A problem with ejecting disks in those older, slot-loading iMacs can be caused by the age-related degradation of a pair of rubber sleeves that grip the disk, as it's pulled into the drive and ejected from it. Over time, they dry out and lose the grip factor. This causes them to slip, while attempting to eject the disk. My iMac DV 400 does this, but is able to push the disk out far enough to grab it by the edge. Some have suggested cleaning these rollers with a petroleum distillate solution, but that doesn't really restore them to like-new condition. Instead, it chemically softens their surface and makes them somewhat tacky. While this may help with gripping disks, it has the potential to permanently damage the rubber over time. The drive has a manual eject actuator at the far right end of the slot, that can be pressed with a large starightened paper clip . It may be partially covered by the platinum-colored dust gasket, so you can use a piece of cardboard to lift up the gasket at that spot, if necessary. If you've ever had the iMac's bottom housing removed for hard drive replacement, it's possible that during reassembly, the middle of the three interlocking tabs wasn't properly inserted in its slot, before pivoting the housing closed. You'd be able to verify this by feeling the joint (above the optical drive's slot) right in the middle, where the upper and lower housings meet. If the two surfaces are perfectly flush, the tab is engaged. If not, it probably isn't and this can cause a jam when trying to eject disks. If this is the case, reinstall the lower housing, making certain that all three tabs are aligned with the slots before pivoting it closed. This should only be considered, if the lower housing was removed for service.
