I have this exact same problem with my Japanese Megadrive + Mega CD (model 1). It plays audio CDs fine, but when trying to load a game it just keeps playing the bios screen. I have fully recapped both consoles and even changed a new laser to Mega CD, but still same problem. I measured CD-unit flat cable that all the threads are working. Must have something to do with data line :/ Did ViciousTengu or any one else solve this problem? And I have a US region free BIOS installed, but tried Japanese region free too with my MD everdrive.