Compactor Piston stays down even though the motor is running

If the drawer is stuck because the piston is in it, you will have to take the back off to lift the piston in order to remove the drawer.

With the drawer out, tip the compactor on its back to easily maneuver the otherwise heavy piston. Working from the front remove the trunnion nut cover (two hex screws) and then the bad trunnion. You may need to move the front of the piston up or down to release the nut.
Remove all the debris and wipe the shaft from old grease and debris.
Grease the shaft with supplied grease. With the piston about 1/3 of the way down, screw the new trunnion nut until it touches the housing. Move the front of the piston up or down to seat the nut. Put the nut cover back on and screw it in position.
The whole job took less than 30 minutes.