>Help,
> The grid current meter on my SB220 is all the way to the right
>with key down, even on SSB mode of the exciter. On dekey the meter pegs
>the left side. Is this a tube problem or meter circuit problem.
>Suggestions please.
>
> Thanks,
> John
> KO4A@juno.com
I suspect that R1 [0.82 ohm] is open. Reverse grid current is an
indication that the filament may be out of line and touching the grid
cage when the tube is warm. [see photo on p. 15 in 9/90 QST]
Be sure to change the cutoff bias method from voltage to resistive AND
put diodes across the meters or across the meter current shunt resistors.
Rich---
R. L. Measures, 805-386-3734, AG6K
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