Nintendo Switch owners are dealing with a variety of hardware issues ranging from minor nuisances to system failures requiring a replacement, but the problem that’s getting the most attention — and is likely the most widespread concern — is the issue of the left Joy-Con controller desyncing. On the Switch’s launch day last Friday, Nintendo suggested in a page on its support site that the Joy-Con problem could be caused by wireless interference. But from a new teardown of the controller, it appears that the true culprit is the design of the device.

Teardown aficionado Jon Downey, who goes by Spawn Wave Media on YouTube, took apart both Joy-Con controllers in a video he posted yesterday. Aside from the known differences between the two units — the right Joy-Con has two extra internal components, an NFC chip and an infrared camera — Downey was expecting the controllers to be relatively similar inside. But he found that while the right Joy-Con included a dedicated, stand-alone antenna component for its Bluetooth radio, that particular piece doesn’t exist inside the left Joy-Con.

Downey did eventually find the Bluetooth antenna inside the left Joy-Con, but he discovered two issues with its design that likely contribute to the connectivity problems that players have been having. First, the antenna is printed directly on the controller’s circuit board; it’s not a separate unit inside the device. Second, the antenna is located beneath the controller’s shoulder button and next to the housing for the controller’s joystick. The housing takes the form of a sizable metal box protruding beyond the board, and because of the shoulder button placement, the area is usually covered by fingers. All of that could block or weaken the Bluetooth signal.

At that point, Downey decided to try a do-it-yourself fix for the issue: He would solder a copper wire to the antenna circuit and put the other end of the wire near the bottom of the controller. That would effectively make the antenna bigger, and would also extend it to an area that’s less likely to be obscured by a user’s hand.

“I don’t know if it’s going to work; I have no idea,” said Downey. “But I figure while I’m in here, I might as well take a shot, just to see.”

After tucking the wire beneath the Joy-Con’s battery compartment and putting the controller back together, Downey ran some calibration tests. It seems that he wasn’t having issues with his left Joy-Con before he tried to extend the antenna, but either way, the results turned out to be impressive.

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Downey said both of his Joy-Con units initially worked well from a distance of 12 feet, unless he covered a controller with his hands or put it behind his back. Then he kept trying the Switch’s calibration tool from farther and farther away. At 20 feet from the Switch, which you can see at the 5:25 mark of the video above, Downey experienced serious issues with the right Joy-Con when he was covering the controller. But the left one — with its augmented antenna — was working swimmingly, even when covered.

From 30 feet away, the obscured right Joy-Con was essentially unresponsive when Downey was holding it behind his back. But in the same position, the left controller continued to operate normally for the most part. At 40 feet, neither unit worked reliably.

“Should you do it?” Downey began. “No, I wouldn’t do it. It was kind of [an] extreme case, just to fix the obvious issue.”

Indeed, you shouldn’t try this at home if you aren’t comfortable with taking apart and reassembling sensitive pieces of electronics. (And even then, maybe not!) But at the very least, Spawn Wave’s video seems to demonstrate that the way Nintendo engineered the left Joy-Con is the root cause of the connectivity problems that some players have been reporting.

We’ve reached out to Nintendo for comment, and we’ll update this article with any information we receive.

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