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I found an old Telerate green monitor at a thrift store and figured I could run my computer output through an HDMI -> AV converter with no problem, or a Raspberry Pi composite output signal. Turns out that isn't the case. The monitor will display the HDMI/AV converters test screen, but not my actual computer signal. As for the Raspberry Pi composite signal, won't display anything. I connected a camcorder via the camcorders 3.5mm AV output, and that did display video brilliantly. Just connected a cheap DVD player from the VIDEO OUT port, that worked as well.

Dying to use this thing as a terminal, what needs to be set in the Raspberry Pi config to make the composite output the same as that of a camcorder or DVD player, or is it impossible using a Raspberry Pi. In that case, is there another microcomputer that will display to the screen?

DVD output: DVD output

Back of the unit: enter image description here enter image description here enter image description here

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    This is off-topic because it's about how to configure a modern Raspberry Pi or how to use a modern HDMI to composite converter on a modern PC. The retro monitor apparently works fine.
    – Justme
    Apr 9, 2023 at 8:06
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    Dying to use this thing as a terminal - it's a monitor, not a terminal. Or do you mean to build a terminal, using the monitor, Pi, and a keyboard?
    – dave
    Apr 9, 2023 at 11:56
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    This site has accepted questions about how to configure emulators if the answer imparts something meaningful about the emulated computer. So I think more nuance is needed to persuade that this is off-topic.
    – Tommy
    Apr 9, 2023 at 15:12
  • @another-dave yeah, that's the idea
    – bitterlake
    Apr 10, 2023 at 6:05
  • If you're having trouble getting video output from a Raspberry Pi, the Raspberry Pi StackExchange is where you want to be posting.
    – cjs
    Apr 11, 2023 at 14:53

3 Answers 3

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It is unsure if this will help, but it might just be the monitor after all.

The termination switch on the monitor is incorrect.

It must be set to 75 ohms. It is currently set to no termination which allows loop through to many devices.

Some sources might be able to detect when a TV is connected, and will output video only when connected. Without proper termination the sources will not see a device being connected.

So there is likely nothing wrong with the modern sources and they don't need any configuration to make them work.

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    This was it. Swear I had messed with this switch while sending the video before, guess not. Interesting though, what does termination mean in this context?
    – bitterlake
    Apr 10, 2023 at 6:04
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    In short, it relates to transmission line theory of coaxial cables and thus how video is transmitted throgh coaxial cables. Video signals sent over coax are intended to be terminated by having with a 75 ohm resistor at the receiving end of the coaxial cable.
    – Justme
    Apr 10, 2023 at 7:04
  • Nice catch! That’s not easy to see Apr 11, 2023 at 12:05
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If you can see the test screen from the converter, the converter is generating a signal the monitor understands, but the converter does not understand the input from the computer.

You are most likely giving it a signal in a higher resolution and/or refresh rate than it understands, and it apparently cannot tell the computer what it likes or the computer doesn't listen. Read the documentation carefully to see what resolution you should choose. An educated guess is something corresponding to television standard resolution - that is 480i or 576i. See https://en.wikipedia.org/wiki/480i for details.

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The monitor will display the HDMI/AV converters test screen, but not my actual computer signal.

Guess: The timing for your actual computer signal is wrong, probably because the HDMI input your are presenting has the wrong resolution, or is not interlaced, or whatever.

Do you have any documentation for your HDMI/AV converter? Can you experiment with different resolutions?

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