Sharp MMD24B, MMD24S Component Replacement And Adjustment Procedure, Warning Against High Voltage

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COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

MMD24S

MMD24B

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WARNING AGAINST HIGH VOLTAGE:

Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with the following parts may result in severe, possibly fatal, electric shock.

(Example)

High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..

WARNING: To Avoid possible exposure to microwave energy, please follow the instructions below before operating the oven.

1.Disconnect the power supply cord.

2.Make sure that a definite” click” can be heard when the microwave oven drawer is unlatched. (Hold the drawer in a closed position with one hand, then pull the drawer open, this causes the latch leads to rise, it is then possible to hear a “click’ as the drawer switches operate.)

3.Visually check the drawer and cavity face plate for damage (dents, cracks, signs of arcing etc.).

Carry out any remedial work that is necessary before operating the oven.

Do not operate the oven if any of the following conditions exist:

1.Drawer does not close firmly.

2.Drawer latch hook is damaged.

3.The drawer gasket or seal is damaged.

4.The drawer is bent or warped.

5.There are defective parts in the drawer interlock system.

6.There are defective parts in the microwave generating and transmission assembly.

7.There is visible damage to the oven.

Do not operate the oven:

1.Without the RF gasket (Magnetron).

2.If the wave guide or oven cavity are not intact.

3.If the drawer is not closed.

WARNING FOR WIRING

To prevent an electric shock, take the following pre- cautions:

1.Before wiring:

1)Disconnect the power supply cord.

2)Open the drawer.

3)Wait 60 seconds, then discharge the high voltage capacitor.

2.Don’t let the wire leads touch to the following parts:

1)High voltage parts:

Magnetron, High voltage transformer, High voltage capacitor and High voltage rectifier assembly.

2)Hot parts:

Oven lamp, Magnetron, High voltage transformer and Oven cavity.

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Contents WARNING TO SERVICE PERSONNEL TABLE OF CONTENTSWARNING TO SERVICE PERSONNEL MICROWAVE MEASUREMENT PROCEDUREBEFORE SERVICING Before Servicing WARNING TO SERVICE PERSONNELAfter repairing When the testing is completedA. Requirements MICROWAVE MEASUREMENT PROCEDUREB. Preparation for testing C. Leakage testSERVICE MANUAL DANGER1440 Bridge Gate Dr Diamond Bar, CA If provided, Vent Hood, Fan assembly, Cooling Fan MotorMICROWAVE DRAWER SPECIFICATION DESCRIPTIONGENERAL INFORMATION GROUNDING INSTRUCTIONSDESCRIPTION OF OPERATING SEQUENCE POWER LEVEL P-0 TO P-90 COOKINGOPERATION OFF CONDITIONMICROWAVE SENSOR COOKING CONDITIONCooking Sequence DOOR SCHEMATIC OFF CONDITIONCLOSED, COOK OFF CONDITTION A TOUCH CONTROL PANEL ASSEMBLY TEST TEST PROCEDURESPROCEDURE Before testingC RELAY TEST COMPONENT TESTB KEY UNIT TEST STEPS Check supply voltage and oven power cordDEFROST TEST The rated AC voltage is not present betweenWater load cooking test TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNITF AH SENSOR TEST Checking the initial sensor cooking condition CHECKING CONTROL UNIT R1, R2 22Ω ± 1% 1/2W R3 4.3kΩ ± 5% 1/4W R4 1MΩ ± 5% 1/4WMICROWAVE OUTPUT POWER Refer to the disassembly instructions found on PageG MAGNETRON ASSEMBLY TEST H THERMAL CUT-OUT TESTK MONITOR SWITCH TEST I SECONDARY INTERLOCK SWITCH TESTJ STOP SWITCH TEST M POWER TRANSFORMER TEST L BLOWN MONITOR FUSE TEST4 Reset Circuit TOUCH CONTROL PANEL ASSEMBLYControl Unit and Power Unit 5 Indicator CircuitInternal clock oscillation frequency setting input DESCRIPTION OF LSI IC-1Power source voltage 0V GND Power source voltage +5VSignal coming from touch key SignalSegment data signal Signal similar to P23Signal to sound buzzer Magnetron high-voltage circuit driving signalCommon relay driving signal. Square Waveform 60Hz Signal to synchronize LSI with commercial power source frequency1 Structure of Humidity Sensor HUMIDITY SENSOR CIRCUITventilation opening for sensing 2 Operational Principle of Humidity Sensor4. Other Precautions TOUCH CONTROL PANEL SERVICING1 Servicing the touch control panel with power supply of the oven 2. Servicing of Touch Control Panel1. Employing lead-free solder PRECAUTIONS FOR USING LEAD-FREE SOLDER2. Using lead-free wire solder 3. SolderingWARNING AGAINST HIGH VOLTAGE COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDUREWARNING FOR WIRING To prevent an electric shock, take the following pre- cautionsMICROWAVE DRAWER DISASSEMBLY Un-hook/Attach White AC Wire to Bottom Terminal POWER CORD REPLACEMENTUn-hook/Attach Black AC Wire to Top Terminal Un-hook/Attach Ground to metal Tab on Back PlateRe-install STOP SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVALSTOP SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT After adjustment, check the followingDRAWER/SLIDE RAIL REMOVAL DRAWER ASSEMBLY AND CHOKE REMOVALDRAWER SUPPORT ANGLE REMOVAL 1. Follow the Microwave Drawer disassembly as previouslyACTUATOR REMOVAL/ADJUSTMENT SWITCH ANGLE REMOVAL/ADJUSTMENTSWITCH ANGLE REMOVAL Actuator adjustmentRACK GEAR REMOVAL AUTO DRAWER GEAR REMOVAL/INSTALLATIONBottom cover InstallationHIGH VOLTAGE COMPONENTS to Back PlateFM A Figure S-2. Power Unit CircuitMICRO CN-AUNIT UNITCONTROL F G HA B C D E F G H Figure S-4. Printed Wiring Board of Power Unit2.5A 5.PrintedWiringBoard UnitControlofCOPYRIGHT 2008 BY DACOR, INC ALL RIGHTS RESERVED