4 across the screen, it's not black it's just a different color
Displayed all one color (Red, Green or Blue) the line shows, it's just a little brighter. Also, the TV turns itself off at times.
Televison & Video - Vizio - E500i-B1 50-Inch 1080p Smart LED HDTV
Answers & Comments
If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.