If anyone knows where to start looking with this issue please feel free to let me know.
Also show us a photo close up of the battery area on the MPU as you may have corrosion issues if it's having a mind of it's own. And make sure the ribbon cable is not resting on the tube, route it round the outside of the tube holder.Read cooldans post on similar issue , think I just need a new power supply board … the x pin type
Fairly normal for replacing the burnt out connector on these games. Just tightening the choc block screws may resolve your issues but replacing and restoring to how it should be would be the best way forward.Additional, the original board seems to have had a mod done to it ?