A blank phone screen is a very specific problem. This guide covers solutions for when you have problems like these:
10 Solutions: How to Fix Black Screen Issues on Your Android Phone | No Display | Screen Won't Turn On
Unfortunately, there is no single reason why an Android phone screen will go blank. Here are a few common situations that cause this, but there could be more:
Hold off on buying a new phone… for now. There are a few things you can try to get your Android working again if your phone screen goes black:
Check that the buttons on your device are not stuck. Check for dirt, lotion, lint, and other debris. To loosen them so that you can turn on your phone, press them quickly several times. The buttons should be able to be pressed freely with each press.
