Encyclopedia Arcade And The Case Of The Voltage Drop

Bugs MeaneyWhen we first started All You Can Arcade, it was a bit on faith. We were confident that people would want to rent arcade games by the month, but truth be told, we had no idea how to work on them. Before we knew it our launch was a month away and we had managed to collect about 100 games, but only 10 of them worked!

We knew enough to refurbish a good chunk of the games, but we kept hitting the same symptom over and over again. All of our monitors would display a scrambled image on the screen. It was super frustrating because we had no idea how to fix it. We almost missed our launch, but we finally clued in on what was causing our probablem when we learned about monitor sync 101 and realized that they sometimes need to be hooked up differently depending on the game. On that day, we must have turned on at least 20 games, that we had already put a lot of hard work into, but were missing this final piece of the puzzle in order to be able to play them. This tiny chunk of knowledge, gave us the games we needed to get started and was enough to keep us motivated to keep learning how to fix problems.

Five years later, I still spend more time studying arcade repair, then I ever spent studying in college and the education continues to pay off.

For the last couple of years, we’ve had a mean bug that’s crept into our fleet. The games would work great after refurbishment, but three to six months after getting them turned on, they’d all start to fail. When we measured the voltage running the games, we would consistently see a 0.2 to 0.5 drop in the 5V voltage and couldn’t quite figure out why the PCB board seemed to suck up power.

To solve the symptom, we would boost the power supply to run hot and that would be good for another 3 to six months until the power supplies would burn out. After running into this mystery a couple of times, we started to put the games into deep storage until we could figure out why they all kept failing. Because we assumed, it was being caused by bad circuit boards trying to draw too much power, we missed something much more obvious.

After cleaning the chips, it would sometimes help, but this bug has managed to brick at least 20 of our games. Well today, our Mortal Kombat 2 started to display the same symptoms and quite frankly if we pull that one from the fleet, our customers will riot, so I sat down to get to the root of the case of the drop in voltage.

To do this I took my voltage meter, measured the power at the power supply and then started tracing the 5V line and measuring wherever i could touch wire. When I measured the power before it even went into the edge connector, I saw that the voltage had already dropped. I now suspected the connector between the wire and the power supply. As soon as I crimped over the end of the line to put on a new one, I immediately saw what my problem was.

We love getting a good deal and I would be willing to bet you a quarter, that you cannot find a better deal on the jamma harnesses that we buy. Unfortunately, it looks like we may have gotten what we paid for them.

From the outside, the harness looks like it uses a thick 18 gauge wire to run the power to the board. That’s a lot of metal to conduct a small amount of voltage. It’s part of why I never suspected that it was our culprit.

Once you open it up though, you can see that from the outside it looks 18 gauge, but on the inside it’s short quite a bit of metal. The solution was simple, run a thicker wire from the power supply to the harness and Voila! Mortal Kombat 2 back up and running, just in time for our free play arcade at the Jack of All Trade show this weekend.

While this simple bug should have been spotted sooner and has caused us a lot of headaches, it’s also incredibly exciting to figure out the source of our problem and to know that with very little work, we’ve got another 20 awesome games back on our website. Learning to fix arcade games hasn’t been easy and your education never really ends, but each time you solve a mystery, the next game gets easier and easier to fix.

Hopefully, other people who’ve run into similar trouble, can save themselves the same headache by A.) double checking the wire you’re using when you can’t get your voltage to travel cleanly from your power supply to your circuit boards and B.) paying just a little bit more better quality jamma harnesses.

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