[mclingo]

so it goes black when you are playing, not when you are stopping?, ok that is odd, it suggests you are sending something to your projector it doesnt like, perhaps you havent properly setup 23p modes and you are sending a 444 ful RGB 4k 60hz signal to the projector, it wont be able to show that.

drop your desktop to 4:2:0 10 bit mode until you've got this sorted out, this will ensure max compatibility with your kit and cables.