If they do not match your model, see your user manual for steps to turn off Retail mode. Navigate to General settings. Navigate to and open Settings, and then select General. Navigate to Usage Mode settings. Select System Manager, and select Usage Mode. Set the mode to Home mode. If required, enter a PIN.
Read full guide on how to disable Retail Mode and install new version of Android on Galaxy Tab - https://www.connectedwiki.com/disable-exit-galaxy-tab-s2-t81
Step 1: Disable ECO Mode or Ambient Light Detection. Your first step is to disable the ECO Mode. The feature may also be under the name Ambient Light Detection depending on the model of Samsung television you have. These features usually exist to save power, but they can also be the cause of your dimming issue.
Under Settings, select “Device Preferences.”. From “Device Preferences,” scroll down and select “Usage Mode.”. Find “Retail Mode,” “Store Mode,” or “Demo Mode” and disable it. Some Hisense TVs require you to change the mode to “Home Mode” before you can exit the screen. If you see this option under “Usage Mode