when I power on my monitor the lights goes off after a short while,

@ndubz that is a common issue with this model. The capacitors on the power board most likely have failed, causing the backlight to turn off. You can replace those or replace the board if you are not sure about soldering. Use this guide to work on it. If you need to double check it, post some good images of your power board with your question. For that use this guide so we can see what you see.