Neither the upper nor lower part of the unit will start.
The lights come on in each bay if the respective door is opened. The control panel lights up and all the buttons cause a beep when pressed. The green light next to the Time Dry button does not light up and if pressed when the dryer is completely off then the Sensor Dry mode is activated. Pressing the Start button for either the upper or lower dryer turns off the entire dryer without any sort of pretense at starting - no rumble, no sound of turning over, nothing at all.
A service man was here and tried replacing the circuit board but to no avail.
My guess is a fuse of some sort.