This is a redrawing in KiCad of the original IBM CGA card schematics. I intend to use these to help me repair original boards and build a clone.
Original picture under CC BY-SA 4.0, found here
Help in double checking and finding issues is appreciated: you can find the original manual here, see pages 32-37.
I used this schematic with kicad to build a clone (CGA Redux), which apparently works fine.