How They Work - Score extra step
Judging by the butchering that I've seen operators do, this is one of the most misunderstood circuits and units in a bingo.
|score extra step assembly|
So what's it do? Well, on most machines with advancing odds, it's possible for the odds to increase more than one step when a single coin/credit is played.
The gizmo looks like this thing on the left, and it lives
right about in the middle of the mixer shaft.
On games with pick-a-play buttons like the later screen games and the mystic lines games, the odds could jump two steps when the blue button was being played (in blue button play, only score advance and score-related feature enable could occur. You gave up enabling other features, and in exchange you got the scores to step up faster). Blue button score advance is not what we care about at the moment, so let's forget about it.
As you no doubt recall in the spincycle section, the scores are controlled by the score disc (or discs, for games with different payouts for different colors).
We will approach this discussion the same way we do debugging...backwards. We know that we want the score disc to step up more than once, so we start by looking at the score disc to see how it steps up.
|surf club score disc|
We see that we can power the score unit step-up coil from two circuit paths. The purple path is the normal single-step path. CU cam switch #7B closes once per spin cycle, so if we manage to get the 50V passed from the green wire through the score disc, then the CU #7B will pulse the step-up coil once to increase the odds one step.
Note that the blue circuit can also feed the purple circuit
for the first couple steps of the score disc. This guarantees
that the scores will advance at least one step for the first
two coins/credits played, because the blue wire is tied directly
to the power line up north of this chunk of the schem.
That leaves us with the yellow circuit, and it has the words "extra step" on a couple switches, so this must be the right place. We start at blue wire #71, which as mentioned above is tied directly to power (until we start playing for extra balls, at which time the #2 E.B. trip relay disconnects this circuit so the scores can't advance when playing for extra balls).
The first switch we run into heading down is the alternator cam switch. The alternator cam is a nasty little guy on the timer cam shaft. It's timing diagram is simple. It's either open or closed for the important times during the spin cycle. It's effect is to disconnect (or connect, if you are a optimist) a circuit every other coin/credit played. So this switch means that we have zero chance of the scores advancing more than once on alternating coins/credits.
Next is CU cam #6B. It's job is to keep the circuit inactive until the right time. Without this switch, the score extra step pulses could reach the step-up coil when the pulse generator is resetting.
The extra step pulse generator switch is kinda literal. It generates the pulses to step up the score unit. The more this thing closes and opens, the higher your scores go. We'll look at this switch later.
Finally, the score extra step relay must be closed. This is probably the
most confusing thing, so we'll look at that last.