My Broan 1051D was quite full. I compacted additional trash and near the bottom of the stroke, when I usually hear the ram reverse and begin its upward return, there was a house-shaking "pop" (as if a major metal part had sheared). Unlocking and then relocking the door latch caused the ram to return to the top position, as usual. I replaced the bag with an empty, and tried the cycle again. The ram bottomed out but did not automatically return to the top position, instead, it seemed to cycle through an up/down motion for a second or so. Unlocking/relocking the door latch caused the usual retun to the top position.
I have removed the back and visually inspected the works, from a layman's viewpoint. There are no apparent sheared bolts or shafts, no apparent broken welds, no teeth missing from any of the gears, and an apparently healthy chain.
Any ideas?