CRT Rebuilding Video

[Yamamaya42]

From what I understand, it takes a vacuum pump setup an order of magnitude higher than what you have used before.
https://en.wikipedia.org/wiki/Ultra-high_vacuum
Something I believe that ETF inherited from Hawkeye, and even after that, the inside of the neck is flashed with a very reactive material like barium, zirconium, titanium, and aluminum, and so on, anything to soak up what the pump could not pull out, or what is stuck to the elements.
As far as the gun itself, that's the hard part, replace the tired cathode, with the correct active surface on it, that also must be activated, the grids may be reused in most cases, put it all carefully back together hope that it all lines up, no cracks or leaks. Risky Business !

[bandersen]

No to steps 1 and 2.

You score the neck while it is under vacuum. The fine crack will allow air to very slowly seep in over minutes (or hours) to avoid blowing phosphor off the screen.

The base, neck and gun are removed in one piece. This is the easiest part of the process.

Attaching new flanged neck glass, inserting a new gun, sealing the button base - that all requires experience and skill. You can see all this in numerous videos out there.

Then, put it in the oven and heat.

Next, pump out the air, seal off the exhaust stem.

Slowly cool the CRT over hours to relieve stress.

Blast the getter - not sure if you do this while it's hot or after cooling.

Activate the cathode.

Check for glass stress with polarizied viewer. Check for leaks leaks if needed.

[Chris K]

Originally Posted by Yamamaya42

From what I understand, it takes a vacuum pump setup an order of magnitude higher than what you have used before.
https://en.wikipedia.org/wiki/Ultra-high_vacuum
Something I believe that ETF inherited from Hawkeye, and even after that, the inside of the neck is flashed with a very reactive material like barium, zirconium, titanium, and aluminum, and so on, anything to soak up what the pump could not pull out, or what is stuck to the elements.
As far as the gun itself, that's the hard part, replace the tired cathode, with the correct active surface on it, that also must be activated, the grids may be reused in most cases, put it all carefully back together hope that it all lines up, no cracks or leaks. Risky Business !

Thanks for the info and the link although I doubt the extent of vacuum associated with UHV is needed. UHV is more for high energy physics applications and it's hard for me to believe the machinery and sealing surfaces shown in the video can pull anything close to UHV levels. That being said, I agree with you typical lab vacuum pumps, even in series probably won't cut it. The ETF has one of these evac pumps? The one in the video was 2 stage. I'll need to look at the closeup of the gauges again to check the levels. Unfortunately, the camerawork in the video is pretty poor with significant operations being performed out of frame. I received a PM from the individual at RACS in Paris who did the training and I'm going to open a discussion via email with him. He related Nick's situation and responsibility challenges so I better understand the current state of the project.

[Yamamaya42]

Originally Posted by Chris K

Thanks for the info and the link although I doubt the extent of vacuum associated with UHV is needed. UHV is more for high energy physics applications and it's hard for me to believe the machinery and sealing surfaces shown in the video can pull anything close to UHV levels. That being said, I agree with you typical lab vacuum pumps, even in series probably won't cut it. The ETF has one of these evac pumps? The one in the video was 2 stage. I'll need to look at the closeup of the gauges again to check the levels. Unfortunately, the camerawork in the video is pretty poor with significant operations being performed out of frame. I received a PM from the individual at RACS in Paris who did the training and I'm going to open a discussion via email with him. He related Nick's situation and responsibility challenges so I better understand the current state of the project.

From what has been told, when Hawkeye closed down, all the equipment was donated to the museum, including the needed pumps, the state of operation after all these years is unknown, I do believe that bandersen did a walk through when he was just there, and posted a vid on his channel with someone telling of the process.

[Chris K]

"Attaching new flanged neck glass, inserting a new gun, sealing the button base - that all requires experience and skill. You can see all this in numerous videos out there."

The basic manipulations here are something that can be practiced on inexpensive substitute materials. Has anyone heard of or reached out to the YouTubber jdflyback? She makes her own vacuum tubes and is very proficient with glass manipulation, sealing glass around tube leads, pulling and trapping vacuum etc.

[Yamamaya42]

Originally Posted by Chris K

"Attaching new flanged neck glass, inserting a new gun, sealing the button base - that all requires experience and skill. You can see all this in numerous videos out there."

The basic manipulations here are something that can be practiced on inexpensive substitute materials. Has anyone heard of or reached out to the YouTubber jdflyback? She makes her own vacuum tubes and is very proficient with glass manipulation, sealing glass around tube leads, pulling and trapping vacuum etc.

Another YouTubber who makes tubes and is VERY good at it, is glasslinger, but keep in mind, glasslinger is a bit older, and a bit, unusual.

[Chris K]

Yes…the dress! JD has made her own small CRTs for fun and games so. I can reach out just to get some ideas.

[jhalphen]

Hi to all,

to add to the conversation....

Vacuum, final goal is 10 minus 8 Torr minimum for a good, long-life vacuum. Reaches 10 minus 9 Torr after Getter flashing (in sufficient quantity).

Pumps: like a rocket, 2 stages.
Centrifugal "roughing pumps" removes most of air down to minus 3/4 Torr.
Then a Molecular diffusion pumps gets you down the rest of the journey.

Preserving cut neck tubes before processing: i seem to remember RACS pumping inert Nitrogen if tubes were to "sit" a few days, otherwise just a protective plastic sleeve over the open neck.

Sometimes miracles happen:
The one & only 15GP22 rebuilt was an ETF "floor sweep" i picked up.
Phosphor dot plate only had a few tiny defects.

Rebuilt tube Color Bars display :
http://www.earlytelevision.org/2010_...tion_racs.html

Many more photos here, especially the last two, (ETF Convention 2010), Thanks! to old_tv_nut (Wayne B.):
https://www.flickr.com/photos/old_tv...ith/4556079347

Best Regards
jhalphen
Paris/France

[Allison Rae]

A few thoughts on this, since I spent a portion of my career working with Instrumentation and Automation at facilities that did a lot of R&D. I have been around a lot of high vacuum equipment. If the oil used in their high vacuum pump is something like Fomblin, its super expensive. Plus doing high vacuum work is something that takes a while to learn, there are a lot of nuances to this equipment along with safety concerns.

What is see as the biggest stumbling block is the gun assemblies, I do not see them as being something that can economically produced in limited quantities due to the specialized equipment and materials required. Sadly I imagine that much of this equipment no longer exist in the western world and some of the materials used may be difficult to get and touchy to work with due to toxicity.

[Chris K]

Want to get back into this in a couple of days. I’m waiting for some email responses and I’ll update everyone. I’m not under the delusion that I’m going to be the one who finally gets CRT rebuilding off the ground and available to the restoration community and I understand the skeptics who are resisting pouring ice water over my head to shock me out of it. I just don’t want this endeavor to fade and die a slow death. I’ll be retiring in a couple of years and I want to at least give this the effort it deserves and have a challenge I can devote time towards.

[Yamamaya42]

Originally Posted by Chris K

Want to get back into this in a couple of days. I’m waiting for some email responses and I’ll update everyone. I’m not under the delusion that I’m going to be the one who finally gets CRT rebuilding off the ground and available to the restoration community and I understand the skeptics who are resisting pouring ice water over my head to shock me out of it. I just don’t want this endeavor to fade and die a slow death. I’ll be retiring in a couple of years and I want to at least give this the effort it deserves and have a challenge I can devote time towards.

Well I know that glasslinger is in Houston TX, that's even farther away from ETF than I am here in the Austin area, and for someone who is prob in their 70s or 80s, that would be far for them!

[Chris K]

Nick is in MD, about 3 hours from me but I'm reaching out to JD as well

[Chris K]

Originally Posted by Allison Rae

A few thoughts on this, since I spent a portion of my career working with Instrumentation and Automation at facilities that did a lot of R&D. I have been around a lot of high vacuum equipment. If the oil used in their high vacuum pump is something like Fomblin, its super expensive. Plus doing high vacuum work is something that takes a while to learn, there are a lot of nuances to this equipment along with safety concerns.

What is see as the biggest stumbling block is the gun assemblies, I do not see them as being something that can economically produced in limited quantities due to the specialized equipment and materials required. Sadly I imagine that much of this equipment no longer exist in the western world and some of the materials used may be difficult to get and touchy to work with due to toxicity.

Hi, thanks for posting. I believe there are a limited supply of guns at the ETF and there has been some contact with a European company about production of new ones.

[Allison Rae]

Hi, thanks for posting. I believe there are a limited supply of guns at the ETF and there has been some contact with a European company about production of new ones.
Not trying to toss cold water on you, just looking at this from the perspective of someone who works in product development and manufacturing.
I knew of the limited number of guns at the ETF, hence my concern. I think the only hope for a project like this is to approach one of the remaining vacuum tube manufactures about making guns and the downside it you would need to get a decent quantity for a good ROI. I only have met one person during my career that could of done this kind of work by hand (he did our custom switch parts when I worked for a Thermostat manufacturer) and it takes a ton of time and some special jigs and likely would cost a fortune.

[Chris K]

Not looking to start a business with a profit model and ROI prospectus…just seeing if it can be done with a reasonable effort by someone or a team of someones and take it from there.