On Jun 26, 1:58*pm, "Richard Knoppow" wrote:
"BH" wrote in message

...
On Jun 25, 7:12 pm, wrote:

The following web page shows several photos of vacuum
tubes that glow
because they’re either gassy or induce florescence in the
their glass
bulbs. Although the English is a little choppy, the
narrative and
pictures are informative:

http://www.jacmusic.com/html/article...w/blueglow.htm

The author claims he’s revived gassy tubes by re-heating
the getters.
Has anyone tried this?

-Dave Drumheller, K3WQ

Sounds like hog wash. No blue or blue in tubes is probably
normal.
Magenta is probably gas.

* * *Its very common to see a blue glow on the envelope when
there is fairly high voltage on the tube. I've forgotten the
mechanism but its not gas. Gas can cause a glow between
elements.
* * *AFAIK, there is no way to re-flash the getter.

--
---
Richard Knoppow
Los Angeles, CA, USA


Two comments.
1) I do recall certain 807s in the intermediate stages of a WWII
transmitter that exhibited blue fluorescence of the glass envelope due
in IMO to electrons missing the plate/anode and striking the glass.
Say this because one could see a definite pattern of the electrode
structure in the fluorescence of the glass, rather like sunlight
shining through a patterned window onto a wall or floor. It was not
just a 'fuzzy' indistinct glow! These 807s were fine and worked
perfectly as drivers and modulators to the final/PA.
A 'soft' or 'gassy' tube on the other hand would have a glow inside
its electrode structure; rather similar to a gas voltage regulator
tube; such as an OD3 VR150 etc.
2) It MIGHT be possible to get rid of gas in a tube by reheating the
getter; there might be active 'getting' material left? No expert on
tube manufacture but understand those getters were heated by RF. So
could be done again?
Whether the gas has leaked in over the years or is residual gas from
original rushed manufacture during say war time conditions might also
be a factor? If air leaks into the tube albeit slowly over many years
it may continue to do so? Although using the tube (i.e. hot) may
discourage (slow down) or encourage (hasten) that?
002 from here.
Newfoundland; where in Dec. 1901 Marconi received the first
Transatlantic wireless telegraph message!