Still not permanently fixed in place but the RGB socket is there from the TMS-RGB on my HX-10 #MSX. Plug in the Megadrive2 #RAD2X and I have a clear HD output.

So I've given the TMS-RGB with #Sega #Megadrive2 video port a permanent home in my #Toshiba HX-10 #MSX. It's still off and needs some more work doing but with the #RAD2X fitted it is a fully working HDMI output MSX.