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A gallery of gassy tubes
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 |
A gallery of gassy tubes
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. |
A gallery of gassy tubes
"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 |
A gallery of gassy tubes
On Jun 26, 4:58*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 Usually take as the tube has gone soft , slight air leak over the years ? soft vlave = soft vac , slight residual gas .. so assume 'gone' soft taken as loss of vac ?.. or may be impurity's in the metal have boiled out due to over heating ? G .. |
A gallery of gassy tubes
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! |
A gallery of gassy tubes
terry wrote:
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? You can heat them again, but it will be to no good purpose. The getter is a tray filled with a getter metal, such as barium. The tray is usually in the shape of a loop so that it is easy to induce RF current into the loop and heat it very hot. The metal all evaporates and deposits on the cool glass (usually) It is very unlikely that there is anything left over. -Chuck |
A gallery of gassy tubes
Chuck Harris wrote: terry wrote: 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? You can heat them again, but it will be to no good purpose. The getter is a tray filled with a getter metal, such as barium. The tray is usually in the shape of a loop so that it is easy to induce RF current into the loop and heat it very hot. The metal all evaporates and deposits on the cool glass (usually) It is very unlikely that there is anything left over. -Chuck Several years ago a friend gave me several 304TLs. He didnt want them because they were gassy(glowed blue). This was about 1971. Two of the tubes still work fine used in a stereo amp, a couple more I gave to a friend building a modulator the others still sit on the shelf in case i ever need spares. Jimmie |
A gallery of gassy tubes
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A gallery of gassy tubes
On Jun 26, 7:22*pm, Chuck Harris wrote:
terry wrote: 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? You can heat them again, but it will be to no good purpose. *The getter is a tray filled with a getter metal, such as barium. *The tray is usually in the shape of a loop so that it is easy to induce RF current into the loop and heat it very hot. *The metal all evaporates and deposits on the cool glass (usually) *It is very unlikely that there is anything left over. -Chuck Chuck: Yes that's logical and I would defer to your knowledge of tube manaufacture. That's why it was worded 'MIGHT' be possible. Thanks for the comment additional info. Terry |
A gallery of gassy tubes
"Chuck Harris" wrote in message ... terry wrote: 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? You can heat them again, but it will be to no good purpose. The getter is a tray filled with a getter metal, such as barium. The tray is usually in the shape of a loop so that it is easy to induce RF current into the loop and heat it very hot. The metal all evaporates and deposits on the cool glass (usually) It is very unlikely that there is anything left over. With there now being a spot of getter metal on the glass in the vicinity of the getter loop, I'd think that applying intense RF energy to the area would also heat that spot (the way silvered or gilded patterns on a china plate, or even more dramatically the coating on a CD, heat up and spark in a microwave oven). Assuming this heat was enough to re-vaporize part of the spot, and the glass didn't break from the thermal shock, I'd wonder if the vaporized metal might capture enough extra air in a slowly leaking tube to make a difference for a short time. |
A gallery of gassy tubes
HiTech RedNeck wrote:
With there now being a spot of getter metal on the glass in the vicinity of the getter loop, I'd think that applying intense RF energy to the area would also heat that spot (the way silvered or gilded patterns on a china plate, or even more dramatically the coating on a CD, heat up and spark in a microwave oven). Assuming this heat was enough to re-vaporize part of the spot, and the glass didn't break from the thermal shock, I'd wonder if the vaporized metal might capture enough extra air in a slowly leaking tube to make a difference for a short time. Re-heating the getter flash might work, but it also might release all of the gases the getter trapped on the first go around. It depends on what happens when you heat barium oxide, barium nitride, barium hydride, ... along with the barium metal, to a few thousand degrees F in a vacuum. And, the getter does nothing towards trapping helium that diffused through the glass... though that shouldn't be too much of a problem, as helium is rather scarce in our atmosphere. -Chuck |
A gallery of gassy tubes
HiTech RedNeck wrote:
With there now being a spot of getter metal on the glass in the vicinity of the getter loop, I'd think that applying intense RF energy to the area would also heat that spot (the way silvered or gilded patterns on a china plate, or even more dramatically the coating on a CD, heat up and spark in a microwave oven). Assuming this heat was enough to re-vaporize part of the spot, and the glass didn't break from the thermal shock, I'd wonder if the vaporized metal might capture enough extra air in a slowly leaking tube to make a difference for a short time. Remember, it's a reactive metal. When it's worn out, it's worn out because it's oxidized. Reheating it won't do any good; you have to get the oxygen out of the tube. At best, reheating will boil off the oxygen and fill the tube back up with it. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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