My Samsung LE37R74BDX has developed a fault that starts after about 5 minutes after the set is switched on.
Irrespective of what input is selected, the picture becomes unstable in a similar way to what used to be referred to as vertical hold (ie: picture seems to hop up and down) - which then gets progressively worse.
Looks like the fault is a heat related component failure on the Control Board.
A hair-dryer brings the fault on fast.A freezer spray on one component stops it fast.