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EM-W3000W
Microwave Oven
Service Manual
REFERENCE NO. SM-GA0005
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INTRODUCTION This Microwave Oven Service Manual is printed in a loose-leaf format. Each part is divided into sections relating to a general group of components and each section is subdivided into various parts describing a particular component or service procedure. The subdividing of the subject matter plus the loose leaf form will facilitate the updating of the manual as new or revised components and service procedures are introduced. Each page of this service manual will be identified
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S SA AF FE ET TY Y P PR RE EC CA AU UT TIIO ON NS S PRECAUTIONS TO BE OBSERVED BEFORE AND DURING 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 o
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E EM M- -W W3 30 00 00 0W W M Miic crro ow wa av ve e O Ov ve en n E Ex xp pllo od de e D Drra aw wiin ng g 3
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E EM M- -W W3 30 00 00 0W W M Miic crro ow wa av ve e O Ov ve en n P Pa arrtts s //C Co om mp po on ne en ntts s L Liis stt PART NO. PART CODE NO NAME QTY PART NO. PART CODE NO NAME QTY P01 GA-1000AP30P01 Oven cavity 1 P26 GA-1000AP30P26 Door latch 1 P02 GA-1000AP30P02 Touch key board 1 P27 GA-1000AP30P27 Choke cover 1 P03 GA-1000AP30P03 Door release button 1 P28 GA-1000AP30P28 Inner viewing barrier 1 P04 GA-1000AP30P04 Button spring 2 P29 GA-1000AP30P29 Shaft 1 P05 GA-1000AP30P0
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1 1.. T TH HE E H HE EA AT TIIN NG G P PR RIIN NC CIIP PL LE E O OF F M MIIC CR RO OW WA AV VE E Microwave is one kind of radio wave whose wavelength is very short, frequency is very high. Therefore, it is called ultrahigh frequency electromagnetic wave. Microwave can heat food mainly result in the mutual affect of the food in the microwave field and the microwave field itself. Under the affect of microwave field, the thermal effect mechanism produced from the mutual affect of the mic
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K Stands for a constant E Stands for the microwave frequency. f Stands for the microwave frequency. tgδ Stands for loss angle tangent of the heated matter. Er Stands for relative dielectric constant of the heated matter. 2 2.. T TH HE E S ST TR RU UC CT TU UR RE E A AN ND D W WO OR RK KIIN NG G P PR RIIN NC CIIP PL LE E O OF F M MIIC CR RO OW WW WA AV VE E O OV VE EN N.. Microwave oven can be classified to many kinds according to various construction, volume and control functi
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2 2..2 2 M MIIC CR RO OW WA AV VE E G GE EN NE ER RA AT TE ER R.. Microwave generator is the heart of microwave oven. The quality of a microwave oven mostly depends on the quality of the microwave generator. A microwave generator is mainly composed of magnetron and its power supply circuit, FIG.2-3 is the typical circuit diagram of the present used microwave oven’s generator. The power supply circuit is composed of rectifying circuit and filament circuit. Usually, we adopt continuous wav
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2.4.1 DOOR INTERLOCK SWITCH 2.4.1 DOOR INTERLOCK SWITCH Drawing 2-5(a) is the circuit and construction diagram fuse main latch switch of the door interlock switch of a microwave oven. It mainly consists of interlock switches (S1, S2), and S1 monitor switch (S3), door hook and starting mechanism of the door interlock switch. There fixed hooks on the oven door, and opened two L pilot switch rectangle hole at the corresponding place at the right of S3 E N the oven and the hook. Inside each
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those microwave oven which have the power control function. FIG.3-1 is the power control circuit diagram of brand microwave oven, WP700. This is a typical instance of conduction ratio control. This oven adopt time and power controller as a whole. When a 120V, 60Hz alternating current is inputted, the time and power motor is always at working condition. At the FIG.2-7, S5 is always conducted. Made the S5 working 30 seconds as a circle, the conduct time can be successively adjusted from 5 se
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8). It is the most liable place where microwave leakage occurs. Especially, after a long time using, the microwave leakage would enlarge at the hinge and the hook. Anyway, mechanic damage would also cause large amount of microwave leakage. Therefore, the main methods designed for preventing microwave leakage of the door are as follows: 1) Assemble a layer of steel filament or a thin metal plate with many holes at the middle of the window to made it is possible to observe the heating as well
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Fig.3–1 is the practical circuit diagram of a microwave oven. Its corresponding working conditions are as follows: The door closed, SW1 and SW2 turned on, SW3 closed, power control relay has no power, R1, R2 is cut off. When cooking, touch the starting switch to power the timer and the power relay. RY1, RY2 closed the power supply to the anode of the magnetron and the filament, changing the power frequency electric energy to microwave energy, the microwave energy then transferred to the he
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4 4..2 2 T TH HE E D DO OO OR R C CO OM MB BIIN NA AT TIIO ON N six-angle screw To disassemble, 1. Pull out the power plug. 2. Take off the cabinet. hinge(up) 3. Loosen the two six –angle screws of left hinge (up) with a socket wrench (FIG.4 - 2). oven 4. Push the door release button to have the hook out (FIG.4 -3). 5. Pull the hinge with the door out of the oven together, and take off the washer of the hinge (low) shaft (FIG.4 - 2). 6. Pick up the ten inverse hooks which around
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FIG.4 – 1. 4. Tear off the adhesive protective paper of the lining and stick it on the door as FIG.4 – 1, slip the hook on the doorframe, and fix the doorframe on the door, tighten it with “+” – screws. After assembled, check whether the hook working in normal and whether the hinge (UP) is its position. 5. According to the FIG. 4 –4 shown, paste the inner lining inside the doorframe, make sure it is pasted smoothly, and should have no air bubble. 6. Slip the washer in the hinge shaft, then
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magnetron vertically, and also tighten the screws of the lampshade (FIG.4 - 8). 3. Plug in the two terminals of the magnetron filament and the thermal cutout. 4 4..5 5 T TH HE E T TR RA AN NS SF FO OR RM ME ER R.. Firstly, do as the 1,2,3, steps at Ⅲ of this part. Dismantling steps for the transformer: (as FIG.4 -9). 1. Pull out all the terminal of the transformer. 2. Turn the microwave over. 3. Take off the right baseboard with the transformer after loosened the four screws, which fix
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1. Assemble the fan motor as FIG.4 – 14. Drip the glue on the “★” place of the fan motor shaft, and fix the fan on the earthing screw motor, make sure it must be fixed to the bottom of the shaft. Attention: The fan motor shaft should not be curved, the fan should have no abnormal stick up. After assembled, check whether the running fan would knock the fan holder. 2. Assemble the fan holder as FIG.4 – 13, Then connect the power supply cord with the two wires of the fan motor, and tighten
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1. Insert one end of the diode to one feet of the capacitor’s connect piece. 2. Fix the diode with one screw (pay attention to the polarity of the diode, refer to FIG.4 - 16). 4 4..9 9 T TH HE E T TU UR RN NT TA AB BL LE E C CO OM MB BIIN NA AT TIIO OM M.. Firstly, do as the 1, 2, 3, stops of Ⅲ of this part. To disassemble, 1. Turn the microwave oven over (FIG. 4- 17). 2. Take off the two screws which fix the middle base board with a “+” – screwdriver and take off the middle cover
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door to check whether the door is flexible. If it does, back screw and front position of the holder should be adjusted. latch switch hold Provided the up hook is loose, the door should be pushed front door pla more closely to the oven, and pull the holder inside closely after loosen the screw which fix the holder, then, tighten the screw and check whether it is still loose. If it is not or the loose is minor, it would be OK. Open the door, then close it lightly, check whether the hook is
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5 5.. B BR RE EA AK KD DO OW WN N A AN NA AL LY YS SIIS S A AN ND D T TH HE E M ME EA AN NS S O OF F O OV VE ER RH HA AU UL LIIN NG G Before overhauling a microwave oven, you should judge the breakdown and the cause correctly, then you can repair it with corresponding ways. The overhauling must be proceed in order, any hasty conclusion is not recommendable, otherwise over-working would be done when repair. The microwave oven may occur compound breakdown due to all kinds of different
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speed of the probe should not exceed 25mm per second, and the measuring direction should be the same with the outing direction of the probe should not exceed 25mm per second, and the measuring direction should be the same with the outing direction of the microwave leakage (FIG.5 - 2).. When measuring the ultimate value of microwave leakage of all the measure position should not exceed 1 milliwatt/cm2, of should be considered as abnormal. Fig.5-3 5.2.4 EXAMINE WHEN THE OVEN AT OPERATING
