Sharp R1481 Manual

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SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. COOKING TIME PROGRAMMED
3. VARIABLE COOKING CONTROL HIGH
4. START PAD TOUCHED
Figure O-2. Oven Schematic-Cooking ConditionFigure O-1. Oven Schematic-Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2.  CLOCK APPEARS ON DISPLAY
MAGNETRON 
TEMPERATURE FUSE
FUSE 
20A
TURNTABLE
MOTOR
FAN
MOTOR
STIRRER
MOTOR
MAGNETRON OVEN LAMP
MONITOR
SWITCHBLK WHT
POWER
TRANSFORMER
HIGH VOLTAGE
CAPACITOR
0.94µF
HIGH VOLTAGE...

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DESCRIPTION AND FUNCTION OF COMPONENTS
DOOR OPEN MECHANISM
The door is opened by pulling the door handle, refer to the
Figure D-1.CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE TEST THE DOOR SENSING SWITCH,
PRIMARY INTERLOCK RELAY (RY2), SEC-
ONDARY INTERLOCK SWITCH AND MONI-
TOR SWITCH FOR PROPER OPERATION.
(REFER TO CHAPTER TEST PROCEDURE).
NOTE: MONITOR FUSE AND SWITCH ARE REPLACED
AS AN ASSEMBLY
TEMPERATURE FUSE (MG)
The temperature fuse located near the waveguide  is
designed...

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TROUBLESHOOTING GUIDE
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many
of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which
will be found in the Test Procedure section.
IMPORTANT:If the oven becomes inoperative because of a...

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CK = Check / RE = Replace
POSSIBLE CASE AND 
DEFECTIVE PARTS
PROBLEMTEST PROCEDURE
CONDITIONOFF

CONDITION
IDLE

CONDITIONMICROWAVE
COOKING
CONDITION

Home fuse blows when power cord is plugged into wall receptacle.
  
Monitor fuse blows when power cord is plugged into wall receptacle.
  
Display does not illuminate when power cord is first plugged into wall 
receptacle.
  
Display does not operate properly when STOP/CLEAR key is touched. 
(The time of day should appear on...

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BPOWER TRANSFORMER TEST
TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT 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. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check
across the magnetron filament leads should indicate less than 1 ohm.
5. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads...

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TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT 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. If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads
and check for short or open between the terminals using an ohmmeter.
Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate
continuity for a short time...

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TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT 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. Before performing this test, make sure that the secondary interlock switch and the primary interlock
relay are operating properly, according to the above Switch Test Procedure. Disconnect the wire lead
from the monitor switch (COM) terminal. Check the monitor switch operation by using the...

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IBLOWN MONITOR FUSE TEST
TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT 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. If the monitor fuse is blown when the door is opened, check the primary interlock relay, secondary
interlock switch and monitor switch according to the TEST PROCEDURE for those switches before
replacing the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR...

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TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT TEST
Resistance between;
BLU (1) AND YLW (4) = 0W(Shorted)
BLK (2) AND YLW (4) = 32W
BLU (1) AND BLK (2) = 32W
BLK (2) AND WHT (3) = 20W
WHT (3) AND RED (5) = 45W
123
45 BLU BLK WHT
YLW RED
6-PIN CONNECTOR
OF HOOD FAN MOTOR
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
LTOUCH...

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TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT TEST
7) Reconnect the power supply cord after the outer case is installed.
8) Run the oven and check all functions.
2.  Control Unit.
The following symptoms  indicate a defective control unit.  Before replacing the control unit, perform
the Key unit test (Procedure M) to determine if control unit is faulty.
2-1  In connection with pads.
a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads,...