Sharp R-1880LS Service Manual page 31

PROCEDURE
LETTER
should be installed and screws tightened.
(1) Fill approximately 00 milliliters (7. oz) of tap water in a 1000 milliliter measuring cup.
() Place the container on the center of tray in the oven cavity.
(3) Close the door.
(4) Touch SENSOR COOK pad. And touch the number pad 1. And touch the start pad. The oven will operate for
the first 3 seconds, without generating microwave energy.
NOTE: ERROR will appear if the door is opend or STOP/CLEAR pad is touched during first stage of sensor
cooking.
(5) After approximately 3 seconds, microwave energy is produced, oven should turn off after water is boiling
(bubling).
If the oven does not turn off, replace the AH sensor or check the control unit, refer to explanation below.
To determine if the sensor is defective, the simplest method is to replace it with a new replacement sensor.
(1) Disconnect oven from power supply and remove outer case.
() Open the door and block it open.
(3) Discharge the high voltage capacitor.
(4) Remove the AH sensor.
(5) Install the new AH sensor.
(6) Reconnect all leads removed from the components during replacing.
(7) Re-install the outer case.
(8) Reconnect the oven to the power supply and check the sensor cook operation proceed as follows:
9-1. Fill approximately 00 milliliters (7. oz) of tap water in a 1000 milliliter measuring cup.
9-. Place the container on the center of tray in the oven cavity.
9-3. Close the door.
9-4. Touch SENSOR COOK pad. And touch the number pad 1. And touch the start pad.
9-5. 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.
() Open the door and block it open.
(3) Discharge the high voltage capacitor.
(4) Disconnect the wire leads from the cook relay.
(5) Disconnect the sensor connector that is mounted to lower portion of control panel.
(6) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.
(7) Reconnect the oven to the power supply and check the sensor cook operation proceed as follows:
7-1. Touch SENSOR COOK pad. And touch the number pad 1. And touch the start pad.
7-. The control panel is in the sensor cooking operation.
7-3. After approximately 3 seconds, push plunger of select switch. This condition is same as
judgement by AH sensor.
7-4. After approximately 3 seconds, cooking operation turns off, an audible signal will sound, and
the display will then revert to the time of day.
If the above is not the case, the control unit is probably defective.
If the above is proper, the AH sensor is probably defective.
Sensor Dummy Resistor Circuit
TEST PROCEDURES
COMPONENT TEST
TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT
CHECKING CONTROL UNIT
To connector (F)
on Control Unit.
F-1
F-2
F-3
CONNECTOR
31
R1,R2 : 22 ohm ± 1% 1/2W
R3 : 10k ohm ± 5% 1/4W
R4 : 1M ohm ± 5% 1/4W
1
2
R1
3
R3 R4
R2
R-1880LS/LST
Plunger
NC
NO
COM
NO
COM
NC