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How do I get these Crts to display an Image? (lemmy.ohaa.xyz)
submitted 1 year ago by to c/askelectronics@discuss.tchncs.de
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I recently got a bunch of old 80's crts which I cant find any information about online.
I do have the service manual tho link
Looks like standart composite with external Horizontal and Vertical Sync to me but I'm not 100% sure and I dont want to fry anything

Thanks,
Oha

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[–] [S] 3 points 1 year ago* (last edited 1 year ago) (2 children)

While I know(at least to some extend) what I'm doing, I still appreciate the warning. The Monitors.only interface seem to be these Pins labeled J1 in the Manual.
Heres a picture of the entire Board in case that helps:
(I know, that brown discoloration looks horrible but it still generates high voltage and makes that high pitched crt whine)

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  • [–] 2 points 1 year ago* (last edited 1 year ago) (1 child)

    A3.2 and B2.1 in the manual show you the pinouts of that jack and the expected signal, unfortunately section 6.1 schematics and sec D timing diagrams seem to be missing. You’re going to need to find a suitable driver circuit. Without looking at the timing it might accept input from an old MDA adaptor or similar.

    https://en.wikipedia.org/wiki/IBM_Monochrome_Display_Adapter

    Edit: While this in behind a paywall it looks like this old article has a circuit for composite to TTL monochrome that would be what is needed.

    https://www.elektormagazine.com/magazine/elektor-198812/47485

    This one is from the 1980s itself and there also seem to be a lot of TTL to composite circuits out there that use fairly modern (and a lot fewer) components so with a bit of looking you might find a modern composite to TTL driver circuit. Look at the retro computer and retro arcade game forums, etc.

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