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 Extra Ball Unit

All bingos having an extra ball feature have another stepping switch in the backbox called the extra ball unit. This stepper is advanced pseudo-randomly during extra ball (yellow button) play, the depositing of extra coins by a player attempting to obtain extra balls to play.



This unit has ten positions, the first being reached when the yellow button is first pressed indicating that the player wants to try for extra balls and lights the "extra balls" light on the backglass. The next nine positions light in turn, the other extra ball lights(first, extra, ball, etc.) The first two lights for each ball are teasers trying to tempt the player into trying again. When each extra ball is attained disk contacts on this unit, in conjunction with the trough switches in the ball trough beneath the playfield, control the raising of extra balls and their re-raising if one should fall into the ball return hole at the bottom of the playfield.