One side of screen is dark.

No Dont your panel uses fluorescent tubes for the backlight. So this could be an issue with the CCFL tubes which are inside your panel (most likely) or the backlight inverter. At this point and with the amount of work etc. I’d cross my fingers and go with a new inverter first. Just buy it from somewhere that has a decent no-questions-asked return policy. If that does not change anything it’ll be time to think about replacing the CCFL. Once you have the back cover removed from your TV post some good pictures of all the boards as well as the label on the back of the LCD panel. that way we can see what you see. iFixitでの質問に画像を追加する方法