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[Amps] al80a

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Subject: [Amps] al80a
From: (2)
Date: Fri, 2 Aug 2002 05:25:18 -0700
>carl seyersdahl wrote:
>>  One more comment here, Please??  I turned the amp on and noted that the
>> plate(anode to the new generation) turned a little red, indicating that the
>> plate (anode) is drawing current !! ( maybe too much??)
>I had these symptoms in a friend's AL80B.  The problem was a grid-filament 
>which showed up only when the tube was hot.  

Another way to find a tube with a bent filament is with a high-potential 
tester.   A grid-filament breakdown of under 5kV indicates a bent 
filament that may short when the filament is hot.   C. 8kV is normal.  
[note -- New, out of the box 3-500Zs have a filament-grid breakdown 
potential of 8 - 9 kV.]  Operating aero-mobile in an acrobatic airplane 
is probably not a very good idea if one is using a 3-500z amplifier.  
However, if one does an equal amount of inside and outside loops, the 
filament should stay fairly straight.  

>Try a new tube.
>Vic K2VCO
>Fresno CA

-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,  

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