[Amps] Gassy tubes

[R L Measures]

On Jul 21, 2006, at 10:58 AM, Tom W8JI wrote:

>> The way I see it, it's the same, as that connection is in
>> series with any anode fuse or glitch resistor. The way I
>> also see it, if a tube starts to arc, it's gassy and needs
>> to be replaced.
>
> That's absolutely incorrect for large power grid tubes!

Wow, and I used to think gas was a problem.
>
> Large  power grid tubes often have noticeable seal leakage.
> It comes from the less than perfect bond between the leads
> and the envelope. A perfectly good tube that sits unused, in
> particular if it has been stored unused  in a humid
> environment, can have seal leakage.
>
> Also elements inside the tube can outgas. The most common
> gettering material is zirconium. Zirconium is used on the
> outside of graphite or molybdenum anodes in 3-500Z and other
> tubes.

I don't see anything but graphite on the anodes of my Amperex 3-400Zs.

> ...
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>

R L MEASURES, AG6K. 805-386-3734
r at somis.org