A bad screen or an inverter board can cause problems with the picture quality on your LCD TV. Diagnose problems with these components by looking for a number of different visual clues. The type of issue you find can also help you determine which component needs to be fixed or replaced.
Look for color issues. If certain parts of the screen always display as black or white, this could indicate dead pixels within your LCD screen. This issue is caused by a manufacturing defect or by broken transistors, and means the affected crystals are either always receiving electricity, in which case they are black, or never receiving electricity, in which case they are white.
Inspect the screen for any cracks, chips or other damage. If your screen is damaged, it could cause parts of the screen to become discolored, blurry or blank. Due to the structure of LCD screens, damaged screens can't be repaired and need to be replaced.
Turn on the television. If the screen is blank but the audio is playing normally, this indicates a problem with the inverter. Likewise, if the picture disappears or flickers on and off, but the audio is normal and the TV is still powered on, this can also signal that the inverter needs repairing or replacing.