[Hallicrafters] Bumblee Caps

[WA1KBQ at aol.com]

I have been accumulating a stash of good NOS early oil filled Black  Beauty 
caps for possible use in a future SX-88 restoration purely to retain  
originality on a specific receiver. A few years ago I found a one  owner SX-88 
which had been put back in its original box with all the  original factory 
packing material after apparently being used for only a short  time. I don't 
necessarily need for this one to display working order  but want to have a set 
of NOS replacement caps to keep with it which would  restore working order 
and retain original factory content if desired. I can't  explain why some 
oil filled Black Beauties test very good while others test  nearly shorted but 
that's been my experience. It is also quite common to find  the plastic 
cases split and leaking oil on the early oil filled version.  Possibly old used 
caps are often discovered failed because of the voltage that  has been on 
them but I have also found some in low voltage circuits that  are still good. 
You certainly don't want to leave leaky caps in screen and plate  bypass or 
grid coupling positions in particular. When I occasionally  exercise old 
vintage equipment here which I want to keep original I always  meter voltage 
and current and monitor tube and transformer temperatures.  For example; you 
don't want to recap a Hallicrafters S1 Special where only  two are known to 
still exist without thinking about what you are doing first.  Sorry abt the 
late reply. 
 
Regards, Greg
 
 
In a message dated 11/3/2012 11:22:53 A.M. Eastern Standard Time,  
hallicrafterssr2000 at k9axn.com writes:

Questions regarding the history of these  components.

1.  Who manufactured the Bumble bee, Black beauty,  Black cat, etc
capacitors?

2.  Did General  instruments ever make paper caps and when did they
start building Polyester caps?

3.  Does anyone have a good Bumble  Bee cap in their possession?

The SX-100 and other early 50Kc I.F.  systems used 10% non–inductive (High 
quality?)Bumble Bee caps on the band  width switch.  I have not found a 
single one of those caps that were  within measureable tolerance due to leakage. 
 

Note that the  SX-117, HT-44, SR-150, and later radios used General 
instruments non-inductive  Polyester, not paper caps, that are as good today as 
when they were  built.  They look like the old paper caps but are not --- they 
also have  the General instruments logo.

One of the most common mistakes when  restoring the later radios is to 
replace all of the paper caps with ceramic  disc caps.  Bad move, they are 
Polyester and stable, not paper, whereas  the high K ceramic are unstable, 
unpredictable and totally inappropriate for  these circuit designs.

When replacing the caps on the 50Kc band width  switch, use Polypropylene 
or Polyethylene film not ceramic disc caps.   BTW, all of the Hallicrafters 
radios used non-inductive caps in the 50Kc  bandwidth selection circuits. 

Kindest regards Jim  K9AXN

______________________________________________________________
Hallicrafters  mailing list
Home:  http://mailman.qth.net/mailman/listinfo/hallicrafters
Help:  http://mailman.qth.net/mmfaq.htm
Post:  mailto:Hallicrafters at mailman.qth.net

List Administrator: Duane Fischer,  W8DBF
** For Assistance: dfischer at usol.com ** 


This list  hosted by: http://www.qsl.net
Please help support this email list:  http://www.qsl.net/donate.html