samsung 50" horizontal line

[mali67]

Hi, i have a 50" samsung here that has a pixle width horizontal line,
i checked all ribbons firstly
i know it could be the screen its self , but i ordered a buffer board off ebay, it came , i ftted and nothing at all on the screen,
i messaged the guy off ebay and he told me it wasnt the buffer but it was the screen at fault.
the buffer (same part ) gave me no picture at all made to quiet ticks and a green led flashed on the central control board.
am i mssing something ?
could do with some quick ideas before i send the board back and incre postge cost, cheers