Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Often enough, if one channel has a problem, but the other channels are OK, it is a problem at the upstream end of the transmissions of channels, and not at all a problem with your TV.
In fact I cannot recall even one instance where such a problem was eventually proved to be at your end, or in the TV.
You should try inquiring - if it's broadcast TV, inquire with the channel itself, Channel 7.
If it's cable TV, inquire with your cable service provider (e.g. Comcast, etc)
It may be a problem everyone else is reporting too. They may be working on it. And getting your subscriber info with regard to the problem, may localize the problem for them and help with troubleshooting.