Chosen Solution
Model #UNHU6840FXZA KS02 Factory reset and also removed all devices…powered back on same result. Shine flashlight on screen and can see picture. Everything seems to operate and function, just unable to see image on screen. Please advise how to repair, what part(s) need to be replaced to correct. Thanks
Hi @jringo4u , Try the following: Disconnect the power from the TV and then remove the back cover from the TV and then disconnect the cable that runs between the power board and the mainboard. Reconnect the power to the TV and turn on the TV. The screen’s backlighting should turn on. There will be no picture because the mainboard has been disconnected. If the backlights turn on there may be a problem with the mainboard. If the backlights don’t turn on then there may be a problem with the power board, the cable between the power board and the LED backlight array or the connections and / or LEDs in the array. Measure the voltage at the LED backlight cable connection point on the power board. If it measures between 180 -250VDC then most probably the problem is in the array. It it measures between 0 - 30VDC then most probably there is a problem with the power board. Here are a couple of videos that show how to test and fix problems in the LED array. video 1 video 2 If it is determined that it is the power board search online using the power board “board number” only in the search term e.g. BN44-00755 A Rev xxx or similar, to get results for suppliers If you can’t find the board number search for UN(insert the screen size)HU6840FXZA power board e.g. UN55HU6840FXZA power board (if this is the size of the screen) If it is determined that it is a mainboard problem search for it the same way. Be sure to insert the screen size into the model number to make certain that you get the correct board. You missed it in your post. ;-)
