[TenTec] Centurion 422 Bias Circuit

Carter k8vt at ameritech.net
Thu Feb 5 14:41:52 EST 2009

k0bx at arrl.net wrote:
>  I just received a 422 Centurion. My question is: How do I determine
>  if the newer Bias circuit is installed?? This circuit cuts off the
>  bias when the rig is in transmit but is in idle.

I think you sort of answered your own question.... if it's in transmit 
but idle, plate current should be zero. Going back 10 or 12 years ago, 
my bias board failed and then there was about 300 ma of plate current in 
idle. You could take it out of its case and check the revision suffix on 
the board (see below). Otherwise, I don't believe there is an easy way 
to tell.

I had the original bias board that failed; as of ten years ago, I 
believe TT  had a -B and then a -C rev of the board.

Note: all of the above is subject to the vagaries of my memory.   <grin>

>  QSL review from 1994 S/N 10A10091 had the old bias circuit and they
>  indicated that the newer one had the modifiy circuit. My S/N is
>  80A10042. But no date of purchase was indicated in the manual. Any
>  ideas? Any ideas on when the 80A10042 was built?

Probably ask TT.

It's a nice amp! Enjoy it.

Carter   K8VT

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