LCD screens cannot self-illuminate, and require a third-party backlight to brighten the colors produced by the liquid crystals. VIZIO's LCD TVs use two types of backlights: cold-cathode fluorescent lamps, or CCFLs, and light-emitting diodes, or LEDs. While VIZIO claims its LCD TVs last up to 100,000 viewing hours, most LED and CCFL backlights have just a fraction of that longevity. Before your backlight burns out completely, it will show warning signs, such as flickering, flashing, a pinkish hue and dimming. Even if your backlight is dead or dying, the liquid crystals will still produce their colors: shining a flashlight at a 45 degree angle allows you to see those colors, signifying that the screen itself is still working, but that the backlight doesn't have enough power to illuminate it.
Inverter failure can also cause your VIZIO's screen to flicker. The VIZIO's master inverter supplies a constant source of energy to the TV, while the slave inverter actually lights the lamp. If either one of these inverters is damaged, it will prevent enough electricity from reaching the backlight. To test the inverter board, remove your TV's back panel using a screwdriver and gently set it aside. Disconnect the backlight connector from your VIZIO's inverter board and connect it to a multimeter. The voltage displayed on the multimeter should read between 12 and 20 volts. If it's any lower than that, the inverter won't have enough power to illuminate the backlight properly.
An improperly connected cable -- whether it be a power cord or a coaxial cable -- can lead to a screen that flickers. Check the connection for your power cord and cable outputs, located on the bottom rear of your VIZIO TV. The connections should be secure, and the cables extending from them should be free from any damage, including any crimped or frayed portions.
The images on your VIZIO's screen are only as strong as the signal the television receives. If you subscribe to cable or satellite service, a weak signal could cause a screen to flicker or flash, as well as a wide range of audio and video problems, including distorted audio, pixelation and freeze framing. If you subscribe to satellite service, make sure your satellite dish is properly aligned to receive the strongest signal possible. Next, try resetting your set-top receiver box by unplugging it temporarily from its power source. This forces the box to automatically scan for the latest software and programming updates from your service provider.
Certain settings on your VIZIO TV can create a flickering screen. Use your remote to access your Advanced Video settings menu and select "Backlight Control" -- increasing or decreasing the brightness of your backlight can eliminate flickering. Additionally, some VIZIO TVs -- like the E470VL -- have an ambient lighting sensor which tracks changes to the lighting in the area immediately surrounding your television. Turning off this sensor inside the Advanced Video settings menu may also solve the problem. Other VIZIO models, like the SV470VXT, have an Advanced Adaptive Luma setting, which automatically adjusts the brightness and contrast of your onscreen picture. VIZIO suggests turning this feature off to reduce flickering.