Poco F3: Persistent Issue Despite Multiple Component Replacements

[phonetic]

I have a problem with my Poco F3, so I was wondering if someone had the exact same one and if you found a solution?

There are two main problems that I'm facing and I'll explain everything in detail below:

1. Phone is not being recognized by the PC or OTG
2. Strange buzzing vibration

The phone is not recognized by the PC, it starts charging, but data over USB doesn't work. I tried different cables, multiple PCs and even OTG adapters. It just doesn't work. It was working before, but now it doesn't.

Also, whenever I plug in the phone to charge it and disconnect the cable afterwards, it's like the vibration motor is bad and whenever there is a haptic feedback, instead of a normal vibration, it's vibrating and buzzing. And when I restart the phone, it goes back to normal. But if the phone is still connected to the charger and I restart it, the buzzing vibration is not there at first, but once it fully boots up, it starts.

Now the thing is, I replaced almost every possible component (USB board, vibration motor, main flat cable, the battery, and the power button) and the issue still persists.

It might be a software or a hardware problem, I don't know anymore, since the strange buzzing vibration comes back to normal after a restart, but the USB data connection was working before, even with the same ROM, and it also didn't have the issue with the vibration.

Another thing I've noticed is that the buzzing vibration also starts when I connect two phone with a USB-C to USB-C cable, but even though the Poco F3 is the phone that is charging another phone, the buzzing vibration still happens. It does not start for example if I connect the headphones via the USB-C to 3.5mm adapter.

But the strangest thing is that the vibration motor works perfectly, if I go into the Hardware Test Menu (CIT) to test it, it's working fine there and it's also working fine if for example I use a gesture to swipe left to go back. But when I try to use the keyboard or I turn on Vibrate mode, long press the Power button to show the options to Turn off the phone, restart it or anything else, the buzzing vibration is there.

Here is some info about the phone and the ROM, if anyone is facing the same issues, I would like to know if they started with this "update" or if you have a different ROM installed and still have the same problems?

ROM: MIUI 14.0.8.0.TKHCNXM | Stable by xiaomi.eu
Model: M2012K11AG
Android: 13 TKQ1.220829.002

 

[Dandruida]

Exactly the same thing happens to me.

 

[Dandruida]

Hola, ¿has conseguido que vuelva a funcionar? He cambiado componentes y ese tampoco parece ser el problema.

 

[Nix.Lon]

I've also experienced this issue on my POCO F3 but with more severe results, I almost planned to bring my POCO F3 to an official Mi repair center.

But I had a different experience per se, it's interesting but let's say that the "buzzing vibration" issue kinda disappeared recently in my case.

I'll update this comment if there are any changes to my POCO F3 at this state.

ROM: MIUI 14.0.8.0.TKHCNXM | Stable by xiaomi.eu
Model: M2012K11AG
Android: 13 TKQ1.220829.002

 

[phonetic]

Unfortunately there might not be a solution, since it's probably a hardware problem, but maybe some people really have a bad USB board, so replacing it might fix the problem with the USB.

I have tried to reflash the same ROM I already had, and also a previous version, thinking that it might have been a software problem (something with the ROM that was causing the issue), but it wasn't. So in my case at least, it's a hardware problem.

Unfortunately, a lot of people are having these issues. And in my case, the problem is that the CPU itself is starting to fail. Now, you might find that people are talking about reballing a CPU and how that will fix the problem, but that is not a permanent fix, just a temporary one, and it will probably last a couple of months at best, as people who did the reballing method are also saying. That is because the problem are not the solder balls under the CPU, but the bumps inside the chip itself. Now if you just heat the chip a little, the USB might work and probably will start working again, and the buzzing vibration will also go away. That is what's happening when they reball the chip. They don't actually have to do the reballing, they just have to heat the chip a little to make it work again.

Here are some videos if you are interested in a more detailed explanation of why that is:

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When I applied heat to the back of the phone to open it, that heat is in my case probably enough to even heat the main board a little and the chips on it, so my USB started working again for a short time. So, if you want, you can try heating the back of your phone with a hair dryer and it might start working for you too. But of course, that will really not last long at all, just maybe a couple of minutes. You can try this method if you maybe bricked your phone and really need the USB port to flash a new ROM file, then it might be worth it, but other that that, there is no solution.