Adjusting the Ball Trough on WOZ
Get perfect launches into the shooter lane [almost] every time!
Posted by Daniel Tonks on August 7, 2013 at 1:28 AM
Pinplay Photo #46
After you’ve unboxed and are enjoying your brand new Wizard of Oz pinball, you may come across a situation where the game randomly has trouble loading balls into the shooter lane – they seem to pop up, hit something in the exit, and then fall back down... where the cycle repeats. Sometimes this happens half a dozen times (or more) in a row. Increasing or decreasing the ball trough VUK coil strength might seem like an easy solution, but in my case this reduced the frequency of occurrences, but didn’t solve them completely.

At first, the culprit would seem to be the little free-moving metal flap that swings closed over the trough exit to prevent balls from falling out and damaging your playfield when it’s lifted into the vertical position – but this is not actually the case. The most likely cause is the thick piece of metal on the other side, the one that deflects the balls on their way up. It’s supposed to direct them safely into the shooter lane, but in certain instances balls rebound at too sharp an angle, whacking hard into the opposite side and falling back down. Now, this particular piece of metal has been adjusted at the factory to operate correctly, but since the factory doesn’t test games at the normal incline of 6.0 or 6.5 degrees that you probably have in your home, it’s possible that further tweaking is needed.

After one game where I watched my Toto ball save timer run out before a ball was even successfully served, I contacted JJP tech support and the ever-helpful Lloyd provided the following instructions (slightly edited here):

Pinplay Photo #47
Pinplay Photo #48

  1. Power off the game.

  2. Remove the lockdown bar and glass.

  3. Lift the playfield and slide it out of the cabinet, resting the support bars on the cabinet front. How far is up to you.

  4. Standing in front of the playfield, you’ll see two screws holding the apron down. Remove them. (Since mine were extremely tight, I would suggest using a socket head instead of a screwdriver.)

  5. Carefully slide the apron forwards, up, and off.

  6. The ball trough exit will now be exposed. Using a pair of pliers, grab the thick, bent piece of metal on the right side of the trough and bend it just a little bit outwards, towards the side of the cabinet, to reduce the sharpness of the angle (see photo above, on left side).

  7. It could take several tries to get this adjustment just right, and you might want to experiment with also increasing or decreasing the coil strength under “Settings: Coil Settings: Trough VUK Strength”.

    Note that you can test serving balls in the service menu under “Tests: Coils: #22 5-Ball Trough VUK”. To do this, enter the coil test screen, hit ENTER twice to switch to “Manual” mode, then highlight coil #22. Close the coin door, and press the START button to automatically serve and launch a ball. After my first adjustment, I served upwards of 50 balls in a row and didn’t have a single failure.

  8. Once you’re satisfied, re-install the apron. It goes on in the reverse of how you took it off, with the metal tabs sliding into slots to hold it down in front, and two screws in the rear. Then, close up the game.

Pinplay Photo #49

After making this simple adjustment, failed serves are now an extremely rare occurrence, and always corrected on the second attempt. This is as good as or better than my other pinballs.

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2 reader comments
My WOZ machine had that random issue of failing to load a ball when I needed to. I dreaded and dreaded because I couldn't find anyone in Kelowna to fix it. I did so much research t- that's how I know it's a common problem, and finally I found an appliance company of all things, <a href="">Speedy Appliance Repair Ltd Kamloops BC</a>, to take a look and they did because my wife knows the manager. I could have saved the headache if only I had read this article 3 years ago! Thanks so much for the tips nonetheless, gonna print this page off just in case.
Thanks for the clear writing and helpful pictures, you are doing a great job documenting a new owner's finds and fixes. Kudos!