What Causes Horizontal Lines on an LCD Panel?by Ryan Goodrich
LCD display screens on notebooks, monitors and TVs alike are made up of two thin layers of glass containing liquid crystal material between them. When the glass becomes damaged, debris infiltrates the crystal layer or another issue occurs with the display function, this causes vertical lines of color to appear when the monitor is fully illuminated. These lines are either permanent due to internal failure or temporary due to faulty display connections.
What the Line Indicates
Diagonal, jagged and both horizontal and vertical lines typically indicate panel damage. A single set of horizontal lines could indicate damage, a graphics system failure, or loose internal video cables. Broken signals from cables or graphics hardware creates impurities in reproducing an image on an LCD screen, conditions that often manifest in the form of vertical or horizontal lines of color.
If the lines are infrequent in their appearance, or are not permanently visible, a loose video cable is often the problem. As devices are carried, dropped and bumped, cables become loose even in laptops. Laptops are built with casing to absorb and dissipate small shocks, but even some bumps can cause cables to become loose. Even televisions and monitors, while often stationary, can still have loose cables if not properly seated.
If you've ever opened your laptop to clean underneath the keyboard, you might see numerous things like food particles, hair or even dust. On the rear of monitors and televisions, they also contain a series of holes or slits that dust can creep into the inner workings and cause problems. Regularly cleaning out a laptop's keyboard and dusting off the rear of a monitor or television can greatly extend its useful life. This is a preventative measure and rarely works in removing any existing lines on a screen.
How to Fix It
The first step in troubleshooting is determining the extent of the damage. For external monitors or televisions, re-seat any video input cables or consider replacing the cables with new ones. Should the lines continue to display, this indicates an internal failure, something few consumers are able to fix on their own. Instructions exist online for individual products to disassemble a monitor, laptop or television to replace broken parts, but the most suggested course of action is shipping it to the manufacturer for a warranty repair. If no warranty is active for the device, consumers are then advised to replace the device entirely with a new one, as this is usually the cheapest solution. Lines on an LCD panel indicate the LCD screen or screen ribbon cable need to be replaced, parts that can cost several hundred dollars.