Is this a bad t con? Don't know much about t.v.

I have a 55 inch TCL roku tv. a couple months ago it started having vertical lines on the left side of the screen, so I switched it with the tv in the basement which we barely used. It occasionally would have so many lines that you couldn't even see the picture but after being on for a few minutes, it would call down and only hab e a few lines, and still be able to watch. Now the screen totally went black, but still has that I guess black glow, like when it is on an input with nothing connected. The sound is fine. could this be a t con problem? also, when the screen was working (still with lines) when I would power on, and it said “TCL"…. there were no lines, they would come right after this screen came on. Please help, I am broker than broke and can't afford a new t.v!