Okay it seems like the issue was resolved on the newer version of the board!
You can see on the newer boards the +5V has a link to the CYSNC and the component values have been updated also.
Hope this helps someone else as I’ve been scratching my head for a long time.
Shit it's saturday: This board is so simple to assemble that you can solder this while being shitfaced. Stupid easy simple sega amp designed by @Voultar. Works on SMS, Genesis 1/2, Sega CD and more! Provides a cleaner image and bypasses the cxa1145 encoder and more! pic.twitter.com/fNjTiZnyLh
— iFixRetro (@iFixRetro) August 4, 2018