On many, but not all,

Question

on many, but not all, dvds the tv picture has four rows of short white lines, intermittently. The dvds play perfectly on other equipment. Looks something like this:- - - -- - - -- - - - - - - -I have played, without problem, the dvds on the same model dvd (sony) player on a different tv. The problem is possibly with the tv (but the lines do not appear during tv reception and not on playing some dvds). Any ideas?