Sharp R-420DK, Service Manual

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17
R-420DK
R-420DW
WARNING : The oven should be fully assembled before following procedure.
(1) Place one cup of water in the center of the turntable tray in the oven cavity.
(2) Close the door, touch the " steaks / chops " pad once.
(3) The oven is in Compu Defrost cooking condition.
(4) The oven will operate as follows
1ST STAGE 2ND STAGE
WEIGHT
LEVEL TIME LEVEL TIME
0.5lb 60% 25sec. 40% 20sec.
6. Re-install the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
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 leads to the primary of the power transformer.
5. Ensure that these leads remain isolated from other components and oven chassis by using insulation
tape.
6. After that procedure, re-connect the power supply cord.
7. Remove the outer case and check voltage between Pin No. 1 of the 2 pin connector (A) and the
common terminal of the relay RY1 on the control unit with an A.C. voltmeter.
The meter should indicate 120 volts, if not check oven circuit.
RY1 and RY2 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated ............. Defective relay.
DC. voltage not indicated ........ Check diode which is connected to the relay coil. If diode is good,
control unit is defective.
RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS
RY1 Approx. 24.3V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 Approx. 23.4.V D.C. Power transformer
8. Disconnect the power supply cord, and then remove outer case.
9. Open the door and block it open.
10. Discharge high voltage capacitor.
11. Reconnect all leads removed from components during testing.
12. Re-install the outer case (cabinet).
13. Reconnect the power supply cord after the outer case is installed.
14. Run the oven and check all functions.
L COMPU DEFROST TEST
Key Unit
K RELAY TEST
5
4
3
2 1
0 9 8 7 6
START
BEVERAGE
POPCORN
Power
Level
MINUTE
PLUS
Fresh
Rolls/
muffins
Frozen
entrees
CUSTOM
HELP
Ground Meat
(SENSOR COOK)
Stop
Clear
Fresh
vegetables
G 8
G 9
G10
G11
G12
G13
G14
G 7 G 6 G 5 G 4 G 3 G 2 G 1
Chicken
Pieces
Steaks/
Chops
Baked
Potatoes
Frozen
Vegetables
Clock
Kitchen
Timer
Fish
Seafood
Frozen
Rolls/
muffins
Ground Meat
(COMPU DEFROST)
SENSOR
REHEAT
Rice
Chicken
Breast