Quoted from jgelman:

I have that machine. I wish there was a sound mod where you could hear "we can rebuild him"or "better, stronger, faster" or "a man barely alive" when you drain the second to last ball.
Anyhow, good luck on that machine. I have had a 6MDM for a long time. An easy game for people without pinball experience to walk up to and like to play IMHO.
I moved it to a central place in my home recently, and I connected the J2 backwards. It was supposed to have a polarization key so it could only connect the correct way. Anyhow, 110V went where it did not belong. That led to a loud noice and a strange smell and every light burnt out among other problems. That was repaired, and the plan is to do some LED and other upgrades.
Good luck!