Are all the scores reels reading zero ?

Sounds like they are as the score motor stops. Does the ball kick out and the "ball in play" light is set at "1" ?

I would start by looking at the jones plugs on the game. These are the connectors between the head, playfield and body. Look for loose connectors or broken wires. Clean the male pins with a wire brush and then check again. Also check the fuse clips that they have tension.