There a small PCB under the playfield - soldenoid expander board - remove and check for dry joints. There is also a 555 globe in the vicinity. If that is not working, then you will have strange issues like this.
Second thing to try is to reseat the connectors to the Solenoid Driver and MPU
Third thing to try is reseating the PIAs on the MPU - U10 and U11.
You can run a simple test with the game on - the "test" button on the front door. Cycle through to the solenoid test and check that each solenoid is working during test.
