Mobius Strip Tech has just open sourced his custom RGB board for the top-loading CDi 400 & 500 models. This board allows for the best quality output from a top-loading CDi, or potentially any CDi that utilized the BT (brooktree) output chips:
Github: https://github.com/mobiusstriptech/CD-i-RGB
Oshpark: https://oshpark.com/shared_projects/50hB7uB8
While the design is now free for anyone to use, it looks like Retro Gamer Stuff will soon be carrying them in their store. They’re also the current main sellers of the 3DO RGB kit, so they seem like the perfect vendor to carry on selling these.
Thanks again to Mobius for both making such a cool project, as well as open sourcing it!
Anyone who can't build their own – we have permission to make them and will be on our store as soon as possible
— Retro Gamer Stuff (@RetroGamerStuff) November 16, 2020