Steps to troubleshoot a black screen issue:

1. Check the power outlet for connected power cables and make sure the plug is firmly seated.
2. Unplug the TV from the outlet and wait 30 seconds before plugging it back in.
3. Check if the video cable that connects your TV to the external device is properly connected.
4. Confirm if the external device you are connecting to the TV is powered on.
5. Ensure that the picture settings on your TV are not set to a low brightness.
6. Check if your TV's menu settings are set to the default settings.
7. Make sure that the sleep timer of your TV is not enabled.