For about 5 seconds when I power on my tube there is a greenish spot that is about 1 inch thick and 4 inches long along the right side edge of my TV. It looks like there is an unshielded speaker next to my TV. But there is nothing. This is a Sony XBR970. As soon as I notice it, it starts to fade out.. Then its fine. This only happens when the TV has been off for awile. Any idea what it is?