Tv turned on I changed channel then screen went pink for about a second then went black. When power applied, led comes on and goes off as normal when power button pressed. The screen lightens momentarily but returns to permanent black. There is no sound. I have checked all the voltages on the boards and connecters as described in the service manual and they all seem OK. There is a very slight hum on the Y board so any help would be appreciated. Thanks in anticipation.