To operate an old slide projector, first gather slides, and arrange them one at a time in the slide carousel. Slide the carousel into place, and attach it. Turn the projector on by flipping the switch or button on the top panel of the projector. Find the focus buttons and adjust the image as needed. Switch the slides using the advance or reverse buttons.
In order for the slides to be visible, the viewing area needs to be a solid white screen, sheet or wall. Many slide projector carousels only hold 80 slides. If you have more than 80, make coherent slide groupings or use multiple carousels, if available.. Place the projector on a steady, flat surface. Because it moves when in use, the stand it is on needs to be heavy enough to prevent shifting, which affects the focus.
If viewing slides in the daytime, use the projector in a room without windows, or use blackout curtains or blankets to minimize the light. If the room is already as dark as possible but the slides are still too dim, check the light source, the mirror and the heat protector for smudges. Replace the light source, if needed.
Do not leave the projector on too long to prevent overheating. Always store the slides in a safe place when not in use. Store the projector in a safe place as well. Cover it to prevent dust, scratching or additional damage.