Vizio model L30WGU made in 2005 .

It works just fine accept 20 or so very fine , as thin as a pencil line
..red lines going up & down the entire screen evenly spaced . If i
choose normal picture mode with black bars on both sides the lines do
not show in the black side bars . Also the red lines do not show on top
of any on screen menues .
When the set is on with no signal those lines are there , when i plug a
video input ito the video jack the lines go away for a half second .

Any ideas ?