If an LCD is not clearly cracked, there are other factors in diagnosing a screen that is not working. There are three parts that go the LCD image, the LCD data cable, the FL inverter and the LCD. If you have a dim screen, either the LCD cable is bad and is not getting power to the inverter that powers the bulb, the inverter is bad and is not getting power to the bulb or the bulb inside the LCD is bad and the LCD needs to be replaced. Make sure there is 6V of power going through the LCD inverter before you replace the LCD.