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

Bob McGraw - K4TAX RMcGraw at Blomand.net
Mon Feb 9 22:53:34 EST 2009


I put some in both of my 238 tuners with great success.  Good seller and 
good price and good quality components.

73
Bob, K4TAX


----- Original Message ----- 
From: "Ron Castro" <ronc at sonic.net>
To: <Gary at doctorgary.net>; "Discussion of Ten-Tec Equipment" 
<tentec at contesting.com>
Sent: Monday, February 09, 2009 9:46 PM
Subject: Re: [TenTec] Doorknobs needed - Was: Ig drift on amps


> 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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>>
>
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