CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Direct view HD color tubes aren't even on the table. If you want that, you'd better win a BIG lottery or otherwise acquire millions to spend.

barclay66 · Posted: Fri Jan 27, 2017 1:19 pm Post subject:

Hi,

These were amongst the biggest CRT televisions in Europe:
http://www.radiomuseum.org/r/grundig_super_color_m_95_4909_tex.html?language_id=2
37.5'' Tube, net weight 125 kg / 275.33 lb. This model included two steel rods which were needed for moving it around...

Regards,
barclay66

**kal** · Posted: Fri Jan 27, 2017 1:56 pm Post subject:

jbmeyer13 · Joined: 03 Dec 2010 Posts: 1135

**kal** · Posted: Fri Jan 27, 2017 3:00 pm Post subject:

Frankenyokes? That was from 2006!

http://www.curtpalme.com/forum/viewtopic.php?t=2498

Kal

garyfritz · Joined: 08 Apr 2006 Posts: 12026 Location: Fort Collins, CO

**kal** · Posted: Fri Jan 27, 2017 4:06 pm Post subject:

garyfritz · Joined: 08 Apr 2006 Posts: 12026 Location: Fort Collins, CO

Hah!! That guy lives/lived about 40 mins from me. I coulda had a 40" TV! Laughing

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Hey, at least I make an effort to do more than just be a consumer of this stuff. I TRY to offer some form of improvement.

Most people can't even say that. Most people have no thought of trying to develop something new, put together a group buy,
or do anything to contribute to the community except talk. Which is fine.

But for people to look at these things I've tried to do, for you as much as for free, and criticize my lack of success with any of them while they themselves have made no attempt to contribute something new to the community is a bit...how to put it...some combination of rude, arrogant, and ungrateful seems about right.

The frankenyoke project, that's something you'll have to address yourself because the correct answer varies according to which yokes you are trying to use. I know that some types just aren't going to work because they want to be placed on the neck where they can't go because the deflection/convergence assembly is too long and gets in the way of proper focus yoke placement.

I'm no longer really worried about that frankenyoke projectd anyway. I never made a time off it and put too much time in it and results were not consistent. Maybe if someone had so much as offered me a dollar in thanks if they got them working well in their machine, but right now it's not a project I can bring myself to care about

**kal** · Posted: Fri Jan 27, 2017 7:35 pm Post subject:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

In a word, no. But you KNOW that there are plenty of people here who are only hear to read and learn something and that's all they're here for. That's fine, it's how it usually works.

I tend to take exception to people who have critical words regarding me when I'm trying to contribute more than another post in another forum, and it doesn't work, but the critics have not even attempted to make any special contributions.

Kal, your contributions as administrator and much more are very appreciated. Be sure of that.

To everyone else, I simply ask, "What have you done to make the CRT forum or the CRT experience better for anybody other than yourself?". If the answers is "nothing" then I feel justified in saying I don't particularly appreciate you being critical of me for trying to do exactly that, regardless of my success or failure. At least I TRY.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I had a conversation with the CEO of one of the companies that could conceivably make QD phosphor CRTs today, and he
said that he didn't see any way for that experiment to be profitable for his company so they'll not be doing those experiments out of their own engineering budget.

BUT....he did not rule out the possibility of helping out if someone else did the legwork.

By that I mean, if he were to provide me with a bell assembly that's ready for the phosphor coating and I were to obtain the
phosphor and use the appropriate binder and attempt to coat it myself, and then send the bell back for completion, that could
be done but with zero guarantees, and I'd pay their usual and customary cost for that tube and what I get is what I get.

If I were to choose to do that, I'd start with a red tube as that would be the one tube that would expand the color gamut the most.

Not at all sure I want to do that. Oh, it'd be kind of fun, but I'm not sure I want to commit that much cash out of pocket.

**kal** · Posted: Sat Jan 28, 2017 12:27 am Post subject:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I actually happen to enjoy horses, too. I ride when I can. They are among the coolest of animals. But I never, ever use a whip. Very Happy

justin_f · Joined: 27 Nov 2010 Posts: 51 Location: Australia

somehow this sh*t always gets off topic or derailed.

i dont know a thing about this phosphor you speak of but heres an idea.

you could use hot wire wrapped around the sides of the tube face held with tension and give it a tap once hot enough to crack the tube seperating the tapered rear from the face nice and clean.

you would have to pierce the tube neck before doing this. I watched a video where a tube repairman pierced the neck of the tube with a die grinder and a fine point tip.

then mix your said bonding material with this new phosphor material and let it dry however you choose.

then place the cut tube face in front of a working crt tube and hope that the light leaving the tube can excite the new phosphor? or does it not work like that?

anyway, i have seen on youtube someone used a glass bottle under vacuum and had their own phosphor mix on the bottom of the bottle. the setup eludes me but it was under vacuum just like a real crt.

just some thoughts.

* EDIT: https://youtu.be/jlV-2gcO0_0

it depends what exactly you need to test before even considering forking money out to have a tube manufacturer try this new phosphor. if its just the bonding under semi simulated conditions, this may be worth entertaining? yes its not under real conditions, but at least you will have tried than not and always wondered?

I must admit, its going to be a very small market. those who have a late model 9" set probably already have enough spare lugs to see them out for a number of years and probably have no intention of spending any more money?

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

That wouldn't work. The electron beam has to directly strike the phosphor layer. Unless the original CRT was outputting UV that excites the QD phosphor layer, but there would be a massive problem with focus and also loss of efficiency.

I'd stand a better chance of just trying to open a tube and rebuild it myself in my own garage (learning glasswork along the way, ha ha) and figure out a way to evacuate it without the benefit of a vacuum pump (which I don't have) or a functional hollow stem as that was sealed off when the tube was first made. Even if I got that far the getter would be depleted so if there was any residual gas in the tube it'd STAY in the tube, affecting performance.

Mr Jaeger · Joined: 24 Mar 2015 Posts: 41

This experiment CM J what would you think it will cost for a finished product? Then for a set of tubes.
The light output in the modified tubes? "with much darker wider colors gamut"?
You have to have a small screen to reach a minimum light output target way under 80-90".

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I don't even know if there will be an experiment. Way too soon to guess at anything.

IF I get approval to proceed, IF I can afford it, IF I decide to actually do it, IF I actually do it, IF it is successful,
too many IFs to make any predictions.

I would choose rec. 2020 UHD color space phosphors which allow the mapping of all other gamuts into it.
Light output is anticipated to be higher than standard as QD phosphors are more efficient.

Why do you say "ou have to have a small screen to reach a minimum light output target way under 80-90"."? That's
frankly kind of silly. Most CRT enthusiasts are running larger than screen sizes larger than even if they have only an 8" machine.

My screen size is 96 inches wide, or120" diagonal/107" 16/9 ratio and it's quite adequately bright. If you squint at full brightness scenes, you have all the brightness you need.

Basically, most CRT enthusiasts already run bigger screens than you suggest. There's no reason to limit yourself to such a tiny screen unless you have a 7" machine and want to prolong tube life.

What is your light output target, anyway? Air raid light?

QD phosphors are substantially more efficient than conventional phosphors. We'll get more output and a broader color gamut
without any need for corrective colored C elements. Clear C elements will be all we need on QD tubes.

If someone wanted to be a bit more conservative and choose rec. 709 ("regular" HD) colorspace values, that could be done, too.
But why bother? With rec. 2020 colorspace phosphors available, there's no reason not to use them. More limited colorspaces can be mapped into a broader colorspace.

geisemann · Joined: 30 Nov 2009 Posts: 33

Hi

Its been a wile since I have been in a form but when we order our simulation grade tubes we order with 2 options that cost more. We can order them without the options but the military customers that use simulators require a certain foot-Lambert on the screen and if it does not meet spec then they will return the tube.

Years ago we tried to win the tube contract with various Air force bases so we kept asking for changes to the tubes and the tube factory we use wanted the business so they kept making changes to improve the tube. The final outcome was a slightly different gun and a more perfect glass. In fact they wanted the front glass back from us when we get a large shipment and there be broken ones because the glass cost a couple of hundred more.

I called my factory rep recently to ask about different phosphor types and even making custom tubes. The volumes are so low now they really don't want to make any changes except from the ones they did before because of the sales volumes are so low.

We are still selling tubes but not anywhere near the volume we used to . Most of our military customers have moved to SXRD and we are now heavy into the SXRD engine business .

If anyone would like to order a tube with special upgrades I can call the factory but I know the only two will be special glass and special guns. I can ask for Phosphor upgrades but they would most likely require an order of over 100 tubes and they might say no but I can ask.

Last week a customer wanted me to make a custom 300MHZ neck card and wile I can do it before investing over 3 months of testing there needs to be a economic reason to invest time and material . The markets are just too low now to make a 300 MHZ neck card possibly just get orders from a few people. The last people who have CRT units don't tent to want to invest a lot of money for upgrades. Our mod sets wile much better than our mods 3 years ago don't sell very quickly and we even have a new Barco HDMI card. I have some new RF transistors that I can use but need to balance the circuit and also do parasitic oscillation testing and that can take a month alone.

This week I am ordering some tubes for a few customers so will let you know what they say about the min order. If they can do it I can place an order but I don't think we can get 100 people to order .....

Greg

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Nice to hear from you, Greg!

It would be helpful if you were to state the price that these tubes would have to command, in order for there to be any way to gauge interest in them. Are we talking about 1000 dollar tubes, or 3000 dollar tubes, or what?

I would ask that you at least inquire about doing the very simple QD phosphor experiment: Obtain a sample quantity of a QD phosphor at the desired peak emission color, mix it with a suitable binder, apply it as normal, build the tube, then evaluate it.

That's all that's really necessary to determine if they'll even work. Commit ONE tube and ONE sample of QD phosphor to it.

It honestly does not have to be made into a great big production with hundreds of engineering and testing hours going into it. Just make the one test article, see if it runs, and if it does, then send it to someone else who is willing to invest time and effort into determining its actual performance specifications.

There are forum members here who can perform every relevant functional test. Output, MTF and resolution, even luminance retention over time at defined drive levels.

Let's just throw this out there: If a QD phosphor tube can be made for an upcharge of 100 dollars per tube, and a set of QD tubes offers the benefits that I believe it would, namely an accurate HD or UHD color gamut without color filtering, improved linearity particularly in blue, requiring less gamma correction, higher light output, increaesd resolution, and longer tube life, then I think
that some CRT enthusiasts would actually be willing to spend the money to buy THESE new tubes if the price was not excessive.

Basically, if it can be done for less than the cost of a decent digital projector offering roughly similar specifications, then it's a potential winner.