I know rolf is a lot more experienced than I am but I do have an 8 ball, and the ball switch in at the top of of the ball guide lane upper right of machine. that is what deactivates same player shoots again. that wire leads to the extra ball relay located on the bottom of the pf or when you have it open and raise the upper left corner. I believe its the very top contact that engages for sameplayer shoots again.
HTH