Similar to any other TV, an Insignia TV set may run well for a long stretch of time but suddenly encounter a problem that renders the TV either unusable or partially crippled. Cable connections, video input settings and magnetization issues are common problems that can all affect your Insignia TV, but there are steps you can take to diagnose these issues and alleviate their symptoms whether or not you have experience with troubleshooting.
Make sure your Insignia TV is properly plugged in. This includes checking to make sure the power and assorted cable connections are plugged in and have not come loose or disconnected. Make sure the power cord is firmly plugged into either the wall outlet or the surge protector.
Check the Insignia's display for noise or what appears to be moving white dots. Even if the coaxial cable appears to be firmly in place in the back of the Insignia TV and has not become disconnected, it may need to be fastened tighter into the cable port. If not properly in place, the loose coaxial cable can cause distortion on the Insignia TV's display, most commonly referred to as "snow." This noise on the display can be remedied by refastening the coaxial cable so that it is more snug in its port.
Check the A/V cables that hook up your cable or satellite receiver into the back of your Insignia TV. The A/V cables have a set of prongs on either end, with three prongs to each set. Each set has one red, one white and one yellow prong. Take note that the A/V ports for these prongs on the back of the TV and the back of the cable/satellite receiver are also red, white and yellow. Ensure that the A/V cables are color-matched and in the appropriate ports.
Check the video input on your Insignia TV. When using an external, connected device such as a game system or a DVD player, the video input must be switched in order for the device's content to display correctly. You may have simply forgotten to switch the video input back to the regular cable/satellite TV input, resulting in a lack of a cable/satellite feed. Find the "Input" button on your remote and use it to toggle back through your video input options until you reach the cable/satellite input.
Check your Insignia TV's display for blotches. TVs--particularly of the big screen variety--can suffer from magnetization brought on by other electronic devices that are improperly placed too close to the TV. This results in blotches on the display. Use a large magnetic coil (see Resources) to alleviate this problem. Slowly wave the coil in circles close to the front of the Insignia TV's display to demagnetize the TV and repair the display.