[TenTec] Ig drift on amps

Bob McGraw - K4TAX RMcGraw at Blomand.net
Mon Feb 9 23:00:21 EST 2009

If the leads to the caps are black then that says "they are heating".  Loose 
connections can cause this.  Make sure the mounting screws are tight and 
that a proper internal tooth lock washer is installed between the wire 
terminal and the capacitor terminal. Same for the bottom side with the lock 
washer between the capacitor and chassis.  Due to circulating currents in 
this circuit any and all contact resistance can spell problems.  Heating 
causes resistance to change which causes loading to change which causes grid 
current to change.

Bob, K4TAX

----- Original Message ----- 
From: "Gary Smith" <Gary at doctorgary.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Monday, February 09, 2009 7:04 PM
Subject: Re: [TenTec] Ig drift on amps

> Stuart,
> Yes I did. They suggested there could be many things including a
> bandswitch issue. They said the only way for them to be sure would be
> to send it to them for a check. They said I would need to send the PS
> too but that I could remove the transformer. Probably an honest
> answer but before incurring that expense, I'd like to see if the
> public opinion might have hit the nail on the head.
>>From what I've been able to understand from the replies on & off
> list, the answer seems most likely to be in the padding caps.
> I took the cover off after getting back in to see what's reality and
> a couple of leads to the doorknobs were quite black and almost looked
> burnt while the lead to the ceramic cap for 160 had leads that were
> shiny. The 15KV 400pf doorknob might be fine but there was an area
> that was clean & shiny inside (the area closest to the 160 coil) but
> the other areas in the HEC were solid black. Perhaps one or more of
> the caps have failed.
> I'm looking for replacement caps & will post that momentarily.
> Thanks,
> Gary - KA1J
>> Gary,
>> Did you say if you have called Ten Tec service on your problem?  They
>> may be able to zero in a cause over the phone and tell you what part(s)
>> to check.
>> Stuart Rohre
>> K5KVH
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