A method and apparatus for conversion of signals from a first type of image sensor to a second type of camera control unit is presented. An anchor fixing agent which comprises an alumina cement, a lime andor a portland cement, and water. The invention also relates to a device for carrying out said method. Means is further provided of allowing the directions of intake and exhaust to be inverted in an entire device by changing the direction of rotation of an exhaust fan provided for the cooling system for the area around the lamp between forward and backward.