Won't charge when I plug it in

Hi Adam,

Well, you've covered the first step of many in figuring out why your phone won't charge.

Definitely the first thing on the list is to make sure your cord is good, which you've done. Next off, you need to make sure your wall charger is putting out the right power, either by trying a different one or plugging in a different device to the one you have.

Assuming that checks out, next is the charging port on your phone itself. Get yourself a magnifying glass and a bright light and check inside the port for any dirt, dust, pocket lint or anything else that's stuck in the charging port that's not supposed to be there. Clean it out with some 90% or higher concentration isopropyl (rubbing) alcohol, an eyeglass cleaning cloth and maybe a toothpick.

If you've gotten through those items and it still isn't working, then unfortunately that's all you can do without opening up the phone. The main problems we see in cases like this are that either the battery has failed or the charging port has. At this point we don't have any way to determine which one it may be; on phones with wireless charging you can pin it down by whether it charges wirelessly or not, but unfortunately that's not an option on your phone.

It's a crapshoot whether to try the charging port or the battery first; personally I'd go with the battery, since they do eventually wear out and having a brand new battery won't hurt even if that isn't the problem.

Regardless, here's a video showing how to replace the charging port on your phone.

Samsung galaxy A21 charging port replacement

You can find the port at all the usual places like Amazon, eBay and AliExpress; here's the first one that came up for me on a cursory search.

Amazon.com: Replacement USB Charger Charging Port Flex Cable Board Dock Connector for Samsung Galaxy A21 SM-A215U A215U A215A SM-A215F A215R4 A215U1 US Version : Cell Phones & Accessories

I didn't happen to find any guides for replacing the battery on your phone, but once you've got the back off, it's mainly a matter of disconnecting the flex cables that run across the top of the battery, then carefully prying the battery up from the adhesive holding it to the frame. Batteries aren't terribly expensive either, so you could consider just getting both parts so you have them when you open up the phone.

Amazon.com: Replacement Battery Scud-WT-N6 (Upgraded) for Samsung Galaxy A21 SM-A215U SM-A215U1 with Adhesive Tape Tool Repair Kit : Cell Phones & Accessories

This isn't a recommendation to buy those particular parts, but rather just examples of ones that are available. The other things you'll want are adhesives; one for the battery to resecure the new battery to the frame, and one for the rear cover so it sticks back on and gives you back some of your water resistance.

Good luck; I'd be interested to hear what you find and how it all turns out!