How do I know if my backlight on my LG tv is working

LED backlight strips

Turn on unit. Use a flashlight and shine from top down on the panel. Look very close. If you see a very faint image of anything. The power supply board needs replacing.

Hi Terry,

If you can see the faint picture in flash light means the power supply and the main board is working. The real culprit is the backlight. Even one bad LED in the backlight will switch off the whole array. To repair this fault the panel has to be opened and the defective LED or LEDs are to be replaced.

This is a complicated, delicate and risky job and must be attempted by an expert only. You may end up damaging the screen permanently if you have not done it before and try to DIY.

The problem is defective LED back lights.

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

Sounds like you have a backlight problem. To verify this, turn on the set, dim the lights in the room, and shine a bright flashlight on the screen. If you see a faint picture you have a backlight fault. It could be as simple as a bad capacitor in the power supply, or a faulty inverter board, or in rare cases a bad backlamp.

When the screen goes blank, dim the lights in the room. Take a bright flashlight and shine it on the panel. If you see a faint picture, you have a backlight failure

You could be having a backlight malfunction.
Easy way to check is:
While tv has sound
Shine a flashlight on the screen
Look very closely and see if you can see a faint image on screen

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/jason_77a19afa8d604dee

It's either the backlight lamp or backlight light inverter is busted due to the power failure.Here's how to determine which is which:

1. Grab a flashlight.
   
2. Turn on the TV.
3. Shine the flashlight onto the screen.
4. If you cannot see any display even a faint one, the backlight inverter is dead, else the backlight lamps are busted.
5. Replace which ever is the culprit.
   

If you power it on, take a flashlight and shine it on the lcd at and angle and look real close to see if you can see a faint image. If you can, then your backlight in the screen is not working.
Also, you can attatch an external monitor to it, while its off, then power it on and see if it lights the external monitor. Try that and let me know your results.
If you get a picture ok on the external, and you can see a faint image on the lcd using a flashlight, then it could be the backlight inverter board or the bulb itself inside the lcd went out.
If you don't get any picture at all, using an external monitor and can't see a faint image on the lcd using a flashlight, then I would say there's other problems with the laptop itself. Could be a mainboard problem, power issue, etc..