@caius is one century ahead of everybody on the design and reproduction of custom arcade chips.Already decapped and reproduced by me a whle ago.Sorry, you are too late
Anyway, your schematics are wrong and not acccurate.First of all, pin 9 is tied to +12V on PCB and not +5V.Then, there are hidden film printed resistors and you didin't include them in your schematics.Then, how do you think to power the NJM4560 OP-AMP if there is no positive voltage applied to pin 8 but only two capacitors with their negative terminals connected to GROUND?
tested and verified by me!Already decapped and reproduced by me a whle ago.Sorry, you are too late