@julzryu the very first thing you need to let us know is if the LED indicator is flashing red. If so, count how many times it flashes and let us know. If the LED indicator flashes red, reset the TV by disconnecting the AC power cord from the TV for two minutes, then turn on the TV.
Then start with the basics by checking the items as follows:
No picture (screen is dark) and no sound
Check the antenna (aerial)/cable connection.
Connect the TV to the AC power outlet (mains socket), and press / on the TV or remote control.
No picture or no menu information from equipment connected to the video input jack appears on the screen
Press to display the connected equipment list, then select the desired input.
Check the connection between
If that does nt work you need to check your power board and/or your mainboard. You also want to check the T-con board. First thing there is to check the fuse. Post some images of all of your boards with your question. For that use this guide Adding images to an existing question so we can see what you see.
If you do already have it apart, check a few things according to the SM