Lines across the LCD screen

Two things can cause lines across the LCD either horizontal or vertically. The first (and most likely) is a small crack in the display wafer. LCD stands for Liquid Cristal Display. They are very fragile and can be easily damaged if dropped. I broke one in my pants pocket.

The second would be if a pin on the ribbon cable (to the LDC wafer) was not making good contact. If you disassemble the camera it is possible to clean the contacts using contact cleaner (or alcohol). Only attempt this is you are willing to replace the camera if you don’t put it back together properly.