My Sony KD-28DX50 TV has done the following since new. When TV is first turned on the screen is Black for about 4 secs. Then very briefly the screen shows some green banding before the picture comes up. This lasts about a second and then the picture is normal. What I need to know is do I have anything to worry about or is this fairly normal, & if so why does it do it. A friend said it was the initial energisation of the tube?????? If anyone can advise I would be grateful as things like this stress me out.