Why is phone not charging?

Xiaomi Redmi 3x - I developed a charging problem with my Xiaomi because of using a fast-charge cable that apparently wasn’t compatible with the phone and the phone dropped to 0% and just wouldn’t charge.

Please note: If the light below the home button isn’t on (Solid, not blinking), the phone isn’t charging. I left the phone plugged in for 18 hours and it had no effect.

1. Remove the back cover (that was quite difficult without the correct tools and I ended up snapping off some of the siding. Would recommend the correct tools and watching a few youtube videos on this.)
2. Unclip the battery cable to the main circuit board.
3. Plug the phone in, this will cause the screen to come on
4. While the Mi-Logo is displayed attach the battery cable again (before the battery percentage displays)
5. The phone will enter a charging state for around 2 minutes and then stop charging again.
6. Repeat step 2-4 until you’ve got the phone up to around 8% battery (the battery % indicator will fluctuate anywhere between 8-20%)
7. Boot up your phone
8. While the phone was on I had the charging state fail several times until the phone reached 11%. I just repeatedly plugged it out and back in. After around 11% the phone continued to charge normally.
9. Other things to note: One post said to turn the volume up to Max and disable Wifi, I did both

PS: Using a USB cable to PC wasn’t good enough as the small charge provided wasn’t enough to charge the phone to where the screen would turn on properly.

PPS: In some cases the phone went into a loop of screen-on/screen-off. In this case, I disconnected both the battery connector cable and the battery sensor cable and left it to vibrate for a while, connecting and disconnecting the cables while in a “boot” state, seemed to get it out of this state eventually.

PPPS: If the battery connector cable disconnected from the main PCB then the battery percentage will always display 0% even if it’s not the correct charge.

Part of me is afraid that if the phone battery ever hits 10% the problems will occur again, but hopefully it won’t.

I’ve also ordered a new charging circuit PCB on the internet to replace the current one in the phone.

At first I thought it might be the battery that’s the problem, but after reading many posts and realizing that the charging PCB is cheaper than a new battery, I thought I’d give that a try.

Unconfirmed:

Deeper research states that there’s a “zener diode” on the main PCB board that can burn out when your use a charging cable that’s voltage is too high. This can be removed and will allow the phone to charge, but it’s not recommended as the phone’s voltage input won’t be regulated anymore.

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Edit: I eventually replaced the charging PCB on the phone when the new one I’d ordered online arrived, which resolved the issue completely.

It’s not terribly difficult, just removing the back cover, unscrewing, unplugging it and screwing in, plugging in the new one.

A new charging PCB is most definitely cheaper than buying a whole new phone.

Please do make sure that you get the right model number though, as it needs to fit perfectly into the phone. The one I bought ended up being slightly off from the original, so the phone case at the back is distended after closing everything up.

Check if the adapter and the usb cable are working properly ( even if you use the original one. ) If they are okay, then probably the problem is lint. Try cleaning the charging port with a toothpick or paper. Try restarting the phone and charge again.

If nothing works, its best to take your phone to the service center.

I had the same problem the solution that worked for me is to shut down the phone and charge it.

after a few days of doing that it goes back to charge normally

I had the same problem with 2x redmi note 3 pro. It was supposed that quick chargers interact with the phones before sending higher than 5V though the usb, but apparently, they dont.

The first time, it burned a fuse that is right before the USB connection of the upper board. I had to remove ti with some pliers. After that the phone worked normally, but the phone was unprotected by not having the fuse.

Now, some months later, the phone refuses to charge with many chargers and/or cables. even on the PC it charges only when it is recognized as a device, which makes me think that is a deeper problem, probably, the chip controlling power or charging are half dead. For this phone according to the schematics, the chips are: PMi8952 (power management) or SMB1351 (charger chip). The fuse that needed removal appears as FV2106 in the schematics and it’s a ESD5661D07-2 if you wanna get it of aliexpress and replace it.

It’s noteworthy taht the lower charging board also has the same fuse. This fuse is expensive, so ALL the chinese fake lower PCB replacement don’t have it, they simply replace it with some resistors. If you comapre both board (original and chinese replacments) they differ heavily both in PCB layout and components.