[ARC5] [Milsurplus] OK Smart People - Mystery 211s

[J. Forster]

You MAY be able to regenerate the gassy tubes.

Apply full filament.
Hook up an adjustable grid supply.
Apply a few hundred volts plate through a current limiting resistor.

Slowly adjust the grid supply so as to draw 10-20 mA plate current. Let it
run that way for a week.

The running under plate voltage and current MAY getter the gas.

Good luck,

-John

==========


> Just finished testing my stash of 211 transmit tubes
> by putting them in the BC-375.
> More than half were bad- mostly gassy.  sniff....
>
> Anyways, here's a mystery:  A few would not
> draw much current or put out much power in the
> PA stage, but they seem to work just fine
> in the Oscillator stage.  If this was low emission,
> I'd think they'd fail in either stage.  As a result,
> I've got four tubes marked "OSC ONLY."
>
> What's up with this?
>
> 73 Dave AB5S
>
>
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