Horizonral lines on screen

@bsearle that is usually caused by a bad panel. You would need to remove the back of the TV set and try to get to the ribbon cables that enter the panel. Then put some pressure on those flat ribbon cable near where the lines appear. If this changes the lines, you will have a TAB error. No easy fix with that. Sometimes applying some strong tape over the ribbon cables to exert extra pressure may help for a while. It will help if you can post some images of what your screen shows, as well as what your set looks like with the rear cover removed, we might be able to assist you further. Use this guide for that so we can see what you see.