Notice all the open switches on the schematic up by the Motor 1C switch. If any of those switches closes, even momentarily, the score motor should start running. W, C, D, E, O, Q, S, U, SB1, SB2
W = 2nd Chute Relay
C = Add Bonus Relay
D = 500 Point Relay
E = #8 Hole Relay
O = Ball Return Relay
Q = Ball Return Control Relay
S = Start Relay
U = Control Bank Reset Relay
SB1 = Reset Control Relay (in reset bank)
SB2 = Reset Control Switches (also in reset bank. no coil associated with these switches)
All of these are normally open, Any of them close and the score motor starts turning. The motor is kept turning by the Motor 1C switch until the motor reaches its next home position.
There will be multiple switches in these relays. You can use the schematic to identify these switches by wire colors. All of them will have Brown with Red Stripes on one side and Red with White Stripes on the other.
All that being said, You have manually triggered a few of these relays already and the score motor has never started running. I suspect the fuse is bad.