I am working on a King Kool (1972 Gottlieb) machine, I have gone through the entire game--cleaned and adjusted everything and the game plays. The problem is that the player unit is missing steps and therefore does not keep the ball count correctly. In a single player game, after ball one drains (having scored), the player unit only steps twice, rather than the required four steps. The next ball steps the player unit once when it drains, likewise for ball three. Now ball two in play shows and the sequence repeats. A two player game works correctly switching to player two but then only takes one step instead of three when player two's ball drains.

I have read many of the threads that relate to the player unit and understand the intended sequence and the various 'paths'. I have rechecked all the associated switches, even taking out the player unit switch stacks to check for bad contacts. One thing that I do not understand is how the 'P' relay stays closed long enough for all four pulses since it is only closed by the passage of the ball over the trough switch (I do not believe there is anything else controlling it). I have, however, held the relay closed by hand and the problem still exists.

Thank you both for your posts. I now have the player unit working properly (although I'm not convinced I know what I did!).

Rolf--In a round-about way your comments about the bonus unit reset got me on the right track. It wasn't until after I had it working that I realized that the comments about the bonus unit were just an explanation of why the 'O' relay goes twice (I had figured out that that behavior was normal). Even though I could not see why it mattered (from the schematic), I cleaned the bonus unit zero position switches again. Now the player unit worked. I did realize later that since the last time that I had tried a game, I was checking the score motor again. I suspect that what I may have done is to make the 2B contacts work. Until reading your notes I had not realized the role of that switch. I have now also cleaned those switches again, just to be sure.

Thanks again for your help. Although I have worked on many EM machines --I still come across new challenges and expert advice such as yours is always greatly appreciated.