Sharp R1500 Service Manual

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SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME PROGRAMMED.
3. VARIABLE COOKING CONTROL "HIGH".
4. "START" BUTTON PRESSED.
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.
NOTE: "    " indicates components with potential above 250V.
MAGNETRON 
TEMPERATURE FUSE
FUSE 
20A
TURNTABLE
MOTOR
FAN
MOTOR
MAGNETRON OVEN LAMP...

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DESCRIPTION AND FUNCTION OF COMPONENTS
3. If the door is opened, and the secondary interlock relay
(RY2) and primary interlock switch contacts fail to open,
the monitor fuse blows simultaneously with closing of the
monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE TEST THE DOOR SENSING SWITCH,
SECONDARY INTERLOCK RELAY (RY2),
RELAY (RY1), PRIMARY INTERLOCK
SWITCH AND MONITOR SWITCH FOR
PROPER OPERATION. (REFER TO CHAP-
TER "TEST PROCEDURE")....

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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...

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CK = Check / RE = Replace
POSSIBLE CASE AND 
DEFECTIVE PARTS
PROBLEMTEST PROCEDURE
CONDITIONOFFCONDITIONIDLECONDITIONMICROWAVECOOKINGCONDITION
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 button is touched. 
(The time of day should appear on the display...

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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...

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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...

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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 primary interlock switch and the secondary interlock
relay are operating properly, according to the above Switch and Interlock system Test Procedures.
Disconnect the wire lead from the monitor switch (COM) terminal. Check the monitor switch...

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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 secondary interlock relay, primary
interlock switch and monitor switch according to the "TEST PROCEDURE" for those switches before
replacing the blown monitor fuse.
CAUTION: BEFORE REPLACING A...

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TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT TEST
Resistance between;
BLU (1) AND YLW (4) = 0Ω(Shorted)
BLK (2) AND YLW (4) = 33Ω
BLU (1) AND BLK (2) = 33Ω
BLK (2) AND WHT (3) = 11Ω
WHT (3) AND RED (5) = 22Ω
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 CONTROL PANEL...

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TEST PROCEDURES
PROCEDURE
LETTERCOMPONENT TEST
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, no pads produce a signal.
2-2 In connection with indicators
a) At...