The revision 2 02-01 mainboard is currently the only one of my two Aiwa mainboards passing power through to the Game Unit section.

That makes it extremely useful for cross-testing.

I can connect both Game Units to the same comparatively functional host board, including the unit whose Mega-CD BIOS I previously removed and socketed.

If both Game Units behave on this mainboard, that helps separate faults in the Game Units from faults elsewhere in the boombox.

At this point I suspected the missing power path on the other mainboard might involve a switch, but I was still investigating and had not confirmed that.

Finally, having two broken Aiwas is starting to become useful.