Procedure Q: Ah Sensor Test - Sharp R-990KS Service Manual

Convection microwave oven

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Operation manual (41 pages)

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Table of Contents

R990K(W)

The rated voltage is applied to primary side of power transformer.

Only pattern at "a" is broken.

Pattern at "a" and "b" are broken.

NOTE: *At the time of making these repairs, make a visual inspection of the varis-

tor.check for burned damage and examine the transformer with an ohmmeter

for the presence of layer short-circuit (check primary coil resistance). If any

abnormal condition is detected, replace the defective parts.

CARRY OUT 4R CHECKS.

[17] Procedure Q: AH SENSOR TEST

Checking the initial sensor cooking condition

1) The oven should be plugged in at least two minutes before sensor cooking.

2) Room temperature should not exceed 35°C.

3) The unit should not be installed in any area where heat and steam are generated.

The unit should not be installed, for example, next to a conventional surface unit.

Refer to the "INSTALLATION Instructions".

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 the oven is started on sensor cooking condition, 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 two minutes before checking sensor cook operation.

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 REHEAT SENSOR pad twice and touch INSTANT COOK/START pad. Now, the oven is in the sensor cooking condition and "SOUP", "SEN-

SOR" and "REHEAT" will appear in the display.

5) The oven will operate for the first 16 seconds, without generating microwave energy.

When the AH sensor is defective (open or short), ERROR will appear in the display after 16 seconds cleaning time

.If ERROR appears check sensor wire connections and/or AH sensor.

NOTE: ERROR will appear if the door is opened or STOP/CLEAR pad is touched during first stage of sensor cooking.

6) After approximately 16 seconds, microwave energy is produced, and the display should start to count down the remaining cooking time and oven

should turn off after water is boiling (bubbling).If the oven does not turn off, replace the AH sensor or check the control unit, refer to explanationbe-

low.

1. 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:

a) Fill approximately 200 milliliters (7.2 oz.) of tap water in a 1000 milliliter measuring cup.

b) Place the container on the center of tray in the oven cavity.

c) Close the door.