[Boatanchors] Ballast tube for Hallicrafters S-47 (Nytron 24B870) - data needed

[Bob Groh]

More info dug up: The "Ballast Tube Handbook" is on the web in a
downloadable pdf form.

Does not have the exact tube that I am looking for but two close one's
(also used by Hallicrafters).  The handbook references Ryder 21-7.  So now
off to see what I can find there.

Bob Groh


On Sun, Aug 30, 2020 at 11:55 AM Bob Groh <bob.groh at gmail.com> wrote:

> Thank you. That is a start on what I am looking for. Regarding the idea of
> using a resistor, that certainly is a possibility but the behavior is of
> the 24B870 is more like a 'constant' current device.  Piecing together the
> information given so far, it would seem that the device would have 24V
> across it at 300 mA.  As the voltage across the tube varies, the current
> would stay more or less the same.  IF that makes sense. I'll keep
> looking!!
>
> Bob
>
> On Sun, Aug 30, 2020 at 7:28 AM Rob Atkinson <ranchorobbo at gmail.com>
> wrote:
>
>> The page on ballasts in the Tube Lore II book says 24B means it drops
>> 23 or 24 v. at 300 ma.  The B means it has a pin for one lamp.   There
>> was a 126 page Ballast Tube Handbook by A.P. Jacobi that Antique
>> Electronic Supply sold with 1991 and 1994 editions.  I do not have a
>> copy.  Maybe you can simulate the "tube" with a resistor.
>> 73
>> Rob
>> K5UJ
>>
>> On Sun, Aug 30, 2020 at 12:39 AM <manualman at juno.com> wrote:
>> >
>> > According to the Riders drawing, it's a 330 ohm plug-in ballest.
>> > Pete
>>
>