Ok, this is a new one for me. When playing Monopoly the game will randomly kick a ball out of the trough and put it into play while a ball is already in play. It does not advance the ball count and when one of the two drains it does not stop play. It may be coincidence, but it seems to mostly happen when a shot to the "Roll Dice" is made.

My son also said that during Land Grab the machine indicated a coil failure. From what I read I could have a bad opto in the trough. Could this also be the problem causing an additional ball during play? Thanks guys!

Bump. Have the day off today, so trying to troubleshoot.

Thanks guys! You were right. The emitter opto had bad solder work on the pins. You could put pressure on the pins and the lights would go out. I took both opto boards off and reflowed the pins on each. Works perfect now - thank you!