Understood. This indicates an issue with the TV itself vice the various inputs. Have you checked around your local area for estimates to fix TVs like yours?
Honestly, for the cost and hassle of getting it repaired, it might just be time for a new HDTV (5 years is a good run).
Well $250 to fix it is still not to bad for a 65" but it is up to you as to weather you want to spend that much on such a old TV on the other hand you are not going to get a 65" for even $250 so there is that.
What model is yours?