SERVICE MANUAL MICROWAVE OVENS Microwave Oven ELECTROLUX HOME PRODUCTS Corso Lino Zanussi,30 I - 33080 PORCIA /PN (ITALY) Tel +39 0434 394850 Fax +39 0434 394096 SOI Edition: 03.2006 SOI 03.06 FV Publication No.
SOI 03.
TABLE OF CONTENTS CAUTION, MICROWAVE RADIATION / GENERAL IMPORTANT INFORMATION .......................4 SERVICING / GENERAL INFORMATION .......................................................................................5 PRODUCT SPECIFICATIONS.........................................................................................................6 APPEARANCE VIEW .......................................................................................................................7 OPERATING SEQUENCE .
CAUTION CAUTION MICROWAVE RADIATION Personnel should not be exposed to the microwave energy which may radiate from the magnetron or other microwave generating devices if it is improperly used or connected. All input and output microwave connections, waveguides, flanges and gaskets must be secured. Never operate the device without a microwave energy absorbing load attached. Never look into an open waveguide or antenna while the device is energized.
SERVICING WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with the following parts will result in electrocution High voltage capacitor, High Voltage transformer, Magnetron, High voltage rectifier assembly, High voltage wires. REMEMBER TO CHECK 3D REMEMBER TO CHECK 4R 1) Disconnect the supply. 2) Door opened, and wedged open. 3) Discharge high voltage capacitor.
PRODUCT SPECIFICATIONS SPECIFICATION ITEM DESCRIPTION Power Requirements 230 Volts(EU)/230-240 Volts(UK) 50 Hertz Single phase, 3 wire earthed Power Consumption Microwave cooking Grill cooking Dual cooking Power Output Case Dimensions Cooking Cavity Dimensions Turntable diameter Control Complement 1.42kW Approx. 6.3A 1.0kW Approx. 4.2A 2.4kW Approx. 10.2A EU 1.4/6.2 1.0/4.3 2.35/10.4 UK 1.42/6.3 1.0/4.2 2.4/10.
APPEARANCE VIEW OVEN 1 Front trim 2 Oven lamp 3 Control panel 4 Door open button 5 Waveguide cover 6 Oven cavity 7 Seal packing 8 Door seals and sealing surfaces. 9 Fixing points (4 points) 10 Ventilation openings 11 Outer cover 12 Rear cabinet 13 Power supply cord support clip. 14 Power supply cord (EU) 15 Power supply cord (UK) 16 Low trivet 17 High trivet Turntable support system Turntable Turntable support Coupling 1.
APPEARANCE VIEW CONTROL PANEL MCD2660E / MCD2661E / MOA4226 1 Digital Display 2 Indicators The appropriate indicator will flash or light up, just above each symbol according to the instruction. When an indicator is flashing, press the appropriate button (having the same symbol) Or carry out the necessary operation.
APPEARANCE VIEW CONTROL PANEL EMS2685 1 Digital Display 2 Indicators The appropriate indicator will flash or light up, just above each symbol according to the instruction. When an indicator is flashing, press the appropriate button (having the same symbol) or carry out the necessary operation.
APPEARANCE VIEW CONTROL PANEL ZM266ST 1 Digital Display 2 Indicators The appropriate indicator will flash or light up, just above each symbol according to the instruction. When an indicator is flashing, press the appropriate button (having the same symbol) or carry out the necessary operation.
APPEARANCE VIEW CONTROL PANEL JMW9161 1 Digital Display 2 Indicators The appropriate indicator will flash or light up, just above each symbol according to the instruction. When an indicator is flashing, press the appropriate button (having the same symbol) or carry out the necessary operation.
APPEARANCE VIEW CONTROL PANEL MO926G 1 Digital Display 2 Indicators The appropriate indicator will flash or light up, just above each symbol according to the instruction. When an indicator is flashing, press the appropriate button (having the same symbol) or carry out the necessary operation.
OPERATION SEQUENCE OFF CONDITION Closing the door activates the door interlock switch (monitored latch switch). IMPORTANT When the oven door is closed, the monitor switch contacts COM - NC must be open. When the microwave oven is plugged in a wall outlet (230V (EU) / 230-240V (UK) 50Hz), the noise filter is energized. Figure 0-1 on page 32 NOTE: When the oven door is opened, the oven lamp comes on at this time.
OPERATION SEQUENCE HIGH, MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW COOKING When the microwave oven is preset for variable cooking power, the line voltage is supplied to the power transformer intermittently within a 32-second time base through the vary contact. The following levels of microwave power are given. SETTING HIGH MEDIUM HIGH Approx. MEDIUM Approx. MEDIUM LOW Approx. LOW Approx. NOTE: The ON/OFF time ratio does not exactly correspond to the percentage of microwave power, because approx.
FUNCTION OF IMPORTANT COMPONENTS DOOR OPEN MECHANISM The door can be opened by pushing the door open button. MONITORED LATCH SWITCH (SW1) 1. When the oven door is closed, the contacts (COM - NO) must be closed. 2. When the oven door is opened, the contacts (COM - NO) must be opened. DOOR LATCH HOOK MONITOR SWITCH (SW2) MONITORED LATCH SWITCH (SW1) MONITOR SWITCH (SW2) 1. When the oven door is closed, the contacts (COM - NC) must be opened. 2.
FUNCTION OF IMPORTANT COMPONENTS FAN MOTOR The fan motor drives a blade which draws external cool air. This cool air is directed through the air vanes surrounding the magnetron and cools the magnetron. This air flows through the oven cavity to remove steam and vapours given off from the heating foods. It is then vented through the exhaust air vents at the rear of oven cavity. NOISE FILTER The noise filter prevents the radio frequency interference that might flow back in the power circuit. SOI 03.
TROUBLESHOOTING CHART When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which will be found in the “Test Procedure” section. IMPORTANT: If the oven becomes inoperative because of a blown fuse F2. Check the monitored latch switch and monitor switch before replacing the F8A fuse.
TEST PROCEDURES PROCEDURE LETTER A COMPONENT TEST MAGNETRON TEST NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION. CARRY OUT 3D CHECK Isolate the magnetron from high voltage circuit by removing all leads connected to the filament terminal. To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron filament terminals, the meter should show a reading of less than 1 ohm.
TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST NOTE: The operation time of the microwave oven is “t + 3” sec. 3 seconds are needed for magnetron filament heat-up time. Measuring method: 1. Measure the initial temperature of the water before the water is added to the vessel. (Example: The initial temperature T1 = 11°C) 2. Add the 1 litre water to the vessel. 3. Place the load on the centre of the turntable. 4.
TEST PROCEDURES PROCEDURE LETTER C COMPONENT TEST HIGH VOLTAGE RECTIFIER ASSEMBLY TEST CARRY OUT 3D CHECKS. Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C of the high voltage rectifier and note the reading obtained. Reverse the meter leads and note this second reading.
TEST PROCEDURES PROCEDURE LETTER E COMPONENT TEST SWITCH TEST CARRY OUT 3D CHECKS. Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the following table. Table: Terminal Connection of Switch Plunger Operation COM to NO COM to NC COM; Common terminal Released Open circuit Short circuit NO; Normally open terminal Depressed Short circuit Open Circuit NC; Normally close terminal If incorrect readings are obtained, replace the switch.
TEST PROCEDURES PROCEDURE LETTER H COMPONENT TEST BLOWN FUSE F8A (F2) CARRY OUT 3D CHECKS If the fuse F8A (F2) is blown when the door is opened, check the primary latch switch, monitor switch and monitor resistor. If the fuse F8A (F2) is blown by incorrect door switching replace the defective switch(es) and the fuse F8A (F2). CARRY OUT 4R CHECKS CAUTION: Only replace fuse with the correct value replacement.
TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 3. Connect the voltmeter, set to 250V AC, across the motor terminals. (Refer to the relevant motor test procedure or pictorial diagram for the correct terminal numbers.) 4. Arrange the meter in a position where it can be read during the test. (Do not touch the meter, meter leads or oven circuitry while the oven is active.) 5. Close the oven door. 6. Set the power level to 900W and set the relevant timer for about three (3) minutes. 7.
TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 4. Relay Unit a) Grill cooking is not possible. L SWITCH UNIT TEST If the display fails to clear when the STOP key is depressed, first verify the lead wire harness is marking good contact, verify that the stop switch operates properly; that is the contacts are closed when the door is closed and open when the door is open.
TEST PROCEDURES PROCEDURE LETTER N COMPONENT TEST GRILL HEATING ELEMENT TEST CARRY OUT 3D CHECKS Before carrying out the following tests make sure the heating element is cooled completely. 1. Resistance of heating element. Disconnect the wire leads to the heating element to be tested. Using ohmmeter with low resistance range. Check the resistance across the terminals of the heating element as described in the following table.
CONTROL PANEL ASSEMBLY OUTLINE OF CONTROL PANEL The touch control section consists of the following units as shown in the touch control panel circuit. (1) Switch Unit (2) Control Unit (3) LED Unit (4) Relay Unit The principal functions of these units and the signals communicated among them are explained below. Switch Unit The switch unit is composed of a matrix, signals generated in the LSI are sent to the switch unit through P22, P23 and P24.
SERVICING 1. Precautions for Handling Electronic Components This unit uses CMOS LSI in the integral part of the circuits. When handling these parts, the following precautions should be strictly followed. CMOS LSI have extremely high impedance at its input and output terminals. For this reason, it is easily influenced by the surrounding high voltage power source, static electricity charge in clothes, etc. and sometimes it is not fully protected by the built-in protection circuit.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before operating the oven. 1. CARRY OUT 3D CHECKS. 2. Make sure that a definite "click" can be heard when the microwave oven door is unlatched. (Hold the door in a closed position, then push the door open button slowly. This causes the latch heads to rise, it is then possible to hear a "click" as the door switches operate.) 3.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE HIGH VOLTAGE COMPONENTS REMOVAL (HIGH VOLTAGE CAPACITOR AND HIGH VOLTAGE RECTIFIER ASSEMBLY) To remove the components, proceed as follows. 1. CARRY OUT 3D CHECKS 2. Disconnect the filament lead of the high voltage transformer secondary wire from high voltage capacitor. 3. Disconnect the high voltage wire B from the magnetron. 4. Remove one (1) screw holding earth side terminal of high voltage rectifier assembly. 5.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE FAN MOTOR REPLACEMENT REMOVAL CAUTION: 1. CARRY OUT 3D CHECKS. 2. Remove the one (1) screw holding the noise filter to the chassis support. 3. Release the noise filter from the tabs of the fan duct. 4. Remove the one (1) screw holding the chassis support to the oven cavity front flange. 5. Remove one (1) screw holding the chassis support to the magnetron. 6. Remove the chassis support from the oven cavity. 7. Disconnect the wire leads from the fan duct. 8.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE OVEN LAMP REMOVAL 1. CARRY OUT 3D CHECKS. 2. Disconnect the wire lead from the oven lamp 3. Lift up the oven lamp from the clips of the air intake duct. 4. Now, the oven lamp is free. Lock Bulb Socket Oven lamp POWER SUPPLY CORD REPLACEMENT Removal 1. CARRY OUT 3D CHECKS. 2. Remove the one (1) screw holding the green/yellow wire to the cavity back plate. 3. Disconnect the leads of the power supply cord from the noise filter, referring to the Figure C-4(a).
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE MONITORED LATCH SWITCH, MONITOR SWITCH AND STOP SWITCH REMOVAL 1. CARRY OUT 3D CHECKS. 2. Remove the control panel assembly referring to "CONTROL PANEL ASSEMBLY REMOVAL". 3. Disconnect the all leads from the switches. 4. Remove the two (2) screws holding the latch hook to the oven cavity. 5. Remove the latch hook. 6. Push the retaining tab slightly and remove the switch. MONITOR SWITCH TAB MONITORRED LATCH SWITCH TAB STOP SWITCH TAB Figure C-2.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE DOOR DISASSEMBLY REMOVAL 1. Disconnect the power supply cord. 2. Open the door slightly and remove the built in frame assembly(Ref: to chapter built in frame assembly removal). 3. Remove the choke cover taking care not to break clips by inserting an iron plate (thickness of about 0.5mm) or flat type screw driver to the gap between the choke cover and door panel as shown Figure C-4 to free the engaged parts. 4. Release choke cover from door panel. 5.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE INNER SEALER FILM Door film Backing film Installation 1. Tear away the backing film. 3. Put the pasted side of the inner sealer film on the door panel. Figure C-6.
TEST DATA AT A GLANCE Parts Thermal cut-out (OVEN) Oven lamp High voltage capacitor Magnetron Symbol TC01 OL C MG Power transformer T Fuse Fuse Thermal cut-out (Magnetron) F1 F2 TC02 Value / Data 145°C 240-250V 25W 1.02µF AC 2100V Filament < 1Ω Filament – chassis ∞ ohm. Filament winding < 1Ω Secondary winding Approx. 160 Ω. Primary winding Approx. 2 Ω. F20A 250V F8A 250V 125°C WIRING/RE-WIRING WARNING: WIRING / RE-WIRING. Before carrying out any work; carry out 3D checks. 1. Disconnect the supply 2.
SOI 03.06 FV 36/38 ASYMMETRIC RECTIFIER MONITOR SWITCH MONITORED SWITCH LATCH OVEN THERMAL CUT OUT H.V.RECTIFIER CAPACITOR HEATING TURNTEBLE MOTOR OVEN LAMP FAN MOTOR CONTROL UNIT SWITCH STOP F1 FUSE LIVE NOISE SOPPRESSION COIL EARTH FUSE MAGNETRON THERMAL CUT OUT NOISE FILTER UNIT ASYMMETRIC RECTIFIER MONITOR SWITCH MONITORED SWITCH LATCH OVEN THERMAL CUT OUT H.V.
SOI 03.06 FV 37/38 ASYMMETRIC RECTIFIER MONITOR SWITCH MONITORED SWITCH LATCH OVEN THERMAL CUT OUT H.V.RECTIFIER CAPACITOR HEATING TURNTEBLE MOTOR OVEN LAMP FAN MOTOR CONTROL UNIT SWITCH STOP LIVE F1 FUSE NOISE SOPPRESSION COIL EARTH FUSE MAGNETRON THERMAL CUT OUT NOISE FILTER UNIT ASYMMETRIC RECTIFIER MONITOR SWITCH MONITORED SWITCH LATCH OVEN THERMAL CUT OUT H.V.
SOI 03.06 FV LATCH SWITCH MONITOR SWITCH STOP SWITCH TURNTEBLE MOTOR MAGNETRON THERMAL CUT-OUT 38/38 OVEN LAMP TOP HEATER OVEN THERMAL CUT-OUT POWER TRANSFORMER H.V. RECTIFIER H.V. CAPACITOR SHORT PROTECTOR FAN MOTOR MAINS SUPPLY CORD HIGHT VOLTAGE COMPONENTS MAGNETRON (*) NOISE FILTER UNIT PICTORIAL DIAGRAMS Switch PWB Figure S-1 Pictorial Diagram .
