Abstract: Apparatus and method for detecting a failure in an automatic defrost system for a refrigerator. A current sensor means monitors the current supplied to the defrost heater and generates an "on" signal when current is sensed in the defrost heater circuit. A microprocessor determines the "off" time, that is the time between successive "on" signals, and compares this time to a predetermined reference time longer than the normal "off" time. A user discernible signal is generated upon detection of an "off" time greater than the reference time, signifying to the user that the defrost system is not operating properly, and corrective action may be necessary.

Abstract: An improved over-temperature warning system for a refrigerator/freezer appliance comprises a temperature sensor responsive to the temperature in the freezer compartment of the appliance and logic circuitry responsive to the sensor operative to detect a first over-temperature condition when the sensed temperature is greater than a first reference temperature and less than a second reference temperature and to detect a second over-temperature condition when the sensed temperature is greater than the second reference temperature. The logic circuitry times the duration of the first and second over-temperature conditions and provides a user discernible warning signal when the first condition exceeds a first predetermined time period or when the second over-temperature condition exceeds a second predetermined time period shorter than the first time period.

Abstract: Apparatus and a method for detecting fault conditions in an automatic icemaker system of the type having an ice forming mold and an electric motor and mold heater which are energized during ice cube ejection cycles. A current sensor monitors current in the icemaker motor and mold heater circuit and generates an "on" signal when current is detected. A microprocessor measures the duration of the "on" signals and the elapsed time between successive of "on" signals. A diagnostic code is displayed signifying a fault condition in the icemaker circuit when the time between successive "on" signals is less than the normal time required to freeze cubes or the duration of an "on" cycle exceeds the normal ejection time.

Abstract: A capacitive attenuator type touch switch cell arrangement employs a touch responsive pad or electrode and a receiver electrode of comparable surface area on opposing surfaces of a dielectric substrate for capacitive coupling therebetween, which capacitive coupling is alterable by the human touching of or proximate to the touch pad. A scan signal is coupled from signal generating circuitry to the touch responsive pad by a separate transmitting capacitor. Signal detection circuitry senses the signal coupled to the receiver electrode to detect attenuation of the coupled signal signifying the touching of the touch pad. The use of a separate capacitor to provide the transmitting capacitance reduces the touch pad area requirement, thereby permitting closer spacing of touch switch cells for greater switch density on a control panel.

Abstract: A start circuit arrangement for a microwave oven including a power control relay circuit which is independently responsive to a user actuable momentary start switch and to a programmed electronic controller to facilitate operation in a delay start mode. The relay circuit includes a start latch circuit, a door switch and an arm switch. User actuation of the momentary start switch sets the latch circuit. A signal from the electronic controller resets the latch circuit. The door switch is closed by closure of the oven door. The arm switch is closed by an arm signal from the electronic controller when an actual cooking cycle is to begin. The arm signal is removed upon expiration of the cooking cycle. The arm switch, start latch means and door switch are all operatively coupled to the relay such that the relay only enables energization of the power circuit for the oven when the arm switch and door switch are closed and the start latch is set.