My Technika Advanced 26'' TV is humming to me! Why?

My Technika Advanced 26'' HD Digital LCD TV makes a buzzing/humming sound, quite loudly when the picture goes dark, whilst still being annoyingly noticeable when the screen is lighted normally. Only when the picture is displaying an abnormal level of brightness, say an explosion or something, does the sound cease. Why is this so, and how can it be remedied? Or should I just ask for my money back?