My 55 inch LG tv (55le5500) stopped working it has no picture or sound with all lights off you can look in back of tv and see lights blinking and with a flashlight you can see the menu can you help

I just keep on turning it off in on... Then tapped it hard where the button is at bame it's on

If you have sound then you have to go through the flashlight test which is the first step in the blank screen fault with sound. If video is fine then you have to test the LED Backlight supply voltages if you are familiar and good in the electronic repair. First you have to check if bulging capacitors in the LED Backlight drive voltage circuit, replace them which most probably the reason when you turn it OFF & ON after keeping the TV ON for 30 minute. In case if capacitors are good then you have check the backlight LEDs which most probably not required in your case as you can see the logo by switching OFF & ON after 30 minutes operative. Attached videos and links may help you for the repair and replacement of backlight LED strips or LEDs itself depending on the type of LED strips used in your model.
https://www.youtube.com/watch?v=Z1DEkSguWtg
https://www.youtube.com/watch?v=YgaL6X6eSaU
https://www.youtube.com/watch?v=EZVQKEp6jxk
https://www.youtube.com/watch?v=T2FboV-1PJg
https://www.youtube.com/watch?v=2pyuXwNkBMA

Invariably a bad or defective back light inverter in LCD tv.
or LED driver board.

Perform a flash light test and follow the steps as shown in the LCD LED TV Repair No Image Blank Black Screen Flashlight Test How to Fix...