tubes age 234
needs to hit the flashing many times before it reacts, the time required for the
getter flash to clear the gas from decades-old tubes (assuming that there is
enough flashing present to do so) is measured in months or years, not
minutes. Thus, "residual gettering" can keep a tube relatively gas-free if it is in
regular operation and the gas ingress is slow, but it is not a very promising way
to react decades of gas ingress from a tube that has not been operating. If you
want to try, put the tubes into an oven (you want to heat the envelope evenly so
as not to produce thermal stress), heat them just short of the point where the
glass
collapses, and leave them there for a few months.
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Date: Wed, 2 Mar 2011 12:43:47 -0700
Subject: Re: [R-390] Gettering old tubes
Ever tried putting one in a microwave? (GRINNNNNN)
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Date: Wed, 2 Mar 2011 13:46:11 -0600
Subject: Re: [R-390] Gettering old tubes
This is probably getting out of hand but maybe put together a chassis with
multiple sockets and a filament supply to keep your tubes warm
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Date: Wed, 02 Mar 2011 15:01:47 -0500
Subject: Re: [R-390] Gettering old tubes
Filaments alone won't even get the envelope to full operating temperature, so
this would only be better than storing them at room temperature if you did it
constantly for all of your spare tubes. And then, you'd have to worry about (i) the
decreased in-service heater life due to the "storage" operation of the heaters,
(ii) "cathode interface," and (iii) the deposits of cathode oxides boiled off and
deposited on the grid. When the tube is operating (drawing plate current), most
of these boiled-off cathode oxide molecules are moving too fast to deposit on
the grid. When the tube is cut off, they are drifting slowly and tend to deposit on
the grid. Cathode oxides on the grid lead to grid emission and thermal
runaway when the tube is operated.
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Date: Wed, 2 Mar 2011 15:05:28 -0500
Subject: Re: [R-390] Gettering old tubes
I was searching for tube rejuvenating methods and found a site with some
postings from around 2006 where some guys were trying just that. Some had
(14 pages)
(10 pages)
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
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