Have just bought a Series 6 Samsung 50inch, my first big telly. Lovely picture, but disappointed to see a continuous horizontal thin (circa 1 cm) faint grey line about a third of the way down the screen. This is most noticeable on pale backgrounds, for example sky, and particularly if the shot is moving. Shows up quite well, along with less obvious similar lines, in the "white"" or "scrolling" bit of the screenburn protection settings. Not obvious when the screen is full of colour. Occurs with all sources. Is this normal or common? Is it rectifiable?