Sharp MMD24S manual Precautions For Using Lead-Free Solder, Employing lead-free solder, Soldering

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PRECAUTIONS FOR USING LEAD-FREE SOLDER

MMD24S

MMD24B

PRECAUTIONS FOR USING LEAD-FREE SOLDER

1.Employing lead-free solder

The "Main PWB" of this model employs lead-free solder. This is indicated by the "LF" symbol printed on the PWB and in the service manual. The suffix letter indicates the alloy type of the solder.

Example:

Indicates lead-free solder of tin, silver and copper.

2.Using lead-free wire solder

When repairing a PWB with the "LF" symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder may result in cold soldered joints and damage to printed patterns.)

As the melting point of lead-free solder is approximately 40oC higher than tin/lead alloy solder, it is recommend that a dedicated bit is used, and that the iron temperature is adjusted accordingly.

3.Soldering

As the melting point of lead-free solder (Sn-Ag-Cu) is higher and has poorer wettability, (flow), to prevent damage to the land of the PWB, extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time. Remove the bit as soon as a good flow is achieved. The high content of tin in lead free solder will cause premature corrosion of the bit. To reduce wear on the bit, reduce the temperature or turn off the iron when it is not required.

Leaving different types of solder on the bit will cause contamination of the different alloys, which will alter their characteristics, making good soldering more difficult. It will be necessary to clean and replace bits more often when

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Contents WARNING TO SERVICE PERSONNEL TABLE OF CONTENTSWARNING TO SERVICE PERSONNEL MICROWAVE MEASUREMENT PROCEDUREBEFORE SERVICING After repairing WARNING TO SERVICE PERSONNELBefore Servicing When the testing is completedB. Preparation for testing MICROWAVE MEASUREMENT PROCEDUREA. Requirements C. Leakage test1440 Bridge Gate Dr Diamond Bar, CA DANGERSERVICE MANUAL If provided, Vent Hood, Fan assembly, Cooling Fan MotorDESCRIPTION MICROWAVE DRAWER SPECIFICATIONGROUNDING INSTRUCTIONS GENERAL INFORMATIONOPERATION POWER LEVEL P-0 TO P-90 COOKINGDESCRIPTION OF OPERATING SEQUENCE OFF CONDITIONCooking Sequence SENSOR COOKING CONDITIONMICROWAVE CLOSED, COOK OFF CONDITTION SCHEMATIC OFF CONDITIONDOOR PROCEDURE TEST PROCEDURESA TOUCH CONTROL PANEL ASSEMBLY TEST Before testingB KEY UNIT TEST COMPONENT TESTC RELAY TEST DEFROST TEST Check supply voltage and oven power cordSTEPS The rated AC voltage is not present betweenF AH SENSOR TEST Checking the initial sensor cooking condition TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNITWater load cooking test R1, R2 22Ω ± 1% 1/2W R3 4.3kΩ ± 5% 1/4W R4 1MΩ ± 5% 1/4W CHECKING CONTROL UNITG MAGNETRON ASSEMBLY TEST Refer to the disassembly instructions found on PageMICROWAVE OUTPUT POWER H THERMAL CUT-OUT TESTJ STOP SWITCH TEST I SECONDARY INTERLOCK SWITCH TESTK MONITOR SWITCH TEST L BLOWN MONITOR FUSE TEST M POWER TRANSFORMER TESTControl Unit and Power Unit TOUCH CONTROL PANEL ASSEMBLY4 Reset Circuit 5 Indicator CircuitPower source voltage 0V GND DESCRIPTION OF LSI IC-1Internal clock oscillation frequency setting input Power source voltage +5VSegment data signal SignalSignal coming from touch key Signal similar to P23Common relay driving signal. Square Waveform 60Hz Magnetron high-voltage circuit driving signalSignal to sound buzzer Signal to synchronize LSI with commercial power source frequencyventilation opening for sensing HUMIDITY SENSOR CIRCUIT1 Structure of Humidity Sensor 2 Operational Principle of Humidity Sensor1 Servicing the touch control panel with power supply of the oven TOUCH CONTROL PANEL SERVICING4. Other Precautions 2. Servicing of Touch Control Panel2. Using lead-free wire solder PRECAUTIONS FOR USING LEAD-FREE SOLDER1. Employing lead-free solder 3. SolderingWARNING FOR WIRING COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDUREWARNING AGAINST HIGH VOLTAGE To prevent an electric shock, take the following pre- cautionsMICROWAVE DRAWER DISASSEMBLY Un-hook/Attach Black AC Wire to Top Terminal POWER CORD REPLACEMENTUn-hook/Attach White AC Wire to Bottom Terminal Un-hook/Attach Ground to metal Tab on Back PlateSTOP SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT STOP SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVALRe-install After adjustment, check the followingDRAWER SUPPORT ANGLE REMOVAL DRAWER ASSEMBLY AND CHOKE REMOVALDRAWER/SLIDE RAIL REMOVAL 1. Follow the Microwave Drawer disassembly as previouslySWITCH ANGLE REMOVAL SWITCH ANGLE REMOVAL/ADJUSTMENTACTUATOR REMOVAL/ADJUSTMENT Actuator adjustmentBottom cover AUTO DRAWER GEAR REMOVAL/INSTALLATIONRACK GEAR REMOVAL Installationto Back Plate HIGH VOLTAGE COMPONENTSMICRO Figure S-2. Power Unit CircuitFM A CN-ACONTROL UNITUNIT F G H2.5A Figure S-4. Printed Wiring Board of Power UnitA B C D E F G H UnitControlof 5.PrintedWiringBoardCOPYRIGHT 2008 BY DACOR, INC ALL RIGHTS RESERVED