First stop: Rectifier board connectors.
Second stop: Solenoid board connectors.
Third stop: MPU J4 connector.
The game will not be dependable until at least these are rebuilt, both sides, headers and pins.
Then the filter capacitor on the Solenoid board.
Then perform the self diagnostics, including switch tests to see if any problems need to be addressed...like all the rest of the connectors.
Did I mention connectors?