How do i test a backlight for a led tv

The T-con board is for the led backlights!

Are the backlights working? Sounds like yes even before changing the T-con board!

Did you do the flashlight test into the screen to see if there is a faint picture? I guess if you did you didn't see a picture!

This would point to the main board or the cable from the main board to the screen!

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.

This is a backlight issue, it is either the led backlights or the T-con board, further testing with a circuit tester is required to determine which.

bad digitizer

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

hi the led or leds has shorted in the panel, thanks

shaun

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

If you can't see a faint picture with the flashlight then the T-con board is gone. If you can see a faint picture, then the led driver or ballasts for the back lights quit. You can get parts from here: TV Parts Universal TV Stands DLP Chips ShopJimmy

invariably the LCD backlight inverter board or the LED driver board are the usual suspects. or the T.Con board

see the video below and follow the logic of elimination process
LCD LED TV Repair No Image Blank Black Screen Flashlight Test How to Fix...

usually bad power supply, Where did you source your part? return/exchange it. Bad LEDs/ possible but not as likely, Tcon working if you can see images with flashlight. You must also have backlight on signal from main board ,check for 3 to 5v on labeled connecter on power supply. UPDATE---47" & 50" LN series. This model has had LED problems if your TV acts as described by Mr. Hughes in is answer to this problem you have bad LEDs