Sharp MMD24B, MMD24S manual Before Servicing

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BEFORE SERVICING

MMD24S

MMD24B

PRECAUTIONSTO BE OBSERVED BEFORE AND DUR- ING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY

(a)Do not operate or allow the oven to be operated with the door open.

(b)Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary: (1) interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse.

(c)Before turning on microwave power for any service test or inspection within the microwave generating compart- ments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections.

(d)Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner.

(e)A microwave leakage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner.

BEFORE SERVICING

Before servicing an operative unit, perform a microwave emission check as per the Microwave Measure- ment Procedure outlined in this service manual.

If microwave emissions level is in excess of the specified limit, contact DACOR immediately @ 1-800-793-0093.

If the unit operates with the door open, service person should 1) tell the user not to operate the oven and 2) contact DACOR and Food and Drug Administration's Center for Devices and Radiological Health immediately.

Service personnel should inform DACOR of any certified unit found with emissions in excess of 4mW/ cm2. The owner of the unit should be instructed not to use the unit until the oven has been brought into compliance.

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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