On 4/29/2014 2:54 PM, Tidak Ada wrote:
And again there is closing a CRT rebuilding plant. This time in France. A bit too far from my home. See the mail I received from Giorgio. No TCA members in the direct environment... Anyhow, they would have cathodes. eric -----Original Message----- From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On Behalf Of Instrument Resources of America Sent: dinsdag 29 april 2014 5:21 To: neonixie-l@googlegroups.com Subject: Re: [neonixie-l] Neon size limitations? Hello John, I do not know all of the in's and out's of it. But I do recall that a group of early television collectors had tried in vain to preserve several of the original 15 inch color television CRT's by rebuilding them, with the help of a CRT rebuilder, who by the way is now long gone. Not dead, I don't think, just forced into retirement by lack of rebuilding business, or perhaps even willingly. His equipment for rebuilding is now in the hands of "The Early Television Foundation" http://www.earlytelevision.org/ and, http://www.earlytelevision.org/crt_project.html and, http://www.earlytelevision.org/15GP22_rebuild_report.html If you read down through the article in this last link, to the point where you are at the second sentence, before the heading of ""The Way Forward"" you will read the following sentence,,,,""Then the cathodes are activated by heating them using elevated voltage applied to the filaments."""". All of those particular CRT's had gone to air, and it was a requirement for rebuilding them, that new guns be installed since the old guns cathodes were all of no use. Some how or other the cathodes of the guns are indeed activated after assembly, sealing, and evacuation. After that exposure to air renders them useless. There is a lot of interesting reading on these pages and tons of photos, plus even more links. Ira. On 4/28/2014 7:07 PM, JohnK wrote:I was about to reply the same.... then I started to think about what I could actually quote. This implies that a cathode gets activated after assemby and after/during pumping. What is the chemical during construction? What is the chemical during operation? What is the chemical after later exposure to air? If the chemical after later exposure to air is not the same as that during construction, can this later chemical be converted to what is required? I thought I knew this :-( I have just reached down Materials and Techniques for Electron Tubes [revised edition of Materials Technology for Electron Tubes], Walter H Kohl, 1960,Reinhold. John K. ----- Original Message ----- From: "Instrument Resources of America" <iracosa...@hughes.net> To: <neonixie-l@googlegroups.com> Sent: Tuesday, April 29, 2014 9:11 AM Subject: Re: [neonixie-l] Neon size limitations?Also!!! It is my understanding from being a member of T.C.A. Tube Collectors Association, another Yahoo group, that once the 'cathode' of the gun is exposed to 'air' it is DESTROYED, and can NOT be used again. Ira. On 4/28/2014 4:18 PM, NeonJohn wrote:On 04/28/2014 04:47 PM, Matthew Smith wrote:Quoth Tidak Ada at 2014-04-29 06:13 ...I once opened a 50 cm B/W picture tube to make a lamp of it. I carefully packed the tube in thick blankets and then filed off the exhaust nipple. About one minute of hissing and the pressure was equilibrated. No danger at all!Aha! I wanted to get the electron gun and base of a CRT, to re-mount into a longer accelerator structure - was wondering how to break the vacuum safely.That works but it pretty much destroys the evacuation port for future use. I have the same intentions and have collected several B/Wguns.My technique is to use a dental turbine (a dremel will do) and bore an about half mm hole through the neck downstream of where I plan on cutting it. That way I can re-open the tubulation in a controlled manner and reuse it. John-- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visithttps://groups.google.com/d/msgid/neonixie-l/535EE739.9050406%40HUGHES.NET.For more options, visit https://groups.google.com/d/optout.-- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/535F1A7F.6010803%40HUGHES.NET. For more options, visit https://groups.google.com/d/optout.
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