Gentle slaps, though...

Scanners have more delicate moving parts than most gizmos, and it'd be easy to knock something out of register, so don't welly it too hard. My (electronically experienced) gut tells me that this is not something that is likely to be fixed by the "broadband seismic impulse" approach...

First bet, software glitch; reload drivers, fiddle with settings, cold reboot and keep trying. Second bet, dry joint; a little resoldering might do it, if you know someone capable and confident enough to tackle it (Not me! I solder like a pidgeon pooing from several hundred feet!). Third bet, belt it one; nothing to lose...!