Quoted from MarkG:
Can you elaborate on the problem? After ball 1 drains, it serves up another ball but doesn't reset the targets and doesn't advance to ball 2. But then you say it does the same thing on ball 2. How do you get to ball 2? Is the behavior the same on a 1 player game as on a multi player game?
What should happen is that when the ball drains it gets kicked into the shooter lane. On the way to the shooter lane the ball closes the Trough switch which should fire the P/Add Player Unit relay. Switches on the P relay should in turn fire the Player Unit 1-3 times (depending on the number of players) and reset the target banks.
What are your P relay and Player Unit doing when the ball drains?
It looks like the issue is that when the ball drains and enters and operates the ball return switch, the ball immediately fires into the shooter lane and on it's way operates the trough switch, so the "P" coil and Player Unit never operate because of how fast the ball gets shot into the shooter lane, this is the failure mode during the initial ball, the bonus unit runs and stops maybe in the 8th,9th,10th, etc position and never gets reset, all drop targets stay down and they don't reset, the 2nd ball is there waiting in the shooter lane, if you play it everything resets as normal, which I think is due to the fact that the bonus unit is already near the end of it's travel and it gets reset as normal, all targets reset and life is good. This scenario happens with each of the 5 balls. On the first ball of each series I can drop some targets manually then push the ball return switch manually, the P and Player Units operate and the bonus unit runs to it's stopping point, if I then push the trough switch everything works as normal so it appears to be a timing issue, the ball is shot into the shooter lane way too fast.