Welcome, I noticed that you were processed through the website's automated "introduction". Please understand that every visitor to the website gets those exact same computer generated responses, word for word. Honestly, had an actual technician welcomed you here, a very different greeting would have been presented.
At this point the tv needs diagnosis, parts, and service. I can help with that but with these symptoms, DIY diagnosis is going to be very complex (requiring a meter).
If you do not have the needed skills and tools then having it repaired by a local shop will end up costing around $350-$400. Just an in home diagnosis is usually at least $100 up front. You can compare that cost vs a new 50" tv. I can help you locate a repair shop near you, just reply back.
I'm sorry for the bad news. I do understand that finding out your tv needs expensive repairs is not pleasant but at least now you can make the most of your situation without high repair costs and long wait times. You saved a lot of time and money by coming here first.
Remember, I will be here with you throughout this entire process. Unless there is something else you can think of, please take a moment to submit at least a 3 star rating at the top of this page before you go. Rating now does not close your question or prevent future replies which are at no additional cost.