dont have that pin, but would suspect if you can get 5 points consistently, the score motor is not at fault. but it cud be...
I believe there is a 500 point relay that holds the 100 point relay for 5 pulses.
it may also be in the bonus unit??
or maybe the player unit if it has one.
just a guess. but if you went through some of the relays and got some things workin, go through the rest of them, and you will prob have it all workin???