Sharp R-4H55 Service Manual page 20

TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity.
To permit adequate ventilation, be sure to install so as not to block these vents. There should be
some space for air circulation.
(5) Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any
moisture with a dry cloth or paper towel.
(6) The Sensor works with food at normal storage temperature.For example, chicken pieces would
be at refrigerator temperature and canned soup at room temperature.
(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The
sensor will detect the vapor given of by the spray and turn off before food is properly cooked.
(8) After about 41 minutes if the sensor has not detected the vapor of the food, ERROR will appear
and the oven will shut off.
Water load cooking test
Make sure the oven has been plugged in at least five minutes before checking sensor cook opera-
tion. The cabinet should be installed and screws tightened.
(1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
(2) Place the container on the center of tray in the oven cavity.
(3) Close the door.
(4) Touch SENSOR COOK pad and number pads 1 and 0. Now, the oven is in the sensor cooking
condition and SC-10 will appear in the display.
(5) Touch Start pad.The oven will operate for the first 16 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.
(6) After approximately 16 seconds, microwave energy is produced, oven should turn off when
water is boiling (bubling).
If the oven does not turn off, replace the AH sensor or check the control unit, refer to explanation
below:
TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT
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.
(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:
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6-l. 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 SENSOR COOK pad and number 1 pad and 0 pad.
6-5. Touch Start pad. The control panel is in automatic Sensor operation.
6-6. The oven will turn off automatically when the water is boiling (bubling).
lf new sensor dose not operate properly, the problem is with the control unit.
CHECKING 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:
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