As soon as the phone goes black, I will press the primary key to return to the main menu. When I pressed the power off button, the black screen didn't respond. When I press the main menu, I go to the black screen again until the call is over. If you encounter a black screen during a call, we suggest:

1. If the machine supports the distance sensor function, when the distance sensor at the top of the screen is blocked during the call, if it is put to your ear, the screen will be closed at this time, which is normal.

2. If the mobile phone does not block the sensor or does not support the distance sensor, it is recommended to try to press the power button or the home button. If the screen will light up, please restart your phone and make a call.

3. If the call still appears black screen after restarting, please try to update the mobile phone system version.

4. If it doesn't work, please back up the important data in the device and restore the mobile phone to the factory settings.

If all the above operations fail, please bring the purchase invoice, maintenance card and machine to Samsung Service Center, and the engineer will check and handle the machine.