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?