Small horizontal or vertical lines appearing on your TV could result from several issues. Plasma TVs can retain images, leaving a burned-in effect. The HDMI cables or different devices can work improperly with your TV, leaving red lines. Your TV itself could have hardware problems affecting the screen display. Fortunately, these problems have a solution.
Plasma TVs use phosphors to display images on the screen. These phosphors can become too bright, leaving behind traces of images on a screen, such as a red line. The existence of these trace images is often referred to as image burn-in. Burn-in is actually a result of one of two causes, image retention or image persistence. Image retention is permanent and will need professional repair. Image persistence is not permanent and the red line will fade after a few minutes of viewing, but may reappear if another burn-in occurs.
Connection problems between your TV and different devices you use can cause red lines to appear. For example, while you are watching a DVD through a DVD player hooked to the TV with a HDMI cable, red lines appear across the screen. This occurs because the TV is not fully communicating with the device. Generally, connection problems result from faulty HDMI cables. Replace the HDMI cable connecting the device to the TV and test the screen again. Repeat problems may be due to the device itself and will need professional repair.
If your plasma TV screen continues to show red lines across the screen after you have allowed any burn-in to fade and replaced the HDMI cables, the problem may be a faulty plasma display panel. The display panel, or PDP, transmits message to the screen, effectively telling the screen what shapes and colors to produce. Once the PDP malfunctions, images on the screen will appear blurry, discolored or misshapen. Vertical and horizontal red lines can also appear.
A professional repair shop or your TV manufacturer can replace or repair the PDP inside your plasma TV. Check your purchase date and any warranties that you purchased with your device. If you purchased your TV within the return window, you can return or exchange the TV. If your TV fails during the warranty window, you can receive free or discounted repair work and replacement parts through the TV manufacturer.