All LG TVs have a default of turning off over a certain length of time. This is to regulate "eco mode" and to help the environment with using less electricity. You are still able to change this to your requirements and your standards.
The TV will be turned off automatically if the user does not operate the TV or remote control for a certain period of time.
You can also adjust the brightness of the screen or set it to turn off automatically to reduce power consumption. The "energy saving" feature will affect the brightness of your LG TV.
How to change the time of your LG TV from turning itself off
Settings - Energy Saving
Using your "magic remote control", press the "settings" button and navigate to "all settings". Under all settings select "support".
Select the "auto power off" option and you can adjust and extend the period of time of the auto power off setting.
If other issues occur, try performing a "screen self-diagnosis" test on your TV.
If this issue continues to persist please contact our customer service for help.