Not sure you fixed your problem. I just restored a Bowling Queen and went through every switch and relay. First check that one of the wire forms on any of the 12 rollovers is not stuck. Then as Boatcat said check the switches on the associated relay. Look at both relays involved in advancing a backbox ball. 1. The G Relay (Ball Rack Advance unit) with 3 normally open sws on this relay. 2. Also check the P Relay (Series relay) with 4 normally open sws. Specifically the Red-Gr wire sw on the P relay.