23-05-2021, 06:10 AM
(This post was last modified: 23-05-2021, 06:14 AM by ppppenguin.)
CRT HK assemblies are different to those used in valves. I have no idea if new CRT HK assemblies are available or how difficult they would be to make.
Cathodes are activated after the CRT is pumped. The emissive surface is ruined by exposure to air.
For normal CRT regunning, the neck is cut and a new gun assembly fused to the old neck. It is possible to fuse a new "pinch" (the term used for the piece of glass that has the metal-glass seals for the leadouts and also the pumping stem) to the existing glassware. Modern pinches are probably available.
If the CRT is Pyrex (this is mainly for prewar CRTs) you can't attach soft glass parts directly. This would apply, for example, to a mdoern pinch. The differing coefficients of expansion would crack the joint. The solution is a graded seal, with 2 or 3 different special intermediate grades of glass. This requires a high level of glassblowing skill.
My 1987 article: https://www.borinsky.co.uk/vintage_tube.html covers some of this, though in a rather lighthearted way.
PS: I saw a reminder today that Thomas Electronics are still in the CRT business: https://www.thomaselectronics.com/faq/
http://videokarma.org/showthread.php?t=274039
I think I approached them a few years ago and got nowhere.
Cathodes are activated after the CRT is pumped. The emissive surface is ruined by exposure to air.
For normal CRT regunning, the neck is cut and a new gun assembly fused to the old neck. It is possible to fuse a new "pinch" (the term used for the piece of glass that has the metal-glass seals for the leadouts and also the pumping stem) to the existing glassware. Modern pinches are probably available.
If the CRT is Pyrex (this is mainly for prewar CRTs) you can't attach soft glass parts directly. This would apply, for example, to a mdoern pinch. The differing coefficients of expansion would crack the joint. The solution is a graded seal, with 2 or 3 different special intermediate grades of glass. This requires a high level of glassblowing skill.
My 1987 article: https://www.borinsky.co.uk/vintage_tube.html covers some of this, though in a rather lighthearted way.
PS: I saw a reminder today that Thomas Electronics are still in the CRT business: https://www.thomaselectronics.com/faq/
http://videokarma.org/showthread.php?t=274039
I think I approached them a few years ago and got nowhere.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
