Going by memory, so be aware. In the back box, there should be a relay for the 1, 10, 100, and possibly 1000 points. With the machine on, simulate each of those relays closing. The score reel should increment and the chime should sound.
If not, then check those contacts on that relay.
The 10 point relay can energize from the playfield or from a switch on the score reel when going from 9 to 0, same for the 100’s, 90 to 00, etc.