CRT Rebuilding Video

[etype2]

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

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

[Chris K]

Originally Posted by etype2

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.

[Chris K]

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.

[Yamamaya42]

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?
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!
https://frank.pocnet.net/sheets/049/2/24AHP4.pdf

[Chris K]

Originally Posted by Yamamaya42

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?
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!
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.

[Chris K]

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.

[bandersen]

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.

[Yamamaya42]

Originally Posted by bandersen

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!

[bandersen]

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.

[Chris K]

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!

[Electronic M]

Originally Posted by bandersen

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.

Color VS black and white is usually fairly easy to visually discern. Color usually has 3 guns arranged in a delta, except for later inline guns. There's basically always 3 heater cathode assemblies in color regardless of inline or delta so that's another easy identifier.

Originally Posted by Yamamaya42

getter material + air = BAD!

Almost certainly not in this case. The getter on an uninstalled gun is typically a solid chunk of metal. After installation it's "flashed" (induction heated to vaporization) and the vapor film that deposits on the glass is what forms the actual getter. As long as there's enough solid material present to flash it's probably fine if the surface has been exposed to air for a while. They certainly don't make new gun assemblies in a vacuum chamber. They're always in air until they go in a CRT. It's exposure to air after installation in the tube post flashing and cathode activation that's a problem for guns.

[bandersen]

I plan on going back for the October swap meet and will take a much closer look at the inventory and document with photos and video. All I can say for sure is the guns I did see were small, likely more modern B&W and had that loose powder.

[Chris K]

Thanks for offering to do that. I'm hoping by October we'll have a good idea of what kind of shape the equipment is in and how good we are with manipulations. I hope we can find some guns appropriate for 10BP4 and 12LP4 tubes but since they are the oldest magnetic focus commercial CRTs, the availability of NOS guns is probably scarce.

[Chris K]

Post deleted

[old_coot88]

Back in the day, we usta buy (color) rebuilts from a local rebulder in Phoenx. The jugs almost always arced. We had a tool we called the "cattle prod" for clearing arcs. Damned if I can remember what it's called. Some kinda "coil", but not Tesla coil. It was line-operated, and shaped like a very large Dremel tool, with a prod sticking out the end. We would stick the prod to the end of the jug and shoot the juice to it until all the incandescent debris quit flying around inside and stuck somewhere. The treatment was very effective and the jugs gave good service.
Cleanliness would need to be a major objective in any rebuilding endeavor.

Does anybody remember the name of that tool? Looked all over the interweb and can't find it.