What causes vertical lines on a TV screen? Vertical lines on a TV appear for the same reasons as horizontal lines: loose cables and wires, screen damage, or a faulty T-Con board. Leaving the TV turned on for too long can also cause vertical lines. 

What causes a thin black line on my TV?

A bad cable, or a cable that is not securely fastened to the input/output ports, can disrupt the signal and cause horizontal or vertical lines. Verify that the cable in use is secured correctly at both the external device and the TV.
 

What does a black line on TV mean?

The reason that you end up seeing black bars on some TV shows and movie is that many films and shows were, and are, made in a different ratios (usually wider) than what your TV supports.
 

Why is there a black line in my Samsung TV?

1 Check whether the lines on the screen are moving or permanent. 2 If the lines sway, check the input source (HDMI 1, Video, PC, etc.) and connection to see if they are properly connected. Disconnect and re-connect the video cable/HDMI to check if the issue is resolved.