After a MIUI update Poco M3 devices would not turn on, this is due to software problem. So, if you are facing any problem with your Poco M3 smartphone then hear is the solution how can you fix Poco M3 black screen problem.
This problem is due to firmware crash in the device. First you need to force restart. So, press the power button until anything is showing on your phone or just turn on.
If this doesn't work then you need to force reboot. To do that make sure your phone's battery is not low. Then press power button and any volume button (up or down) simultaneously. Then select reboot option by clicking volume button and wait for sometime.
If this way don't work, you need to contact sirvice center. Then you phone have some serious problem. I have a other solution but, for that you need to teardown your phone so, I will not recommend that. Go to sirvice center and contact with manufacturer.