
Introduction
A friend called me about his Stern Roller Coaster Tycoon pinball machine and wondering if I could repair a few problems with it. The owner stated the following problems:
- Error message stating missing ball even though there is four pinballs in the machine
- Right flipper sticks
- Right sling shot is dead
- Left sling shot machine guns
Fixes
The first problem that I looked at was the missing ball error. I figured this was going to be an opto problem in the ball trough, but ended up being wrong. When the machine was in diagnostic mode, I checked the switches and noticed four switches were not working.

This was the clue that I needed and then started to check the white with a blue trace wiring. What I found was a broken wire on the mini flipper stand up target. This also fixed the third problem, right sling shot dead, along with two other switches that didn’t register.
I ended up rebuilding both bottom flippers as the coil stop had flattened along with some slop in the flipper link. This also gave me a chance to use my Coil Sleeve Remover, and did a super job. This fixed the second problem on the list.
Right flipper Flattened coil stop Worn out flipper plunger Coil Sleeve Remover Coil Sleeve Remover Flipper kit Sloppy link
After adjusting the leaf contacts on the left sling shot, it no longer had a machine gun affect.
I noticed quite a few bulbs were not working and thought it was going to be a row or column issue, but ended up just being bad bulbs (or loose connections). I also had to replace two flashers. Finally, cleaning and waxing the playfield completed the repair.

Conclusion
This ended up being fairly straight-forward repair and glad to get it back to the owner. I have played Roller Coaster Tycoon a few times in the past, but nice to have one in shop to repair. It’s been a while since I have had a Stern Whitestar (NASCAR) in for repair. This also gave me some time to put some games on it 😃. The ramps are pretty interesting on this game and its definitely a kid-friendly game. More information about the game can be found on IPDB.