I have found that the two guide plates that the board moves between are too low, & the board sometimes rides over them. Here is an easy fix: for the non-moveable one, grasp each end with a pair of pliers & bend it upwards slightly, so it rides higher up the side of the board. For the moveable one, remove it from the machine [undo the two screws on top of it at its centre & then slide it away from the keypad side till it gets past the side of the drive belts & then lift it upwards]. A tab is bent inward on each end of it, which slides along the machine chassis. Use the pliers to straighten it a bit, then replace the guide & it also will ride higher up the side of the board.