CRTs still being made? - Page 1
Forum section: electronics / general

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: December 03, 2017, 05:53:00 pm
content: http://www.alibaba.com/products/F0/crt_tv/CID634--CN----------------------------351-687.html?spm=a2700.7724838.52.1.lBimKxSeems as if there are a lot of crts still being produced for third world countries.The housings seem as if they are made new, but I'm not sure if the tubes are made new or salvaged from old tvs. It seems as if there might be a tube factory in Guangzhou, China. Any info on this?

author: buck converter
author_rank: Regular Contributor
timestamp: December 03, 2017, 05:57:41 pm
content: even CRO scopes it seemshttps://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=analog+oscilloscope

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: December 03, 2017, 06:10:35 pm
content: I am assuming instek scopes are made with NOS crts.

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 04, 2017, 01:39:30 am
content: https://www.thomaselectronics.com/capabilities/

author: coppice
author_rank: Super Contributor
timestamp: December 04, 2017, 01:55:16 am
content: The last time I checked there was still CRT based colour TV production both in China and India. I think most of the China production is for export. I can't imagine anyone investing in new plant, but while existing plant can still churn out tubes, and all the other components, they can make CRT TVs which undercut even the cheapest LCD ones.As for oscilloscope tubes, if people like Instek have a market for analogue scopes, getting tubes for them shouldn't be an issue. They were never produced in millions, like TV tubes, and they are far simpler to manufacture. There should still be places capable of making the modest quantities required, just making a batch every now and then.

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: December 04, 2017, 03:43:44 am
content: Interesting. I would love to get my hands on some of those crts, they are flat and some state they are 720p and 1080p (though I guess they are terrible and might be lying about resolution).

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 04, 2017, 06:28:09 am
content: 1080p CRTs are real, although they could still be lying, it's China.

author: stj
author_rank: Super Contributor
timestamp: December 04, 2017, 11:26:56 am
content: there is no reason the crt couldnt do 1080 - forget the "p" reference.they are probably developed originally as pc monitor tubes.

author: Vtile
author_rank: Super Contributor
timestamp: December 04, 2017, 03:12:12 pm
content: Interesting information, but the last factory will have monopoly.

author: Ampera
author_rank: Super Contributor
timestamp: December 05, 2017, 11:10:55 am
content: Quote from: blueskull on December 04, 2017, 06:39:07 amDepends on what you would consider PAL/SECAM. Component (YPbPr) uses some of the standards of PAL/SECAM/NTSC (depending on where you are) video, but if you are referring to broadcast, ground RF, or Composite video, then that would be quite interesting indeed. VGA is still RGB and can handle 1080p fairly well.In terms of CRTs I am on the hunt for good ones that are available as cheaply as possible. If I can find a decent 1600x1200 CRT that handles high refresh rates well that would be awesome. Bonus points for Trinitron. Their weight, and the fact that I am not alone in my hunt makes them nearly impossible to get at any decent price, and I am not quite off my rocker (or loaded enough) to spend more than MAYBE 100 bucks for a really really good model.My friend actually likes to spread this article around about John Carmack and his (SGI?) machine that used a 1080p CRT to program Quake.https://www.geek.com/games/john-carmack-coded-quake-on-a-28-inch-169-1080p-monitor-in-1995-1422971/I love CRTs because you can get amazing images off them. I understand why they are dangerous to produce and dispose of, as well as why they aren't so practical at higher resolutions, but I still love them. I unfortunately have no good IBM/SVGA compatible CRT displays (besides CGA, but I have no machines with CGA support besides a C128 if you wish to count that). I also have use for tubes that work at odd refresh rates for VLB cards that output higher resolutions at strange ~40hz interlaced modes (yes, it is weird.)I honestly just need like a 30 minute spree in something like a freegeek backroom and I would be set for most of what I need. Stuff like that is hard to do now adays, and people are happy to charge you on the rare occasion you actually want to BUY junk.Anyways, I've rambled enough. It doesn't surprise me that CRTs are still being made. There's probably some niches out there, maybe as replacement units for systems that would cost too much to have a similar LCD installed (strange video inputs/signals, etc, idk).

author: Berni
author_rank: Super Contributor
timestamp: December 05, 2017, 11:35:51 am
content: I do wonder how the image quality compares these days.I have held on to my CRT monitor for as long as possible for the reason that it had a great image. I ran it at 1600x1200 so about the same as 1080p except that its not widescreen. Even at such resolutions it could run higher than 60Hz and provided a superb sharp image. Even of all the CRTs i had this one had the best image no matter how much i tried to fine tune the adjustments on some of them. I also made use of the fact that CRTs can run at lower resolutions nicely by running most of my 3d games at lower resolutions to squeeze better framerates out of the under powered PC.Eventually that CRT dies and at that point i bought a 1080p LCD monitor to replace it and even tho it only has 5ms of response time i could easily notice the pixels not responding as quickly as on a CRT. In general i preferred the look of the CRT.I haven't looked at a decent CRT since then, perhaps LCD has come far enough by now to beat them but i never got a chance to compare them again.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 05, 2017, 11:53:44 am
content: I still use a CRT, 19" Trinitron, 1600x1200 at 85Hz. Quite good picture, if a bit dim over the years. Only needed one repair in its 16 year life.Tim

author: james_s
author_rank: Super Contributor
timestamp: December 05, 2017, 08:54:12 pm
content: If they are still being manufactured that would be very good news for the classic arcade collecting community as supplies of good burn-free CRTs are drying up. Especially oddballs like the 100 degreen 19" color tube used in the Atari and Sega color vector games. Complete color vector monitors are fetching ~$500 each these days when they turn up, most of the parts can be reproduced fairly easily but the process of manufacturing a color CRT is complex enough that once the plants shut down and the equipment is scrapped I don't think it will ever come back.Anyone who hasn't played the original Asteroids on a real B&W vector monitor should check it out for an example of an application that can only be done with a CRT. Nothing else except maybe a laser projector with a really fast set of galvos can come close to the dynamic range required. You can emulate the game with MAME but the result is nothing like the real deal.

author: dexters_lab
author_rank: Unknown
timestamp: December 05, 2017, 09:41:25 pm
content: it'll all probably be like vinyl... we'll get all nostalgic about scanlines and they will start making them againgoing by the rising price of PVM and BVM monitors it's not going to be long

author: coppice
author_rank: Super Contributor
timestamp: December 05, 2017, 10:05:42 pm
content: Quote from: dexters_lab on December 05, 2017, 09:41:25 pmThis is a spoof, but still....http://www.breakingburgh.com/cathode-ray-tube-tvs-make-roaring-comeback-nationwide/

author: james_s
author_rank: Super Contributor
timestamp: December 06, 2017, 12:39:33 am
content: I'm skeptical of them ever being made again, but I have long foreseen a comeback in popularity amongst a certain crowd, just as happened with tube audio. CRTs do have a certain look that is not easily duplicated. The color is a bit different, the contrast ratio is excellent, and IMHO an analog display tends to look a bit nicer than anything with fixed pixels for a given resolution. I still have an old Sony XBR CRT in the basement that I use primarily with my old console games and it still produces a stunning picture that rivals a lot of HD LCDs despite being only 480p.The thing that did in the CRT is that they're bulky and heavy. I still don't think HD would have caught on the way it did if not for the development of big, flat, thin TVs to replace that huge bulky box. Probably a good 70% of viewers don't even care about picture quality. When CRTs were king the most common TVs were the cheapest junk available and now after more than a decade of general availability of HD I'm still surprised at how many HD TVs I see connected via SD composite or to SD-only sources. People don't even notice or realize that it's not actually HD. That's also why I believe it's a fool's errand TV manufactures are on trying to come up with a killer feature that will make everyone go out and buy a new TV again. Flat panels did it before, not anything related to picture quality or gimmicks.

author: stj
author_rank: Super Contributor
timestamp: December 06, 2017, 08:35:30 am
content: Quote from: james_s on December 06, 2017, 12:39:33 amcolour crt's have fixed pixels (triads actually, groups of 3 pixels(R,G,B))

author: coppice
author_rank: Super Contributor
timestamp: December 06, 2017, 10:20:21 am
content: Quote from: stj on December 06, 2017, 08:35:30 amFIxed pixels and an excitation scheme which can't aim at them properly.

author: stj
author_rank: Super Contributor
timestamp: December 06, 2017, 12:34:42 pm
content: that's why you have a shadow-mask.much simpler than a scaler chip.

author: schmitt trigger
author_rank: Super Contributor
timestamp: December 06, 2017, 02:44:33 pm
content: My first factory job was at a GTE-Sylvania CRT factory in 1979. So I do have a certain fondness and nostalgia for CRTs.Even then, we were feeling the competitive pressure from Sony's Trinitron, which was way ahead of everyone else.The company responded by designing a shadow mask which used rectangular phosphor mask, and increased the anode voltage to 37 kV.....but it was already too late. By mid-1982, the factory was shut down.

author: coppice
author_rank: Super Contributor
timestamp: December 06, 2017, 03:13:24 pm
content: Quote from: schmitt trigger on December 06, 2017, 02:44:33 pmSony Trinitron tubes did well, but never swamped the market. Other designs were sufficiently competitive. I think your plant shut because the US TV makers were unable or unwilling to make appealing TV sets. No US made TVs means no US made TV tubes. US semiconductor makers did OK making silicon for foreign made TVs, but people don't want to ship large fragile components like TV tubes half way around the world to an assembly plant.

author: james_s
author_rank: Super Contributor
timestamp: December 06, 2017, 04:31:21 pm
content: Quote from: stj on December 06, 2017, 08:35:30 amI'm well aware of the anatomy of a color CRT, but it is still not the same as a fixed grid of digitally addressable pixels like you have in an LCD screen. The electron beam is not rigidly linked to each phosphor spot and is not blanked between "pixels", it sweeps smoothly across with one spot getting brighter as it approaches and the previous getting dimmer as the beam passes away. There may be other factors at play here too, I have not studied it in detail but I do know that side by side a good quality SD CRT looks a hell of a lot better than a 640x480 LCD of the same size because I've sat them side by side and studied it with my own eyes.

author: meeder
author_rank: Regular Contributor
timestamp: December 06, 2017, 05:00:29 pm
content: Most CRT's had a better colour rendition as well.When I used my colorimeter to profile the screen the last CRT I had only needed very small adjustments and was very stable over time.All the LCD's that came after it have been a lot worse and needed a lot more adjustments.

author: kosine
author_rank: Regular Contributor
timestamp: December 06, 2017, 05:08:53 pm
content: I still use a Dell 21" Trinitron for CAD work because fine grey lines are more visible. (It's a rebadged Sony underneath.) Haven't tried the very top end LCDs, but on every other standard LCD screen I've used, the lines just disappear, especially when I zoom out.Probably something to do with the electron scanning not being as all-or-nothing as you get with LCD pixels. Would definitely agree there are some (niche) applications where a CRT wins out. Will be a sad day when mine finally dies / becomes unfixable. Weighs a hulking ton and takes up half the desk, but the screen is gorgeous and very easy on the eye at 1600x1200 and 80Hz.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 06, 2017, 05:15:17 pm
content: I wouldn't mind getting one of the 2048 x 1536 x 85Hz monsters, but they still sell for quite a good value actually!Hm, there's a thought, buy up a bunch of broken ones -- good tube but failed circuitry of some sort or another. Also, any with weird inputs (BNCs, 13W3, etc.). Fix them, and replace the interface with an adapter circuit for VGA or DVI (bonus points if it does DVI-D or HDMI!).Tim

author: meeder
author_rank: Regular Contributor
timestamp: December 06, 2017, 10:01:08 pm
content: Those BNC's aren't a problem. They are mostly RGB inputs and you van simply use a VGA to BNC cable. I used that on my IIyama Vision Master Pro 450 19". I still regret getting rid of that thing. SWMBO thought it was to big on the desk

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: December 06, 2017, 10:36:51 pm
content: I doubt it. If you can get past 144hz, you can get the hardcore CS:GO community excited...Only maybe. Response times are good on modern lcds.

author: chris_leyson
author_rank: Super Contributor
timestamp: December 06, 2017, 10:55:23 pm
content: QuoteDefinately one application that only works well with B&W CRTAsteroids might just be doable with fast high voltage drive amps and galvos on heatsinks and even then I don't think you will get anywhere near 50 fps refresh rate, depends how many lumps of rock you have to draw per second.

author: timb
author_rank: Super Contributor
timestamp: December 07, 2017, 04:56:48 am
content: Quote from: chris_leyson on December 06, 2017, 10:55:23 pmAtari also made vector engines that supported color vector displays! It was used in some of the last vector arcade games.They actually used two different types of vector engines in the various vector games they produced. The analog type used a state machine hooked to a pair of DACs and integrators for smooth movement of the beam. The digital type just used the DACs and “stair stepped” the outputs of the DAC to move the beam, doing away with the integrators and other precision analog parts.

author: schmitt trigger
author_rank: Super Contributor
timestamp: December 07, 2017, 02:49:46 pm
content: Quote from: coppice on December 06, 2017, 03:13:24 pmIndeed, by the early 1980s most US consumer electronics companies had already lost the will to fight the Japanese onslaught. Zenith soldiered on for a few more years, but eventually was purchased by LG.I only mentioned Sony because it was the gold standard in TVs, but there were other Japanese manufacturers (Hitachi, Panasonic, JVC) which also had reasonably priced sets that had excellent image quality..... and oh, they were VERY reliable.

author: coppice
author_rank: Super Contributor
timestamp: December 07, 2017, 03:24:51 pm
content: Quote from: schmitt trigger on December 07, 2017, 02:49:46 pmI find the tale of what happened to the British TV makers an interesting example of a changing world. TVs started out unreliable, and so they developed as largely a rental market in the UK. Rental means reliability is someone else's problem, and you have direct support from a solid support network. Things developed such that the main rental businesses were owned by the main TV makers. As TV reliability improved it became more attractive to buy a TV, but burdened with all the rental outlets, and a huge fleet of partially amortised TVs in people's home, the industry just couldn't adapt. For a time there were JVs with Hitachi and with JVC, but it was too little, too late.

author: james_s
author_rank: Super Contributor
timestamp: December 08, 2017, 01:52:11 am
content: Quote from: timb on December 07, 2017, 04:56:48 amYes, I have a bunch of them in my basement, Asteroids, Tempest, Space Duel, Black Widow, Quantum, and Star Wars round out the vector collection, and no, none of these are for saleSega made a series of color vector games as well, I've never owned one but I've worked on several and the G08 monitor they used is a lousy design. My understanding is they had to skirt around Atari patents resulting in rather sub-optimal design decisions, however that aside they're some rather good games.Of the Atari games, only Lunar Lander, Asteroids and Asteroids Deluxe used the digital vector generator. Starting with Battlezone they switched to the AVG which is capable of smooth lines without discrete points. It's a lot more tricky to troubleshoot and repair though, and the polycarbonate capacitors used in the integrators in the later ones are tough to come by. For reasons I don't completely understand these circuits are *really* picky and some types of capacitors that look like they should work well don't. While the AVG sounds good in concept, frankly I'm not convinced it looks any better than the earlier DVG, especially when you factor in the graininess caused by the shadow mask in the color monitors. The DVG used in Asteroids and such was capable of 1024x768 which is pretty phenomenal for 1979. Of course you couldn't light those points arbitrarily but a vector drawn at that resolution looks pretty darn smooth to me.

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: December 08, 2017, 03:31:27 am
content: I played asteroids on a color flat-screen sony trinitron... Maybe I'll try it on an oscilloscope or something.

author: vk6zgo
author_rank: Super Contributor
timestamp: December 08, 2017, 04:17:15 am
content: Quote from: coppice on December 06, 2017, 03:13:24 pmEver converge a Delta tube?Compared to a Trinitron, it is very fiddly & time consuming, & a good result is quite often not achieved.The other competitive designs, like the "Linytron" were mainly efforts by other Japanese manufacturers to make something similar to a Trinitron, but not have to pay Sony for Patent rights.These were just as easy to converge.US & European manufacturers seemed to be "locked into" the Delta tube design until too late, probably because they didn't want to pay Sony either.QuoteI think you're right!QuoteSony had no problem shipping TV tubes to their EU, Singapore, & other factories.When I worked at the TV studio, if we wanted a tube ( even big 27 " ones), if they couldn't source them in Australia, Sony would find us one & ship it "halfway around the world".

author: coppice
author_rank: Super Contributor
timestamp: December 08, 2017, 10:02:25 am
content: Quote from: vk6zgo on December 08, 2017, 04:17:15 amYes, during a work experience period at one of Europe's largest TV plants at the beginning of the 70s.Quote from: vk6zgo on December 08, 2017, 04:17:15 amTrue, but that was not really a problem. The lower cost of a delta tube provided the leeway to pay for any extra alignment work. Once aligned, both Trinitrons and deltas were pretty stable. With later delta tubes there wasn't that much alignment to do at the point of TV assembly, rather like the Trinitrons. Both types of tube were supplied to the assembly plant with the scan coils mounted and pre-aligned.Quote from: vk6zgo on December 08, 2017, 04:17:15 amJust as Sony developed the Trinitron not to be the world's greatest tube, but to avoid paying for other people's patent rights. Initially they struggled to make a big Trinitron, and all we saw were 13" TVs. Even with such a small screen the early ones had problems with the picture breaking up due to modest levels of vibration. Later they cracked the problem with a big grill, and found they had the best way to make 29" and larger tubes.The original Trinitron TVs were based on a series of innovations designed to work around other people's patents. They did more that just develop a new tube. There were long articles written about this work at the time, in various electronics journals. Perhaps a web search would find some. Sony were quite aggressive in driving all the patent fees out of their TVs.Quote from: vk6zgo on December 08, 2017, 04:17:15 amToo late for what? Despite the advantages of Trinitrons, the delta tubes still massively outsold them. Trinitrons were more expensive than deltas in the very curved and "flat square tube" generations of deltas. Trying to make a delta tube perfectly flat might have cost them so much that Trinitrons were cheaper.Quote from: vk6zgo on December 08, 2017, 04:17:15 amI'm not sure what Sony did. Most Japanese TV makers who produced in Europe used European sourced tubes.

author: meeder
author_rank: Regular Contributor
timestamp: December 08, 2017, 05:11:05 pm
content: My IIyama monitor had a Diamondtron tube which is akin to the Trinitron layout.The only downside was the visible support wire. For a TV not an issue but for a PC monitor it could be a bit annoying at times.Still miss that beast though.

author: schmitt trigger
author_rank: Super Contributor
timestamp: December 08, 2017, 05:28:09 pm
content: We performed a lot of competitive analysis of the traditional delta tube vs Trinitron.The delta tubes were indeed more difficult to properly align for a simple reason: The shadow mask in a delta blocked a significantly larger portion of electrons than Trinitron.More blocked electrons mean a dimmer tube, all other factors being equal. Screen brightness is something that users crave. Unconsciously if you will, but all other conditions remaining equal a brighter tube will subjectively look better.Therefore, to achieve the required brightness the guns would be driven with higher current. A higher current means that the electron beam becomes thicker and significantly harder to deflect.As I mentioned, efforts were made by increasing both the anode and focusing voltages, which created some other issues.I'm pretty sure that eventually most problems could have been figured out, but the industry simply. gave. up.

author: coppice
author_rank: Super Contributor
timestamp: December 08, 2017, 06:42:33 pm
content: Quote from: meeder on December 08, 2017, 05:11:05 pmWas the Diamondtron the Mitsubishi tube?The big Trinitron tubes had support wires. I think the 21" Trinitron monitors I used had 1, and our 29" TV had 2. You had to look really carefully to see them, though. They did a great job of minimising their visibility.

author: james_s
author_rank: Super Contributor
timestamp: December 08, 2017, 08:28:14 pm
content: Quote from: coppice on December 08, 2017, 06:42:33 pmYes, the Diamondtron was a Mitsubishi tube, essentially a clone of the Trinitron after Sony's patent expired. There may have been others too but Sony and Mits were the two big makers of aperture grill CRTs.There was a predecessor to the Trinitron, the name escapes me but Sony was doing color with a single electron gun, something that found use occasionally in later specialized applications like miniature viewfinder and avionics color CRTs. Another interesting single gun color tube called a Penetron used layers of red and green phosphor to enable a red-yellow-green display, that was used in some test equipment and (IIRC) avionics displays.

author: james_s
author_rank: Super Contributor
timestamp: December 08, 2017, 08:35:00 pm
content: Quote from: AutogolazzoJr on December 08, 2017, 03:31:27 amA scope will get you closer, although it's still hard to get the brightness of the shots close to what they should be. On a real vector CRT the missiles are blindingly bright shots that look like a magnesium flare sailing across the inky blackness of space. It's nothing like the dull gray barely visible pixel you get on a raster display. Unfortunately it's an effect that is difficult to capture due to the limited dynamic range of anything you'd be watching it on, there's no substitute for the real deal.

author: coppice
author_rank: Super Contributor
timestamp: December 08, 2017, 10:39:59 pm
content: Quote from: james_s on December 08, 2017, 08:28:14 pmPenetrons were amazing tubes. They displayed super crisp 4k x 3k images on a large (29" I think) display at a time when the only thing that could match their resolution was the Tektronix graphics storage tube. Because they were vector scanned there was a limit to how complex a picture they could display, and the colour range was limited. However, they could do a wonderful job in applications that could live with their limitations.

author: james_s
author_rank: Super Contributor
timestamp: December 08, 2017, 10:48:17 pm
content: What used such a large Penetron tube? The first I saw of one was a 9" tube in a prototype color Vectrex that somebody had. I've also seen a scope that had a raster display in the characteristic red-yellow-green which I assumed was a Penetron but it may have actually been a predecessor to the Tektronix NuColor display. I have a scope with one of those and I love it, full RGB color out of a B&W tube with no shadow mask. It does have a bit of DLP-like color fringing at times due to the sequential color but once my eyes are used to it I don't notice it.

author: cdev
author_rank: Super Contributor
timestamp: December 08, 2017, 11:42:59 pm
content: I still have two large Trinitron monitors. One is I think 24 inches, the other 20. All three guns on the large monitor still work but the colors look muddy. Is focus is muddy. Its gotten a lot of use, basically both have.On the 20 inch one which was my favorite, the red gun stopped working some time ago. So I have assumed that it was toast. Both are not in use now but if its possible I would like to get them working again so I could use them for 3D. Is it?Back in the day their color rendition was noticeably superior to LCD monitors.

author: james_s
author_rank: Super Contributor
timestamp: December 09, 2017, 12:26:47 am
content: I doubt the gun itself is bad. Usually when an entire color stopped working it was a bad cable or cracked solder joint, occasionally a fault in the video amplifier.The muddy looking one describes classic symptoms of a worn out CRT, especially if turning dowm the brightness makes the picture sharper, or if high brightness causes streaking to the right. In my experience, Sony tubes respond poorly to attempts at rejuvenation.I have a 14" Trinitron broadcast studio monitor that produces a phenomenal picture, it even does 1080p. I fished it out of an e-waste bin but I think they cost around $10k when new.

author: coppice
author_rank: Super Contributor
timestamp: December 09, 2017, 01:20:15 am
content: Quote from: james_s on December 08, 2017, 10:48:17 pmVery expensive CAD workstations, which I think were only ever made in fairly small quantities, because of their cost.Quote from: james_s on December 08, 2017, 10:48:17 pmAre you sure the mixed colour scope was not just a tube coated with a mix of short and long persistence phosphors of different colours? Those existed, because the long persistence phosphors don't always work well at fast scan speeds, so the mix gives the scope a more balanced performance.

author: cdev
author_rank: Super Contributor
timestamp: December 09, 2017, 03:44:28 pm
content: James, thanks for the tip.I have the service manual for it, so if the gun is still okay, that would be nice.Its a GDM series. And yes, it also will do 1080P I am pretty sure. I think it goes up to around 2500 pixels horizontal resolution. (Both monitors do).I should be able to figure out what's wrong with it, that means its probably worth trying to figure out what happened.The smaller one still had a nice picture when the red gun went out. It was nice when it was working.

author: vk6zgo
author_rank: Super Contributor
timestamp: December 09, 2017, 11:10:08 pm
content: Quote from: james_s on December 09, 2017, 12:26:47 amThe simple trick to pin down if loss of a colour is the tube, the tube socket board, or further afield, is to just swap the drive with one of the operating guns.If the fault changes to another colour, the tube is not at fault.The "muddy look" sounds ominous.Another thing which happens with a dying tube, isapparent"Luma/Chroma intermodulation", where the colour Hue changes with brightness ( I say "apparent", because, although it looks similar, one is a Composite video problem, & the other simply a display device failing)Perhaps the more accurate name would be "Colour tracking".Back in the day, you could get your tube "regunned".This was almost always successful with Trinitrons, but less so with other tube types.Sadly, along with the market for new tubes, that for regunning has died.

author: chris_leyson
author_rank: Super Contributor
timestamp: December 09, 2017, 11:49:08 pm
content: I wish I had kept may Hantarex green screen monochrome monitor, I can't remember the model number but it was awsome, long persistance green much longer than P31. Would have been a nice tube for vector games, never mind

author: Dubbie
author_rank: Unknown
timestamp: December 10, 2017, 12:37:12 am
content: How can someone still argue with a straight face that crt screens look better still? Maybe just when LCDs came out... but they have long been superseded. And before you ask, yes, I used to use $30k grade 1 Sony HD monitor, so I have a good point of comparison. I wouldn’t go back to CRT for anything. Now using a modern OLED and it looks beautiful.

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: December 10, 2017, 01:31:29 am
content: CRTs are good for retro gaming, vector displays, and oscilloscopes. OLED blows away CRTs in every other application.

author: james_s
author_rank: Super Contributor
timestamp: December 11, 2017, 10:33:14 pm
content: Quote from: chris_leyson on December 09, 2017, 11:49:08 pmP39?Long persistence is actually not much use for games because it makes everything streaky. Just for fun I once tried a P39 green tube in the monitor of my Asteroids and it looked neat but not particularly useful. Most of these games used a fast enough draw speed that there is little or no visible flicker. Some of the later stuff like Star Wars had more flicker because there were so many vectors being drawn on the screen during some scenes.Anyway those old monochrome monitors have increased significantly in value with the vintage computer collectors, they're hard to find these days.

author: james_s
author_rank: Super Contributor
timestamp: December 11, 2017, 10:45:10 pm
content: Quote from: Dubbie on December 10, 2017, 12:37:12 amThe same way some people argue that vinyl sounds better than CDs? It's subjective and what's "better" is not the same for everyone. I think it's pretty clear that some people perceive images and sound differently than others and certainly some value certain characteristics that others don't.I use LCD in most things due to convenience, and LCD certainly has better geometry for a computer monitor but I definitely prefer the look of a good CRT, especially for video applications. The contrast ratio LCD is crap even on the good ones and the color is different, especially if you are anywhere outside the sweet spot for viewing position. Doesn't matter to you clearly and that's fine, but CRT looks better to me, especially on equal footing where resolution is the same. The 480i Sony XBR CRT I have in the basement produces a picture roughly on par with 1080p on the LCD upstairs despite the far lower resolution. This is especially true when watching older 480i analog content which looks awful on the LCD. I have modern equipment too, not top end but not cheap crap either.OLED is very promising and indeed looks very CRT-like and natural to me. They are still fairly rare though and it remains to be seen how they perform with age. I've been waiting a long, long time now for OLED to deliver on its promises and *finally* it seems to be taking hold. I still worry that "the enemy of the best is good enough" will come into play and that LCD will eventually win out over OLED due to the fact that something 80% as good is adequate for 95% of people, especially when it's cheaper. Throughout my lifetime the vast majority of TVs I've seen people have are the cheapest big box store junk they could find, most people simply are not picky about picture quality. With the mass market low cost is king.My main use of CRTs though is in vintage arcade and console games where LCD just looks completely wrong. Putting a modern LCD monitor in a 1981 Centipede arcade game is like putting the interior from a 2017 car in a 1957 Chevy, it just looks weird and out of place. Vector games inherently require a CRT due to their reliance on drawing the picture like an etch-a-sketch rather than scanning a raster.

author: chris_leyson
author_rank: Super Contributor
timestamp: December 11, 2017, 10:46:17 pm
content: I think it must have been P39 as it was a much much brighter green than anthing else I had seen on a green screen monitor, and you're probably right about the long persistance, not much good for animated vector graphics. I never turned the brilliance all the way up or left the same image or text on the screen for long but I guess they must have suffered from screen burn.

author: Dubbie
author_rank: Unknown
timestamp: December 11, 2017, 10:50:24 pm
content: Quote from: james_s on December 11, 2017, 10:45:10 pmI can see how this might be true with 480i content, but for reasonable HD content, it should be no contest.Maybe I'm biased because I can't remember the last time I watched something that wasn't at least 720p.

author: james_s
author_rank: Super Contributor
timestamp: December 11, 2017, 10:54:35 pm
content: Quote from: chris_leyson on December 11, 2017, 10:46:17 pmI don't recall screen burn on the green monitors being any worse than others. Actually some of the worst for that were the amber monochrome screens, due largely to the fact that the amber phosphor is much less efficient at turning electrons into light. The P39 green also appears brighter because the very slightly yellowish green is right near the peak sensitivity of the human eye, it would look brighter even if it wasn't.No CRT phosphor is immune to screen burn though, I've seen lots of old computer monitors and terminals with various menus burned into them and most of my arcade games have phosphor burn due to always displaying the same game. Some games were worse than this for others.

author: chris_leyson
author_rank: Super Contributor
timestamp: December 11, 2017, 10:55:45 pm
content: Nippon Electric Glass used to make CRTs or glass for CRTs and closed down their plant in Wales in 2005 to concentrate on LCD products. I think they opened a CRT plant in China around the same time ? If anyone is still making CRTs it's most likely a Chinese company.

author: james_s
author_rank: Super Contributor
timestamp: December 11, 2017, 10:59:05 pm
content: Speaking of screen burn, I think if OLED catches on we are going to see a lot of issues with those stupid @$@& network logos burning into the screens. This was a big problem back in the projection CRT and plasma days and now the logos seem to be larger and brighter than ever. As much as I like OLED it is definitely not immune to burn, especially if left at the retina-searing out of box settings intended to make it stand out on store displays.I hate those logos!

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 12, 2017, 05:43:13 am
content: Quote from: james_s on December 11, 2017, 10:59:05 pmOLED screen burns?!Well alot of modern phones and portable computers are going to have problems then, most of them are OLED now.*researching* Apparently it's not permanent and will fade away with normal use.http://televisions.reviewed.com/features/what-to-know-about-oled-screen-burn-in-problems-causes-image-retentionQuote from: chris_leyson on December 11, 2017, 10:55:45 pmMost of them are Chinese, but I just posted a non-Chinese tube company earlier in this thread, so they do exist elsewhere.

author: james_s
author_rank: Super Contributor
timestamp: December 12, 2017, 07:54:14 pm
content: Yes, OLED can suffer permanent burn.https://www.rtings.com/tv/learn/permanent-image-retention-burn-in-lcd-oledThis should hardly be surprising as it's an emissive technology, each pixel being an individual light source which degrades slightly with use just like a CRT or plasma panel phosphor. If you have some pixels that are used heavily they will degrade at a higher rate than those which are not. Getting acceptable lifespan before brightness drops to an unacceptable level has been one of the big challenges holding up mass proliferation of OLED panels. It's not much of an issue with phones because they rarely display a static image for long periods of time and most people replace them every year or two anyway.I'm still a big fan of OLED and I think the fantastic picture quality they are capable of producing is worth it but this is something people should be aware of. During normal use screen burn should not be a problem but bright static logos are torture on any kind of emissive display. They're torture on my eyes too, I can't even watch content that has them, it's like a blob of something on the screen that I can't wipe off, it's very distracting.

author: coppice
author_rank: Super Contributor
timestamp: December 12, 2017, 09:37:41 pm
content: Quote from: Cyberdragon on December 12, 2017, 05:43:13 amThe quoted lifetime of OLED panels was limited to a few hundred hours for several years. Burn in was a big issue, but these panels were considered adequate for things like phones - phone don't usually last very long, and few people keep the display on for much of the time. There were supposed to be some breakthroughs a while ago, which opened the field for 100k+ hour lifetimes, but who really knows? The obvious answer would be LG, as they are the only ones with deep experience of big TV panels. LG offer a 5 year warranty on their OLED TVs, but when a friend tried to get LG to define what the warranty actually covers, they were vague. They did indicate that a gradual colour shift would probably occur, that this would be correctable by tweaking, and was not considered a warranty claim issue. When probed about burn in they were evasive.

author: james_s
author_rank: Super Contributor
timestamp: December 12, 2017, 10:27:36 pm
content: That has always been the case. In the CRT and plasma days screen burn was not covered by warranty and OLED is going to be no different. Of course it's not something that a TV manufacture wants to talk about because many people will latch onto it as a defect in the product. I view it as a tradeoff one makes in exchange for the superb image quality. It's not uncommon for high performance equipment to require some degree of special care.

author: Berni
author_rank: Super Contributor
timestamp: December 13, 2017, 06:28:16 am
content: Well the more modern CRTs have reduced the screen burn issue quite a bit, but im sure you can still get them to burn in if you blast them with a contrastful image at full brightness for a few days straight.Then again for LCD the dead pixel issues from the old days is what manufacturers claimed as being normal. They could sell you a brand new monitor with a 2 or 3 dead pixels on it and not offer a replacement if you complain about it.

author: james_s
author_rank: Super Contributor
timestamp: December 13, 2017, 11:40:28 pm
content: I haven't noticed much difference in burn resistance between older and newer CRTs. Having worked on a lot of arcade games of from the earliest to the last of the CRT based games heavy screen burn is common. It's rare on home TVs but I have seen a lot of CRT projection and plasma TVs with news logos and ticker bars burned into them. These days virtually all TV channels have permanent logos, I'm not sure why anyone is willing to pay for content that is marred in that manner.

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2017, 11:46:21 pm
content: Quote from: james_s on December 13, 2017, 11:40:28 pmI don't think the rate of images burning into CRTs changed much over time. However, older CRTs, without a really effective ion trap, often burned a large blob in the centre of the screen.

author: james_s
author_rank: Super Contributor
timestamp: December 13, 2017, 11:55:05 pm
content: Those are *really* old CRTs, the aluminum layer they started applying to the back of the phosphor sometime around the 1950s blocked the ions. I've seen the older tubes that had the gun angled in the neck and a magnetic "ion trap" to deflect the beam back to the middle without deflecting the ions.

author: coppice
author_rank: Super Contributor
timestamp: December 14, 2017, 12:03:45 am
content: Quote from: james_s on December 13, 2017, 11:55:05 pmThe ions were trapped in the neck by an ion trap in the neck all through the life of the CRT. The aluminium coating gradually failed if the ion trap magnet was removed.

author: james_s
author_rank: Super Contributor
timestamp: December 14, 2017, 01:13:29 am
content: That's simply not true, CRTs have not had an ion trap in decades. If you look at the tubes that did the electron gun is pointed at a substantial angle in the neck and the ion trap is a separate magnet assembly that clamps onto the neck behind the deflection yoke to deflect the beam back toward the screen. Ions are not deflected by the magnetic field, that's why the ion burns only occurred in the center of the screen and that's how the ion trap worked. The magnet only deflected the electrons toward the screen and the ions harmlessly hit the side of the tube. Once the aluminized coating was developed in the 50s ion traps went away and tubes changed over to having straight guns that pointed directly at the screen. Quite a few earlier TVs got newer replacement tubes and the ion traps were removed. I have quite a lot of experience working with CRTs so this is something I'm very familiar with.https://www.antiqueradio.org/art/Hoffman7M112RaulandCRTPatentDrawing.jpg

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 14, 2017, 06:36:09 am
content: I've seen classic tubes with ion trap magnets, they do indeed look kinda goofy inside, just as the patent drawing shows.Ions are of course not completely undeflected, but the sensitivity is thousands of times weaker (because of the same difference in mass), which is close enough to zero for purposes of a few gauss and a few degrees.Also, only negative ions are of interest here, because of course positive ions get sucked towards the cathode (and cause unpleasantness with the chemical purity and surface condition of the cathode, leading to degradation over time), which is interesting because you're often told that a molecule gets smacked by an electron and loses several in the process, but it's not an exclusive process, and sometimes they stick, and sometimes the molecule breaks (such is the case for water, even in the upper atmosphere) leaving fragments that go whichever way.TIm