Tub would occasionaly not empty.

This is the second timer over the years and the original plastic know was replaced a while back with a good knob with steel insert. Fix required unplugging power cord, removal of two screws at the lower front corners of the control panel, spinning off the control knob, popping of the plastic dial, flipping up the panel, removing the two screws that hold the timer, disconnecting the two power connectors, then installing new timer in the reverse order. Note I used two smaller screws that fit the non tapped holes in the timer.