2 Nov
1998
2 Nov
'98
2:41 a.m.
______________________________ Reply Separator
_________________________________
Subject: Re: CRT decay
Author: classiccmp(a)u.washington.edu at internet
Date: 11/2/98 11:04 AM
At 05:59 PM 11/1/98 -0600, Doug Yowza wrote:
References: <m0za2RV-000IyNC@p850ug1>
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No, I'm not sure. When I first saw it, I thought mold was growing along
the edges, but closer examination showed that that "growth" was inside the
glass, and the patterns were somewhat crystaline. I'll let you know if
it spontaneously implodes.
Is it possible that you're seeing some element that's been vaporized
and is now being re-deposited as crystalline material? There is so
much going on inside a tube with high voltage, heaters, glowing wires,
etc. that something could be vaporizing and cooling.
>Which reminds me of something I'd do as a kid:
pop open vacuum tubes
>and add water to the grey material tucked inside the rings, which
>would then fizz. Maybe it was calcium carbide. I imagine it was
>there to suck up water or gas after the tube had been sealed.
Sounds like you
may be talking about a 'getter' which is used in the
production of vacuum tubes (valves for you gents across the pond) to
eliminate vapor and residual air the vacuum pump can't draw out or may
be in the metal components of the tube (plate, grid, filiment and
arbor). The getter is a compound (barium, magnesium, etc.) placed in
the tube which is ignited after the envelope is sealed. After the
getter ignites it sometimes leaves a silver coating inside the tube.
Marty
- John
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Date: Mon, 02 Nov 1998 09:27:20 -0600
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From: John Foust <jfoust(a)threedee.com>
To: "Discussion re-collecting of classic computers"
<classiccmp(a)u.washington.edu>
Subject: Re: CRT decay
In-Reply-To: <Pine.LNX.3.95.981101175237.508K-100000(a)behemoth.host4u.net