I have 1080p 60hz TV that I sometimes use as a PC monitor via HDMI, out of warranty. Recently, whenever I open it I see a few of these vertical lines in different spots on the screen, all of them towards the left side. What's odd is that after a while, and while the TV is on, they start getting smaller, and after about 30-50 minutes they've usually completely disappeared. They reappear again when I turn it on, after it's been off for a few hours, (during the night for example). I've already confirmed that neither the PC nor the cable is responsible, the lines appear even when it's not connected to anything. It's never been hit. Any idea what could be causing it or what I might be able to do about it?