Ok, I'll admit I'm out of my element on this one. I'm an Atari/Commodore/Apple guy, but I have this Tandy color computer kicking around and a spare Amdek Composite monitor and I thought they would make a nice pair. Unfortunately, it seems that the Color Computer (which I think is a CoCo2) only outputs RF? That can't be right, can it?

What is the generally accepted best practice for connecting a composite monitor to an old Tandy? I know I could get a TV for it, or loop the RF through a VCR, but I was looking for a more elegant solution - I'm game to homebrew if the circuitry isn't too complex.

I did some half-hearted googling, but its more fun to ask here.

2 Answers 2


The TRS-80 Color Computer 1 and Color Computer 2 only supported RF output to a TV. It wasn't until the CoCo 3 that both composite and RGB output were added - RGB being essential for the new 80-column text and higher resolution graphics.

Naturally, there are composite monitor-compatible signals inside the CoCo 2, upstream of the in built RF modulator. And some people have created custom PCB adapters to output composite. This PCB is cool in that it replaces the RF modulator in the CoCo 2 and can be installed without modifications to the computer case.

Of course, the CoCo 3 is superior in many ways, not just the video output ports and resolution. But if you have no aspirations to run OS-9 software, then the CoCo 2 is good for the native software library.

If you are more interested in making significant investment in the CoCo 2, rather than searching for a CoCo 3, then you might be able to acquire the new COCOVGA adapter. This is a much fancier video enhancer that also includes new graphics modes, more colors, and 64-column text.

  • 5
    It's worth noting that retrocomputing stack exchange regular Bruce Abbott has a design for a CoCo 2 composite adapter on his web site, which could be helpful.
    – Jules
    Commented Jun 10, 2018 at 17:42
  • A bit late but I wanted to object to this statement "if you have no aspirations to run OS-9 software, then the CoCo 2 is good" as it is not true. CoCo 2 ran OS-9 Level One perfectly well (I was a very happy user/programmer of OS-9 Level One for many years, and never saw the need to upgrade to CoCo 3).
    – tonypdmtr
    Commented Aug 31, 2021 at 21:30

Or alternatively, you could have the awesome CoCoVGA installed in your CoCo2 and hook it up to any VGA monitor. It will add a plethora of colours and other options the original never had!


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