vintageTek Demo of a 1930's 905 CRT 

Get 3 of them, put color dyes in the phosphors, put lenses in front of them, bam, crt projector with a huge image

so many people are interested they will learn to rebuild the CRTs (it's possible)

@@tankmchavocproductions6907 you'd probably be better off just picking different phosphor colors for each tube: red and blue phosphors exist

If industry is that bad off we will have more important things to worry about than computer games

Just rebuild old crts with a new electron gun. The industry only stopped because of reduced demand meaning no profit was possible.

Go to andeman

No

I agree, I would love to have a brand new tube circuit crt

Maybe not these but color tubes for sure

... why? They look like shit, use a ton of electricity, take up a ton of space, and overall lack any of the quality with current technology. I guess people are into the crap and degradation of vinyl so makes sense they'd be in to CRTs too?

yes, size is very important. anyone that says otherwise is a lier.

How did you make it?

I used an old Heath kit built solid state oscilloscope for an oscilloscope clock using a small CRT driver board and the CRT has a shield over part of it with the power transformer mounted under the chassis in a copper or copper plated can with most of the scope chassis being of the same material. No wobble that I can see.

More like a particle emitter hitting up the phosphor.

Most advanced CRTs can display pictures with HD res, and some professional ones can even output something comparable to 4K !

A similar if not the same tube was used in a lot of low profile wall mounted video door intercoms before LCD monitors were invented. The screen was curved and closer to 30 degree angle and I always enjoyed playing with them, it was so cool to watch the picture through the vacuum. Tubes are still available NOS crtsolutions.ecrater.com/p/10644463/04jm-4-flat-b-w-crt-tube

Now THAT I would LOVE to see!

We must be close to the same age, and therefore the same as the age of Tek's first scope, the 511, which came out in 1947, the year I came out.

The accelerating voltage is so low that ions wouldn't have much energy. Ion traps were only used in TV CRT's with very high accelerating voltages, typically over 20KV.

Yes I see what you mean. Pity for them to have lasted so long for a few decades old particles to flaw them. On the other hand those tubes have more than fulfilled their intended service lives by now. Perhaps upright storage can only add to their continued longevity?

Maybe they are end of life anyway. One of them has a white patch so may have gone to air.

Yes. I'd hate for that 90yr old tube to suffer burn in after surviving this far.

They need to have the aquadag and the lead in the glass to have good picture Otherwise they would look like shit

CRT'S after this one had a conductive aquadag coating (graphite paint) connected to the highest positive voltage. This gave the electrons a place to go after giving up energy lighting the phosphor. In this older CRT, the electrons either wandered back to the deflection plates, or collected on the screen, giving it a charge that could affect the image.

thanks very much for your explanation. I was watching another RU-vid video about restoring old CRTs and they put a coat of aquadag on the outside of the tube as well as the interior, why? totally understand if you haven't the time to reply, quite frankly I'm super happy to get one question answered. thanks again for the great content.

An outside coating would be grounded. With the inner 'dag this would form a parallel-plate capacitor that would act as a filter for the high-frequency high-voltage supply. On color TV CRT's, the coating was usually lead, which would be both a capacitor plate and a shield for X-rays.

x-rays are only a problem if the accelerating voltage is over 20 thousand. This tube is running at only 1200 volts.

The secondary electrons emitted by the screen are collected by the deflection plates, which are the first positive elements they found close to the screen. Old tubes without the internal aquadag film are prone to distortions on the waveform displayed due to the stray currents caused by these secondary electrons when they flow through the relative high resistance path associated to the deflection plates.

And/ or a Faraday cage.

@@gregjones3660 Agreed yet they are = and opposite reactions " either way it would be an interesting outcome?

@@gregjones3660 My guess a Faraday cage. being of an outcome of non interference might make a sharper crisper beam ?

Only because it's larger. If you saw an LCD (tft is a type of LCD) that was scaled up to this size (about 50x50 pixels in a 8" x 8" form factor) you'd be able to see just how simple it is. Like holding a hand in front of a flashlight, but replacing the hand with an rotating paper that is controlled by electricity.

I've often wondered how much the accessibility of early technology fed back into the culture and helped propel the industrial revolution. How many curious kids could sit and watch a steam engine for an hour or so and get a pretty decent idea how it worked, be inspired, and go on to a career in the field and maybe invent something of their own. Now? All of the most ubiquitous tech is basically invisible. Instead the kids that would have grown up to create interesting and useful physical products and building projects start useless tech companies that make us all more depressed and angry. (Not all of them, YT is amazing for sharing knowledge just like this, but there are plenty that are entirely needless.)

Jack Kuehneman You would likely find it easiest to work with an old B&W/monochrome TV CRT tube as they use magnetic deflection coils to steer the electron beam and are well suited to low frequency use (audio being low frequency as it is tops out at ~20KHz). With the electrostatic beam steering used in oscilloscopes you have to drive the steering plates at fairly high voltage while magnetic coils could be driven with simple audio amplifiers and do not require high voltage since they are simple electromagnets. Oscilloscopes use electrostatic steering because it allows for much faster steering of the beam and thus allows an analog scope to operate at much higher frequencies (megahertz and beyond) versus the mere kilohertz of magnetic deflection. But you could certainly use an electrostatic CRT, you just have to build the high voltage deflection power supply and the necessary high voltage amplifiers to drive the deflection (steering) plates - there are two pairs of plates, one set for vertical and one set for horizontal and for each pair of plates if one is being driven positive then the other gets driven the same degree negative, and vice versa - in other words they are always inverted relative to one another such that one is pulling and the other pushing in the direction you wish to steer the electron beam relative to its center “home” position (with no steering applied you get a simple dot in the middle of your screen). Note that because magnetic fields also affect the beam (hence why TVs can utilize slower magnetic deflection) you must also shield your CRT from any nearby magnetic fields if speakers or high power amplifiers are going to be anywhere nearby or you will experience unwanted affects due to the stray magnetic fields they create. Good luck!

Here is a representative TV hack, short on details but has a catchy tune. Be VERY careful with the mains on the power supply and high voltages on the tube. They can do you injury and are easy to get shocked with if you are not experienced and know what you are doing. Sometimes a TV horizontal circuit will need the coil connected that the person unplugged and in these situation you will need to replace it with a yoke from a similar TV so it keeps working and then connect to the coil on the working tube. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-uftMl1efEdk.html

This is not a raster-scan display, it's X-Y, so there is no separate vertical deflection rate. Instead the overall refresh rate would have to be adjusted, which is tricky. I plan to re-do this exhibit to reduce the number of mains-frequency transformers, which will reduce the stray magnetic fields.

I thought that it is using the standard raster scan principle. That's true that in this mode it's more difficult to synchronize the refresh rate to the mains because maybe it depends on the picture that is showing at the display and is no fixed relation to a clock frequency on the board. Really in this situation a SMPS or transformer rearrangement in the box (or magnetic shielding) should solve the problem.

Why not locate the transformers in a separate box and make a cable to connect them to the circuitry? That way the transformers are away from the CRT.

Carlos, you can get leaded acrylic sheet if you don't want glass. There is also bismuth loaded acrylic.

In Portland, Oregon at 4620 SW Beaverton-Hillsdale Highway. See the website at vintagetek.org

We have moved onto the TEK Campus at 13480 SW Karl Braun Drive, Beaverton, at the northeast corner of the campus, contrary to where Google Maps shows this address.

Can't

NV: Perhaps you are thinking of a Carbon Arc lamp, such as those used in searchlights.