This failure is seen across many makers if not all. I can not help you diagnose your TV. For that you use your training in TV repair since these are LETHAL VOLTAGES INSIDE. You'll have your service manual and test gear to follow the troubleshooting in the service manual.
Sometimes folk dive into TV repair without the tools or background. Some understand they are out of their depth, others explode because there is no way for any tech to tell them what exactly to replace.
These are not user serviceable.
I'm really hoping someone out there can help me. I have a LG Smart TV (model 47LN5700) that is 13 months old. When I turn it on, the LG logo flashes and the screen goes dark. I can get audio, though. I cast a flashlight against the screen and was able to see an image, so I thought the issue was the inverter. I replaced the inverter but that didn't fix the issue. Can someone help me identify the issue?