Lg led tv doesn't turn on

1Check power board capacitors if swelled then replace them ,
2 check led output voltage at connector on power board. If voltage down come back from led penal then one or more leds fused.
Please replace it.
3 it may caused power board defective too.

watch this https://www.youtube.com/watch?v=4DS8_utsLPo

Chances are you have bad lamps in the panel...you will need to take the front cover off and get under the panel and test them and see if some are bad, if they are replace the strip...good luck as its not all that easy to get the panel off and back on without damaging it, use extreme care handling it or once you get the lamps working the panel can be damaged and then it has to be recycled as it can't be fixed

1) Check your power plug wiring and replace the fuse.
2) Read the Manual:
http://www.lg.com/us/support-product/lg-47LN5750

Take the screen off connect power and watch LEDs if any don't flash its LEDs only needed to change faulty strip if they all flash its probably t con boards.

Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis. http://electronicshelponline.blogspot.com/ To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

If it was the LEDs, then you should still have some working. My first thought would be the LED driver circuits.

Best of luck.

LG LED TV has no picture (black screen) but still sound ...

www.tomsguide.com/answers/.../led-picture-black-screen-sound-fixed.ht...

7 days ago - My 32' LG LED TV has suddenly lost picture! The sound is all right but theScreen is pitch black. After switching it on the picture flashes for a second and thenthe ... LG LED TV has no picture (black screen) but still sound - can it be fixed? Tags: ... a touch on the screen reveals nothing so it's not the back light.

Monitor going black after 2 seconds [Solved] - CCM.net

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TV with Black Blank Screen Repair How to Troubleshoot ...

? 3:16
https://www.youtube.com/watch?v=kFdVi2ejfzA

if you are getting the logo and snow , I think you are on the wrong channel for programming

This is one of two problems, Bad capacitors in the power supply or your Y Sustain board has failed, I would go for the first, take the back off your tv and look for swollen or domed shaped capacitors on the power supply, They may also leak a brown liquid like substance.
Replace all that you can see and this should cure the fault.