LED backlight failure is common in all LED TVs. With Sharp and RCA Roku TVs, turning down the backlight level isn’t very intuitive.
- Under Settings-> TV Picture Settings Set the TV Brightness to Normal. It defaults to Brightest I’m not sure if this is controlling image brightness or backlight level but safer to set it to Normal.
- With your current input selected (eg HDMI 1), hit * on the remote. Go to Advanced Picture Settings. Set Picture Mode to Low Power, Dynamic Contrast to Off and the Backlight to 60-70. The lower you can tolerate the better. The default for low power is 78 which still seems high. Most picture modes set the backlight at max which will burn out the LEDs.
- Repeat step 2 for all inputs you are using and also check all apps (eg. Netflix, Roku media player you are running.