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Service Manual
Microwave Oven
Model: KOR-634R0S
DAEWOO ELECTRONICS CO., LTD. ht:/v.w.ok tp/scdec.r
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) Damage to or loosening of hinges and latches, (5) Evidence of dropping or abuse. (c) Before turning on power to the microwave oven for any service test or inspection within the microwave generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections. (d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner. (e) A microwave leakage check to verify compliance with the Federal performance standard should be performed on each oven prior to release to the owner.
TABLE OF CONTENTS
SAFETY AND PRECAUTIONS ...........................................................................................................................................2 1. FOR SAFE OPERATION............................................................................................................................................2 2. FOR SAFE SERVICE PROCEDURES......................................................................................................................2 SPECIFICATIONS ...............................................................................................................................................................3 EXTERNAL VIEW................................................................................................................................................................4 1. OUTER DIMENSION..................................................................................................................................................4 2. FEATURE DIAGRAM .................................................................................................................................................5 3. CONTROL PANEL .....................................................................................................................................................6 INSTALLATION ...................................................................................................................................................................7 OPERATIONS AND FUNCTIONS.......................................................................................................................................8 DISASSEMBLY AND ASSEMBLY......................................................................................................................................9 INTERLOCK MECHANISM AND ADJUSTMENT.............................................................................................................16 TROUBLE SHOOTING GUIDE .........................................................................................................................................17 MEASUREMENT AND TEST ............................................................................................................................................21 1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT..................................................................................21 2. MICROWAVE RADIATION TEST ............................................................................................................................22 3. COMPONENT TEST PROCEDURE ........................................................................................................................23 WIRING DIAGRAM............................................................................................................................................................24 PRINTED CIRCUIT BOARD..............................................................................................................................................25 1. CIRCUIT CHECK PROCEDURE..............................................................................................................................25 2. PCB CIRCUIT DIAGRAM .........................................................................................................................................28 3. P.C.B. LOCATION NO..............................................................................................................................................29 EXPLODED VIEW AND PARTS LIST...............................................................................................................................30 1. DOOR ASSEMBLY...................................................................................................................................................30 2. CONTROL PANEL ASSEMBLY ...............................................................................................................................30 3. TOTAL ASSEMBLY..................................................................................................................................................30
1
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. The door gasket plate and oven cavity surface should be kept clean. No grease, soil or spatter should be allowed to build up on these surfaces or inside the oven. DO NOT ATTEMPT TO OPERATE THIS APPLIANCE WITH THE DOOR OPEN. The microwave oven has concealed switches to make sure the power is turned off when the door is opened. Do not attempt to defeat them. DO NOT ATTEMPT TO SERVICE THIS APPLIANCE UNTIL YOU HAVE READ THIS SERVICE MANUAL.
2. FOR SAFE SERVICE PROCEDURES
1. If the oven is operative prior to servicing, a microwave emission check should be performed prior to servicing the oven. 2. If any certified oven unit is found to servicing, a microwave emission check should be performed prior to servicing the oven. (a) inform the manufacturer, importer or assembler, (b) repair the unit at no cost to the owner, (c) attempt to ascertain the cause of the excessive leakage, (d) tell the owner of the unit not to use the unit until the oven has been brought into compliance. 3. If the oven operates with the door open, the service person should tell the user not to operate the oven and contact the manufacturer and CDRH immediately.
IMPORTANT
The wire in this mains lead coloured in accordance with the following code. Green-and-yellow : Earth Blue : Neutral Brown : Live As the colours of the wires in the manins lead of this appliance may not correspond with the coloured markings identifying the terminals in your plug, proceed as follows. The wire which is coloured green-and-yellow must be connected to the terminal in the plug which is marked with the letter `E', earth symbol or coloured green-and-yellow. The wire which is coloured blue must be connected to the terminal which is marked with the letter `N' or coloured black. The wire which is coloured brown must be connected to the terminal which is marked with the letter `L' or coloured red.
NOTE :
The oven is designed for counter-top use only.
2
SPECIFICATIONS
MODEL POWER SUPPLY POWER CONSUMPTION MICROWAVE FREQUENCY OUTSIDE DIMENSIONS (W X H X D) CAVITY DIMENSIONS (W X H X D) NET WEIGHT TIMER FUNCTION SELECTIONS POWER SELECTIONS CAVITY VOLUME MICROWAVE MICROWAVE ENERGY OUTPUT 1,200 W 800W 2450MHz 465 x 279 x 360 mm (18.3 x 11.0 x 14.2 in) 290 x 220 x 306 mm (11.4 x 8.7 x 12.0 in.) Approx. 13 kg (28.7 Ibs.) 59 min. MICROWAVE 5 LEVELS 0.7 Cu. Ft. KOR-634R0S 230V~50Hz, SINGLE PHASE WITH EARTHING
* SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.
3
EXTERNAL VIEW
1. OUTER DIMENSION
4
2. FEATURE DIAGRAM
1. DOOR SEAL Door seal maintains the microwave within the oven cavity and prevents microwave leakage. 2. DOOR HOOK When the door is closed, it will automatically lock shut. If door is opened while oven is operating, magnetron tube will immediately stop operating. 3. DOOR SCREEN Allows viewing of food. Microwave cannot pass through perforations in screen. 4. SPATTER SHIELD Protects the microwave outlet from splashes of cooking foods.
5. OVEN LAMP Automatically turns on during oven operating. 6. SAFETY INTERLOCK SYSTEM 7. CONTROL PANEL 8. GLASS COOKING TRAY Made of special heat resistant glass. The tray must always be in proper position before operating. Do not cook food directly on the tray. 9. OVEN FRONT PLATE 10. ROLLER GUIDE Supports the glass cooling tray.
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3. CONTROL PANEL
1. Display Cooking time, power level, indicators and present time are displayed. 2. Power Used to set power level. 3. Defrost Used to defrost by weight or time. 4. Clock Used to set clock. 5. Auto cook Used to using a program or to reheat.
6. Dial knob Used to set time and weight. 7. Stop/Clear Used to stop the oven operation or to erase all entries. 8. Start/Easy cook Used to start the oven operation and also increase the reheat time by 30 seconds.
6
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 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, antenna or feeder and so on.
4. Away from heating appliances and water taps
Keep the oven away from hot air, steam or splash when choosing a place to position it, or the insulation might be adversely affected and breakdowns occur.
5. Power supply Check your local power source.
This microwave oven requires a current of approximately 6 amperes, 230Volts, 50Hz grounded outlet.
Power supply cord is about 0.8 meters long. The voltage used must be the same as specified on this oven. Using a higher voltage may result in a fire or other accident causing oven damage. Using low voltage will cause slow cooking, We are not responsible for damage resulting from use of this oven with a voltage of ampere fuse other than those specified.
This appliance is supplied with cable of special type, which, if samaged, must be repaired with cable of same type.
Such a cable can be purchased from DAEWOO and must be installed by a Qualified Person.
6. Examine the oven after unpacking for any damage such as:
A misaligned door, broken door or a dent in cavity. If any of the above are visible, DO NOT INSTALL, and notify dealer immediately. 7. Do not operate the oven if it is colder than room temperature (This may occur during delivery in cold weather.) Allow oven to become room temperature before operating.
EARTHING INSTRUCTIONS
This appliance must be earthed. In the event of an electrical short circuit, earthing reduces the risk of the electric shock by providing an escape wire for the electric current. This appliance is equipped with a cord having a earthing wire with a earthing plug. The plug must be plugged into an outlet that is properly installed ant earthed.
WARNING
Improper use of the earthing plug can result in a risk of electric shock. Consult a qualified electrician or serviceman if the earthing instructions are not completely understood, or if doubt exists as to whether the appliance is properly earthed, and either:If it is necessary to use an extension cord, use only a 3-wire extension cord that has a 3-blade earthing plug, and a 3-slot receptacle that will accpt the plug on the appliance. The marked rating of the extension cord should be equal to or greater than the electrical rating of the appliance, or Do not use an extension cord.
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OPERATIONS AND FUNCTIONS
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. When the oven door is opened, the light turns off. 5. The oven door can be opened at any time during operation by touching the door release button on the control panel. The oven will automatically shut off. To restart the oven, close the door and then touch START. 6. Each time a pad is touched, a BEEP will sound to acknowledge the touch. 7. The oven automatically cook on full power unless set to a lower power level. 8. The display will show : 0 when the oven is plugged in. 9. Time clock returns to the present time when the cooking time ends. 10. When the STOP/CLEAR pad is touched during the oven operatiion, the oven stops cooking and all information retained. To erase all information (except the present time), touch the STOP/CLEAR pad once more. If the oven door is opened during the oven operation, all information is retained. 11. If the START pad is touched and the oven does not operate, check the area between the door and door is closed securely. The oven will not start cooking under the door is completely closed or the program has been reset. Make sure the oven is properly installed and plugged into the electrical outlet.
Wattage output chart The power level is set by pressing the POWER pad. The chart shows the display, the power level and the percentage of power. Touch POWER button Once 3 times 5 times 7 times 9 times Power level (Display) P-HI P-80 P-60 P-40 P-20 Approximate Percentage of Power 100% 80% 60% 40% 20%
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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. Use an insulated screwdriver and ware rubber gloves when servicing the high voltage side. 3. Discharge the high voltage capacitor before touching any oven components or wiring. (1) Check the grounding. Do not operate on a 2-wire extension cord. The microwave oven is designed to be used with grounded. It is imperative, therefore, to make sure it is grounded properly before beginning repair work. (2) Warning about the electric charge in the high voltage capacitor. For about 30 seconds after the operation stopped and electric charge remains in the high voltage capacitor. When replacing or checking parts, short between oven chassis and the negative high terminal of the high voltage capacitor, by using a properly insulated screwdriver to discharge. 4. When the 12A fuse is blown out due to the operation of the monitor switch; replace primary interlock switch, secondary interlock switch and interlock monitor switch. 5. After repair or replacement of parts, make sure that the screws are properly tightened, and all electrical connections are tightened. 6. Do not operate without cabinet.
CAUTION : Service personnel should remove their watches whenever working close to or replacing the magnetron.
CAUTION : When servicing the appliance, need a care of touching or replacing high potential parts because of electrical shock or exposing microwave. These parts are as follows - HV Transformer, Magnetron, HV Capacitor, HV Diode, HV fuse.
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1. To remove cabinet
1) Remove three screws on cabinet back. 2) Push the cabinet backward.
2. 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 for reassembly.
NOTE : After replacing the door assembly, perform a check of correct alignment with the hinge and cavity front plate.
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3. To remove door parts.
REF NO. A01 A02 A03 A04 A05 A06 A07 A08 A09 A10 A11 A12 A13 A14
PART CODE 3512203850 3517005620 3515204100 3511706120 3517002800 3512300200 3513100730 3515101310 7001503311 3512603210 3511601500 3511604610 3511604600 3516003940
PART NAME FRAME DOOR BARRIER-SCREEN*O STOPPER HINGE*T AS DOOR PAINTING AS BARRIER-SCREEN*I GASKET DOOR HOOK SPRING HOOK SCREW MACHINE HANDLE DOOR DECORATOR LOGO DECORATOR DOOR*U DECORATOR DOOR*T SPECIAL DOUBLE TAPE
DESCRIPTION ABS XR-401, H-2938 TEMP GLASS T3.2 KOR-63150S KOR-634R0S PE 0.1T PP POM BLACK HSW-3 PAN 5X33 MFZN STEEL NI + CR AL T1.5 STS T0.6 STS T0.6 SI-161 T0.15 27MM
Q'TY 1 1 1 1 1 1 1 1 2 1 1 1 1 1
REMARK
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(1) Remove the gasket door from door weld as. (2) Remove the barrier screen inner from weld as. (3) Remove the door frame from door weld as. (4) Remove the stopper hinge top from door weld as. (5) Remove the spring and the hook. (6) Remove the barrier screen outer from door frame. (7) Reverse 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' · 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.
NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.
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5. To remove control panel parts.
REF NO. B01 B02 B03 B04 B05 B06 B07 B08 B09 B10 B11
PART CODE 3513404620 3511604510 3516003910 3515501530 3516721460 3516907430 PKBPMSZY00 7121401611 PKMPMSZY00 7621301011 3516906320
PART NAME KNOB VOLUME DECORATOR C-PANEL SPECIAL DOUBLE TAPE WINDOW DISPLAY CONTROL PANEL BUTTON FUNCTION SUB PCB AS SCREW TAPPING MAIN PCB AS SCREW TAPPING BUTTON FUNCTION
DESCRIPTION ABS XR-401, H-2938 STS T0.6 SI-161 T0.15 PMMA T2.0 ABS XR-401, H-2938 ABS XR-401, COATING KOR-634R0S T2S PAN 4X16 MFZN KOR-634R0S T2S TRS 4X12 MFZN ABS XR-401, COATING
Q'TY 1 1 1 1 1 1 1 3 1 8 2
REMARK
1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly. 2) Remove screws which secure the PCB assembly to control panel. 3) Disconnect membrane tail from the connector of the PCB assembly. 4) Detach the function buttons and knob from the control panel. 5) Reverse the above steps for reassembly.
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6. 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.
x High voltage circuit wiring
7. To remove magnetron.
1) Remove a screw which secure the magnetron. 2) Remove the magnetron. 3) Reverse the above steps for reassembly.
NOTE : 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.
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8. To remove wind guide assembly.
1) Remove a screw which secure the wind guide assembly. 2) Draw forward the wind guide assembly. 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.
9. To remove H.V.transformer.
1) Remove four screws holding the H.V.transformer. 2) Remove the H.V.transformer. 3) Reverse the above steps for reassembly.
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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. Then the button of the primary interlock switch bring it under ON condition. (2) Secondary interlock switch and interlock monitor switch When the door is closed, the hook pushes the lock lever downward. The lock lever presses the button of the interlock monitor switch to bring it under NO condition and presses the button of the secondary interlock switch to bring it under ON condition. ADJUSTMENT : Interlock monitor switch When the door is closed, the interlock monitor switch should be changed (NO condition) before other switches are closed. When the door is opened, the interlock monitor switch should be changed (NC condition) after other switches are opened. (3) Adjustment steps a) Loosen the two mounting screws. b) Adjust interlock switch assembly position. c) Make sure that lock lever moves smoothly after adjustment is completed. d) Tighten completely two mounting screws. NOTE : Microwave emission test should be performed after adjusting interlock mechanism. If the microwave smission exceed 4mW/cm2, readjust interlock mechanism.
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TROUBLE SHOOTING GUIDE
Following the procedure below to check if the oven is defective or not.
1. Check grounding 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. NOTE : When electric parts are checked, be sure the power cord is not inserted the wall outlet. Check wire harness, wiring and connected of the terminals and power cord before check the parts listed below.
(TROUBLE 1) Oven does not operate at all ; any inputs can not be accepted.
Condition
Fuse blows
Check
Check continuity of interlock monitor switch with door closed (COM NC)
Result
Cause
Malfunction of interlock monitor switch
Remedy
Replace Note 1.
Continuity No Continuity No Continuity
Check continuity of primary interlock switch contact with door partially open until interlock monitor switch contact close
Shorted contacts of primary interlock switch
Replace Note 1.
Continuity
Check continuity of primary interlock switch contact with door partially open until interlock monitor switch contact close (COM NO) Check continuity of primary winding of low voltage transformer
Continuity
Shorted contacts of primary interlock switch.
Replace Note 1.
0 or infinite
Defective low voltage transformer
Replace
Approx. 150~310 (normal)
Disconnect high voltage fuse and operate the unit
Fuse again blows
Defective high voltage transformer
Replace
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Condition
Outlet has proper voltage. Fuse does not blow.
Check
Check continuity of magnetron
Result
No Continuity
Cause
Defective magnetron
Remedy
Replace
Check continuity of noise filter board
No Continuity
Defective line filter board
Replace
Check continuity of power supply cord
No Continuity Normal
Open power supply cord
Replace
Defective touch control circuit
Replace
NOTE : All these switches must be replaced at the same time, please refer to "Interlock Mechanism and Adjustment."
(TROUBLE 2) 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
Result
No Continuity
Cause
Malfunction of primary interlock switch
Remedy
Adjust or Replace
Check continuity of secondary interlock and D.O.M. switchs
No Continuity
Malfunction of secondary interlock and D.O.M switch
Adjust or Replace
Check D.C. voltage being supplied to RELAY (RY2) coil
0V
Defective touch control circuit
Replace
Approx 15 VDC
Faulty contacts of RELAY (RY2) or open relay coil
Replace
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(TROUBLE 3)
No microwave oscillation even though fan motor rotates.
Condition
No microwave oscillation
Check
Check continuity of high voltage capacitor terminals with wires removed
Result
Continuity
Cause
Defective high voltage transformer
Remedy
Replace
Check continuity of high voltage rectifier in forward and backward direction with DC megger
Continuity in backward direction
Defective high voltage rectifier
Replace
Connect megger leads to magnetron terminal and magnetron body Check resistance of primary and secondary coil of high voltage transformer Check continuity of magnetron with wires removed
Continuity
Defective magnetron
Replace
0 or
Defective high voltage transformer
Replace
No Continuity
Defective magnetron
Replace
Check continuity of filament terminal of high voltage transformer Check D.C. voltage being supplied to RELAY (RY1) coil
No Continuity
Defective high voltage transformer
Replace
0V
Defective touch control circuit
Replace
Approx 15 VDC
Faulty contacts of RELAY (RY1) or open relay coil
Replace
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(TROUBLE 4)
The following visual conditions indicate a probable defective touch control circuit or membrane switch assembly.
1. Incomplete segments (1) Segments missing (2) Partical segments missing (3) Digit flickering other than normal display slight flickering (4) " :0" does not display when power is on. 2. A distinct change in the display are not on when they numbers is the display. 3. One or more digits in the display are not on when they should be. 4. Display indicates a number different from one touched. 5. Specific numbers (for example 2 or 3) will not display when the panel is touched. 6. Display does not count down or up with time cooking or clock operation. 7. Oven is programable and cooks normally but no display shows. 8. Display obviously jumps in time while counting down. 9. Display counts down noticeably too fast while cooking. 10. Display does not show the time of day when clear pad is touched. 11. Oven lamp and turntable motor do not stop although cooking is finished. Check if the RELAY 2 contacts close if they are close, replace touch control circuit.
Condition
Display does not show programming at all, even it keyboard is touched
Check
Check each pad for continuity of the membrane keyboard for the following keyboard check procedure
Result
Normal
Cause
Malfunction of touch control circuit of control box sub-assembly
Remedy
Replace control box sub-assembly
Abnormal
Malfunction of the membrane keyboard
Replace the membrane keyboard
NOTE : Before following the particular steps listed above in the trouble shooting guide for the membrane keyboard's, failure, please check for the continuity of each wire-harness between the membrane keyboard and P.C.B. assembly.
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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 with 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. The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190 mm. 3. The oven and the empty vessel are at ambient temperature prior to the start of the test. The initial temperature of the water is 10±2°C (50±3.6°F) It is measured immediately before the water is added to the vessel. After addition of the water to the vessel, the load is immediately placed on the center of the shelf, which is in the lowest normal position. 4. Microwave power is switched on. 5. Heating time should be exactly A seconds. (Refer to table as following) Heating time is measured while the microwave generator is operating at full power. The filament heat-up time for magnetron is not included. 6. The initial and final temperature of water is selected so that the maximum difference between the ambient and final water temperature is 5K. 7. The microwave power output P in watts is calculated from the following formula : P=4187 X vT/t · vT is difference between initial and ending temperature. · t is the heating time. The power measured should be B (Refer to SPECIFICATIONS)W±10.0%.
CAUTION : 1. Water load should be measured exactly to 1 liters. 2. Input power voltage should be exactly specified voltage(Refer to SPECIFICATIONS). 3. Ambient temperature should be 20±2°C(68±3.6°F)
Heating time for power output: A(second) B(W) 70 600 64 650 60 700 56 750 52 800 49 850 47 900 44 950 42 1000 40 1050 38 1100
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2. MICROWAVE RADIATION TEST
CAUTION : 1. Make sure to check the microwave leakage before and after repair of adjustment. 2. Always start measuring of an unknown field to assure safety for operating personnel from microwave energy. 3. Do not place your hands into any suspected microwave radiation field unless the safe density level is known. 4. Care should be taken not to place the eyes in direct line with the source of microwave energy. 5. Slowly approach the unit under test until the radiometer reads an appreciable microwave leakage from the unit under the test.
PROCEDURES 1. Prepare Microwave Energy Survey Meter, 600cc glass beaker, and glass thermometer 100°C(212°F). 2. Pour 275cc±15cc of tap water initially at 20±5°C(68±9°F) in the 600cc glass beaker with an inside diameter of approx. 95mm(3.5in.). 3. Place it at the center of the tray and set it in a cavity. 4. Close the door and operate the oven. 5. Measure the leakage by using Microwave Energy Survey Meter with dual ranges, set to 2450MHz. 1) Measured radiation leakage must not exceed the value prescribed below. Leakage for a fully assembled oven with door normally closed must be less than 4mW/cm2. 2) When measuring the leakage, always use the 5cm(2in.) space cone with probe. Hold the probe perpendicular to the cabinet and door. Place the space cone of the probe on the door, cabinet, door seem, door viewing screen, the exhaust air vents and the suction air vents. 3) Measuring should be in a counter-clockwise direction at a rate of 1 in./sec. If the leakage of the cabinet door seem is unknown, move the probe more slowly. 4) When measuring near a corner of the door, keep the probe perpendicular to the areas making sure the probe end at the base of the cone does not get closer than 2 in. from any metal. If it does not, erroneous reading may result.
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3. 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. (2) Normal readings should be as follows: Secondary winding ...................Approx. 110±10% Filament winding....................................Approx. 0 Primary winding .....................................Approx. 1
2. High voltage capacitor
(1) Check continuity of capacitor with meter on the highest OHM scale. (2) A normal capacitor will show continuity for a short time, and then indicate 10M once the capacitor is charged. (3) A shorted capacitor will show continuous continuity. (4) An open capacitor will show constant 10M. (5) Resistance between each terminal and chassis should be infinite.
3. High voltage diode
(1) Isolate the diode from the circuit by disconnecting the leads. (2) With the ohmmeter set on the highest resistance scale measure the resistance across the diode terminals. Reverse the meter leads and again observe the resistance reading. Meter with 6V, 9V or higher voltage batteries should be used to check the front-back resistance of the diode, otherwise an infinite resistance may be read in both directions. A normal diode's resistance will be infinite in one direction and several hundred K in the other direction.
4. Magnetron
For complete magnetron diagnosis, refer to "Measurement of the Microwave Power Output". Continuity checks can only indicate and open filament or a shorted magnetron. To diagnose for an open filament or a shorted magnetron. (1) Isolate magnetron from the circuit by disconnecting the leads. (2) A continuity check across magnetron filament terminals should indicate 0.1 or less. (3) A continuity check between each filament terminal and magnetron case should read open.
5. Fuse
If the fuse in the primary and monitor switch circuit is blown when the door is opened, check the primary and monitor switch before replacing the blown fuse. In case the fuse is blown by an improper switch operation, replace the defective switch and fuse at the same time. Replace just the fuse if the switches operate normally.
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WIRING DIAGRAM
24
PRINTED CIRCUIT 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 : 230V/Frequency : 50Hz Terminal Voltage 4-7 LOAD AC 25.8 V NO LOAD AC 28.4 V
NOTE : 1. Refer to Circuit Diagram (point 4). 2. Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source voltage. 3. The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.
2. Voltage check
· Key check point NO 1 2 CHECK POINT IC 1 PIN 2, 21, 30, 34 IC 1 PIN 35
0V 5V T T:20ms(50Hz)
REMARK 5 VDC
3
IC 1 PIN 31 OR 32
0V 5V T T: 250 ns (4MHz)
· Check method NO 1 2 MEASURE POINT MP1 MP2 WAVE FORM DC -5V±0.25V DC -12V±2.0V REMEDY Replace VL1, EC1 Replace EC2, D6, D11, D12 REMARK NO LOAD NO LOAD
NOTE : Each measure point must be measured with GND points.
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Measure Point
26
3. When there is no microwave oscillation
1) When touching START pad, oven lamp does not turn on. Fan motor do not rotate, but cook indicator in display comes on. * Cause : RELAY 2 does not operate. ¡ refer to Circuit Diagram (Point 3) - Check method STATE RELAY 2 ON RELAY 2 OFF POINT A -5VDC GND B GND -12VDC
2) When touching START pad, oven lamp turns on. Fan motor and turntable rotate and cook indicator in display comes on. * Cause : RELAY 1 does not operate. ¡ refer to Circuit Diagram (Point 2) - Check method STATE RELAY 1 ON RELAY 1 OFF POINT A -5VDC GND B GND -12VDC
4. When the door is opened during operation, the count down timer does not stop.
¡ refer to Circuit Diagram (Point 1) -Check method STATE 1) DOOR OPEN 2) DOOR CLOSED CHECK NO 1 METHOD Check the stage (ON, OFF) of the door open monitor switch by resistance measurement. POINT A OPEN CLOSE B -5VDC GND REMEDY Replace door open monitor switch.
5. When the digital clock does not operate properly.
¡ refer to Circuit Diagram (Point 5) POINT 1
0V 5V T T:20ms(50Hz)
WAVE FORM
* If clock does not keep exact time, you must check resistor R15, 16, zener diode ZD1.
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2. PCB CIRCUIT DIAGRAM
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3. P.C.B. LOCATION NO.
NAME 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 1 2 3 4 5 6 NAME PCB MAIN BUZZER C ARRAY CAPACITOR CERA CAPACITOR CERA CAPACITOR ELEC CAPACITOR ELEC CONNECTOR WAFER CONNECTOR WAFER CONNECTOR WAFER DIODE SWITCHING DIODE RECTIFY DIODE ZENER DIODE ZENER IC MICOM IC REGULATOR LED DISPLAY R ARRAY R CARBON FILM R CARBON FILM R CARBON FILM R CARBON FILM R CARBON FILM R CARBON FILM R CARBON FILM RESONATOR CERA SW RELAY SW RELAY TRANSISTOR TRANSISTOR TRANS POWER WIRE COPPER WIRE COPPER WIRE COPPER WIRE FLAT PCB SUB CONNECTOR WAFER R CARBON FILM SW ROTARY SW TACT WIRE COPPER M166 BZ1 CA1 C6 C1~5, C7 EC1 EC2 CN1 CN2 CN3 D1~6, D8~10 D11,12 ZD1 ZD2 IC1 VL1 DP1 RA1 R19 R13 R1~R7 R8,9,11,14,20 R15,16,17 R12 R18 CR1 RY1 RY2 Q1~5, Q8~10 Q6 LVT1 J1~J5,J8,J10~13,J15,J17 J9,J14,J16 J6,J7 WF1 M167 CN101 R101, R102 SW101 SW102~SW107 J101 SYMBOL SPECIFICATION 82 X 146.8 BM-20K 5P(4) 1000PF M 50V 102 50V Z AXIAL 104 50V Z AXIAL 16V RSS 100MF 25V RSS 1000MF YW396-02V HLEM15S-1 YW396-05AV 1N4148 KN4004A MTZ- 5.1VB 1/2W MTZ- 3.9VB 1/2W TMP47C440BN-NGO4 MC7905C DDG-631H RGLD4X104J 1/4W 27 5% 5% 5% 5% 5% 5% 5% 1/6W 100 1/6W 330 1/6W 1K 1/6W 10K 1/6W 100K 1/6W 1M PART CODE Q'TY REMARK 3514321140 3515600100 CN4XB-102M CCZB1H102K CCZF1H104Z CEXF1C101V CEXF1E102V 3519150520 4CW215SBDO 3519150510 DZN4148--DZN4004A-DZTZ5R1B-DZTZ3R9B-13GS631R00 1MC7905C-DDDG631H-RA-85X104J RD-4Z270JRD-AZ101JRD-AZ331JRD-AZ102JRD-AZ103JRD-AZ104JRD-AZ105J5PKBR40MKS 5SC0101121 5SC0101404 TZRA106M-TZTA1270Y5EPV035303 85801052GY 85801052GY 85801052GY WSJ-159007 3514321220 4CW215RBDO RD-AZ102J5S10109002 5S50101Z93 85801052GY 1 1 1 1 6 1 1 1 1 1 9 2 1 1 1 1 1 1 1 1 7 5 3 1 1 1 1 1 8 1 1 12 3 2 1 1 1 2 1 6 1 7.5mm SUB PCB 7.5mm 10.0mm 12.5mm MAIN PCB
KBR-4.0MKSTF G5G-1A 1C 1P DC12V OJ-SS-112LM DC 12V KRA-106M KTA-1270Y DMR-631FS 1/0.52 TIN COATING 1/0.52 TIN COATING 1/0.52 TIN COATING 15/90 WH C 82 X 161 HLEM15R-1 1/6W 1K 5% SDB161PVB17F123636 KPT-1115AM 1/0.52 TIN COATING
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EXPLODED VIEW AND PARTS LIST
1. DOOR ASSEMBLY Refer to Disassembly and assembly. 2. CONTROL PANEL ASSEMBLY Refer to Disassembly and assembly. 3. TOTAL ASSEMBLY
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NAME A00 B00 F01 F02 F03 F04 F05 F06 F08 F09 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31 F32 F33 F34 F35 F36 F37 F38 F39 F40 F41 F42 F43 F44 F45 F46 F47 F48
PART CODE
3510801310 7112401011 3516109000 3516109600 7112401011 7122401211 7122401211 35113AEQ0D 4413A90012 7112401011 7122401211 4415D67620 4415D67120 3518606200 7121403011 3963513100 3963512310 3512517000 3511800300 3518002200 3516004000 7272400811 3513003200 3518302200 3518400400 3518701100 3518113700 3516003700 3510311700 7112401011 3512100900 7272400811 3515201101 4415A17352 4415A66910 4415A17352 3513702610 3513811710 4415A17352 3513601600 7121400611 3966310100 3966310110 3518905300 3513003400 3516003700 3511406200 3517400620 3514700710 3512517300 3517203600
PART NAME DOOR AS CONTROL PANEL AS CABINET SCREW TAPPING CAVITY WELD AS CAVITY JOINT AS SCREW TAPPING SCREW TAPPING SCREW TAPPING CORD POWER AS CLAMP POWER CORD SCREW TAPPING SCREW TAPPING FUSE FUSE NOISE -FILTER SCREW TAPPING MOTOR SHADED POLE MOTOR SHADED POLE GUIDE WIND FAN MAGNETRON SPECIAL SCREW TAPTITE SCREW HOLDER HV CARACITOR CAPACITOR HV DIODE HV FUSE HV TRANS HV SPECIAL SCREW BASE SCREW TAPPING FOOT SECRW TAPTITE STOPPER HINGE *U SW MICRO SW MICRO SW MICRO LEVER LOCK LOCK SW MICRO LAMP SCREW TAPPING MOTOR SYNCRO MOTOR SYNCRO THERMOSTAT HOLDER THERMOSTAT SPECIAL SCREW COVER WAVE GUIDE COUPLER ROLLER GUIDE ROLLER TRAY
DESCRIPTION Refer to disassembly and assembly Refer to disassembly and assembly PCM T0.36 GE T1 TRS 4*10 MFZN CAVITY WELD AS CAVITY JOINT AS T1 TRS 4*10 MFZN T2S TRS 4*12 MFZN T2S TRS 4*12 MFZN 3X0.75 70X70 100-RTML NYLON66 T1 TRS 4*10 MFZN T2S TRS 4*12 MFZN 250V 12A 65TS 250V 12A MDA DWLF-M12 T2S PAN 4X30 MFZN 120V 17W OEM-10DWC2-A07 230V 20W MW10CA-M02 PP PP+30%GLASS 2M218H(MF)I T2 BOLT FLANGE 5X12 DACRO TT2 TRS 4*8 MFZN SECC T0.6 2100VAC 0.98uF #187 HVR-1X-3AB 12KV #187 5KV 0.55A HV-41A55-02 DY-N80S0-63T TT3 HEX 4X8 FLG MFZN SBHG T0.8 T1 TRS 4*10 MFZN PP DASF-130 TT3 TRS 4X8 MFZN SCP-1 T2.5 VP-533A-OF SPNO #187 200G VP-531A-OF/SZM-V16-FA-61 VP-533A-OF SPNO #187 200G POM POM VP-533A-OF SPNO #187 200G BL 240V 25W T25 C7A H187 T2S PAN 4X6 MFZN 220V 2.5W GM-16-24FD12 220V 2.5W M2LJ49ZT52 OFF:75 ON:65 H #187 NB PBT TT3 HEX 4X8 FLG MFZN HEATPROOF PP XAREC TEFLON PP 5116MF6 A353B GLASS
Q'TY 1 1 1 3 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 4 1 5 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 1 1
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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 : [email protected]
S/M NO. :
PRINTED DATE: Oct. 1999