So does the step up coil fire when at ball 2 and ball 4? If it is firing, do you see the ball two light go out then came back on? If this sounds like what is happening, make sure there is no sticky stuff on the drive and stop pawl. Inspect the teeth on the ratchet gear, too.

Does this happen in both Multi player and single player? Just trying to narrow things down.

As a single player game, it is odd that it will step from one to Two but not to three.

Below is the ball step up schematic snippet. The red is the path of all the balls counting up in a single player game. As you can see, all balls are dealt with same here, only multi player is different.

So check to see that the outhole Re is energised after ball 2 drains and bonuses collected.
help.jpg

But!!, does the Outhole RE Energise after ball two? We need to find which SW is not in the right position after ball two drains. Then we can trace it back. I expect we will end up at the zero SW on one of the bonus units.

Cool!! anther working EM!!