Finally had some time today after Dayton and getting caught up with
other stuff.
I replaced the series screen resistor and the amp looks like it's
working normally. I need to do some additional checking on other bands
but I think I'm back in business.
Thanks for all of your input.
On 5/14/2012 9:42 AM, Carl wrote:
> 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@wi.rr.com>
> To: "AMPS Mailing List" <amps@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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>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
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>
>
--
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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