Take a look at the section of the schematic that shows the score motor. It will show all the switches that can start the motor running. Can you post a clip of that section?

First, does the score motor take off running if you manually rotate it counterclockwise? If so, let's continue down this path. If not, we need to figure that out first.

Ok. Notice all the switches in the score motor circuit. One is "k". This indicates a switch on the coin relay that is normally open. When the coin relay "k" pulls in, it will close that switch and start the score motor running which will in turn, close those motor switches 1A, 3B, 2C. If that isn't happening. Then we need to start looking for opens in wiring or switches.

When you manually engage "k" relay, the "r" relay should pull in and stay in AND the "k" relay should stay engaged too. If this isn't happening, check the resistance of the coil for "r". I think it should be around 25ohm. Anyone out there who knows better, please correct me on this. I'm going on schematics alone.