I have a Mortal Kombat 4 board that I'm having issues with. I had someone hook it up to a supergun and whenever they tried to power it on they would get I buzzing sound from the board and that's it. He tried it it a couple times with the same result but didn't want to push it and ruin the board. There doesn't seem to be anything missing or broken on it and it's very clean. I'm just getting into arcade games so I'm not sure what's going on. Any help would be appreciated. Thank you.