(If volume down doesn't work, try volume up.) In this case white screen will also help. It's been found that Black screen can reduce the power consumption up to 58. If you had a same problem and same phone type as me, here are some solutions that might help based on my experiences: I tried to restart the phone by holding the power button for a minute, but that doesn't work. A value of gray is often lurking in another color. My phone (Samsung Galaxy E5) is not using extension batteries, so I can't remove them because the batteries are sticks into the phone (like Apple iPhone batteries). Black, white and gray baking screens are often problematic because those colors are found in almost every foreground object. It still can receive calls, messages, chats or any notifications, but the screen is black/blank maybe that's caused by some system problems/errors that affect the screen.
Strangely, the phone works just like usual.
My phone (Samsung Galaxy E5) screen goes blank/black but the buttons (power, home) and bottom lights are still working. A black and white screen on your phone may be due to a few things.
