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

[Gary Smith]

Hi Ron,

That was the second place I went to find them, the first was my box 
of amp parts (or what's left of it). I'm looking for the proper pf 
values but I want to replace what's there with proper sizes so I 
don't have to re-drill. I didn't see pf or size matches on Ebay for 
what came in the amp. I'm adverse to replacing much that wasn't part 
of the original design. Someday I'll sell the amp and I want to have 
the next person know it's got the expected components in it.

If this was a homebrew amp, I'd make room and change the padder pf 
values to make it work.

They are good prices though it looks like a lot of them are overseas.

Gary
KA1J

> 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
>       www.N6IE.com
> 
> ----- 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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> > 
> 
>