[. . . ] Disconnect the power cord and unplug the power cord from the AC socket after the cooling fan stops. [. . . ] Disconnect the power cord and unplug the power cord from the AC socket after the cooling fan stops. Do not attempt to exchange the lens when the projector is installed hanging from the ceiling. Push the LENS RELEASE button all the way in and turn the lens anti-clockwise. The lens is secured by the above method, but for added security, an anti-theft screw is supplied to secure the lens more tightly. â· The screw is designed to be rather long, and to secure the screw, give it about 40-50 turns. [. . . ] The lens is secured by the above method, but for added security, an anti-theft screw is supplied to secure the lens more tightly. [. . . ]