Identifying Your Problem

Working on a pinball machine has two sides. Diagnosing the problem and fixing the problem. The latter, “fixing the problem” is actually very easy. The most skill and work comes when diagnosing a problem. For instance, a particular target is not scoring any points. You have to ask yourself, “Is it the target itself not registering when it is hit?” “Do I have a wire broken or a cold solder joint not allowing electricity to pass?” “What if the issue is with the motherboard and even though the target is sending a signal that it is hit, the motherboard cannot determine what to do with that information.”

You find yourself following that path of electricity. From start to finish, you must have perfect continuity. Meaning electricity is traveling where it should, when it should. We use tools such as a multimeter, to determine if electricity can pass when it should, or if it is passing through when it shouldn’t. This is an invaluable tool when it comes to working on pinball machines.

In the case mentioned above, I pull this from a previous game we did here at Deep 6 arcade. The game was Bally’s 1981 Flash Gordon. Theme from the 1980 Universal Studio’s Flash Gordon movie.
The issue was that some targets were not working. The issue was tracked to one of the trickier problems, the “molex” connectors that attach the wires from each target to the motherboard (The brain of the game). See, these connectors have metal pins inside a plastic plug. When you move a game, these wire are all disconnected so the game can be taken apart and moved in an easier way. For the first decade, this is not an issue. Even for the next two decade, you may never have a problem with these. However, here we are in 2021 and these have been plugged and unplugged so many times that they ware out. Electricity has a difficult time passing through the metal pins in them to the motherboard.

When these connectors were installed at the factory, they used a punch machine to insert the wires. Removing them and installing a new Molex connector requires carefully cutting them out and installing them in a new connector one…at…a…time. Paying close attention to the order of the wires. Taking into account if you have enough wire to afford snipping off the ends in the old connector. Your result is a number of symptoms. The pinball machine should lock up or crash. You can have targets and switches not registering when they are triggered. You could even have lights that never come on when they should.

Here you can see some photos of what Molex connectors look like. Notice how in the first photo they are punched into the old connector.

A great example of a new Molex connector installed in a Bally pinball machine. This will solve a connection issue and guarantee a much more reliable machine.