C.H.
My husband is a tv repair tech. He says a software update might fix the problem through the usb. Or you might be able to adjust the drives in the service menu. If you can't adjust the drives, it is probably the main board. On a big screen he has never seen the blue and red crt go out. Probably a bad focus block. Big screens last about 15 yrs., flat screens lasts about 4 yrs. If you can find a tech up there that knows what he's doing, it can probably be fixed. His repairs average $200. If you can buy a new tv for that price, please tell me where.