Hi Mark - Do you have the schematics ? I have the game, but not the schematics. Player Units in GTB 4 Player games is where 90% of the problem come from. Check each relay in the game and make sure they can all be manually set and reset. Look for any contacts that have moved (leaf contacts) - I'll see if I have a GTB 4 Player schematic handy. I can't recall the bonus feature is a stepper or Relay.