G E Monogram Trash Compactor
I found the problem (I think). The threaded hard plastic nut that the drive screw powers the scissors up and down with was cracked, and giving itself up toward the end of it's life. It looks like it went on the downstroke and didn't have enough friction in the broken part to raise the ram. Thank you for your advice, and I hope this helps other do it yourself types solve what looks to be a common weakness in these machines.