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