What Causes Vertical Lines in LCD?

By Elizabeth Falwell

Updated September 28, 2017

LCD technology is used on TV, computer and personal electronic screens.
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Whether they appear as thin or thick, black or white, in the center of your screen or along the border, vertical lines on a TV or computer screen certainly interfere with your viewing experience. Unfortunately, these lines may signify a severe technical problem that's disrupting the signal between the unit's processor and its liquid-crystal display, or LCD, screen.

T-CON Board Failure

The T-CON board, short for timing control board, is the part of an LCD screen that relays messages between the device's processor -- it's brain -- and the display itself. The T-CON board is responsible for synchronizing different parts of the screen with the information it receives from the processor. When the T-CON board fails, the timing between different parts of the board is disrupted, leading to errant lines, both horizontal and vertical, as well as pixelation. The only fix is to have the T-CON board replaced, which generally means replacing the whole LCD screen and usually the entire device with it.

TAB Fault

TABs, or tape-automated bondings, are an integral part of any LCD monitor. These bondings digitize the information they receive from the processor and send it to the tiny transistors that create the electrical currents that ultimately affect which colors you see on screen. A TAB fault -- also called a TAB failure -- happens when these bondings are damaged or otherwise disconnected from the processor. When this happens, entire rows or columns of pixels go dark because they aren't receiving any messages from the processor to create their colors. TABs can usually be reattached by a professional TV repair person but over time may become so loose and so repetitively problematic that they may need to be replaced entirely.

LVDS Cable

Short for low-voltage differential signaling, LVDS cable systems use twisted copper wires to carry high-performance data. This technology is more energy efficient than earlier electrical systems used in LCD products and can reduce the electricity costs to power the unit. However, when the copper wire that makes up the LVDS is compromised, through either a jolting impact or residual damage, it interferes with the signal it transports from the processor to the LCD screen. As with a T-CON board failure, this results in pixelation as well as vertical and horizontal lines on the screen.

It's Not Your Fault

While some vertical lines are the result of damage to your screen, other causes have nothing to do with you, your screen or even how you use it. Instead, the lines may be tied to the video source. Anything that interferes with an Internet, cable or satellite signal, such as an improperly aligned satellite dish or a frayed coaxial cable, has the potential to cause picture distortion, including but not limited to lines on the screen and pixel problems. Even the source itself can transmit images with lines on it; for example, a local TV news station that suffers signal interference during a live shot may broadcast images with lines, pixelation or ghosting.