Check the fuse under the playfield - near the ball trough. Should be 1 or 1.5 AMP SLO BLO.

With the sound - Check the volume control knob and that the connector near the volume control is pushed in correctly. You should hear static when you turn the volume up. Also, check the ribbon cable from the MPU board to the sound board. Refit the connectors, and make sure they are aligned correctly (pin1 - pin1 etc).