[TenTec] Ten-Tec 411 Centaur Amp Problem

Dr. Gerald N. Johnson geraldj at weather.net
Thu May 27 13:02:35 PDT 2010


In the trouble shooting section it says if the input SWR is high, the 
input board is loose, meaning its lost some or all of its grounds. Seems 
to me that's always a good thing to check, then there's only one bit of 
reactive parts, the low pass filter which has probably been changed for 
one passing 10 meters and a high SWR on one band hints at something 
wrong in that filter.

According to vintage tube amplifier design articles from QST in the 60s 
republished in the vintage ARRL SSB books, the cathode tuned circuit 
does more than match impedance, it also helps the linearity that the 
resistive network in the 411 won't accomplish. Else it depends on the 
low pass filters in the driver to provide that low Q resonance as part 
of the PA tube circuit.

73, Jerry, K0CQ

On 5/27/2010 2:33 PM, Kris Merschrod wrote:
> Thank you Jerry and also Gary for the copy of the manual.
>
> Looking at the boards in the manual it seems straight forward to find
> the board. Finding the "problem" unless there is a nicely burned out
> gizmo, will be a challenge.
>
> Kris KM2KM
> Merschrod
> 123 Warren Road
> Ithaca, NY 14850
> www.merschrod.net
>


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