Black Screen - Redmi Note 2 Doesn't Start Anymore

[matthias]

Hello,
this morning I unlocked my Redmi Note 2 and it was lagging a bit (as it is sometimes) so I just lay it down for a while and did something else. When I returned I couldn't unlock the phone or see anything. I also tried to put out the battery and put it back in - this always worked but it didn't this time. Also tried to boot in recovery and fast boot mode. Nothing.
When I connect it to to my computer (Windows 7) I hear the "device connected" sound and an "Unknown Device" in the device manager. A few seconds after, I hear a "device disconnected"/"device installation failed" sound and it disappears from the device manager list. This repeats every 10-15 seconds.
Just to be clear: I do not see anything on the screen (no background light as well), the touch buttons remain off, no vibration, nothing. Looks like bricked though I am wondering why it is recognized as an unknown device in windows...

I tried Mi PC Suite but it didn't work...

What can I do? I also couldn't find a way to find an official repair shop. Where can I send my phone back? To GearBest (where I bought it)? I live in Germany and I'm not sure if there is any phone shop that can fix it...

Thank you and best wishes,
Matthias

 

[nickzeptepi]

Pull out battery and replace, charge with phone off. Do you see the percentage when u first connect ?
Charge and try boot again

Sent from my Redmi Note 2 using Tapatalk

 

[matthias]

Hello nick,
Thank you for your fast reply! Connecting it to the charger/Windows PC with battery pulled out didn't work as well.
Same strange behavior with the device manager...
The screen shows absolutely no activity, so no charge icon/percentage as well.
I charged the battery tonight, my multimeter says it has 4.28V.

By the way: I tried to connect it to a digital power supply control with 3.70V. When starting, it draws around 440mA and after a while goes down to 140mA, then up again.
I suppose it is a Hardware failure with the mainboard/screen unit(?) or a boot error... However, I wonder why I even can't see the touch button backlights and feel the vibration on startup.
Any other ideas or programs I could use to unbrick my phone? :/

How can I let it repair by Xiaomi?

Best wishes,
Matthias

 

[silas guo]

You can try to replace the battery.If it still has problem, maybe the mainboard has problem.
Redmi note 2 battery is available in dragon-tt.com.