The calculator screen does not work properly

The screen only displays every other line or so of pixels so that the text on screen comes up in stripes of blank and pixellated parts running vertically. I've tried using different faceplates, but the same problem arises. Now the screen displays nothing. There is no physical damage to the screen.

There was some battery corrosion, but that was fixed and the batteries were replaced. I've opened it up and there are no obvious signs of the corrosion moving further than the battery compartment. Is the issue in the screen, the connectors, or what?