First I apologize that its taken this long to get part III up. This is the third and final part of a Gold Ball transformer hack that I had to repair. I was just lucky enough to have had access to the correct parts to remove all of the hack work. In case you missed them part one is here and part two is here.
Now that I had found a suitable rectifier board, I cleaned and serviced it. The next step was to find a transformer. Poking around on the shelves I found a few that looked like what I needed. I pulled the cleanest one and took it to my bench.
As I’m about to set it down I noticed it had a Williams serial number sticker. I started to think my luck had ran out. The numbers were legible so I checked with IPDB.org to find out what game it came from, Truck Stop is the donor of this transformer.
I had forgotten that Truck Stop was a Bally 6803 system, I can’t remember the last time I saw one. The system used in Gold Ball and Grand Slam was used just before the 6803 and is the Bally MPU AS-2518-133, which is similar to the MPU AS-2518-35 and MPU AS-2518-17. A few other games such as Baby Pac-Man and Granny and the Gators used the MPU AS-2518-133. It was a weird few years of different boards and systems mixed together.
There are a few output plugs on the Truck Stop transformer, the only one I was concerned with was the large 12 pin as the other one wasn’t needed so I tied it back. According to the manual, the pinout is identical to the Gold Ball as well as all of the voltages are the same.
It never hurts to double check so I tested each output to make sure the voltages and pinout were correct. Now that I’m sure everything is good I took out the inline fuse and installed the connector and fuse wiring to the bracket on the transformer panel.
Now I can start wrapping this project up. I mounted the transformer and rectifier board on the panel and get ready to install it in the game.
Before I can begin final assembly I have to repair the wiring for the connectors on the output side of the rectifier board. The wiring had been cut and tapped into for the addition of the secondary transformer outputs.
Normally I would cut the wires and install new pins but in this case I would have to cut and re-pin all of them. That would have made them too short and taken a lot more time so I spliced them with solder and heat shrink tubing.
Remove all the added on wiring then cut and strip back the insulation. Make sure to slide the heat shrink tubing on before twisting and soldering them together.
Bend the wires so they form “hooks”, this gives them some extra mechanical strength before soldering them together. Final step is to slide the heat shrink tubing and heat it with a small heat gun.
One of the connectors had the wires cut close to the connector body so for this one I just installed new pins. It did make some of the wires short but not too bad that its not workable.
These connectors were used by Bally for pinball and video games. They are used on the coin door and control panel for example on video games such Ms. Pac-man, Galaga, and Spy Hunter. They are the Molex .084 MLX series connectors (I just call them “oh eighty four pins”), you can still get the housings and pins from distributors such as Mouser. I am working on a book that will have various part numbers for connectors, chips, and other discrete components. More on that later.
The end is in sight. With the wiring repaired and the transformer/rectifier panel ready I can start final assembly.
The last few steps will be securing everything and removing the Gottlieb transformer.
One of the problems to note is the Gottlieb transformer didn’t provide enough power for the zero crossing circuit which caused some of the lights to be dim. Whoever added it had some idea of what they were doing. I have no idea what happened to the original transformer and rectifier board. I can only speculate that it was robbed for another game.
Either way I’m glad we had the correct parts laying around to restore it to as close to factory as I could.
One thing I always stress is that repairs should look like nothing was ever wrong and mods should look factory. A little extra time to make sure everything is done correctly will pay dividends for years to come with reliability and peace of mind knowing you won’t have to fix it again. One thing that keeps me up at night is quick sloppy repairs, there’s never an excuse for it.
Another reason for taking time to make sure all repairs are clean and neat is when time comes to sell your game. If a perspective buyer, especially someone who knows what they’re looking at, sees sloppy hack work they will low-ball you or even pass. All of this is making a sale more difficult.
Thank you for your patience on this last part of the Gold Ball post. Check back soon for more tech tips and repair info!
Gottlieb Systems 80, 80A and 80B battery boards now available!
I now have a battery board for the Gottlieb systems 80, 80A and 80B pinball machines. This is a direct fit part, just remove the old Varta or Data Sentry battery and solder in your new lithium coin cell replacement. Built in blocking diode prevents unwanted battery charging so no additional modifications to your board are required. Get yours here.