Can't adjust because screen is black

William Woljevach all of that will be a depends. We would need to know what exact model you rTV is and what the exact issues are with it. If you have a black screen but have sound shine a flashlight at an angle (in a darkened room). If you can make out shapes and silhouettes it is your backlight that has failed (either power board or backlight array which is common for some LG models) If not then it could be things like power board, main board or possibly even the t-con board etc. So we would need to know more about what is going on to give you a concrete answer.