You can manually rotate the carousel by opening the door where the toner/transfer belt/drum unit/waste bin are located. There is a small slot opening just to the left of the opening to the toner itself. Put a flat blade screwdriver into the slot pushing in the round "button" behind it inward. This will unlock the carousel while pushed in and allow the carousel to be manually rotated one direction. Watch your fingers it can bite you, especially when one cartridge is already removed. Alignment is critical, the toner needs to be centered or it will not clear the opening.