Display shows numbers and letters, but is not moving or advancing. Fuse has blown. If the fuse blows again on a particular station, that station's solenoid or field wires may have a short circuit that needs repair. Power is off to the controller. Determine why power to the controller has been interrupted, and re-establish power.
Display is blank.
If the controller is still receiving power, an electrical surge exceeding the controller's built-in surge protection may have damaged the controller's microprocessor. Unplug the controller and remove the battery. Wait two minutes. Then re-install the battery, and plug the unit in. If numbers and letters return to the display, the power surge did not do permanent damage.