Anyone in the Chicago area know about supergun's

Anyone in the chicago area know about supergun's, I need some help. I need someone to check mine out, and try to make it better, I can pay someone to check mine out, and see why I can't play this mk2 board that I have.

Mortal Kombat should have -5V and requires a sound board. What kind of Supergun do you have? If it's a Nova or HGA it should be plug and play aside form the extra button connector
Check hardmvs for the -5 connection in the project section.

edit: link http://hardmvs.com/html/neg5volt.htm

MK 1+2 also require a power cable for the sound board- but the game would display a perfect picture without it.