Building A Vector Monitor Controller

[fredkono] has a few vintage Atari arcade boards sitting around, and without the rest of the arcade machine – especially the XY CRT – these boards would continue to gather dust. The solution to this terrible shortage of vintage video games was to build a vector monitor from scratch. No, that doesn’t mean building a new CRT, but it does mean rewiring the yoke and building a CRT controller board for tubes salvaged from small, old TVs.

Nearly all the CRTs you’ll find at your local goodwill or surplus shop are raster displays. The CRTs used in the old Atari games were vector displays and extremely similar to the tubes found in old oscilloscopes. [fred] turned the CRT found in an old 9″ color TV into a vector monitor by rewinding the yoke.

With the tube rewired, it was only a matter of connecting the custom deflection circuit boards and getting the old arcade boards running. The images drawn with the new yoke deflector board are great and produce fine, crisp lines of some of the most famous video games in history.

19 thoughts on “Building A Vector Monitor Controller

    1. I know this is a Zombie thread but the Sony PVM/BVM lines used Trinitron tubes which for a couple reasons can’t be “easily” converted to an XY display. Stick with a normal shadow mask static focus TV and avoid the Trinitrons or the various clones thereof.

  1. I have a 5″ B&W CRT that I’ve already stripped the vertical yoke for a similar project. Trouble is the ferrite appears to be a solid ring unlike on the larger tubes so I’m not sure how to go about re-winding it or how to calculate the turns and what gauge wire to use. There doesn’t even appear to be a “rule of thumb” calculation so I anticipate lots of tedious experimenting and measuring inductive reactance.

    1. I used a LCR meter. It ended up being very close to the original atari yokes values so it was good. I think the deflection driver I made would be way overkill for a 5″ B/W yoke. The deflection I made should be cable of driving 27″ TV Yokes. There was a guy that built a deflection driver for a vectrex crt (which is just a BW 9″ CRT) so he could play asteroids on it. Any way he used a nice little circuit that would work better for what you want to do.
      I am sure if you knew the permeability of your yoke core and such you could get a good idea of how many windings you would need for a certain inductance, but in the real world its easier to try a few windings and go from there.

  2. I wonder if anyone has looked at the Microvision ShowWX projectors in a hacking sense? It’s a laser projector that creates images much the same way a CRT does by scanning the image line-by-line.

    The unit’s FGPA controls a tiny mirror which the R, G & B lasers shine onto, the lasers aren’t perfectly aligned to each other so to create a full colour image each line is scanned red then green then blue, with each laser having their own alignment calibration setting.

    60hz is the default refresh rate but with PowerStrip on a Windows PC I’ve managed to get them to run at up to 75hz without a problem, meaning the tiny mirror does up to 108,000 (75*3*480p) scans a second, though I usually run mine at 72hz because that’s a multiple of 24 for viewing smooth playback of film framerate footage.

      1. I was kinda wondering if anyone had hacked them to control the XY of the mirror to create a vector graphic display.

        I have a ShowWX and ShowWX+, the brightness difference between the two is quite noticable which has made the ShowWX redundant, I have had to put my own power connector on the ShowWX because I accidentally ripped the micro USB socket out of it. The only ‘hack’ I can think of doing with it is to pair it up to an old EeePC and mount it sideways to make a ‘digital movie poster slideshow machine’.

  3. The last time I tried to rewind anything with a CRT, I went back in time. It has taken me many years to get back to the days of LCD/LED. I still have decades to catch up on. When rewiring something, try not to rewind it… especially when it involves lots of power holding tubes.

  4. Seeing that built-in VCR gave me a great idea! You know what would be crazy cool? Labeling VHS tapes with the names of the individual games, with electrical contacts behind the flip-up door on the tape, so that, as each tape slides home, it opens and triggers a keypress that starts that particular game. :grin:

  5. Don’t most TVs get their HV from a flyback circuit driven by the horizontal scan? If you convert it into an XY monitor there is no horizontal scan, so do you have to replace the HV section too?

    1. Yes, you are correct. I have not built a separate high voltage circuit yet. I left the TV’s yoke connected, but way off to the side so that the high voltage would come up. My yoke was placed on the tube and controlled by my deflection board.

  6. The best part is that you could probably do this conversion with color support. Not particularly important for atari arcade games, but the 3 electron guns should still be able to light up their distinct colors.

  7. Just to nitpick TV/arcade vector CRTs (which are one and the same) and oscilloscope CRTs are very different beasts. TV/arcade monitors use magnetic deflection ie yokes. Old school scopes typically use electrostatic deflection which is why o-scopes have long (compared to their face) CRTs/necks.

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