Blank screen led light flashing on/off manual switches do not work

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.

Sounds like the backlight has failed.

TV with Black Blank Screen Repair How to Troubleshoot Symptoms for Faster...

These blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices. http://electronicshelponline.blogspot.com/
Blinking codes details to many popular brand TVs are given. Surf the site with patience.

Ur Tuner signal board have problems or dead.Ur power LED light indicator stable for a few mins before the power LED light,and the OPC LED light indicators flashes?After the POWER light and OPC light indicators flashes,just push the power button again for the power recycles again.Probally have to pushes the power button 3 or 4 for power light and opc light indicators flashes,the LCD backlght will lght up and work.Sharp tv have this problems alot,very common in Sharp LCD tvs.

Usually when these develop a fault you will get flashing LED codes. If you are not getting any the power supply may have failed completely.

Try another cable and socket in the first instance and ensure the manual power switch feels normal in action.

Hi its ok now I called out a repair guy.

Thanks Sonny

ITS BROKE - YOU HAVE TO GET IT FIXED OR THROW IT OUT. SAME THING HAPPENED TO US -UNDER WARRANTY BUT WE HAVE TO PAY THE $80 TO SHIP IT TO THEM. WHAT A FARSE.

For some reason, it seems as if your monitor has either lost the video signal or the capability to interpret the siganl. If you have the ability, put a second monitor (or tv) to your computer. See if you get a video siganl. If you do, then your monitor has an internal issue with the signal and needs to be addressed "hands on" by a technician. If you do not see a video, then your problem lies within your video card. Good luck.