Suggestion:
most LCD panels are driven from a T-Con or LCD control board which outputs the signal via two flex cables. One cable runs the left side and the other controls the right side. your problem could be a loose connection on this flex cable, the T-Con board, or the panel. Many times the T-Con cannot be purchased separately from the panel. This is dependent upon the manufacturer and the model. I'm not familiar with the model you listed, I hope the cable is your problem.

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You need to make adjustment with your remote that comes with the LCD TV.
For instructions go to ehow.com