Sharp R-3H57 Service Manual page 19

PROCEDURE
LETTER
(1) Disconnect oven from power supply and remove outer case.
(2) Discharge the high voltage capacitor.
(3) Remove the AH sensor.
(4) Install the new AH sensor.
(5) Re-install the outer case.
(6) Reconnect the oven to the power supply and check the sensor cook operation proceed as follows:
6-1. Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
6-2. Place the container on the center of tray in the oven cavity.
6-3. Close the door.
6-4. Touch Reheat Beverage pad once.
6-5. The control panel is in automatic Sensor operation.
6-6. The oven will turn off automatically after the water is boiling (bubling).
If new sensor dose not operate properly, the problem is with the control unit.
(1) Disconnect oven from power supply and remove outer case.
(2) Discharge the high voltage capacitor.
(3) Disconnect the wire leads from the cook relay.
(4) Disconnect the sensor connector that is mounted to lower portion of control panel.
(5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.
(6) Reconnect the oven to the power supply and check the sensor cook operation, proceed as follows:
6-1. Touch Reheat Beverage pad once.
6-2. The control panel is in the sensor cooking operation.
6-3. After approximately 20 seconds, push plunger of select switch. This condition is same as
6-4. After approximately 3 seconds, cooking operation turns off, an audible signal will sound,
If the above is not the case, the control unit is probably defective.
If the above is proper, the AH sensor is probably defective.
TEST PROCEDURES (CONT'D)
judgement by AH sensor.
and the display will then revert to the time of day.
To connector (F)
on Control Unit.
F-1
F-2
F-3
CONNECTOR
Sensor Dummy Resistor Circuit
COMPONENT TEST
CHECKING CONTROL UNIT
1
2
R1
3
R3 R4
R2
R1,R2 : 22 1% 1/2W
R3 : 10k 5% 1/4W
R4 : 1M 5% 1/4W
17
Plunger
NC
NO
COM
NO
COM
NC
R-3H57