Author Topic: Are CRTs even manufactured anymore?  (Read 701 times)

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Offline Ben321

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Are CRTs even manufactured anymore?
« on: March 20, 2021, 08:28:05 am »
CRTs are old tech, and almost any device that used CRTs in the past now uses LCD screens instead. Anything from TVs and PC monitors, to oscilloscopes, used to use CRTs but now use LCDs instead. However, a few devices like oscilloscopes are still manufactured with CRTs (often times a scope manufacturer will manufacture both versions of the scope, selling both digital LCD scopes and analog CRT scopes, as purely analog scopes have some advantages I thing). However are these analog scopes simply using a slowly depleting supply of CRTs out of their inventory? Or are new oscilloscope CRTs still being manufactured? What about TV and monitor CRTs? While CRT monitors are no longer made, many still exist, and eventually the cathode filament in the back of the tube will burn out just like a lightbulb, meaning that to continue using such a display unit, the CRT must be replaced. Are there companies manufacturing CRTs for consumer equipment, for the sole purpose of refurbishing used video displays where the CRT's filament has burned out?
 

Online ledtester

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Re: Are CRTs even manufactured anymore?
« Reply #1 on: March 20, 2021, 08:44:50 am »
Tangentially related... older tech can get an extended life in the "institutional use" market

Techmoan's "Prison Tech" video:

https://youtu.be/O3PfsndsihY

First sections talk about cassettes, tape players and radios. Skip to 12:27 for the section on CRT TV's.
 

Offline WattsThat

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Re: Are CRTs even manufactured anymore?
« Reply #2 on: March 20, 2021, 03:17:16 pm »
There was one domestic manufacturer of tubes for studio monitors still operating a few years ago, cannot find them now online. Maybe someone here knows.

Back in the day, they used to rebuild color tv picture tubes. They would cut the entire electron gun assembly off the neck of the tube and weld a new gun in place. Heat the glass to red hot, and spin them together. Of course there was a lot more to the process but that’s the general idea.

That stopped in perhaps the late eighties, early nineties as crt’s hit their peak of use and they got to be so cheap it didn’t pay to rebuild, you just replaced the entire tv. This also correlated to the demise of the “console” tv’s, the floor models were the cabinet work was beginning to cost as much as the electronics. Once the table top tv was standard in 19-27 inch models, crt’s became so reliable with 10-20,000 hour life it was a non-issue.

Other than some very specialized stuff left in avionics, which is being phased out as fast as is practical, crt’s are all but gone. Part of the reason for the phase out is cost. An instrument rebuild for older Airbus and Boeing aircraft can run $20-30k with new crt’s.
 

Online JohnnyMalaria

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Re: Are CRTs even manufactured anymore?
« Reply #3 on: March 20, 2021, 04:35:28 pm »
 

Offline drussell

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Re: Are CRTs even manufactured anymore?
« Reply #4 on: March 20, 2021, 05:01:54 pm »
Back in the day, they used to rebuild color tv picture tubes. They would cut the entire electron gun assembly off the neck of the tube and weld a new gun in place. Heat the glass to red hot, and spin them together. Of course there was a lot more to the process but that’s the general idea.

That stopped in perhaps the late eighties, early nineties as crt’s hit their peak of use and they got to be so cheap it didn’t pay to rebuild, you just replaced the entire tv.

The last picture tube rebuilder (for consumer-type tubes) in the USA (Scotty at Hawkeye) closed down in 2010, and the last rebuilder in Europe (RACS in France) closed down in 2013.  They were still rebuilding vintage tubes for the collector market but the main bread and butter of the rebuilders (things like airport departure/arrival displays, bowling alley scoring displays, arcade machine displays, etc.) were simply drying up and the last few remaining guys basically just simply wanted to retire.   :)  Companies like Clinton and Thomas still rebuild expensive, high-tech, specialized displays where the high cost warrants but are impractically priced for most "consumer" units.

The ETF purchased (or were mostly donated?) the equipment from both Hawkeye and RACS and have been in an ongoing process of setting up rebuilding facilities at the ETF museum and have actually managed to get to the point of performing a few rebuilds successfully.  The main issue is essentially manpower to actually do it on a regular basis.  A couple other guys have their own private picture tube rebuilding apparatus but don't offer their services publicly.  (yet)

Quote
After much deliberation, we have determined that it is not currenty practical for the museum to rebuild CRTs for sale to the collecting community. Though we have the equipment and the expertise, we don't have the management to undertake the project. Maybe at some time in the future this will change, but for now the facility at the museum will be used for demonstration purposes. We also intend to include the rebuilding room as a display area for the museum, so that visitors can see the equipment and understand the rebuilding process.

There is another alternative for rebuilding, though. Nick Williams, who lives in Maryland, has purchased all the equipment needed to rebuild tubes. His plan is to start doing this after he retires from the Navy in 2020. Here is a recent status report he prepared on his progress:

Quote
As you may or may not know, the museum presently has facilities for CRT rebuilding. The central issue for getting a regular rebuild schedule going has been the unavailability of an operator in Ohio (me), since I’m the only one with the necessary training and I happen to live out of state.

That being the case I took it upon myself to acquire another set of rebuilding equipment identical to what’s at the museum, and moved it into my workshop here in Maryland. At the moment I’m busy getting the equipment into operating condition, since it requires work like replacement of old gas lines, lubrication of bearings and things of that nature. I hope to complete this work by January. Right this moment I have all the old lines removed and need to order replacement ones, I have also taken the liberty of constructing a preheating torch similar to the equipment I trained on in France, which should help avoid any issues with glass cracking caused by thermal shock during lathe operations.

Once the glassworking lathes are operable to my satisfaction, the next step will be constructing a suitable oven to process the tubes. This is not particularly difficult, just time consuming. I’m still active duty Navy looking at retiring in August of 2020 and I’m also a single parent, so finding the time for these things is a challenge.

Another issue has been the availability of replacement parts for tubes; complete electron gun assemblies or cathodes to rebuild old ones, and piece parts such as getters and glass stems to mount the gun on for installation in a tube. Fortunately a supplier has been located in Russia, and they are very willing to work with us in the states to get old tubes going again. I remain in contact with them, hoping to come to a suitable business arrangement.

Lots of moving parts to this, and none of it will be solved overnight. I feel confident that I can have the plant machinery operational in the coming year, so as long as parts are not an issue tube rebuilding should be a reality as soon as I’m in retirement from the military.

Video by Bob Galanter, documenting the basics of the process at Hawkeye before Scotty shut down:
http://www.antiquetvguy.com/WebPages/CrtRebuilding/HawkeyeMoviePage.html
Edit: also available at https://youtu.be/PFnWYe5MzrY

Video by Nick Williams, who travelled to France to document the processes used at RACS prior to their shutdown and sending the equipment to the ETF museum:
https://youtu.be/byCeMKzPJgM

More info and links at the ETF rebuilding section of the website:
https://www.earlytelevision.org/crt_rebuild.html
« Last Edit: March 20, 2021, 05:29:15 pm by drussell »
 
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Offline cdev

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Re: Are CRTs even manufactured anymore?
« Reply #5 on: March 22, 2021, 01:06:09 am »
CRTs have a number of advantages over flat screen digital diplays, one is the colors ae truer to real life, another is the fact that flat screen displays are slower so some technologies like LCD stereo glasses dont work as well with them. Another is that flat screen monitors have quite noticeable banding and this means that similar colors get effectively merged into the same color. If you are a web developer you'll notice this with sharp edged vector graphics. Sometimes entire parts of images can literally vanish - This is particularly important to avoid with text. Calibrating your monitor's gamma properly makes it much rarer.

There was one domestic manufacturer of tubes for studio monitors still operating a few years ago, cannot find them now online. Maybe someone here knows.

Back in the day, they used to rebuild color tv picture tubes. They would cut the entire electron gun assembly off the neck of the tube and weld a new gun in place. Heat the glass to red hot, and spin them together. Of course there was a lot more to the process but that’s the general idea.

That stopped in perhaps the late eighties, early nineties as crt’s hit their peak of use and they got to be so cheap it didn’t pay to rebuild, you just replaced the entire tv. This also correlated to the demise of the “console” tv’s, the floor models were the cabinet work was beginning to cost as much as the electronics. Once the table top tv was standard in 19-27 inch models, crt’s became so reliable with 10-20,000 hour life it was a non-issue.

Other than some very specialized stuff left in avionics, which is being phased out as fast as is practical, crt’s are all but gone. Part of the reason for the phase out is cost. An instrument rebuild for older Airbus and Boeing aircraft can run $20-30k with new crt’s.


I really miss my old Sony G400 monitor. The colors, particularly the reds, were much better than the monitors I use now. We still have a working, monster G500, which must weigh at least 100lbs. It was their biggest computer monitor. But as happens when they get old, its blurry and the brilliance has faded away, making it semi useless.
« Last Edit: March 22, 2021, 01:11:04 am by cdev »
"What the large print giveth, the small print taketh away."
 

Offline NCG

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Re: Are CRTs even manufactured anymore?
« Reply #6 on: April 04, 2021, 04:10:47 pm »

CRTs have a number of advantages over flat screen digital diplays, one is the colors ae truer to real life, another is the fact that flat screen displays are slower so some technologies like LCD stereo glasses dont work as well with them. Another is that flat screen monitors have quite noticeable banding and this means that similar colors get effectively merged into the same color.

I really miss my old Sony G400 monitor. The colors, particularly the reds, were much better than the monitors I use now. We still have a working, monster G500, which must weigh at least 100lbs. It was their biggest computer monitor. But as happens when they get old, its blurry and the brilliance has faded away, making it semi useless.

For non-daylight or indoor situations OLED has just now reached similar practical quality - 48" LG CX does 4k resolution and 120Hz, FINALLY. And yes, I have still the 3 Sony CRT-s, G520 included.
 


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