Ingenious. I think I understood most of that when I managed to turn on automatic English translation. Those transistors (4:24) look a lot easier to source than a good AD725 for cheap, there seems to be a lot of spurious Chinese fakes of those around, which give bad colors. At least with this circuit you can adjust values of resistors to get the color good. I have a genuine AD725 and was going to try something similar with it, but when I looked up availability for other people to be able to make the same thing, I discovered all the problems with the fakes.

At first I thought you were going to do something like the graphics gremlin https://hackaday.com/2021/05/18/retro-isa-car … heavy-monitors/ or the VGA in 74 series https://hackaday.com/2021/04/30/vga-graphics- … -in-74xx-logic/

This may be useful for me as I have two PCs that have built in CGA graphics and cannot use a CGA card with built in composite output.

Yes, the youtube translator does what he can, even trying to speak neutral Spanish, for Argentines it is difficult jaja, we speak Spanish with an Italian accent, we sound imperative. It is difficult to bring things from outside, like the AD725, I have one to do the experiment, but it is difficult for the boys to get elements, so I made an XOR logic for the synchronisms, and it worked well. Few CGAs arrived here, there are, but they are all in the hands of collectors, I have a couple, but they are not abundant, many during the 2000s ended up in the garbage, like millions of XT. today they are rare. I wanted to share it with you because over the years I have read a lot of interesting things on your forum.
PS: I'm going to manually correct the subtitles, I have another video about lifting an XT with zipdrive and they are corrected by me.
regards

Interesting. I built the Graphics Gremlin and it seems to work nice https://www.8bity.cz/2021/dyi-pc-xt-mda-cga-c … ith-vga-output/, also the composite output does the NTSC color tricks with LSL...