When a television screen displays a blurry picture, it is an indication that something is wrong. A blurry television display can have a number of causes, ranging from incorrect television settings to using an incompatible cable box. In most cases, a blurry picture can be fixed by troubleshooting and finding the source of the problem, which will point the way to a fix.
Unplug the power cord from the TV and plug it into a different outlet. The current electrical outlet could be delivering interference, cause the display to blur. A high-quality surge protector will often help eliminate electronic interference.
Move nearby electronic devices away from the television. Computers and other electronic equipment as well as household appliances are often the source of electrical interference responsible for a blurry picture.
Inspect the cable connections between the television and the cable box. Ensure that you are using the correct cables; on a high-definition TV, use HDMI cables, which are specifically designed to transmit high-definition signals to the television. Do not use analog cables or RCA connectors with this type of TV. RCA connectors are commonly colored red, white and yellow.
Turn off the digital noise reduction feature on the television. Digital noise reduction adjusts the natural image of the picture displayed on the screen by changing lighting levels, sharpness and other visual properties. Sometimes, this setting can interfere with picture quality, causing it to degrade.
Review the specifications of the television and the cable box. If the TV is high-definition (HD) but the cable box is not, upgrade the cable box and replace it with an HD-compatible model. HDTVs will not display a proper picture without an HD cable box.
Adjust the display settings until the picture is no longer blurry. If you watch a standard-definition channel on a HDTV, the picture will be stretched out and distorted to fit the television screen. Adjust the display settings so the picture doesn't appear stretched or distorted.
Close the curtains and turn off the lights in the room where you are viewing the television. Glare on the screen can reduce the quality of the picture.