Rather than re-write the excellent guides on the sites above, I’ll just produce PDFs with some additional notes for now (of course giving credit to the original author)
Sept 2012, the Stereo mod has been updated with a new circuit to amplify it to a more suitable level. I’ll add my photos soon showing how I interpreted MKL’s diagram :-)
July 2020, last time I made a CMVS, I used a PCB to get the proper RGB and Sync signals, check out philnotfound on GitHub.
Here’s my finished CMVS, not as pretty as some of them out there, but not bad either!