Look for a uniform outage not sporadic dimming or a single dim line suggesting led individual lights or entire led strip failure.
Led tv backlight driver board.
Backlight led driver and wled driver solutions from ti for backlighting extend battery power reduce board space and enhance lcd screen performance.
If an entire quadrant of the led backlight on your tv has gone out it s possible that you have a driver board failure and not burned out led s.
Led tv is the same as lcd tv the only difference is that lcd tv uses ccfl as backlight and inverter as driver board but led tv uses leds as backlight and boost driver board as driver leds use dc voltage to work unlike normal leds the high power leds that used in tv works at 3vdc per led.
If your outage looks similar to mine taking up 1 4 of your screen try replacing your led driver board.