BINGO PINBALLS

 

Techno Stuff
How They Work - Timer Unit

Ball Count

timer circuit
surf club
timer step-up
Right, let's clear up the timer unit's role in counting balls. Basically, it doesn't. It does inhibit the first ball from being raised to the playfield as discussed in the ball lifting section, but after that, it pretty much passes 50V to the ball lift motor all the time. On the pic of the unit, this happens when the wiper marked #91-1 is connected to the rivets marked #38-3.

On Surf Club, the timer unit is reset in two ways (red circuits):

  • by switch 6C on the shutter motor, which closes when the shutter panel opens. This reset circuit is suppressed when the hold feature is being triggered, since at that time the shutter opens but the game is not being reset.
  • when the shutter is closed and the control unit timer cams operate, the timer unit is reset via CU switch 5A. This happens when extra balls are being played for.

Once the unit is reset, it is stepped up by a switch on the ball lifter motor cams - for the first four balls. As shown in the green circuit and the wipers on the contact plate pic (wiper marked #23-3 and rivets 43-2), when the fourth ball is raised, the timer unit step-up now goes through the blue branch circuit (rivet/wire #85-9). The way the box is drawn and numbered on the schem actually reflects what is going on. The numbers represent balls, so the top part of the green line is moving to the right as the timer unit steps up.

We also see another set of contacts numbered 2 and 3 in the right side of the box on the schem. The wire leaving the box off to the right is heading to the shutter motor. So when ball #1 is shot, ball #2 is raised to the playfield and the timer unit advances to step 2 which sends 50V off to the shutter motor. Why 50V is also directed to the shutter motor at step 3 I don't know. A switch on the shutter motor open when the shutter panel is closed, which happens at step 2. I suppose it prevents a race condition that can occur if people are shooting the balls fast, but that seems a little unlikely to happen.

Another question is why is the blue circuit there? Well, here is where the timer unit is not really counting balls, because it can't step backwards if a ball goes through the return hole to be shot again. The timer unit cannot step up past the fourth ball position until the selector lock trip relay is tripped. So what? Well, the selector lock trip relay is what turns off the ability to manipulate the spot number/magic line feature, and turns on payout.

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