Monthly Archives: September 2018

The Lost World Jurassic Park Pinball Machine (Sega,1997)

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Symptom: Snagger releasing ball too early, or not lowering enough to grab ball.
Location: Lakewood, Colorado

The snagger mechanism on a Lost World pinball machine uses both optos and microswitches to determine the ends of travel.  Or more accurately, the microswitches are wired in series with the motor to cut-off the power when at one end or the other. The game MPU has no knowledge that this has occurred. The MPU instead uses the optos to determine when it is at one end or the other. So the microswitches are acting as safety switches to stop the motor if the optos fail or are unplugged, etc. The game code also has a timer to flag an error and disable the snagger if it doesn’t reach one end or the other in the allotted time.  When using the special test function in the Diag->Lost menu, the display will show the status of the optos, but relies on the switches to stop the motor at one end or the other. But during game play, the optos are used. So adjusting the switch levers had no effect.

Over time, the gears and belts develop mechanical play or slop. The original designer never accounted for this. The only adjustment is the center of travel, basically the flag that interrupt the optos. This can be loosened, rotated, and re-tightened on the motor shaft.  One could also loosen one of the pulley screws and accomplish the same thing. But this only adjusts the center of travel. If I adjusted it so that the ball would release and fall into the Jeep properly, the snagger wouldn’t lower far enough at the other end to grab the ball. If I adjusted it to grab the ball properly, it wouldn’t raise far enough and the ball would release on the edge of the Jeep and just sit there.

The largest source of play is the cam on the left side of the last hinge of the snagger.  As of this writing, Marco Specialties sells the shaft and the end housing of the snagger.  I wasn’t able to remove the last pulley due to damage of the set screw, so replacing it wasn’t an option.

What is really needed is a way to move one of the optos so that the motor runs a little bit longer to account for the slack in the mechanics.

I removed one of the optos and with a very small Dremel bit, created slightly curved slots for the opto leads in the circuit board. This would allow for the opto to be adjusted.

Showing new position of opto before final adjustment in the machine.

Added wires to leads to allow for movement

After determining the ideal position for the opto and adjusting the center travel (as mentioned above), I put a little drop of hot-glue on the top side of the board at the end of the opto to hold it in place.

The snagger now works perfectly.  Not the prettiest solution, but sometimes things need a slight design tweak. If there were more Lost World machines out there, I’d design an aftermarket board that would make this a lot easier.

Wizard of Oz Pinball Machine, Jersey Jack (2014)

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Symptom: Version 2.0 LED Board replacement project
Location: Parker, CO and Highlands Ranch, CO

[This post has been updated to reflect the 2.0 Light Upgrade Kit shipping in the Fall of 2019.  The kit contains improved instructions along with a check-off sheet to make sure your kit is not missing anything.]

The Wizard of Oz (WOZ) pinball machine was state of the art back in 2013/2014.  There were many things about it I admired, and the biggest standout was RGB LEDs used everywhere, including the lowly general illumination. Previously pinball machines had fixed colors for their lights.  On this machine every LED can be individually controlled to be any color.

However, with time, the lighting system has proven to be problematic and there were several attempts during production at making it more reliable. It’s a situation that didn’t become apparent until machines were built and out in the real world. Many people suspect the problem is static electricity building up and damaging the LED driver chips. All of the LED boards are in a serial chain, and if one of the boards in the chain fails, every LED downstream will no longer work correctly.  Often when the lights are malfunctioning, it can be traced to a single board that has failed. The bad board can be bypassed by moving cables and updating the settings to let the software know a board has been bypassed. If a replacement board is available, the bad board can be replaced. If a replacement is not available, you’d have to wait until JJP decides to make more, or upgrade to the 2.0 system.

There are now 4 generations or versions of light systems for this pinball machine. The first three are all controlled with the serially connected signals as mentioned above.

  • The original system used in machines built prior to September, 2014, is often referred to as “5 volt unbuffered”.  This is the least reliable system.
  • There is a later system referred to as “5 volt buffered”, where the serial control signals are buffered with a driver chip.  I was told by a person who works at Jersey Jack Pinball that this is the most reliable of the serial systems.
  • There is another referred to as “7.5 volt”, which uses a 7.5 volt power supply rather than 5 volt. The serial control signals are also buffered.
  • And finally there is the “Version 2.0” system, which uses an entirely different LED control scheme and is the system used on newly-built Wizard of Oz machines, as well as The Hobbit and Dialed-In.

What follows are some tips to anyone who is upgrading to the 2.0 system.

It’s not a trivial task to do the upgrade. In a nutshell, you’re replacing every LED board (there are 48) and the associated wiring. Most of the boards will need new mounting holes drilled and use different screws than the original boards. This includes removing the two mini-playfields and replacing the boards used on them. Depending on your experience, mechanical aptitude and patience, you should be able to do the upgrade in 8-12 hours.

There were 29 pages of printed instructions provided with the kit. This includes a listing of all parts in the kit and a photo of each part, which is a great improvement over the earlier kits. It’s very important to inventory the contents of the kit.  It will familiarize you with the parts and you can take care of any shortages before starting the project.

Unfortunately, as of this writing, they still don’t provide L brackets for mounting the new power supply to the cabinet and you will have to go to a hardware store to purchase them.  You’ll also need some M4 x 6 machine screws to mount the L brackets to the power supply. In the past I’ve used 1″ brackets and it’s possible 3/4″ brackets will work.

Personally, I like to do steps 9 (installing brackets onto light boards), 15 (installing BAG controller to bracket) and the first part of 17 (attaching cables to the power supply) beforehand.  Hold off on the last part of step 17 (mounting the power supply) until you get to it because you’ll be using screws leftover from earlier steps.

Diagram of positions of light boards next to playfield.

Another personal preference I have is to print two copies of the light board placement from page E20 of the WOZ manual on 11×17 sheets of paper and tape them up on both sides of the backbox.  It is important when installing the new smaller boards, to put them in the orientation as shown or else the cables may not be long enough to reach them. Plus it is handy because each light board is referenced by a number in the blue circle.

The most time-consuming aspect of this project is each GI or single RGB LED board has different mounting holes than the original boards.  There are about 38 of these total, which translates into positioning, marking and drilling pilot holes for the new mounting screws on all three playfields.

This is optional for the user who is only doing this upgrade one time: I used two mini rechargeable drills; one to drill holes, the other to drive the screws.  This is easier than constantly changing bits.  I used an extender for drilling due to having to drill around wiring harnesses and playfield support rails. For the screws you will need a #1 Phillips bit, which are not as commonly available as the number #2. Also when driving screws, set the clutch to the lowest setting to avoid damaging the screw heads or stripping the hole.

Drill with bit extension to reach tight areas.

In step 4, place a piece of tape on the end of the cable and label it with “Step 26”.  It will need to be re-routed over to the W7 board in the lower left. By placing a label on it, you’ll be able to find it later and not to forget it.

Another personal preference is to do the mini-playfields (steps 24 and 25) before step 17, and get all of the light boards installed before diving into the cabinet and routing all of the new cabling.  Just be sure to check off each step so that you don’t leave anything out.

Other than the tips above, just follow the steps provided with the upgrade kit and eventually you’ll be finished.