My sansui sv2118i has 5 or six visible flyback lines across the centre of the screen. ?

My sansui model sv2118i has a perfect picture,except for a 5 or 6 flyback lines across the centre of the screen. This occurs om all channels. The picture is about 2 inches away from the bottom and the line is worse at switch on.the picture size comes perfect when the set warms up but the line stays but gets better.

Tony Tromp
March 2010