In the manual there is no schematic, just the Jamma pinout (or you want to use JVS).
interesting that pinout looks very different than what was mentioned earlier with buttons 1-3 mapped normally and button 4 on the kic harness, this has the 4 buttons place of the joystick, which honestly makes more sense for this game.
I suppose it's possible that outputs are supported by JVS, I wonder if there is any mention of output testing in the game test mode.
But the way I figure how the buttons would work is that they get permanent 5v or 12v and the ground is connected to the micro switches, so when you activate the microswitch the button light up as it then takes ground via the switch
I don't know about that, when the button is not pushed the lamp would be trying to draw off of the game board through the button connectors, that seems like it would risk blowing out a buffer on the game PCB.
How much are the original OBSA buttons? Or do they come in both flavours 5v and 12v?
they come in many different configurations 5V, 12V, 24V, incandescent and LED. the ones at Sophia Corp are 12V incandescent I believe.
EDIT: I just loaded this up in MAME and interestingly the joystick AND the buttons are mapped to the buttons. So you can use up, down, left, right, or you can use buttons 1-3 on the JAMMA edge plus button 4 on the kick harness... either works.
there doesn't seem to be any lamp output options in MAME but the JVS options are disabled because there is no JVS IO connected. does anyone know how to connect a virtual JVS IO for System 12 in MAME?