In addition, big manufacturers such as Sony, Microsoft, and Apple explicitly note or imply in their official agreements that their year-long manufacturer warranties—which entitle you to a replacement or repair if your device is defective—are void if consumers attempt to repair their gadgets or take them to a third party repair professional.

If you own a gaming console, laptop, or computer, it's likely you've seen one of these warnings in the form of a sticker placed over a screw or a seam: "Warranty void if removed."

To be clear, federal law says you can open your electronics without voiding the warranty, regardless of what the language of that warranty says.

What almost no one knows is that these stickers and clauses are illegal under a federal law passed in 1975 called the Magnuson-Moss Warranty Act .

"Apple and others have crafty attorneys that know darned well that Magnuson-Moss exists as do anti-trust laws against 'tying agreements.' The contracts are very clever and appear to be within the law—but are anything but in practice," Gay Gordon-Byrne, executive director of the Repair Association, a group lobbying for right to repair laws around the country, told me. "Manufacturers threaten to do things they cannot do legally but 99.9 percent of consumers have no idea of their actual rights."

However, warranty conditions that forbid consumers from opening or repairing their devices are illegal under a provision of the 1975 Magnuson-Moss Warranty Act that forbids "tying," meaning the conditions of the warranty "tie" the consumer to using a specific service or specific types of parts, experts told Motherboard.

"Manufacturers threaten to do things they cannot do legally but 99.9 percent of consumers have no idea of their actual rights"

These warranty agreements and stickers exist almost entirely to help manufacturers maintain a monopoly on repairing the devices that they sell us—for example, most people won't attempt the relatively simple process of replacing a broken iPhone screen (which is not covered by warranty) if they believe that in doing so, Apple will refuse to replace the headphone jack if it malfunctions (which is covered by warranty).

But the law applies to all consumer devices that cost more than $15, including electronics. Last year, the Federal Trade Commission issued a new guidance that explains the law's bans on the types of warranties that are common in consumer electronics.

The MMWA is a relatively obscure statute that is most famous for creating "lemon law" for cars. If you've ever heard about it before, it's probably in the context of car warranties: a warranty cannot be voided simply because someone uses aftermarket parts in their device or car.

The burden is on the manufacturer—not the consumer—to prove that the aftermarket part caused the failure in the other part of the car. With a smartphone, this means that if you do a successful repair on one part of the phone, the manufacturer can't refuse to replace another part of it if it breaks down the line. For example, if you crack the screen (not covered by warranty), replace it, and, months later, the charging port malfunctions, Apple must prove that your screen repair somehow contributed to the charging port failure. (Of course, manufacturers aren't required to fix things that you break—they just can't stop you from fixing it yourself or having someone else fix it.)

The car warranty is a good way to visualize the way the MMWA works. If you replace your Honda transmission with a used one you bought off your neighbor or one manufactured by a third party, Honda can't refuse to replace the engine if it blows while under warranty, so long as the aftermarket transmission didn't directly cause the engine to fail.

"If you replaced the screen yourself with an appropriate one, then they could not claim that voided the warranty"

The statute itself states "for example, a provision in the warranty such as, 'use only an authorized ABC dealer' or 'use only ABC replacement parts,' is prohibited where the service or parts are not provided free of charge pursuant to the warranty."

"Generally, the MMWA prohibits warrantors from conditioning warranties on the consumer's use of a replacement product or repair service identified by brand or name," the FTC wrote. This means that there can be no such thing as an "unauthorized" repair or an "unauthorized" replacement part.

Of course, without government intervention, much of this is theoretical. Manufacturers can get away with their warranty policies because no one ever challenges them on it—it's much easier to buy a new phone than spend months in court over a couple hundred bucks.

"If you replaced the screen yourself with an appropriate one, then they could not claim that voided the warranty," Steve Lehto, a lemon law attorney in Michigan, told me. "However, it would be something too costly to litigate and this is why pro-consumer laws, which allow for the recovery of attorney fees and court costs in cases like this, are so important."

The FTC has shown that it's willing to use MMWA to go after manufacturers for misleading warranties, though I was unable to find an example of the FTC enforcing it against an electronics company. In the agreement for cars in BMW's MINI division, the company noted that "regular maintenance of your vehicle … performed by your MINI dealer" was a condition of the car's warranty. Last year, the FTC issued a formal complaint against BMW under the MMWA and eventually settled with the company. Under the terms of the settlement, BMW is expressly forbidden "from representing that, to ensure a vehicle's safe operation or maintain its value, owners must have routine maintenance performed only by MINI dealers or MINI centers" and "must provide affected MINI owners with information about their right to use third-party parts and service without voiding warranty coverage."

"The manufacturers know that the litigation costs would be prohibitive in any given single case"

Representatives for Apple, Microsoft, and Sony's Playstation division did not respond to Motherboard's request for comment. To be clear, not every manufacturer puts this type of language in their warranty agreements (look up the warranty information for your devices if you're interested), but such language is also found in medical equipment and other electronics.