@crashxxx backlight on without video is usually a main board problem you did not tell us if you get any sound. You need to check out all your video inputs and see if that changes anything. If it does not remove the back of the beast and take a look at all the boards for any obvious damage (leaking or domed looking caps etc.). Post pictures of your boards so we can see what you see. Use this guide [guide|21499|commentid=417084] for that. The problem could be the panel but it could also be the power board or the main board.