Help! I have recently noticed a faint black line across the top and bottom of the projected picture in 16:9 format. Basically just a slight difference from the pixels immediately below and above the line. The line is about 2-3 pixels down from top and up from the bottom. It is almost like a horizontal line of pixels top/bottom has changed slightly? Anybody have any ideas? I have 500 hours on my lamp/projector. Maybe an adjustment somewhere?