Hello there. This is my second post about a Zip-A-Doo pinball machine that I just purchased. This is my first pinball machine and I am hooked. It is way cool. I have three questions. First is there somewhere that I could find out about the game-play on this machine? Like what gets you a free ball, etc? That leads to my second question in that it seems like a player is often given many chances to play the same ball. Sometimes you can play your ball 2-3 times before it advances to the next ball. I took the cover off and I can drop the ball directly into the hole where it is returned and it will keep popping back into the shoot tube without the ball number advancing. I do not see any pattern to it and the free play light is often not not lit up when the player gets to play that ball again. Is there a setting or a particular sensor that controls the ball advancement? Lastly is there a suggested way of refurbing the various devices in this machine. It is entirely electro-mechanical and I have already had to file some of the sensors on some of switches as they would get stuck. Any help or suggestions would be greatly appreciated.