[ARC5] OK Smart People - Mystery 211s

[J. Forster]

And connecting across a neon sign transformer won't?

The method I outlined earlier will work and will not damage the tube. It
runs the tube as was intended, only keeping the E fields below the
breakdown point, while the getter functions as intended to clean up the
vacuum. I've done it with 100s of tubes and it has about a 90% success
rate with NOS tubes from WW II that have been in storage for near 70
years. The physics is sound.

The neon sign method relies on essentially a sputtering effect, which was
never intended by the maker.

YMMV,

-John

======================


>> Connect the grid to the plate, and apply normal filament voltage to the
>> tube.
>> Insert a millimeter in the plate voltage lead, and apply something like
>> 45 volts
>> to the anode, or whatever voltage is necessary to achieve about 250 mA
>> of
>> plate current. Watch the meter. At some point in time, plate current
>> will start
>> to rise, and may rise very rapidly. At this point, shut off the anode
>> voltage.
>> The tube should be ready to use.
>
> Surely this will lead to severe grid damage?
>
> 73 de Neil ZL1ANM
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