Horizontal line on my LED tv

There is a small horizontal line that suddenly appeared one day on my 50 inch Micromax LED TV (5 year old).

The super thin line is black towards right and kind of transparent towards left. The left part seems to be changing colors based on the content shown around it. The right part remains black. There is no flickering of the line or anything of that sort. The local repair guy said I will need to replace the “tv board". I am not sure if such an extreme step is required. Please help and advise. Pictures attached. Thanks.