S/M No. : G875T2S001 Service Manual Microwave Oven Model: KOG-875T2S DAEWOO ELECTRONICS CO., LTD. http : //svc.dwe.co.kr Feb.
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 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 POWER SUPPLY 230V ~ , 50Hz single phase with earthing MICROWAVE POWER CONSUMPTION 1,400 W OUTPUT POWER 900 W (IEC 705) FREQUENCY 2,450 MHZ GRILL POWER CONSUMPTION 1,400 W COMBINATION HEATING POWER CONSUMPTION 1,400 W OUTSIDE DIMENSIONS (W X D X H ) 501 X 320 X 413 mm (19.7 X 12.6 X 16.2 in.) CAVITY DIMENSIONS (W X D X H) 310 X 229 X 320 mm (12.2 X 9.0 X 12.6 in.) NET WEIGHT 17.6 kg (38.9 Ibs.
NAMES AND FUNCTION OF PARTS 1 2 6 3 4 5 DEFROST M/W GRILL COMBI WEIGHT-TIME PROGRAM COOK M/W GRILL KG TIME WEIGHT DEFROST DEFROST COMBI +1MIN PROGRAM COOK 1. Roast Beef 2. Roast Port 3. Roast Chicken 4. Fish Fillets 5. Vegetable SPEEDY COOK STOP/CLEAR START/CLOCK 7 8 9 1 Door latch When the door is closed it will automatically lock shut. If the door is opened while the oven is operating. The magnetron will automatically shut off. 6 Heater Grill or Combi-Mode has need for the heater.
CONTROL PANEL When blinking, the oven is operating in WEIGHT DEFROST. When blinking, the oven is operating in COMBI cooking. When blinking, the oven is operating in GRILL cooking. DEFROST When blinking, the oven is operating in MICROWAVE cooking. When blinking, the oven is operating in PROGRAM cook. Microwave Power Level Used to select the variable microwave power level. If this button is pressed for more than 1.3 seconds, number is scrolled up automatically.
INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS 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 lever downward.
(2) Monitor interlock switch When the door is closed, the hook pushes the lever forward, and pushes the Latch Lever downward the lever press the button of the interlock monitor switch to bring it under ‘OFF’ condition. The latch Lever press the button on the secondary interlock switch to bring it under ‘ON’ condition. - Adjustment Interlock monitor switch When the door is closed, the monitor switch should be opened before other switches close.
PRECAUTIONS FOR DISASSEMBLY AND REPAIR - Cautions to be observed when trouble shooting. Unlike many other appliances, the microwave oven is high-voltage, high-current equipment. It is completely safe 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. (Refer to Fig. 1) 1) Remove three screws on cabinet back. 2) Push the cabinet backward. Fig. 1 2. To remove guide wind assembly. (Refer to Fig. 2) 1) Release two screws 2. 2) Remove back-cover 3. 3) Pull the fan 5 to the motor shaft. 4) Release two screws 1 which secure the motor shaded pole 4. 5) Reverse the above steps for reassembly. 2 1 5 4 3 9 Fig.
3. To remove H.V. transformer. (Refer to Fig. 3) 1) Remove four screws 1 which secure the H.V. Transformer bracket to the base plate. 2 2) Remove the H.V. Transformer 2. 1 Fig. 3 High voltage circuit wiring Mognetron H.V. Copacitor H.V.Diode H.V. Trans H.V.
4. To remove magnetron. (Refer to Fig. 4) 1) Remove a screw 2 which secure the magnetron 1. 2) Remove the magnetron. 3) Reverse the above steps for reassembly. Fig. 4 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.
5. To remove control panel assembly. (Refer to Fig. 5, 6) (1) Remove a screw holding control panel assembly to the oven front plate. At the same time, draw forward the control panel assembly from oven front plate. (2) Remove the Dial knob. (3) Remove nine screws which secure the main and sub PCB assembly to control panel. (4) Remove buttons. Fig. 5 (5) Remove the Window display and Decorator Panel. B01 B05 B11 B02 B10 B03 B09 B06 B08 B07 B04 Fig. 6 REF NO.
6. To remove door assembly. (Refer to Fig. 7) 1 1) Remove two screws 1 which secure to hinge. 2 2) Remove door assembly 2. 3) Remove door above for reassembly taking case to replace fixing glue. 7. To remove door part. (Refer to Fig. 8) Fig. 7 (1) Remove the Gasket door (2) Remove the Door seal Ass’y. (3) Remove the Hook and Spring. (4) Remove the Barrier Screen. (5) Remove a screw holding the handle. (6) Remove the Handle form the Frame door. A10 A08 A09 A07 A05 A11 A01 A12 A06 A02 A03 Fig.
8. Method to reduce the gap between the door seal and the oven front surface. (1) To reduce gap located on part ‘A’. 1) Remove the cabinet. 2) Loosen a screw on top door hinge, then push the door to contact the door seal to oven front surface. 3) Tighten a screw. A C DEFROST M/W GRILL COMBI WEIGHT-TIME PROGRAM COOK M/W GRILL KG WEIGHT TIME DEFROST DEFROST COMBI +1MIN PROGRAM COOK 1. Roast Beef 2. Roast Port 3. Roast Chicken 4. Fish Fillets 5.
9. To remove tray motor and under Heater. (Refer to Fig. 9) 1) Cut the tray motor cover parts from the base plate (Refer to Fig. 9). 2) Remove two screws 2 which secure the tray motor 1. 1 2 CUTTING(8EA) Fig.
10. To remove grill heater assembly. (Refer to Fig. 10) 2 3 1 4 Fig. 10 1) Remove the cabinet. 2) Release two screws 1 , and remove the Top cover 2. 3) Release a screws 3 , and remove Air Guide outlet 4. 4) Release grill Heaters Bracket 5. 5) Release the above steps for reassembly.
TROUBLE SHOOTING GUIDE Following the procedure below to check if the oven is defective or not. 1. Check earthing before trouble checking. 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 check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to your meter.
Condition Outlet has proper voltage. Fuse does not blow. Check Result Cause Remedy Check continuitymagnetron No Continuity Defective magnetron Check continuity of noise filter board No Continuity Defective line filter board Replace Check continuity of power supply cord No Continuity Open power supply cord Adjust. Normal Defective touch control circuit Adjust.
(TROUBLE 3) Condition No microwave oscillation No microwave oscillation even though fan motor rotates.
(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. Condition Turn table motor, and oven lamp do not turn on Check Check continuity of primary interlock switch Check continuity of secondary interlock and D.O.M. switch Result Cause No Continuity Malfunction of Primary interlock switch Adjust or replace Malfunction of secondary interlock and D.O.M. switch Adjust or replace No Continuity Check D.C.
(TROUBLE 5) The following visual conditions indicate a probable defective touch control circuit or membrance switch assembly 11. Incomplete segments, (A) Segments missing. (B) Partical segments missing. (C) Digit flickering other than normal fluorescent slight flickering. (D) 0 does not display when power is on. 12. A distinct change in the brightness of one or more numbers is the display. 13. One or more digits in the display are not on when they should be. 14.
BUTTON KEYBOARD CHECK PROCEDURE 1. Type of encoding and button names. 2 3 4 5 TIME DEFROST 53 8 8 52 6 6 51 4 4 50 2 2 R12 100K C2 102 RA3 RGLD7X104J 10 12 14 15 10 12 14 15 GRILL SPEEDY COOK WEIGHT DEFROST M/W +1min COMBI CN101 HLEM15R-1 PROGRAM COOK START STOP CLEAR TACK SWITCH KPT-1115AMX10 CA1 B7102M Fig.
MEASUREMENT 1. Microwave Output Power CAUTION : 1. Water load should be measured exactly to 1 liter. 2. Input power voltage should be exactly volts as specified. 3. Ambient temperature should be 20 2 (68 3.6 ) 1-1. Standard Method 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.
2-2. Judgement The value of resistance should be applied to the value specified below. Door Open Closed Primary Interlock Switch 0 Secondary Interlock Switch 0 Interlock Monitor Circuit 3-3. Procedures 1) Prepare 600cc glass or plastic container. 2) Pour 275±15 milliliters of tap water initially at 68±9˚F (20±5˚C) in the container. 3) Place it at the center of the tray and set it is a cavity. 4) Operate oven.
COMPONENT TEST PROCEDURE 1. High voltage is present at the high voltage terminal of the high voltage transformer during any cook 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 8). 1. High voltage transformer 4. Magnetron (A) Remove connections from the transformer terminals and check continuity.
WIRING DIAGRAM 26
SCHEMATIC DIAGRAM 27
28
EXPLODED VIEWS AND PARTS LIST 29
NO PART CODE A00 3511710030 B00 PKCPSWVG10 1 PART NAME DESCRIPTION Q'TY DOOR AS KOG-875T0S 1 CONTROL PANEL AS KOG-875T2S 1 3516108660 CAVITY AS KOG-87050S 1 2 3516503900 REAR PLATE *0 SBHG-1 T0.6 1 3 3511403800 COVER WAVE GUIDE MICA T0.
NO PART CODE PART NAME DESCRIPTION 41 3512515500 GUIDE AIR OUTLET SA1D T0.5 1 42 7S427W40A1 SCREW SPECIAL TT2 HEX FG 4X10 SE MFZN 2 43 35113ACSJ5 CORD POWER AS 3X1.5 40X40 120-RTML 1 44 7122401011 SCREW TAPPING T2S TRS 4*10 MFZN 2 45 3518905000 THERMOSTAT OFF:100 ON:90 V#187 1 46 7121300611 SCREW TAPPING T2S PAN 3X6 MFZN 1 47 3510800800 CABINET PCM 0.
PRINTED WIRING BOARD 1.CIRCUIT CHECK PROCEDURE 1) Low voltage transformer (DMR-984FS) check. The low voltage transformer is located on the P.C.B. Measuring condition: Input voltage: 230VAC/50Hz 1 6 Terminal Voltage 7 1-3 230.0V 6-7 9 VAC 7-8 9 VAC 9-10 2.3 VAC 8 9 3 5 10 NOTE 1 : Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source voltage. NOTE 2 : The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.
3) Display problems NO CAUSE MEASUREMENT RESULT 2.6VAC REMEDY 1 Poor contact between P.C.B. and display filament. Check the voltage of display pin 1 & 25 Fix the pin 1 & 25 on the P.C.B. 2 The display has some trouble in its segment or gril. Refer to “The display trouble shooting data” below Replace P.C.B. assembly. 3 Loss vacumm in the display. Find white spot. Replace P.C.B. assembly. The display trouble shooting data. TROUBLE DISPLAY NAME & PIN NO. MICOM OUTPUT IN PIN NO.
4) When there is no microwave oscillation. (1) When touching “M/W” button, oven lamp turns on. Fan motor and turntable motor rotate and cook indicator in display comes on. * Cause : Relay 1 (RY1) dose not operate. B A RY1 G5G-1A-DT MAGNETRON Q7 KRX106M 40 D6 1N4148 V2 CHECK METHOD POINT A B STAGE 5VDC GND RY1 “ON” RY1 “OFF” GND 12VDC (2) When touching “M/W” button, oven lamp dose not turn on. Turntable motor dose not rotate, but cook indicator in display comes on.
CHECK METHOD POINT A B STAGE VDC GND RY4 “ON” RY4 “OFF” GND 12VDC 5) When there is not heater. When touching “TEMP COOK & COMBI” button, oven lamp turns on. Fan motor and turntable motor rotate and cook indicator in display comes on. * Cause : Relay 2 (RY2) dose not operate.
6) When the door is opened during operation, the count down timer does not stop. CN2 35313-0210 COM R28 4.7K R22 4.7K R23 330 1 2 NO 47 D.O.M R25 4.7K C12 104 C13 104 A R24 100K B V1 CHECK METHOD POINT A B OPEN CLOSED +5VDC GND STAGE DOOR OPENED DOOP CLOSED NOTE : Check the state of the secondary interlock switch. 7) When “ ” comes on display. D1 1N4148 1N4004 6 V1 B A R17 4.7K C7 473 C5 473 Q1 C3198 R16 4.7K C1 R15 4.7K 45 INT1 C5 102 R13 4.
RED WHITE BLUE 37 5 10 9 8 7 6 EC4 220uF 50V EC3 1000uF 35V C7 473 D1 1N4148M F1 D9 1N4004 D8 1N4004 D7 1N4004 FAN MOTOR CS11-12SH RY4 TRAY MOTOR, LAMP V2 F2 EC5 220uF 50V D10 1N4004 EC2 1000uF 35V 0V(GND) +5V +12V -24V V2 V3 V3 V3 V1 VOLTAGE SYMBOL ZD1 4.7V C15 104 R26 Q1 C3198 1.2K,1/4W R13 4.7K C11 104 V2 R16 4.7K KRC106M C14 104 Q5 Q6 KRC106M C6 473 R17 4.7K V2 D3 1N4148 V2 D2 1N4148 Q7 KRC106M Q8 KRC106M ZD3 5.
MAIN P.C.B. ASS’Y PART LIST NO. 1 NAME PCB MAIN SYMBOL SPECIFICATION PART CODE Q’TY M218 93X213 3514314980 1 M219 91.
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) 360-8184 TEL: 02) 360-8183 E-MAIL : G7F00E@WEB.DWE.CO.KR S/M NO.
