Hi MarkG
good topic, good post-1. I fully agree. Think of "Humpty Dumpty ... Space Walk" - evolution, advancement. It is hard to make a machine foolproof - it is impossible to make a pin to run under any condition. Over the years the engineers did a lot of work to handle the silly / strange things "players did at the arcade times" - like pressing the Start-Button when the pin in play is busy giving 500 points (and so the motor is running to help making the 500 points - at that time the motor cannot do a complete startup). My Ice Revue (1965) is wired the same as Your Sweet Sioux.

To stick to the problem --- Coin-Reflectors were invented - and the Coin-Lockout-Coil (should be called STOP-Coinlockout-Coil (thats its functionality)) --- I have seen it in late Bally pins - whenever the motor runs: This Coil moves its armature (back) so temporarily Coins are reflected. JUST BECAUSE some people at the arcade times were so stupid to throw-in some coins at times they should not.
(((When I study an schematics and I do not understand "what is this switch for" - it usually is for to handle "extraordinary situations caused by weird behaviour of players". Greetings Rolf

Hi astyy
do You know the lovely feature on Bally and Williams pins "pressing the left flipperbutton turns on the Playfield- and the Backbox-Lights" ? These pins may look toggled-off / unplugged --- but they have current to the transformer - they come alive when pressing the left flipperbutton / throwing-in a coin - they may need an operater-note on the pin "Out of order" (so people do not throw-in a coin). So some people "had this idea with later games". (((In the arcade times walking up to an unlighted Bally / Williams pin: I always tried the "left flipperbutton feature" - if it did light-up I then threw-in a coin. I only did throw-in a coin on an Gottlieb pin when it was lit - at least the Tilt-Light in the Backbox.)))
What model is Your Bally EM-Pin ?
In the arcade times all Servicemen knew "motor must be in Home-Position for to minimize problems" --- they turned the motor manually or they did the "throwing-in a coin" trick. Greetings Rolf