My captian had the same problem. I'd start on the score motor, third stack from front, bottom pair. If, when game is ready to play with ball in shooter, pull ball, &lift play field. Then on the switch stack I mention -lift up on stack and bank should reset. If it does and coil fires strongly, then spin motor and c how well the motor closes the gap on that pair contacts . Mine had to b closed as the upper contact of the pair had lifted enough to make the coil fire wimpy, giving erotic resets.
If further chasing is required, next would b (tho I forget which) but I thnk maybe ball reset/outhole relay also has a pair of contacts on it for the drop reset motor. Mind u it's been a few weeks since I fixed mine, and it's late, so I
my memory might b a little off....