When using HDMI port the image is pastel like. I have had a service man in to check out my

Question

I have had a service man in to check out my Phillips 50" Plasma TV. He told me the board/box where you attach all the inputs and outputs is bad. He has ordered the part 4 times and every time he states that the board/Box is bad. He may be correct... but 4 times. That seems off. When he substitues the board/box the TV only gets sound, no picture. Now he is saying he can't fix it. He is getting the parts direct from Phillips but I have to admit, the parts always look like pulls. They are never pristine like you would expect from a new part. They do come in boxes directly from Phillips as I have seen. I am trying to find the part number for this. My TV is a 50PF7220A/37. I am also trying to find where I can get this part. Thanks in advance for any help you can give me. Craig