If you have replaced your screen on your white macbook 13.3" and now you can see the content on the screen but there is no light behind the LCD it may be your inverter board or one of the cables that connect to it. Check out this video to help trouble shoot. If you are wanting to replace your macbook screen check out my other video below
http://youtu.be/sCN3u9sOALM
Also a great place to buy macbook parts is http://powerbookmedic.com
