Most all overhead projectors in the classroom have a built-in lamp changer. Lamp changer location is noted with a sticker on the machine. In some units, the changer is located underneath the top cover. Prior to changing lamps, make sure that the power to the overhead is turned off. If you notice either blue or brown edging in the corners of the screen image, the tuning dial may alleviate the problem.
Clean acetate is located on the rolling stand under the overhead.
If you run out, simply remove the cardboard acetate core from the front of the machine and place it on the rear roller assembly, placing the new acetate on the front. The IMC uses several different models of slide projectors in the classroom. Each have similar features and functions. However, their locations are often different. The purpose of the timer is to allow the slides to automatically advance after a specified time.