[TenTec] Doorknobs needed - Was: Ig drift on amps

Ron Castro ronc at sonic.net
Mon Feb 9 22:46:35 EST 2009

Gary:  Do a search on e-bay for "doorknob capacitors" and you'll two pages 
of 'em!  The 16 kV Russian military caps are what I used in my TT 238 tuner 
mod, and they seem to be every bit as good as their US equivalents.   The 
seller claims they were used in 12 kW antenna tuners and have 30 MHz current 
rating of 15 Amps.  At 5 for $19.50 you can't go wrong!

         Ron  N6IE

----- Original Message ----- 
From: "Gary Smith" <Gary at doctorgary.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Monday, February 09, 2009 5:29 PM
Subject: [TenTec] Doorknobs needed - Was: Ig drift on amps

> It appears I likely need to replace at least some of the padding
> capacitors in the tank on my 425 to stop the Ig drift on the lower
> bands. To do a clean sweep, what I need to replace are the following.
> A. (C6, C7) Two 1000pf @ 5KV series 858s doorknobs
> B. (C17)     One 500pf @ 5KV series 858s doorknob
> C. (C18, C20) Two 300pf @ 5KV series 858s doorknobs
> D. (C15)     One 400pf @ 15K Series HEC HT57 doorknob
> E. ( C16) One 270pf @ 2KV disc: Ceramic?/Mica? which is about
> 1"x3/32" and is glossy yellow. On the side it reads:
> RMC   270    J
> 2KV    P     3
> I would like to change "E" to an 858 series doorknob, making it a
> 270pf @ 5KV series 858 doorknob.
> The Drifting Ig issue is really a problem on the low bands and I'm
> concerned about damaging the tubes. If you have any of these caps in
> as new condition available, please contact me off list.
> Thanks!
> Gary
> KA1J
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