I have that happen to a lot of boards.
Some I have fixed, some I haven't. Most of the time it's a chip going out or if you are really really lucky, it's a simple connection problem.
There are dozens of sites that can give you tips on how to fix this. Google for "PCB Board REPAIR Tips".
In a nutshell, if it's doing something screwy, try testing cleaning all the connections to the board. See if it has the proper voltages going to it. Clean all of the contacts, and if you are bold go and reseat all of the little chips that snap in.
After that, if you have issues, you need to go further and use a logic probe and hope you can find the defective chip with it. You need to have a power supply and some time and patients. Once you find the chip, you can replace it and fix the board.
If all of that seems like it's too much, then you can hire the board fixed by checking RGVAC group or some other net group. They always have people (as mentioned above) that will fix the board for you for various prices.
If this is ALL too much, buy an Xbox

Cause keeping these old arcade machines going is getting tougher every year as they age.