How to Fix a Line Running Through an LCD Screen

By Elizabeth Falwell

Every liquid crystal display, or LCD, monitor is made up of tens of thousands - or even millions - of pixels arrayed in a series of columns and rows. Sometimes, these rows or columns go haywire, resulting in horizontal or vertical lines running across your LCD screen. But these lines aren't always the result of a technical glitch. Human error or your display's settings may be behind this issue.

Step 1

Check your screen's aspect ratio; 4:3 and 16:9 are the most common video formats. The aspect ratio on your LCD must match the video format setting of your source. If these don't match, and you are playing a movie shot in 16:9 on a screen set to 4:3, for example, you'll see thick, black columns on the outer edges of your display.

Step 2

Install the latest updates for your monitor. Philips LCD TVs display thin, vertical lines when the product's firmware is out of date. Log on to your manufacturer's website for brand and product-specific instructions for downloading and installing firmware and software updates.

Step 3

Inspect your LVDS -- short for low-voltage differential signaling -- cable for crimps, frayed portions or other signs of damage; replace if necessary. This cable transports high-performance data from your computer or television's processor to your LCD screen; when damaged, it interferes with the video signal, resulting in everything from horizontal and vertical lines to pixelation and tiling on the screen.

Step 4

Examine the cables connecting each LCD screen, such as a TV or computer monitor, to the video signal source, such as a cable box or processor. Damage to these cables leads to compromised video quality on screen, including horizontal and vertical lines of differing sizes. Tighten loose cable connections or replace damaged cables if necessary.

Step 5

Contact your service provider to see if there have been any signal interruptions at the source. Just as a video or Internet signal within your home can be compromised by damaged equipment, the signal between your device and your service provider can be impaired by signal interference or degradation.

Step 6

Call your LCD's manufacturer for information on your screen's warranty. Problems with your display's timing control board, which is responsible for synchronizing the video and audio on screen, and tape-automated bondings, which convert information from the video source into digital information for use by individual electric transistors, are serious issues that can cause dark lines to appear on your LCD. Only a professional can diagnose and repair these complex problems.

Tips & Warnings

  • Do not attempt to take apart your LCD screen in order to repair a line running across it. If troubleshooting the aspect ratio, cables and connections does not eliminate the problem, a professional should inspect the display. Taking apart the screen may nullify any existing warranty on the product, making you wholly financially responsible for any repairs.