Look for something common to them. Broken wire, loose connector.

LTG : )

Check connectors on rectifier board.

Not all the playfield lights just some? There is a solid blue wire that solders to the switched lamp bus on the playfield. I'm guessing it came off. Trace the bus wiring on all the lamps that are out. Somewhere along the way a blue feed wire should be attached.

On some EBD games, not sure if this one is included, there is a single isolated bulb on the lower part of the play field that has to be working in order for the accessory lamp board to receive voltage. I can't remember which side, but this could account for your problem in some games.