- Unplug machine
- Turn machine over and unscrew all screws (number of screws varies by model) to remove the bottom cover
- Swing the roller assembly (black piece with 2 wheels located in the center of the bottom) up to pull off
- Height adjustment knob will be visible
- Rotate knob by reaching around the front of machine to turn till it can be removed
- Insert replacement height adjustment knob (into front/top), rotate until secured
- Replace roller assembly, insert tabs into notches and swing down
- Reattach bottom cover & secure with screws
