Hi, My HCN553W TV turns on but after about 10 minutes, the right and left sides of the picture start to close in and the tv cuts off. When I press the power button, the red light on the TV turns on and remains on but there is no picture or sound. I then have to unplug the TV and plug it back in. When I press power again, the TV turns on but only lasts about 5 to 10 minutes before it cuts off again. Please tell me what part I need to order. Thanks.