Stepper Units

The large backbox of bingo machines contains a number of stepping switches that perform various functions. Most of these are mounted on the back door.

The Timer Unit

The timer unit has two functions. First it acts as a ball counter indicating which of the first five balls has been raised to the playfield. The adept player may notice the sound of this unit being stepped up as each new ball of the normal five balls is raised. This unit controls the tripping of selector lock, and other ball in play sensitive features.



The other function of this unit is that of play timer. After the fourth ball is shot, this unit begins to step up at regular intervals. When it reaches the top step, after quite some time, it causes the machine to tilt, thus terminating the game if the player leaves the machine without completing the game.