LONDON (AP) -- Toothbrushes used to be simple, powered only by your hand so they never broke down. Nowadays, rechargeable electric toothbrushes are increasingly popular because they make brushing easier and more effective, but they are a headache when they stop working properly.

Inside an electric toothbrush's waterproof housing is a battery that powers a tiny motor which rapidly rotates or vibrates a replaceable brush head. The batteries are usually rechargeable but don't last forever. The question of their longevity, and toothbrush repairability as a whole, is the subject of many online forums.

If you've ever owned one, you've probably noticed recharging intervals becoming more and more frequent. At some point you might decide to throw it out, adding to the world's growing pile of electronic waste.

But all is not lost. You can pay someone else to repair it, or -- with some online help -- do it yourself. Here are some pointers:

According to the manufacturers, the answer is usually no. They warn people against disassembling the devices, saying it's dangerous or that it will void the warranty. But that doesn't mean you can't do it yourself, repair advocates say.

You can find websites and YouTube channels devoted to showing people how to fix their battery-powered brushes.

Toothbrush manufacturers will say the devices are not "user serviceable" but it's "blatantly untrue," said Shahram Mokhtari, lead teardown engineer at iFixit, a right-to-repair advocacy group. "Some of these devices have very replaceable batteries," and in most cases, it's just a matter of getting inside the device and learning how to do a little bit of soldering or taking it to someone can do it, he said.

DIY fixes might soon be standard practice. The European Union, a pioneer of global tech regulations, is drafting rules to promote the repair of electrical devices, while several states have introduced right-to-repair legislation.

Every model is slightly different but models from Oral B and Philips Sonicare -- two of the most popular brands -- can be dismantled using the same general procedure.

Most Oral B brushes can be opened by holding the toothbrush and the charging stand together, and then twisting the stand to pop the bottom cap off. On some models, you might instead have to use the stand as a lever to pop it off.

Philips Sonicare models are a bit trickier. You'll need something to pry off the bottom cap, such as a small flathead screwdriver or a plastic tool known as a " spudger."

Whatever the model, if it's too tight some websites advise softening up the plastic housing by placing the brush in hot water for a few minutes.

Once it's off, you'll need to slide the electronic innards out of the housing. You might need to first remove a metal or plastic ring on the brush head spindle. Then push the spindle against something hard to slide the motor assembly out the bottom. You might need to pry open some plastic tabs first. Again, each toothbrush is different so it's best to consult, if possible, the guide to your specific model on iFixit or other repair websites.

On some models, the battery is not so easy to remove because it's soldered to the circuit board. But if you feel handy, you could do it yourself, Mokhtari said. You will need a soldering iron to undo the wiring connection and then you'll have to re-solder a new battery in. If you've never done it before, there are videos. Be careful, the soldering iron is hot.

"We would encourage people to learn that skill because it's not a difficult thing to learn," said Mokhtari. The soldering process for toothbrushes are generally similar, and will be "a little bit delicate" and "a little bit difficult," he said.

Yes, but you'll have to make sure it's the right size. It's usually a cylindrical cell similar to the Energizer or Duracell AA batteries in your TV remote, but don't assume it's the same.

It could could be longer, shorter or have a different diameter than a standard AA. Some have metal tabs that need to be soldered to the circuit board. Whatever the type, it should be available online.

Oral B is making it easier for consumers to do DIY repairs with their IO line of toothbrushes, which can be fixed without specialist tools. Some versions even come with a circular charger that's specifically designed for use as a tool to twist off the bottom cap when turned upside down. After sliding out the mechanism, simply pop the battery out.

The downside is that IO models, and their brush heads, are more expensive than other Oral B model lines, according to the U.K. website toothbrushbattery.com, which has a buyer's guide ranking electric toothbrushes by their ease of repair.

Some upstart brands like Suri and Quip highlight their repairability as part of their sustainable appeal. Suri, however, says owners should send them back to be fixed and shouldn't do it themselves, and only if they've signed up for a brush head subscription plan.

Other types may vary. Mokhtari demonstrated for the Associated Press the procedure for taking apart a brand new Philips Sonicare 6100 model. It took him more than 15 minutes to get the bottom cap off and remove the electronics, then tackle a complex desoldering process.

"This is just not consumer friendly. This is not repair friendly." he said. "We're already way beyond what would be reasonable for a DIY repair job."

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