[TenTec] Centurion 422 Bias Circuit

pfizenmayer pfizenmayer at qwest.net
Thu Feb 5 23:46:10 EST 2009

Just checked my Centurion circa Feb of 2005 and it is exactly the same as 
Bob's - 150 ma  idle while QSK relays are still in . With the Orion even at 
100 percent CW QSK DELAY the meter barely damps out to show idle current. 
Having had two bias board failures and one QSK board failure and going 
around with TT about those - I am quite sure its working as it should for 
that vintage.

73 Hank  K7HP

----- Original Message ----- 
From: "Carter" <k8vt at ameritech.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Thursday, February 05, 2009 6:00 PM
Subject: Re: [TenTec] Centurion 422 Bias Circuit

> Bob McGraw - K4TAX wrote:
>> My 1996 Centurion shows about 150 ma when in transmit and 0 when not in
>> transmit.  I've always thought that to be quite normal and certainly
>> acceptable.  Same for CW operation between characters.
> Bob,
> I won't agree or disagree with your comments on linearity.
> However, I am not sure about the 150 ma you are experiencing in the idle
> condition. The earlier Centurions (like mine) were notorious for having
> the bias board fail. Furthermore, Ten Tec went through at least two
> iterations beyond the initial board to solve this known problem..
> Again, I don't know enough to address the linearity issue, but the bias
> board, really the "Filament-AC board" (81537), is supposed to help
> extend the life of the amp by reducing plate dissipation in the idle
> mode. You may want to give TT a call and see if that 150 ma is normal.
> 73,
> Carter   K8VT
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