Is WOZ Auto-Launching Balls? Check Your Switches!
Over-sensitive switches can trigger unexpected behavior.
Posted by Daniel Tonks on August 24, 2013 at 8:17 AM
Adjusting Leaf Switches
Once you�ve identified the switch (or switches) causing you trouble, chances are high it�ll be a leaf switch � and that�s good, because adjusting these is quite simple... if somewhat brutish. As it seems is the case with most pinball adjustments, you�re going to need to bend something. Sounds rather inelegant... but that�s just how it is!

Pinplay Photo #56
Essentially, a leaf switch is comprised of a series of thin metal strips. When the pinball hits either the plastic target of a standup or the rubber of a sling-style switch, it pushes two of the leafs together � thus making electrical contact. The sensitivity of such a switch is determined by the �gap� between these two leafs, and is why adjusting them is called �gapping�. There are typically a few other components, such as a stiff backer with a foam pad to absorb abuse and prevent the switch from depressing too far, but the part you want to concentrate on adjusting is the middle leaf � the stationary and occasionally shorter leaf that waits for contact.

Either bend it towards the front to close the gap and make the switch more sensitive, or away from the front to open the gap and decrease sensitivity. I�d recommend using a pair of slim needle-nosed pliers to grab the leaf securely, or you can buy a special leaf switch adjustment tool from some pinball specialty stores.

Always bend near the base of the switch, where the metal layers are sandwiched together, and not at the top or you�ll risk kinking and/or snapping a leaf. With the generic standup switch pictured above (specifically my Glinda switch, which needed to be removed for proper adjustment), you�ll notice that the pair of primary leafs are each made up of two metal components: the taller electrical contact portion, and the shorter support section, and you�ll want to bend these together as a pair.

Pinplay Photo #57
Pinplay Photo #58

A different type of leaf switch is used for The Wizard of Oz�s rollovers � and there are seven such switches in the game. These have only three metal leafs (left photo): the two electrical contact portions, and a bent/angled spring support. General operation remains the same: the clear plastic target lowers from the weight of the ball rolling over, and pushes the first piece of metal into the second, which is held in place by the third and most visible metal piece under the playfield. In this situation you�ll want to adjust the third piece so that your rollover switches are quite sensitive, but not so much that you can�t lightly brush the tops with your finger. Yet another version of these are used for pop bumpers (right photo, above), with an added plastic support arm on top.

Pinplay Photo #59
Pinplay Photo #60

There are still other types of switches used on WOZ � specifically optos (left photo) and microswitches (right photo). However, those will be left for another time...

Pinplay Photo #61
As a final note, another possible cause for unexpected ball launches is a slow return switch. This is a switch that is gapped correctly and otherwise tests perfectly normal, but for some reason occasionally takes extra time to return to its normal open state. While testing my switches I noticed that the foam backer used by JJP tended to feel a little sticky and sometimes held onto the back of the standup, which could be one reason why otherwise good switches occasionally cause issues.

In the end, I made a number of adjustments to both oversensitive and undersensitive switches, and immediately afterwards had my best scoring game ever � nearly doubling my previous high score. Mere coincidence? I doubt it, and I�d attribute the improvement to Tin Man not being so hard to collect, and both slingshots being more responsive and not allowing balls to drift lazily into the outlanes quite so often.

I hope this helps, and for now I�ll leave you with a photo of an apple-tossing tree... just daring me to play another game!

Pinplay Photo #62
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