Sharp R-320BB Service Manual page 21

PROCEDURE
LETTER
(1) Disconnect the power supply cord, and then remove outer case.
(2) Open the door and block it open.
(3) Discharge high voltage capacitor.
(4) Disconnect the sensor connector that is mounted to control panel.
(5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.
(6) Disconnect the leads to the primary of the power transformer.
(7) Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
(8) After that procedure, re-connect the power supply cord.
(9) Check the sensor cook operation proceed as follows:
9-1. Touch Reheat pad once.
9-2. The control panel is in the sensor cooking operation.
9-3. After approximately 20 seconds, push plunger of select switch for more than 3 seconds. This
9-4. After approximately 3 seconds, the display shows " X X . X X " which is the remaining cooking
time, and the display count down.
If the above is not the case, the control unit is probably defective.
If the above is proper, the AH sensor is probably defective.
(10) Disconnect the power supply cord, and then remove outer case.
(11) Open the door and block it open.
(12) Discharge high voltage capacitor.
(13) Disconnect the dummy resistor circuit from the sensor connector of control panel.
(14) Carry out necessary repair.
(15) Reconnect all leads removed from components during testing and repairing.
(16) Re-install the outer case (cabinet).
(17) Reconnect the power supply cord after the outer case is installed. Run the oven and check all
functions.
(18) Carry out "Water load cooking test" again and ensure that the oven works properly.
TEST PROCEDURES
CHECKING CONTROL UNIT
condition is same as judgement by AH sensor.
To connector (F)
on Control Unit.
1
F-1
2
F-2
3
F-3
CONNECTOR
Sensor Dummy Resistor Circuit
COMPONENT TEST
R1, R2 : 22 1% 1/2W
R3 : 4.3k 5% 1/4W
R4 : 1M 5% 1/4W
COM
R1
R3 R4
R2
19
Plunger
NC
NO
COM
NO
NC
R-320BB
R-320BK
R-320BW