[Amps] Alpha 8100/GU74B Tetrode question

[Carl]

That is there as both a parasitic damper and a fuse in case of a screen 
short. Likely problem is a blown tube due to a tuning or antenna fault. OTOH 
you may be lucky.

Carl
KM1H


----- Original Message ----- 
From: "Gary K9GS" <garyk9gs at wi.rr.com>
To: "AMPS Mailing List" <amps at contesting.com>
Sent: Sunday, May 13, 2012 3:10 PM
Subject: [Amps] Alpha 8100/GU74B Tetrode question


> Hello all,
>
> I have an Alpha 8100 with a pair of GU74B/4CX-800 Tetrodes.  I recently
> had a problem occur with the amp going into a fault condition as soon as
> any drive was applied.
>
> Through some help from RF Concepts, I isolated the problem to an open
> series resistor that supplies screen voltage to the tubes.  It's a 15
> ohm/1 W resistor.
>
> My question.....what would be the most likely cause for this resistor to
> fail open?
>
>
> -- 
>
>
> 73,
>
> Gary K9GS
>
> Greater Milwaukee DX Association: http://www.gmdxa.org
> Society of Midwest Contesters: http://www.w9smc.com
> CW Ops #1032   http://www.cwops.org
>
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