Try to rebuild it as Ms.Pac. So processor back on the extension board, insert the ribbon cable into the processor socket again and re-install the two EPROMs you removed. Do I dare to say that you should take great care that everything mentioned above is to be put in the right orientation ?
If it works, you are lucky and probably only the new Pac Man Eproms are damaged...
Also, you did put the correct EPROM in the correct location right ? So 5F at 5F and 5E at 5E and not the other way around....