Service Manual Microwave Oven KOR-61155 KOR-61151 DAEWOO ELECTRONICS CO., LTD.
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.
PROPER USE AND SERVICE PRECAUTIONS CAUTION : THIS DEVICE IS TO BE SERVICED ONLY BY PROPERLY QUALIFIED SERVICE PERSONNEL. CONSULT THE SERVICE MANUAL FOR PROPER SERVICE PROCEDURES TO ASSURE CONTINUED SAFETY OPERATION AND FOR PRECAUTIONS TO BE TAKEN TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY. 1. For Safe Operation Damage that allows the microwave energy (that cooks or heats the food) to escape will result in poor cooking and may cause serious bodily injury to the operator.
SPECIFICATIONS ITEM SPECIFICATION POWER SUPPLY MICROWAVE 120V~60Hz, SINGLE PHASE WITH EARTHING POWER CONSUMPTION 920 W OUTPUT POWER 600 W (IEC 705) (FULL MICROWAVE POWER) FREQUENCY 2450 MHz OUTPUT DIMENSIONS (W X H X D) 465 X 274 X 360 mm (18.3 X 10.8 X 14.2 in.) CAVITY DIMENSIONS (W X H X D) 290 X 200 X 290 mm (11.4 X 7.9 X 11.4 in) NET WEIGHT APPROX. 12.5 kg (27.6 Ibs.) TIMER 35 min. DUAL SPEED POWER SELECTIONS 5 LEVELS CAVITY VOLUME 0.64 Cu.Ft.
FEATURES DIAGRAM 2 4 1 9 12 11 8 3 5 6 7 ¤ Safety Interlock System ¤Ł Door Viewing Screen - Allows viewing of food. The screen is designed so that light can pass through, but not the microwave. ¤Ø Door Hook - When the door is closed, it will automatically shut. If the door is opened while the oven is operating, the magnetron will immediately stop operating. ¤Œ Oven Cavity ¤º Door Seal - Door seal maintains the microwave energy within the oven cavity and prevents microwave leakage.
INSTALLATION 1 Steady, flat location 2 Leave space behind and side This microwave oven should be set on a steady, flat surface. All air vents should be kept a clearance. If all vents are covered during operation, the oven may overheat and, eventually, cause oven failure. 3 Away from radio, and TV sets Poor television reception and radio interference may result if the oven is located close to a TV, Radio or antenna, feeder and so on.
OPERATION 1 Connect the main lead to an electrical outlet. 2 After placing the food in a suitable container, open the oven door and put it on the glass tray. The glass tray must always be in place during cooking. 3 Close the door securely. 4 Choose cooking power by setting V.P.C. Knob to the desired position. Refer to cookbook for recommended power levels. 5 Determine cooking time. Consult cookbook for recipe timing. ¢” Oven light turns on and cooling fan starts to operate.
MEASUREMENT OF THE MICROWAVE OUTPUT POWER Microwave output power can be checked by indirectly measuring the temperature rise of a certain amount of water exposed to the microwave as directed below. PROCEDURE 1. Microwave power output measurement is made with the microwave oven supplied at rated voltage and operated at its maximum microwave power setting with a load of 1,000¡ 5cc of potable water. 2.
MICROWAVE RADIATION TEST WARNING • Make sure to check the microwave leakage before and after repair of adjustment. • Always, start measuring of an unknown field to assure safety for operating personnel from microwave energy. • Do not place your hands into any suspected microwave radiation field unless the safe density level is known. • Care should be taken not to place the eyes in direct line with the source of microwave energy.
POWER SUPPLY : SINGLE PHASE~ONLY 10 RD 1 M GY : GRAY GE : GREEN/YELLOW BK : BLACK GN : GREEN BR : BROWN BL : BLUE OR : ORANGE BL TM SECONDARY INTERLOCK SWITCH BK INTERLOCK MONITOR SWITCH BK WH TIMER SWITCH GY 2 3 GY WH GY GM : GEARED MOTOR FM : FAN(BLOWER) MOTOR GY V.P.C. : VARIABLE POWER CONTROLLER TM : TIMER MOTOR RD GY V.P.C. : HIGH TIMER : ON DOOR : CLOSED [ CONDITION ] CL GM FM GY CL : CAVITY LAMP V.P.C.
GN N N GN L L FUSE FILTER ASS’Y POWER SUPPLY : SINGLE PHASE~ONLY 11 RD WH 1 M GY : GRAY GE : GREEN/YELLOW BK : BLACK GN : GREEN BR : BROWN BL : BLUE OR : ORANGE BL TM TIMER SWITCH GY 2 3 GY WH GY GM : GEARED MOTOR FM : FAN(BLOWER) MOTOR GY V.P.C. : VARIABLE POWER CONTROLLER TM : TIMER MOTOR RD GY V.P.C. : HIGH TIMER : ON DOOR : CLOSED [ CONDITION ] CL GM FM GY CL : CAVITY LAMP V.P.C.
CIRCUIT DESCRIPTION 1. When the food is placed in the oven cavity and door is closed. • The contact of the interlock monitor switch open. • The contacts of the primary interlock switch and secondary interlock switch close. Primary Interlock Switch 15A Fuse Timer Switch Interlock Monitor Switch TM CL GM FM Secondary Interlock Switch TM Timer motor CL GM Cavity lamp Geard motor FM Fan motor Fig. 1 2. When the timer is set to the time desired. • The contact of the timer switch close.
HIGH VOLTAGE TRANSFORMER H.V. CAPACITOR MAGNETRON H.V. FUSE H.V. DIODE Fig. 2 3. When the door is opened during cooking. • Primary interlock switch and secondary interlock switch open to cut off the primary voltage to the high voltage transformer to stop microwave oscillation. • Fan motor, timer motor and turntable motor stop rotating. • Oven lamp turn off. • As soon as the door is opened, monitor switch close (NC) to create the short circuit.
PRECAUTIONS FOR DISASSEMBLY AND REPAIR ƒ¡Cautions to be observed when trouble shooting. Unlike many other appliances, the microwave oven is a high-voltage, high-current equipment. It is completely safety during normal operation. However, carelessness in servicing the oven can result in an electric shock or possible danger from a short circuit. You are asked to observe the following precautions carefully. (1) Always remove the power plug from the outlet before servicing.
DISASSEMBLY AND ASSEMBLY 1. To remove cabinet Remove three screws on cabinet back. 2. To remove door assembly (1) Remove two screws ¤ which secure the stopper hinge top. 1 (2) Remove the door assembly ¤Ø from top plate of cavity. 3 (3) Remove the above for reassembly. 2 NOTE : After replacing the door perform a check of correct alignment with the hinge and cavity front face. 3.
(1) Remove the gasket door ¤ from door plate ¤Œ. (2) Remove the barrier screen inner ¤ºfrom door plate ¤Œ. (3) Remove the door frame ¤Łfrom door plate ¤Œ. (4) Remove the stopper hinge top ¤Øfrom door plate ¤Œ. (5) Remove the spring ¤ and the hook ¤ . (6) Remove the barrier screen outer ¤ from door frame ¤Ł. (7) Remove the above steps for reassembly. 4. Method to reduce the gap between the door seal and the oven front surface. (1) To reduce gap located on part ‘A’.
5. To remove control panel parts (1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly. 5 2 Control Panel 6 7 3 8 4 1 9 10 (2) Remove the door open lever ¤ from the control panel. (3) Remove two screws ¤Łwhich secure the timer assembly ¤Ø. (4) Remove the timer assembly ¤Ø. (5) Pull out the timer knob ¤Œ from the timer assembly ¤Ø. (6) Pull out the timer coupler ¤ºfrom the timer assembly ¤Ø. (7) Remove the screw ¤ which secure the V.P.
6. To remove high voltage capacitor (1) Remove a screw ¤ which secure the grounding ring ring terminal of the H.V. diode ¤Łand the capacitor holder ¤Ø. 1 3 (2) Remove the H.V. diode ¤Łfrom the capacitor ¤Ø. (4) Reverse the above steps for reassembly. 2 High voltage circuit wiring Magnetron H.V. Capacitor H.V. Diode H.V. Transformer 7. To remove magnetron (1) Remove four screws ¤ magnetron ¤Ł. which secure the (2) Remove the magnetron ¤Ł. (3) Reverse the above steps for reassembly.
CAUTION : Never install the magnetron without the metallic gasket plate which is packed with each magnetron to prevent microwave leakage. Whenever repair work is carried out on magnetron, check the microwave leakage. It shall not exceed 4mW/cm2 for a fully assembled oven with door normally closed. Magnetron Antenna Metallic Gasket Plate Wave Guide Magnetron Antenna Cooling Fin Metallic Gasket Plate Magnetron Filament Terminal 8.
INTERLOCK MECHANISM The door lock mechanism is a device which has been specially designed to completely eliminate microwave radiation when the door is opened during operation, and thus to perfectly prevent the danger resulting from the leakage of microwave. (1) Primary interlock switch When the door is closed, the hook locks the oven door. If the door is not closed properly, the oven will not operate. When the door is closed, the hook pushes the button of the micro switch.
(2) Secondary interlock switch and interlock monitor switch When the door is closed, the hook pushes the push lever downward, the push lever presses the button of the interlock monitor switch to bring it under “OFF”, condition and presses the button of the secondary interlock switch to bring it under “ON”, condition.
TROUBLE SHOOTING GUIDE TROUBLE DOOR SHUT, TIMER SET BUT NO COOKING TAKES PLACE. 1. Does the fan motor work when you shut the door and turn the timer? NO Does 15A fuse blow? NO continuity YES Check continuity of interlock monitor switch with door shuted. continuity *All these switches must be replace at the same time. Replace fuse. Both continuity Replace primary interlock switch, secondary interlock switch and interlock monitor switch.
2. Does the fan motor when you shut the door and turn the time? YES NO Does the oven lamp light? Does the turntable turn? YES Check continuity of filament of magnetron. No microwave oscillation. Check continuity of filament of magnetron. NO continuity NO continuity *Do not operate when you check this continuity NO Check continuity filcontinuity ament tap (3.3V) of high voltage transformer. Replace or repair oven lamp, turntable motor. Replace magnetron. Replace high voltage transformer.
COMPONENT TEST PROCEDURE 1. High voltage is present at the high voltage terminal of the voltage transformer during any cooking cycle. 2. It is neither necessary nor advisable to attempt measurement of the high voltage. 3. Before touching any oven components or wiring, always unplug the oven from its power source and discharge the capacitor (see page 13). 1. High voltage transformer 4. Magnetron (A) Remove connections from the transformer terminals and check continuity.
6. Interlock switches • You can test continuity of safety interlocks and monitor switch by using switch tester or ohmmeter. • The switch operation is checked by zero/unlimited. the meter should indicate zero resistance. • The sequence of check is interlock monitor switch; primary and secondary interlock switched check. 1) In case of interlock monitor switch check POWER SUPPLY CORD Condition 1) Door is opened. 2) Common terminal of the monitor switch disconnected.
EXPLODED VIEW AND PARTS LIST 1.
2.
KOR-6115 Parts List REE NO.
KOR-61151 Parts List REE NO.
DAEWOO ELECTRONICS CO., LTD. 686, AHYEON-DONG, MAPO-GU, SEOUL, KOREA C.P.O. BOX 8003 SEOUL, KOREA TELEX: DWELEC K28177-8 CABLE: “DAEWOOELEC” FAX: 02) 364-5588/5305 TEL: 02) 360-7114/7315~7 PRINTED DATE: MAR.
