It may be the HDMI or main board. Since you don't know the model number no one can guess much more. Get repair estimates.
I am not very tech-savvy with TVs, so I will do my best to explain the problem with the most detail that I can. I have a 60" plasma TV (I am not sure what model it is). There are two HDMI ports on the back of the TV. It has worked fine until just the other day. I turned it on but certain things were not working. To break it down:
When the X-box is plugged into either HDMI port (yes, I moved them around to see if it was a certain port) it will display in standard definition (SD) with no audio. The cable box when plugged into either port with show the start up prompts for the xfinity X1 platform but when the cable is able to stream the screen displays in blue only.
When either device is plugged into a different TV however, they both work with no issues, so I was able to determine if the TV was the problem. The TV is about five years old and I know plasmas tend not to last along, but because some things are still displaying I was hoping to not have to replace it.
Any ideas? Thank you!

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