Sharp R-990C Service Manual page 20

R-990C(S)
PROCEDURE
LETTER
STEPS
1
2
3
4
NOTE: *At the time of making these repairs,
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", "SENSOR" 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
(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 explanation
below.
TEST PROCEDURES
OCCURRENCE
The rated voltage is not applied between Pin
No. 9 of the 5-pin connector (A) and the
common terminal of the relay RY1.
The rated voltage is applied to primary
side of power transformer.
Only pattern at "a" is broken.
Pattern at "a" and "b" are broken.
make a visual inspection of the varistor.
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.
of sensor cooking.
COMPONENT TEST
CAUSE OR CORRECTION
Check supply voltage and oven power cord.
Power transformer or secondary circuit defective.
Check and repair.
*Insert jumper wire J1 and solder.
*Insert the coil RCILF2003YAZZ between "c" and "d".
18
d
b
a
c