HELP - Video Issues Super Mario Arcade

[pborneman]

Hello all! New here and hoping you can help.

I inherited a super old and beat up super Mario brothers arcade the other day. It's an old Donkey Kong Jr. cabinet that was switched to the unisystem vs Super Mario Brothers. When I first got it I plugged it in and everything seemed to work (minus the sound). However, the plug was missing the ground so I replaced the end of the plug. After that it worked fine for a day and then suddenly stopped working.

When I turned it on the screen would just turn gray and nothing would work. I checked voltage at the game board and wasn't getting any voltage so I assumed it was the power supply. I upgraded the power supply and fired it up (without connecting the game board) and checked all the voltage and it was good and the monitor turned on. However, when I plugged the game board in the monitor just goes black and I have no picture. I checked the voltage at the game board and I was getting the appropriate 5v so I am not sure what else it could be at this point.

Can anyone help provide me suggestions?

[mourix]

Are you sure all voltages and grounds are on the connectors, and they are put in the right way around? According to this pinout.