I have a 12-year old Sony TV.  We have a good old-fashioned terrestrial aerial and Freeview. Recently the picture started to break up on a range of channels and there were increasingly horizontal pixelated bars of interference on the screen with audible clicks also present.

I have tried Digital Auto Tuning. Sometimes the TV finds zero channels, sometimes up to 80 or so.  If it finds channels, there is no signal at all now. Not even the pixelated poor-quality signal. 

I have checked aerial connections. I have checked the booster in the loft. I have checked for local transmitter changes. I have checked that neighbour's' signals are OK. Ruled out all of those.

I have plugged in an Aerial Signal Strength Monitor. Full row of green lights.  I have plugged in another digital TV set at the same location and retuned it. Perfect set of channels found, perfect reception on them all.

My conclusion, having ruled out everything else I can think of, is that the problem is with to the TV set itself. Does this sound like the sort,of thing that can happen to a TV?  Is there's anything else I can try? Is it time to replace It?

Thanks!