Wouldn't the upper flipper optos be used to enter high scores and change the roll over lanes in CFTBL?
Don't have a CFTBL myself, but I know on a mate's WCS94 (2 flippers), the 2nd optos are used to move the lit roll over lanes and for the high score entry.
The WCS94 would only register the 2nd opto if you pounded the button, so that during a game the button wouldn't get pressed hard enough to trigger the 2nd opto and after a few games, the machine would decide that it was broken and chuck a credit dot. You could clear the dot everytime by pounding the button.
Fixed by carefully bending the opto interupter a little so it cleared the 2nd opto.
