Samsung 65" smart LED TV. Lost picture, has sound. No backlights are visible. Replaced power board/led board.Can see picture with a flashlight,no backlight. Menu has a backlight value of 20. Help!

Do the flashlight test and if you see a faint picture the backlights are not working replace either the led backlights or T-con board, If no picture replace the main board.

Replace the backlight driver power supply or driver board.

The led driver is on the main board.

The Audio and Video are two separate components and operate independently of each other. Therefore: The Video portion requires technical repair by a technician with the proper test equipment.

Do flashlight test - if you can see image you need t con board. If no images seen, inverter board. TV Parts Universal TV Stands DLP Chips ShopJimmy

If you saw no faint picture with the flashlight, then it's the T-con board.

I wouldn't replace a power board before measuring to see if the voltages are there and correct....

The most likely problem is the Backlight Inverter. It supplies the power to the LED array which illuminates the screen. If you are brave and also technically able, it can be replaced at home. Here is a video to help. LCD TV Repair Tutorial How to Replace the Backlight Inverter Board in LG...

Here is what to check when your TV is turned on, power light is ON, but no picture is seen or sound is heard:

1 - Be sure the component you are using (Xbox, Cable, SAT, ROKU) is turned ON.
2 - Check to be sure all cable and cords are securely connected to the TV inputs and component outputs.
3 - Make sure you are on the correct input as some TV's will show a black screen if there is nothing connected to that input.
4 - Unplug the input you are trying to use from the TV (such as an HDMI Cable) and plug it back in.
5 - Check for signs of damage on all cords and cables from the TV to all components.
6 - Make sure the TV is not in ENERGY SAVE MODE, press the button on the remote control to go back to normal mode.
7 - Unplug the TV for 10 minutes to see if there was a temporary one time issue with the TV.
8 - Disconnect the TV from power for 2 minutes, then when plugging it back in PRESS AND HOLD THE POWER BUTTON ON THE TV FOR 10 to 20 SECONDS to try and force the TV to reset.
9 - If after checking all these different issues, you may have a Faulty Power Supply Board, A Bad Capacitor on the Power Supply Board, Loose Wire Harness, or Loose Ribbon Connector in the TV itself.
10 - Most likely when a TV has the power light ON but NO PICTURE and NO SOUND, it is the Power Supply Board that has failed.

BTW, here are solutions for you to play iTunes movies on Samsung smart TV