Assuming this is a fairly modern TV?, there may not even be a 'service manual' as such - and if there is it's likely to be worse than useless, they don't normally even contain circuit diagrams any more.
Repairs are only to board replacement level, and the manuals are just a spares list of a VERY small number of PCB's and a few cosmetic parts, and spares are generally only available for a very short time anyway. It was common with Samsung for all spares to be no longer available while the sets were still under warranty.
What's wrong with it anyway?, that set looks to be one with the usual LG sub-standard panel with too few LED's where the LED's fail in a very short time.