S/M No. : C972T0S003 Service Manual Microwave Oven Model: KOC-972T0S KOC-972T2S KOC-982T1S KOC-982T2S KOC-983T1S KOC-983T2S KOC-984T1S KOC-984T2S KOC-985T1S KOC-985T2S ✔ Caution : In this Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information,please refer to PPL(Parts Price List) in Service Information Center (http://svc.dwe.co.kr). 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 w ith the door open.
SAFETY AND PRECAUTIONS 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. IF ANY OF THE FOLLOWING CONDITIONS EXIST, OPERATOR MUST NOT USE THE APPLIANCE. (Only a trained service personnel should make repairs.) (1) A broken door hinge. (2) A broken door viewing screen. (3) A broken front panel, oven cavity. (4) A loosened door lock. (5) A broken door lock.
SPECIFICATIONS M ODEL KO C -972T 0S K O C-972T 2S P O W E R S U P P LY 230V ~50H z 230V~50H z M IC RO W AVE 1450W 1450W G R ILL 1200W 1200W C O N VE C T IO N 1550W 1550W PROGRAM COOK 1850W 1850W C O M B IN AT IO N 2600W (S im ultaneous) 1550W (S equential) M IC R O W AV E EN E R G Y O U TP U T 950W (IE C 705) 950W (IE C 705) M IC R O W AV E FR E Q U EN C Y 2450M Hz 2450M H z O UT S ID E D IM EN S IO NS (W X H X D) 526 x 345 x 413 m m (20.7 x 13.6 x 16.1 in.
EXTERNAL VIEW 1.
EXTERNAL VIEW 2. FEATURE DIAGRAM KOC-972T 1. Door seal - Door seal maintains the microwave energy within the oven cavity and prevents microwave leakage. 2. 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. 3. Door viewing screen - Allows viewing of food. The screen is designed so that light can pass through, but not the microwave. 4.
EXTERNAL VIEW KOC-982T/983T/984T/985T 1. Door seal - Door seal maintains the microwave energy within the oven cavity and prevents microwave leakage. 2. 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. 3. Door viewing screen - Allows viewing of food. The screen is designed so that light can pass through, but not the microwave. 4.
INSTALLATION 1. Steady, flat location This microwave oven should be set on a steady, flat surface. This microwave oven is designed for counter top use only. 2. Leave space behind and side All air vents should be kept a clearance. If all vents are covered during operation, the oven may overheat and, eventually, cause failure. 3. Away from radio and TV sets Poor television reception and radio interference m ay result if the oven is located close to a TV, radio, antenna or feeder and so on.
CONTROL PANEL When blinking, the oven is operating in "COMBI" cooking mode. When blinking, the oven is operating in "WEIGHT DEFROST" cooking mode. When blinking, the oven is operating in "GRILL" cooking mode. When blinking, the oven is operating in "TIME DEFROST" cooking mode. When blinking, the oven is operating in "MICROWAVE" cooking mode. When blinking, the oven is operating in "PROGRAM COOK" cooking mode.
DISASSEMBLY AND ASSEMBLY Cautions to be observed when trouble shooting. Unlike many other appliances, the microwave oven is 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. 2.
DISASSEMBLY AND ASSEMBLY 1. To remove cabinet (1) Remove four screws on cabinet back. (2) Push the cabinet backward. 2. To remove guide wind assembly (1) Remove two screws for earthing and for fixing to rear-plate. (2) Remove the noise filter from the guide wind. (3) Pull the fan from the motor shaft. (4) Remove two screws which secure the motor shaded pole. (5) Remove the motor shaded pole. (6) Reverse the above steps for reassembly.
DISASSEMBLY AND ASSEMBLY 3. To remove H.V.transformer (1) Remove four screws which secure the H.V.transformer to the base plate. (2) Remove the H.V.transformer. (3) Reverse the above steps for reassembly. 4. To remove high voltage capacitor (1) Remove a screw which secure the grounding ring terminal of the H.V. diode and the capacitor holder. (2) Remove the H.V. diode from the capacitor holder. (3) Reverse the above steps for reassembly.
DISASSEMBLY AND ASSEMBLY 5. To remove magnetron (1) Remove three screws which secure the magnetron. (2) Remove the magnetron. (3) Reverse the above steps for reassembly. CAUTION N ever install the m agnetron w ithout the m etallic gasket plate which is packed w ith each m agnetron to prevent m icrow ave leakage. W henever repair w ork is carried out on m agnetron, check the m icrow ave leakage. It shall not exceed 4m W /cm 2 for a fully assem bled oven with door norm ally closed.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) DISASSEMBLY AND ASSEMBLY 6. To remove control panel assembly KOC-972T, KOC-982T (1) Remove a screw which secure the control panel assembly to the oven front plate.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) DISASSEMBLY AND ASSEMBLY KOC-983T (1) Remove a screw which secure the control panel assembly to the oven front plate. At the same time, draw forward the control panel assembly from the oven front plate.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) DISASSEMBLY AND ASSEMBLY KOC-984T (1) Remove a screw which secure the control panel assembly to the oven front plate. At the same time, draw forward the control panel assembly from the oven front plate. (2) Remove the dial knob.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) DISASSEMBLY AND ASSEMBLY KOC-985T (1) Remove a screw which secure the control panel assembly to the oven front plate. At the same time, draw forward the control panel assembly from the oven front plate. (2) Remove the dial knob.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) DISASSEMBLY AND ASSEMBLY 7. To remove door assembly (1) Remove two screws which secure the stopper hinge top. (2) Remove the door assembly from top plate of cavity. (3) Reverse the above steps for reassembly.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) DISASSEMBLY AND ASSEMBLY KOC-983T (1) Remove the gasket door. (2) Remove the door seal ass’y. (3) Remove the hook and spring. (4) Remove the barrier-screen *o. REF. NO.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) DISASSEMBLY AND ASSEMBLY KOC-984T, KOC-985T (1) Remove the gasket door. (2) Remove a screw holding the handle. (3) Remove the handle from the frame door. (4) Remove the door seal ass’y. (5) Remove the hook and spring.
DISASSEMBLY AND ASSEMBLY 9. Method to reduce the gap between the door seal and the oven front surface. (1) To reduce gap located on part ‘A’ • Loosen two screws on stopper hinge top, and then push the door to contact the door seal to oven front surface. • Tighten two screws. (2) To reduce gap located on part ‘B’ • Loosen two screws on stopper hinge under, and then push the door to contact the door seal to oven front surface. • Tighten two screws.
DISASSEMBLY AND ASSEMBLY 10. To remove motor syncro and under heater (1) Cut the syncro motor cover parts from the base plate. (2) Remove two screws which secure the motor syncro and supporter to bracket syncro motor. (3) Remove two screws and under heater assembly in cavity 11. To remove grill heater assembly KOC-972T (1) Remove a nut which secure the heater holder inserting the wire of grill heater to side plate. (2) Remove two nuts and a screw which secure the heater bracket to grill heater.
DISASSEMBLY AND ASSEMBLY KOC-982T,KOC-983T,KOC-984T,KOC-985T (1) Remove two screws which secure the cover insulator *t to top plate. (2) Remove the harness between heaters. (3) Remove two screws for removing heater brackets. (4) Remove heaters. (5) Reverse the above steps for reassembly. 12. To remove convection part assembly (KOC-982T,KOC-983T,KOC-984T,KOC-985T only) (1) Remove cover *b and cover insulator *b protecting convection part assembly. - release two lances of cover insulator *b.
INTERLOCK MECHANISM AND ADJUSTMENT 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 microswitch.
TROUBLE SHOOTING GUIDE Following the procedures below to check if the oven is defective or not. 1. Check grounding before checking trouble. 2. Be careful of the high voltage circuit. 3. Discharge the high voltage capacitor. 4. When checking the continuity of the switches, fuse or high voltage transformer, disconnect one lead wire from these parts and then check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to your meter.
TROUBLE SHOOTING GUIDE CON DITION CHECK RESULT CAUSE REM EDY O utlet has proper voltage Fuse does not blow.
TROUBLE SHOOTING GUIDE (TROUBLE 3) No microwave oscillation even though fan motor rotates.
TROUBLE SHOOTING GUIDE (TROUBLE 4) Display shows all figures selected, but oven does not start cooking, even though desired program and time are set and start pad is tapped. CON DITION CHECK RESULT CAUSE REM EDY Turn table m oto r and oven lam p do not turn on C heck con tinuity of prim ary interlock sw itch No C ontinuity M alfunction of prim ary interlock sw itch A djus t or replace C heck con tinuity of secondary interlock and D .O .M .
TROUBLE SHOOTING GUIDE (TROUBLE 6) The following visual conditions indicate a probable defective touch control circuit or button P.C.B. assembly. 1. Incomplete segments (1) Segments missing (2) Partial segments missing (3) Digit flickering other than normal fluorescent slight flickering (4) 0 does not display when power is on. 2. A distinct change in the brightness of one or more numbers exists in the display. 3. One or more digits in the display are not on when they should be. 4.
TROUBLE SHOOTING GUIDE BUTTON KEYBOARD CHECK PROCEDURE 1. Type of button names (key metrix and circuit diagram) The tact switch keyboard consists of 10 keys which configurations are described above. 2. Key check procedure To determine if the tact switch keyboard is defective or not, check the continuity of each button(key) contacts with a multimeter.
MEASUREMENT AND TEST 1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT 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 wit the microwave oven supplied at rated voltage and operated at its maximum microwave power setting with a load of 1000 ± 5cc of potable water. 2.
MEASUREMENT AND TEST 2. ELECTRICAL CONTINUITY CHECK OF INTERLOCK SWITCH NOTE R em ove the pow er plug from the w all receptacle before testing. PROCEDURE 1. Primary interlock switch (1) Disconnect two connectors from primary interlock switch. (2) Connect the ohm-meter leads between the terminals of the primary interlock switch. 2. Read the value of resistance between the terminals of the switch, when the door is opened, and when the door is closed. 3.
MEASUREMENT AND TEST 3. MICROWAVE RADIATION TEST WARNING M ake sure to check the m icrow ave leakage before and after repair of adjustm ent. A lw ays start m easuring of an unknow n field to assure safety for operating personnel from m icrow ave energy. D o not place your hands into any suspected m icrow ave radiation field unless the safe density level is know n. C are should be taken not to place the eyes in direct line w ith the source of m icrow ave energy.
MEASUREMENT AND TEST 4. COMPONENT TEST PROCEDURE • High voltage is present at the high voltage terminal of the high voltage transformer during any cooking cycle. • It is neither necessary nor advisable to attempt measurement of the high voltage. • Before touching any oven components or wiring, always unplug the oven from its power source and discharge the capacitor. 1. High voltage transformer (1) Remove connections from the transformer terminals and check continuity.
WIRING DIAGRAM 34
SCHEMATIC DIAGRAM 35
SCHEMATIC DIAGRAM 36
SCHEMATIC DIAGRAM 37
EXPLODED VIEWS AND PARTS LIST 1.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) EXPLODED VIEWS AND PARTS LIST PARTS LIST REF NO.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) EXPLODED VIEWS AND PARTS LIST REF NO.
EXPLO DED VIEWS A ND PA RTS LIST 2.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) EXPLODED VIEWS AND PARTS LIST PARTS LIST REF NO.
EX PLO DED V IEW S AND PARTS LIST Caution : In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) REF NO.
PRINTED WIRING BOARD 1. CIRCUIT CHECK PROCEDURE 1. Low Voltage Transformer check • The low voltage transformer is located on the P.C.B. • Measuring condition (input voltage) : 230 VAC / 50 Hz KOC-972T/982T KOC-983T/984T/985T L.V.T. : DMR -101FS L.V.T. : DMR -984FS Term inal Voltage Term inal Voltage 1-2 230VA C /50H z 1-3 230VA C /50Hz 4-5 13.0 VA C 6-7 10.5 VA C 6-7 35.0 VA C 7-8 10.5 VA C 8 - 10 3.0 VA C 9 - 10 2.
PRINTED WIRING BOARD 3. Display Problems NO CA USE MEASUREME NT RESULT R EMEDY 1 P oor contact betw een P.C.B . and display filam ent C heck the voltage of display pin 1 & 25 2 T he display has som e trouble in its segm ent or grid R efer to T he display trouble shooting data below Replace P.C .B . assem bly 3 Loss vacuum in the display F ind white spot Replace P.C .B . assem bly 2.6 VA C Fix the pin 1 & 25 on the P.C .B .
PRINTED WIRING BOARD 4. Case of no microwave oscillation (1) Situation : When touching M/W button, oven lamp turns on, fan motor and turntable motor rotate and cook indicator in the display comes on. • CAUSE : Relay 1 (RY1) does not operate.
PRINTED WIRING BOARD • Check method STAGE POINT A POINT B R ELAY O N +5 V D C GND R ELAY O F F G ND +12 V D C 5. Case of no heating of upper heater When touching TEMP COOK & COMBI button, oven lamp turns on, fan motor and turntable motor rotate and cook indicator in the display comes on. • CAUSE : Relay 2 (RY2) does not operate. KOC-972T/982T KOC-983T/984T/985T • Check method STAGE POINT A POINT B R ELAY O N +5 V D C GND R ELAY O F F G ND +12 V D C 6.
PRINTED WIRING BOARD 7. Case of no stopping of the count down timer When the door is opened during operation, the count down timer does not stop. KO C-972T/982T KO C-983T/984T/985T • Check method STAGE POIN T A POINT B D oor opened O pen +5 V D C D oor closed C losed GND NOTE C heck the state (ON , O FF) of the secondary interlock sw itch by resistance m easurem ent. 8.
P.C.B. CIRCUIT DIAGRAM 1.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) P.C.B.
P.C.B.
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr) P.C.B.
