too.

So, yes, replace those Black Beauties.

73,
Craig
W3CRR