If Marty's arm does not move freely, the arm gear may have been tightened too much during assembly, causing it to jam. Loosening the gear can allow the arm to move again. ===== Loosen the arm gear ===== Turn Marty off before adjusting the arm gear. - **Loosen the upper arm gear screw** by turning it anticlockwise, as shown in the demonstration below. - **Pull the upper arm gear slightly away from the body** until the arm moves freely. {{ :undefined:arm_will_not_move_1_.gif?nolink&316 |Loosening the upper arm gear screw and moving the gear slightly outwards}} The demonstration shows an arm that is jammed by an overtightened gear, then moving freely after the screw is loosened and the gear is eased outwards.