CRT Rebuilding Video
 

I just watched an old ETF video of CRT rebuilding at RACS and it was fascinating. I’m a science guy and have spent most of my life in a lab creating jigs and glassware to support biological research and I have to say, watching someone with a cigar hanging from his mouth mixing barium and phosphorus weighed out on a rusty balance from the 1940s with a dirty kitchen spoon and mixed in an old juice jar makes me wonder just how hard this is. Then I watched the video just shot in the rebuilding room at the museum and after hearing the current state of the equipment and availability of key components I came to the conclusion this is something that would never happen. I guess it’s a question of the availability of time to invest? If the specialized equipment to do the job still exists, I don’t see a reason why the process of rehabbing said equipment to like new condition couldn’t at least start given someone who has the time and the resources. I’m looking for a retirement project. Probably pie in the sky as I know there have been many attempts by well intentioned hobbyists who have hit challenges that stopped them cold. It doesn’t look that daunting. I can hear the snickers and outright laughter going on right now!!! 😂😂😂😂😂😂😂😂😂😂😂😂😂😂

Sure, but who has the knowledge to rehab the equipment? Some of it is custom made or modified. The biggest issues are the oven, vacuum pump and RF getter flasher. All are custom and critical to the process.
Actually, we have had a couple folks with knowledge comment on the recent video. Apparently, they do have the knowledge and may be able to help.

RACS video:
https://youtu.be/byCeMKzPJgM?si=vT1-mRcWrS8_cuEU

Recent ETF rebuilding tour:
https://youtu.be/CBvJgR-GDgw?si=_DyqOdHCU4W7Shie

I saw the video a few years ago, the thing that got me was the guy was smoking the entire time! :smoke::smoke::D That could not have been good for quality control! :scratch2:

Honestly, back in college I considered trying to build the equipment myself and give it a go. The main things that have stopped me are money and space.
If I were 3 hours or less from the museum instead of 8-9 I would have volunteered to learn and do the process pro-bono on weekends (provided I was allowed to do my own tubes for part of the rebuilds I do without charge).

If you want to volunteer and can convince the museum to let you do it then by all means go for it...I think we all would love to see the museum offer the service.

There seem to be two problems: no one living near enough to the ETF
who wants to do it, and the impossibility of getting a reliable supply of guns.

The latter is fatal.

I'm not so sure that's fatal. RACS was replacing heater cathode assemblies on unavailable guns with modern heater cathode assemblies. It's some extra steps, but should be workable.

Even if someone with the skills did live near the museum, it's still a lot to ask. You can only rebuild one at a time, it takes a day or two and the process needs to be monitored.

All these problems can be solved with enough $$, but how much are collectors willing to pay?

With the popularity of vintage electronics and so many collectors hoarding nearly dead CRTs for the day when rebuilding becomes available, I would think they’d be enough interest and potential customers to at least try something. Is the ETF the only place in the US where rebuilding equipment is available? I thought there was a person on the east coast who at one time was very passionate about doing this but I haven’t heard anything about it for years. I think he was waiting to retire from the Navy before going at it full bore? Maybe I’m thinking of something else. I’m in the Philly area and the museum would be a stretch to drive but if there’s somebody with equipment in NJ or DE it might interest me. Anyway what got me thinking was the fact it looked doable and not the impossible task I have always heard it would be.

Scan about half way down the page to "drussell - Super Contributor".

https://www.eevblog.com/forum/review...tured-anymore/

Thank you so much and I got the PM. So it appears the largest hurdle is not the actual process, it's securing space and permits for the use of chemicals and disposal. That makes sense and gives me a better ideal of the challenges. It appears step one in this, if it is to operate as a business, is to recruit an investor who would see value in offering this service.

That being said, what about the process would require the most specialized piece of equipment? Rinsing and cleaning seems like it would be possible to replicate without the multi-station equipment that serves a production setup. Glass etching and phosphor deposition seems like a reasonably replicated process as would be graphite "painting" of the inside neck region. The 12JP4 and 10BP4 CRT's would not need aluminum vapor deposition.

Perhaps the entire process does not need to be completed at this point in time and a collection of tubes could be stockpiled at some step where storage, for now, is a reasonable win? I wonder if partially processed tubes at the rinsed out and cleaned step would move the ball down the field enough to at least eliminate some of the initial challenges and redefine the starting point? I guess I'm suggesting there's no harm in collectors breaking vacuum, etching the neck break point, removing the gun assembly and sticking a rubber stopper in it for now. That's something that could be done in a home shop. Maybe we don't need to think about this as if we need to hit a base clearing home run...just an RBI single for now to get a run or two across the plate.

You're thinking about Nick Williams (he goes by miniman82 here). As I understand it he did retire from the Navy, but instead of living close to the museum he moved to the east coast, bought his own set of rebuilding equipment, got busy with family and is rarely heard from.

A couple of thoughts.
1.) Don't break the vacuum on color tubes! The shadow mask can rust from extended exposure moisture in the air (creating dead phosphor triads) and phospor can also be damaged from prolonged exposure (especially if condensation forms). The only tubes I would recommend breaking vacuum on and storing are monochrome tubes with significant phospor damage (burned center spot, ion burn, vertical collapse burn line, projection or monitor tubes with raster/image burn in, etc) that HAVE TO be rescreened anyway. (Ones without phospor damage don't necessarily need rescreening...a new heater-cathode assembly is all they genuinely NEED to be nicely functional)

2.) There were aluminized versions of the 10BP4 (the 10FP4) and 12LP4 (the 12KP4) they're brighter and more desirable than the non-aluminized versions. And while it's not necessary to convert them to aluminized it is something that adds value to the tubes so if it can be done without too many equipment/operator issues it would likely be a desirable process that some would pay extra for.

We're just trying to re-gun at this point. No permits or disposal issues.
No chemicals or phosphor recoating. Cut the neck, insert new gun, pump out the air, activate the getter, active the cathode.

How often does the screen phosphor have to be replaced? I would think that it's very rare that it's damaged badly enough for it to need any attention, ion and pattern burns aside, tired cathodes would be the big problem one would think.

Well if replacing the gun is what’s needed then that makes it much less daunting…not easy but maybe within reach. So break vacuum, cut the neck clean, remove the gun and desolder from the base and remaining neck glass…then I have only a vague idea of what to do. I understand reweld the glass and pull a vacuum. What kind of material is the getter and is it flashed with induction heat? I know the vacuum needs to be very high but I have three lab grade pumps that could be setup in series. I also have a vacuum setup to pull enough to essentially freeze dry and preserve protein isolates, bacterial cells etc.

1. De-solder and remove the base. Easily done.
2. Break tube vacuum by nipping the glass seal nipple at the base of the tube.
3. Score the neck. Can this be done by modifying a pipe cutting tool? Replace the
cutter with a scoring carborundum wheel. There must be tools that allow perfect
circumference scores and breaks on a glass tube. Practice on a glass tube of similar size and
thickness.
4. Remove the gun

Then what needs to be done?

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 !

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.

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.

"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. :D

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

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

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.

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!

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

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.

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.

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.

John Yurkon’s attempt at building an all glass 15GP22. Useful information pertaining to this discussion.

https://www.earlytelevision.org/yurkon_15g_project.html

I wonder why I didn't see this before? Thanks so much!

I have emails out to several folks still. Waiting to hear back. I like this idea of building the rigs to manipulate the tubes in the way we will need to since not all of the equipment will be in an orientation that's standard...in fact...everything will need to be custom.

I believe I have the skill set to do this. I'm a woodworker, custom furniture maker, acoustic guitar maker, mechanical watch maker, published biologist, college professor, clinical quality manager...and fledgling vintage TV restorer!!! Maybe I'll add CRT rebuilder to the list.

According to an email from Nick W and Jerome in Paris, the equipment is ready to go. Obtaining guns is all that's holding this up. As many have said, the war in Ukraine has messed up the communication and availability of guns from the most promising source. Money changes a lot of things. I wonder if the ETF and folks here are willing to setup a fund raising campaign or a GoFundMe initiative etc. to raise enough capital to get it off the ground? In the interim, I'll brainstorm with Nick regarding practicing the rebuilding technique on old tubes, maybe with their own used up guns, to become more proficient in breaking down a CRT and glass welding it back together. I'll see if I can find some comparable glass tubing for practice as well.

We all have tubes that we would like to see rebuilt, I'm sure, just waiting for the day that it ever starts up again within reason price wise.
It MIGHT, happen, right? :D :banana:
I still have that hardly working 24AHP4, I'd like to see renewed some time, which has many characteristics of the CRTs that the Philco Predictas used, just a lot larger! :yes:
https://frank.pocnet.net/sheets/049/2/24AHP4.pdf

Nick and I will need to pick a weekend that works for us and I'll take the drive to his place so I can get a better idea of what's involved. Nobody should get too excited just yet for rebuilds to start by the end of the summer but, I think if the process is reasonable and he and/or I get proficient in it, then maybe we start an all out effort for a bulk purchase of guns. We're a long way off from that but Nick was once very jazzed about this and perhaps some of my enthusiasm will rub off. In this endeavor, 2 people pursuing it is better than one going solo.

More information to come hopefully later today. I contacted a well known YouTube electronics guru who graciously said he would provide troubleshooting advice for the project if his time permits him to do so. He does not have the time to participate in the process nor did I expect him to do so and I don't know if his contribution can help but frankly, I don't know of a single person who has more expertise on a variety of topics well beyond radio and TV restoration than him.

There is a bit of confusion regarding the availability of on hand B&W guns so if there's any additional information on that please post. One advisor seems to believe we need a source of new guns and another has suggested there are more than enough on hand to at the least get started.

All I can tell you is there are a few dozen plastic bins of gun assemblies at the museum in Ohio. Color vs. B&W, neck diameter, filament voltage/current I could not say.

Also, I opened a few bins and the contents were not promising. Some of the plastic bags the guns come it were open to the air. Many had loose powder in the bags. I think it was the getter material that had fallen out of the getter cup.

Now I ony looked in 3 or 4 bins. There are many more that may have better gun assemblies.

As for flare neck glass tubes. There was one full box of the diameter for something like a 10BP4. There remaining 20 or so boxes seemed to all be smaller diameter for newer CRTs. Like the 21FDP4 used in Predictas.

getter material + air = BAD! :tears:

I'm not so sure about that. I think it has a protective coating and needs to be activated with an RF blast. The cathode coating is another concern.

Great I think I understand the gun situation enough to proceed with the first steps and meeting with Nick so I can get eyes on the equipment and compile a needs list. Again...I'd like to focus on equipment maintenance and initial techniques so there's a level of confidence in machinery and protocol competence. Thanks Bob for your update on what you saw at the ETF. It sounds promising. Best way to proceed is to practice until we can break and reseal an evacuated tube...not to make a viable tube but to become confident in technique. Once the interested parties feel we're ready to take the next step, I'll contact Steve M. and let him know where we are in the project and if he has thoughts or suggestions regarding how to move forward and what he thinks is the best way to use the available gun stock. It would be kinda silly of me to ask him for the museum stock of guns when we haven't touched or operated the equipment yet in fact, he'd probably and rightfully tell me to get lost! :thumbsdn: :thumbsdn: :nono: :nono: :no: :no: :no: