EM-Z2000S Microwave Oven Service Manual REFERENCE NO.
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.
SAFETY PRECAUTIONS 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 other damage). (4).
EM-Z2000S Microwave Oven Explode View EM-Z2000S Microwave Oven Components List COMPONENT No. COMPONENT C01 GA-1000AS23C01 C02 CODE Name Model QTY Fuse 65TS 125V 20A 1 GA-1000AS23C02 Fan motor SP-6309-120 1 C03 GA-1000AS23C03 H.V.Capacitor CH85 1.0µF 2200V 1 C04 GA-1000AS23C04 H.V.
EM-Z2000S Microwave Oven Parts List PART PART CODE NO PART PART CODE NO P01 NAME QTY NAME PART PART CODE NO NAME QTY PART PART CODE NO GA-1000AS23P01 Oven cavity 1 P32 GA-1000AS23P32 Air duct 1 P02 GA-1000AS23P02 Door frame 1 P34 GA-1000AS23P34 Wire fastener 2 P03 GA-1000AS23P03 Outer enclosure 1 P36 GA-1000AS23P36 Upper hinge 1 P04 GA-1000AS23P04 Stainless door 1 P37 GA-1000AS23P37 Sponge 1 P38 GA-1000AS23P38 Spacer 1 steel NAME QTY QTY P05 GA-1000AS23P05 Door w
THE HEATING PRINCIPLE OF MICROWAVE 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 microwave and the food includes two aspects.
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. THE STRUCTURE AND WORKING PRINCIPLE OF MICROWWAVE OVEN. Microwave oven can be classified to many kinds according to various construction, volume and control function. But anyhow, the main electric parts are all 120V composed of high voltage rectification, cooling system.
1.2 MICROWAVE GENERATER. 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 wave magnetron.
1.4.1 DOOR INTERLOCK SWITCH Drawing 2-5(a) is the circuit and construction diagram of the door interlock switch of a microwave oven. It mainly consists of interlock switches (S1, S2), and monitor switch (S3), door hook and starting mechanism of the door interlock switch. fuse main latch switch S1 There fixed hooks on the oven door, and opened two rectangle hole at the corresponding place at the right of the oven and the hook. Inside each rectangle hole, there fixed a micro switch.
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.
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.
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.
1.6 THE DOOR COMBINATION six-angle screw To disassemble, 1. Pull out the power plug. 2. Take off the cabinet. 3. Loosen the two six –angle screws of left hinge (up) with a socket wrench (FIG.4 - 2). 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.
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.
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. 1.9 THE TRANSFORMER. 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 the board on the oven. (4-10). 4.
1. 2. 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 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. earthing screw Assemble the fan holder as FIG.
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). 1.13 THE TURNTABLE COMBINATIOM. 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 (FIG.4 - 18). 3.
door to check whether the door is flexible. If it does, back and front position of the holder should be adjusted. Provided the up hook is loose, the door should be pushed 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 in position, if not, readjustment is needed.
BREAKDOWN ANALYSIS AND THE MEANS OF OVERHAULING 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 reasons, thus, when overhaul, they all should be taken into consideration.
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. 1.17.
1.17.5 EXAMINE THE STARTING AND THE 8A FUSE OF THE MICROWAVE OVEN. Pull out the power plug, take off the cabinet, discharge the capacitor, measure the resistance value of the primary winding and the secondary winding of the transformer with an avometer (FIG.5 – 10 and FIG.5 - 9). The resistance value of the primary winding should be about 2.2 ohms, the secondary winding should be about 130 ohms. Otherwise, it indicates the transformer has broken, and should be replaced by a new one.
1.18 REPAIRING METHOD OF SEVERAL BREAKDOWN 1. Repair when there occurred large amounts microwave leakage. There are many factors which may cause microwave leaking. Following mentioned may be the main causes of microwave leakage: (1) The door deformed, the hinge loosed or damaged that caused the door can not close tightly. (2) The door pressing cover or the embed piece damaged or come off. (3) Obvious damage or uneven of the oven. (4) There are filth between the door and the oven.
the microwave leakage is larger at those hole position of the window board. The oven should be turned off to inspect whether there are crack among them (fig.5 - 16). If several holes formed a crack, it would enlarge the microwave leakage. If that is the case, it indicates the door has broken, and should be replaced with a new door. 2. Means of repair when the oven can heat, but the turntable glass can’t move Firstly, check whether the turntable holder is placed correctly.
(To those 700W microwave oven) to make the oven operating in normal. When the bell of the timer rings, open the oven door, the water should have boiled. If it have not been boiled yet, but is very hot, check whether the voltage is less than 120V. If the voltage below 120V but the water can be boiled after a little more time beating, it is normal. 1.19.
COMMON BREAKDOWN OF MICROWAVE OVEN AND MEANS OF REPAIRING PHENOMENON CAUSE REPAIRING MEANS 8A fuse broken. Change a new fuse. The primary and secondary winding of the transformer are short – circuited. 1. When starting the oven, the lamp is not on, the turntable tray can’t rotate and the food can’t be heated The earthing or the polarity of the polarity of the capacitor is punctured. The pilot switch can’t cut off. The interlock switch hasn’t closed.
9. The door can’t open After long time using, the wear and the rust –eaten enlarged the gap of the door shaft and the shaft hole, thus cause the door crooked. Adjust the hinge to rectify the position of the door. Change the hook. The door hook broken. 10. The door button fall off release 11. Electricity leaking Worn out and aged after long time operating Overhaul it or renew it The earthing insulation resistance of all the motors or the transformer are less than 2 megaohms.
