The fact that it's for a CRT is the surprising part, but "universal" replacement boards for LCD TVs have been available for a while too. Here's a rare review of one, on a site that has sadly disappeared within only a few years:
I guess that one reviewer either didn't bother to order one with the right connector, or received it with the wrong one, but the pinouts are usually very standardised so there's no need to resolder the LVDS cable.
There's lots of videos on YouTube about these boards; unfortunately the vast majority seem to be in Indian or some other Asian country's language (despite English titles and descriptions). Here's one of the few English ones I could find: https://www.youtube.com/watch?v=C2YTL25iyHU
China is paradoxically filled with brilliant engineers making genius products, and mediocre engineers making products whose listings appear to be genius.
That's a great observation. I've bought stuff there that I could not even believe was as cheap as it was, I thought the price must be a typo and for sure it'll be adjusted. For electronics the pricing tends to be lower than the BOM at maximum volume discount when sourced from a large Western supplier.
And the vast majority of it just works, though I've had one or two duds.
But you need to be sharp when it comes to things that plug into a wall socket, open them up to inspect that they are safe.
Electronics are crazy. Depending on the amount of skill and/or effort you have available, there is an enormous spread of possible implementations at different price points.
For instance, I develop a product that we sell for $2500. When the company brought me in, the raw cost of the electronics was about $250. Right now I've got it down to $50, and I expect it to fall to $20 or $30 once we start producing at scale.
Youβd want to hope your margins are that good distributing and marketing physical products. Gets expensive particularly if youβre retailing it and the retailer chain wants your margins for the honor of distributing with them!
Thanks for finding the original, and I did suspect it was translated from Russian due to the odd phrasing, but if it weren't for that site translating a copy and Google subsequently finding it, such interesting things might've never gotten discovered. As I mentioned in the other comment here, there's lots of videos on YouTube about these boards too, but barely any in English.
Oh there are a ton of interposer boards you can buy shipped direct from China that add CarPlay to an existing oem head unit the same way you can get reverse camera support (high jacking the video output when a certain but is pressed or the gear shift changes). Itβs just that they all have massive quirks. Iβve seen the Porsche Classic CarPlay retrofit and itβs absolutely the best, but these third party solutions are available for most makes and models but all have to a of quirks and idiosyncrasies that are never presented up front.
This video and reading the recent article referencing Brimar valves (of the vacuum tube variety) [1] led me down the rabbit hole of, how hard can it be to make a few CRTs. Despite growing up with them, it turns out I had no idea. Lots of ovens and nasty chemicals involved - see for yourself in this great old video [2]. I wonder if anyone in the retro scene is eccentric and rich enough to give it a goβ¦
I remember hearing the main issue is that the glass is made up of a significant amount of led so even if it was commercially feasible it would be legally impossible to sell, import or manufacture new CRT tubes due to the regulations many developed nations have in place.
Lead glass is only used for the back and sides of the tube. It can't be used for the faceplate because x-rays make it turn brown. Instead, barium-strontium glass is used for the faceplate. It seems that use of lead is only a cost optimization, and the whole thing could use barium-strontium glass instead.
Searching for "lead glass CRT browning" on Google found this sample chapter from an unidentified book, provided by the The Society of Photo-Optical Instrumentation Engineers, which includes some details:
There are exemption. And if you think of it, it is a lot easier to properly dispose and recycle the plates in a car battery than in electronics solder or glass.
From the transcript (I dislike watching videos), it appears the video never discusses the chemicals involved - but Iβm sure some of them are rather toxic. It is an old film, and when it was produced people didnβt see the toxicity of chemicals used in manufacturing processes as being as worthy as note as people do today - both environmental and workplace health/safety issues were less on peopleβs radar. Plus it obviously is marketing/PR for the manufacturer, and who wants to mention toxic chemicals in something like that?
It's worth mentioning though that in general as our technology has gotten more exotic, so too the chemicals needed to manufacture it have gotten more toxic.
Is there some underlying rule/"law" of fabricated products shrinking in scale requiring increasing energy density/control for their manufacture (more reactive chemistries) presumably to counter a general backdrop of entropy / entropy-density?
Sounds like hydrofluoric acid to me, which is even more dangerous. But seeing as you're making a vacuum chamber anyway, perhaps oxygen plasma could be substituted.
oh, that's great. Anyone selling kits of this? Or an Aliexpress version less geared towards TV and more towards gaming monitors, with VGA, composite and other useful input for retro computers?
RGB hacking is a thing though so for 15khz (~240 x 60hz) aka 240p it is often just simpler to tap into the OSD display chip (lookup jungle chip mod) input an RGB signal.
Been there, it works, but if the original crt board has issues (and youβre not good at diagnosing them) it would be great to get a good quality replacement
What I would like to see is a board made for larger 100/120hz TVs. They often get no love from gamers due to the lag/processing of 240p content so they get junked. It would be a good solution to the lack of multimode CRTs. They are so rare/expensive.
I remember fixing up a CRT on an arcade machine I had in my office at work at one point. I read up on how to discharge it and made a makeshift tool to do the job (i.e. an insulated screwdriver with a wire attached to ground). I was pretty scared and even made sure to do it during work hours when others would be around in case I got zapped unconscious. :) Once I got was able to do it a couple of times, it really was no big deal, but I did take care not to get too close to the back of it while the thing was on and exposed.
This is a case where having the right tool is actually a good idea. It'll have plenty of insulation and usually a VU meter showing the voltage (so you can see if it was charged and watch it drain). A screwdriver doesn't really have enough separation between you and the 20+ kV :-/
Its not a matter of not having the right tool is not a good idea, but sometimes, because of cost and or circumstances, you have to improvise and/or make due with what you have.
Worse, itβs never been made clear to me which parts are the dangerous one. Just a lot of vague hand waving. Which I guess is fine if you donβt want liability?
The cathode ray tube is a giant capacitor. During operation it is charged to 20+ kilovolts, and it takes a long time to discharge even after being unplugged from the wall. (Some but by no means all TVs have a circuit which discharges the tube). There are also large capacitors in the power supply which maintain hundreds of volts even after being unplugged. When the TV is connected to power, the flyback transformer (a large circular device soldered to the main board) generates a range of voltages from hundreds up to 20+ kV which are wired to various parts of the tube. Some of these are present on the neck board which is exposed at the pointy end of the tube.
US TVs are extra spicy because they sometimes have no earth, so if the power is wired backwards (either in the plug or more insidiously from the wall), everything metal inside the set can be live.
If you overvolt the tube (a worry with this replacement board actually) then it can emit x-rays. Most "modern" CRT main boards have a circuit which detects this, but maybe older ones or cheap knock-offs don't.
In short, if you don't know what you're doing, stay away.
Ok. I can identify all of those parts and once did a cap replacement on a pac-man monitor. But that's enough to keep me from making it a regular thing.
If unsure or nervous around electricity, just ground the segment you are working on first.
But the parts that should make you extra cautious have wires with a lot of insulation so they look thick. those are the 20Kv bits. you also will want to take the time to drain any big capacitors. you can just short the leads or if you are feeling conscientious(and don't like sparks) drain them with a resister(100kohms or so) between the leads.
When I took a TV servicing class in high school in the 1970s we were told just to keep our left hands in our back pockets so the discharge will ground through our right side and not across our hearts. The biggest hazard was breaking our hand on the chassis as we jerked back from the shock.
I never heard of any kids getting hurt, so it was fine.
The risk of death or serious injury messing with CRT displays is grossly overstated (note the lack of data on related fatalities). Use common sense and you'll be fine.
Surgical latex gloves are not what I picture when someone says "rubber gloves" but something more substantial typically used when cleaning in a shape that borders on a rubber gauntlet.
I know but not everyone who reads this would be as experienced to know this :)
Some people would still think "it's rubber so it doesn't conduct electricity so I'm fine messing with this TV".
But yeah CRTs are now so rare that I agree that it's very very unlikely for someone without much knowledge to tinker with them. You have to be really an enthusiast to even still own one let alone try to repair one instead of picking up a nice cheap flatpanel.
Personally I'd forgo the gloves (real protective ones are so clumsy it's hard to really do something productive with them) and make sure the caps are fully discharged. Though generally I'd steer clear from this stuff as I know I don't understand it well enough. I came up in electronics during the final years of CRTs so as my knowledge grew they became deprecated and I never really got the full grasp of them.
Mike's Amateur Arcade Monitor Repair on YouTube reviewed a similar 25" Universal Arcade Monitor Chassis a couple years back and was "blown away" by it. Definitely worth the money. High praise from a guy that knows CRTs inside out.
Not entirely related but I didn't find much information about the NTSC/PAL decoding schemes. Lots of introductory material but nothing about what they actually did in televisions back then (especially the filtering side). I guess it's because of patents...
http://web.archive.org/web/20190511065920/http://redlightgre...