Stromberg Carlson Charactron Tube

Flat panel TVs have spoiled us. It used to be that a big display took up a lot of room on your desk or living room because of the depth of the CRT’s electron gun. We wonder what the designers of the charactron would think if they could see our big flat screens today. Never heard of a charactron? Check out [uniservo’s] video of one of these old character display tubes.

You might think the device is just a simple small CRT. However, it is much stranger than that. Inside the tube was a stencil that contained all the characters the device could display. A deflection coil would move an electron beam to light up a particular character. Then another coil would deflect the patterned electron beam to the desired space on the screen. In some cases, the entire set of stencils would get the beam and the first deflection coil would pick which character made it through an aperture. Either way, the tube was not just a display, but a character generator.

These tubes were staples in the SAGE project and also created text and numbers to record on film in some applications. The [uniservo] tube is relatively short because it has a 5 inch screen. A 21 inch device was said to be six feet long.

We were hoping he would light the tube up, but he hasn’t got the data sheets on the device. If you have details, we are pretty sure he’d be happy to hear from you. Meanwhile, if you want to see what one of these beasts looked like, there’s a (presumably overdubbed) Russian video below, that talks about how they work and has a few images.

This probably reminds you of NIMO, but it works a bit differently.We take displays for granted these days, but it wasn’t always so easy.

20 thoughts on “Stromberg Carlson Charactron Tube

  1. The very first prototype is sitting on my friends meuseum items
    Table in her shop. Her father developed the tube for Hughes/Convair when he worked there and brought it with him when he purchased that divisions assets and started his own company. It’s a remarkable device. I will take a few pictures of it next time I am down there.

  2. I worked with those in the Air Force from 1970 to 1974. The first deflection routed the beam to the character in the mask and the second deflection re-centered the shaped beam. The third deflection positioned the beam on the screen, which exposed either one of two photographic film carriers. Each film carrier had its own develop, clear, and rinse pads and an air dryer. The film then went to a UV flash which exposed one of two secondary film carriers and that film was developed by a heat platen. The secondary film then moved to the projection window where red, green, and blue light was shined through each quarter of the film and projected onto a screen. All 4 stations could be updated and displayed in under a minute (but not much under). The screen was 16′ by 16′ and each station displayed on an 8′ by 8′ quarter of the screen. The control panel for the machine had about 50 relays and the D to A converter used small vacuum tubes. The whole system was designed in the 1950’s.

  3. Here’s a link to one of the Typotron tubes used in the SAGE system:
    The 19″ Charactron in the SAGE display consoles looks like this:
    Information about the operation of the SAGE Charactron and Typotron can be found in these T.O.s:
    The 19″ Charactron could display both vector and character information.

    1. Interesting (and impressive) technology. These gems of the past seems so easily to be forgotten. We think we can do everything these days but on days like these it reminds you that in the past that they had some pretty clever tricks up their sleeves to achieve the unthinkable. What we might consider today as impossible with he old tech, simply because we are so caught up in thinking in larges memories and high speed digital circuits that we sometimes forget that there are (many) other ways achieve a similar effect/device/goal.

      I love these articles, please keep ‘m coming.

      Thanks Mike Loewen for these wonderful images.

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