How to repair black screen

@hyundai you are not giving us a lot of information here. 5 words is really not enough to expect a very helpful answer. It would be nice to know what you have checked and what the real symptoms are. You are not telling us if it is plugged into your computer and if your computer's video card is working. You need to check that with another monitor first.

This is assuming that this is just about your monitor and that you have checked all the rest. The no video issue can be related to a bad backlight inverter circuitry. A simple check for that would be to darken the room and turn the monitor on. Then use a flashlight and angle the light at the screen on different areas. You might make out some shadows or see a slight grey color. If you do, it's your backlight that has failed.

If you do not see anything, unplug your monitor and remove the back cover. Then visually check the boards for any obvious damaged component, like domed or leaking capacitors. Check all the wiring and unplug the wires and plug them back in, make sure they are properly seated. Post some images of your boards with your question. Use this guide iFixitでの質問に画像を追加する方法 for that so we can see what you see.

Led strip not working