My experience of ancient CRT devices is that the display gets gradually dimmer. I once had a TV that was only really usable after dark -- but that's the only ti

My experience of ancient CRT devices is that the display gets gradually dimmer. I once had a TV that was only really usable after dark -- but that's the only time I wanted to use it anyway -- and a huge Sun monitor that was only just about readable in total darkness, but we kept it because we also had a Sun server that we didn't know how to connect to any other monitor and we were worried that one day we wouldn't be able to SSH to it, but in fact the server never once failed.