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S/M No. :
R868G7S001
Service Manual
Microwave Oven
Model: KOR-868G7S
✔
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 CORP.
http : //svc.dwe.co.kr
Jun. 2003
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 the dealer immediately.
IMPORTANT
The wire in this mains lead coloured in accordance with the following code.
Green-and-yellow : Each
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
This oven is designed for counter-top use only.
2
SPECIFICATIONS
MODEL
POWER SUPPLY
POWER
CONSUMPTION
MICROWAVE
GRILL
COMBINATION
MICROWAVE ENERGY OUTPUT
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
KOR-868G7S
230V-50Hz, SINGLE PHASE WITH EARTHING
1350W
900W
2450MHz
495 x 294 x 384 mm (19.5 x 11.6 x 15.1 in)
320 x 237 x 343 mm (12.6 x 9.3 x 13.5 in)
APPROX. 13.5 kg (29.7 lbs)
59 min. 99 sec.
MICROWAVE
10 LEVELS
0.9 Cu. Ft.
* 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
0
DOOR OPENING BUTTON
To open the door push the door opening button. When door is closed, it will automatically lock shut. If door is opened while oven is operating, magnetron tube will immediately stop operating.
q
ROLLER GUIDE
Supports the glass cooking tray.
5
3. CONTROL PANEL
1
4
5
7
0
9
8
2
3
6
1
Display
Cooking time, power level, present time are displayed.
2
Auto Cook
Used to cook using a program or to reheat.
3
Auto defrost
Used to defrost foods (by weight)
4
Power
Used to set power level.
5
Defrost
Used to defrost foods.(by time)
6
Clock
Used to set clock.
7
Time set pad
Used to set the cooking time and the present time.
8
Reheat Meal
Used to reheat meal or dinner plate.
9
Stop/Clear
Used to stop the oven operation or to delete the cooking data.
0
Start/Speedy Cook
Used to start a selected 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 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. Position the oven as far from them as possible.
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 12 amperes, 230 Volts, 50 Hz.
• 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 damaged, 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 the 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 plug. The plug must be plugged into an outlet that is properly installed and 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 plut, and a 3-slot receptacle that will accept 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.
7
OPERATIONS AND FUNCTIONS
This section includes useful information about oven operation.
1. Plug power supply cord into a 230V 50Hz power 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. Shut the door. Make sure that it is firmly closed.
1
When the oven door is opened, the turns off.
2
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.
3
Each time a pad is touched, a BEEP will sound to acknowledge the touch.
4
The oven automatically cook on full power unless set to a lower power level.
5
The display will show ":0" when the oven is plugged in.
6
Time clock returns to the present time when the cooking time ends.
7
When the STOP/CLEAR pad is touched during the oven operation, 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.
8
If the START pad is touched and the oven does not operate, check the area between the door and door seal for obstructions and make sure the door is closed securely. The oven will not start cooking until 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 pad
once twice
3 times
4 times
5 times
6 times
7 times
8 times
9 times
10 times
11 times
Power level(Display)
P-HI
P-90
P-80
P-70
P-60
P-50
P-40
P-30
P-20
P-10
P-00
Approximate Percentage of Power
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
8
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 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.
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 two-wire extension cord.
The microwave oven is designed to be used while earthed.
It is imperative, therefore, to make sure it is earthed 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 15A 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.
WARNING : 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.
9
1. To remove cabinet
1) Remove three screws on cabinet back.
2) Push the cabinet backward.
2. To remove door assembly
1) Remove one screw 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.
10
✔
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).
3. To remove door parts.
REF NO.
A01
A02
A03
A04
A05
A06
A07
A08
A09
PART CODE
3512207900
2TE16A27CL
3517008200
3515204100
3511711800
3517006000
3512302000
3513100700
3515101300
PART NAME
FRAME DOOR
DOUBLE TAPE
BARRIER-SCREEN*O
DESCRIPTION
ABS SG-175 SG-0760D
0.16T X 27MM CLEAR 550M
SAN T1.5
STOPPER HINGE*T AS KOR-63150S
DOOR PAINTING AS KOR-866T0S
BARRIER-SCREEN*I
GASKET DOOR
PE 0.1T
PP
HOOK
SPRING HOOK
POM
PW1
1
1
1
1
Q’TY
1
-
1
1
1
REMARK
11
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part ‘A’
Loosen a 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/cm 2 .
12
✔
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).
5. To remove control panel parts.
REF NO.
PART CODE
B01 3516911300
B02
B03
3518522240
PART NAME
BUTTON DOOR OPEN
MEMBRANE
441G430171 SPRING BUTTON
B04
B05
3516729700
3516911100
CONTROL PANEL
BUTTON FUNCTION-A
B06 PKMPMSAQ20 MAIN PCB AS
B07 7122401211 SCREW TAPPING
B08
B09
3516911200
3513703100
BUTTON FUNCTION-B
LEVER DOOR OPEN
DESCRIPTION
ABS SG-175, SG-0760D
KOR-868G7S
SWP DIA 0.7
ABS SG-175 SG-0760D
ABS SG-175 SG-0760D
KOR-868G7S
T2S TRS 4X12 MFZN
ABS SG-175 SG-0760D
PP
1
5
1
1
Q’TY
1
1
1
1
1
REMARK
13
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.
◆
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/cm 2 for a fully assembled oven with door normally closed.
Metallic gasket plate
Magnetron antenna
Cooling fin
Filament terminal
<MAGNETRON>
14
8. To remove wind guide assembly.
1) Remove a screw for earthing.
2) Remove the noise filter from the wind guide.
3) Remove a screw which secure the wind guide assembly.
4) Draw forward the wind guide assembly.
5) Pull the fan from the motor shaft.
6) Remove two screws which secure the motor shaded pole.
7) Remove the motor shaded pole.
8) 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.
15
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 “OFF” 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 opened before other switches are closed.
When the door is opened, the interlock monitor switch should be closed after other switches are opened.
(3) Adjustment steps a) Loosen the mounting screw.
b) Adjust interlock switch assembly position.
c) Make sure that lock lever moves smoothly after adjustment is completed.
d) Tighten completely the mounting screw.
NOTE :
Microwave emission test should be performed after adjusting interlock mechanism. If the microwave smission exceed
4mW/cm 2 , readjust interlock mechanism.
16
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
Check continuity of both primary and secondary interlock switch with door colosed
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
Disconnect high voltage fuse and operate the unit
RESULT
Continuity
No Continuity
No Continuity
Continuity
Continuity
0
Ω or infinite
Approx.
1160
Ω
(normal)
Fuse again blows
CAUSE
Malfunction of interlock monitor switch
Malfunction of interlock switch
Shorted contacts of primary interlock switch.
Defective low voltage transformer
Defective low voltage transformer
REMEDY
Replace
Replace
Replace
Replace
Replace
17
CONDITION
Outlet has proper voltage Fuse does not blow.
CHECK
Check continuity of magnetron
Check continuity of noise filter board
Check continuity of power supply cord
RESULT
No
Continuity
No
Continuity
No
Continuity
Normal
CAUSE
Defective magnetron
Defective magnetron
Open power supply cord
Defective touch control circuit
REMEDY
Replace
Replace
Replace
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 button is pressed.
CONDITION
Turn table motor and oven lamp do not turn on
CHECK
Check continuity of primary interlock switch
Check continuity of secondary interlock switch
Check D.C. voltage being supplied to RELAY (RY2) coil
RESULT
No
Continuity
No
Continuity
0 V
Approx.
-15 VDC
CAUSE
Malfunction of primary interlock switch
Malfunction of secondary interlock switch
Defective touch control circuit
Faulty contacts of
RELAY (RY2) or open relay coil
REMEDY
Adjust or replace
Adjust or replace
Replace
Replace
18
(TROUBLE 3) No microwave oscillation even though fan motor rotates.
CONDITION
No microwave oscillation
CHECK
Check continuity of high voltage fuse
Replace high voltage fuse
Check continuity of high voltage capacitor terminals with wires removed
Check continuity of high voltage rectifier in forward and backward direction with DC megger
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
RESULT
Continuity
Continuity
Continuity in backward direction
Continuity
0
Ω or
No
∞
Continuity
Check continuity of filament terminal of high voltage transformer
Check D.C. voltage being supplied to RELAY (RY1) coil
No
Continuity
0 V
Approx
-15 VDC
CAUSE
Defective high voltage transformer
Defective high voltage rectifier
Defective magnetron
Defective high voltage transformer
Defective magnetron
Defective high voltage transformer
Defective touch control circuit
Faulty contacts or
RELAY (RY1) or open relay coil
REMEDY
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
19
(TROUBLE 4) The following visual conditions indicate a probable defective touch control circuit or membrane switch assembly.
1 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.
1 2. A distinct change in the display are not on when they numbers is the display.
1 3. One or more digits in the display are not on when they should be.
M/W Def.
1 4. Display indicates a number different from one touched.
1 5. Specific numbers (for example 2 or 3) will not display when the button is touched.
1 6. Display does not count down or up with time cooking or clock operation.
1 7. Oven is programable and cooks normally but no display shows.
1 8. Display obviously jumps in time while counting down.
Lock g
1 9. Display counts down noticeably too fast while cooking.
10. Display does not show the time of day when cancel button 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 if membrane keyboard is touched.
CHECK
Check each pad for continuity of the membrane keyboard for the following keyboard check procedure
RESULT
Normal
Abnormal
CAUSE
Malfunction of the P.C.B main-assembly
REMEDY
Replace the
P.C.B mainassembly
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.
20
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
▲
T/t
•
▲
T 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 liter.
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
21
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/cm 2 .
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.
22
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. 140
Ω
±10%
Filament winding....................................Approx. 0
Ω
Primary winding .....................................Approx. 2
Ω
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
Ω once the capacitor is charged.
(3) A shorted capacitor will show continuous continuity.
(4) An open capacitor will show constant 10M
Ω
.
(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
Ω 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
Ω 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.
23
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
DC 12 V
NO LOAD
AC 30.5 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
REMARK
-5 VDC
T:20ms(50Hz)
3 IC 1 PIN 31 OR 32
T:250ns(4MHz)
• Check method
NO MEASURE POINT
1
2
MP1
MP2
WAVE FORM
DC -5V±0.25V
DC -12V±2.0V
REMEDY
Replace VL1, EC1
Replace EC2, D12, D13, D14
REMARK
NO LOAD
NO LOAD
NOTE :
Each measure point must be measured with GND point.
25
MP2
MP1
Measure Point
26
3. When there is no microwave oscillation
1) When touching START pad, oven lamp does not turn on.
Fan motor does not rotate, but cook indicator in display comes on.
* Cause : RELAY 2 does not operate.
→ refer to Circuit Diagram (Point 3)
- Check method
POINT
STATE
A
RELAY 2 ON -5 VDC
RELAY 2 OFF GND
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
POINT
STATE
A
RELAY 1 ON -5VDC
RELAY 1 OFF GND
B
GND
-12 VDC
B
GND
-12 VDC
4. When the door is opened during operation, the count down timer does not stop.
→ refer to Circuit Diagram (Point 1)
-Check method
POINT
STATE
1) DOOR OPEN
2) DOOR CLOSED
A
OPEN
CLOSE
CHECK NO
1
METHOD
Check the stage (ON, OFF) of the door open monitor switch by resistance measurement.
B
-5VDC
GND
REMEDY
Replace door open monitor switch.
5. When the digital clock does not operate properly.
→ refer to Circuit Diagram (Point 5)
* If clock does not keep exact time, you must check resistor R26, R27, C5.
POINT
A
WAVE FORM
T:20ms(50Hz)
27
2. PCB CIRCUIT DIAGRAM
28
3. P.C.B. LOCATION 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).
NO.
1 BUZZER
NAME
2 C ARRAY
3 CAPACITOR CERA
BZ1
CA1
C5
SYMBOL
4 CAPACITOR CERA
5 CAPACITOR ELEC
C1~4,6
EC1
6 CAPACITOR ELEC EC2
7 CONNECTOR WAFER CN1
8 CONNECTOR FILM CN2
9 CONNECTOR WAFER CN3
10 DIODE RECTIFY D1~7,9~12
11 DIODE RECTIFY
12 DIODE ZENER
D13,14
ZD1
13 DIODE ZENER
14 IC MICOM
15 IC REGULATOR
16 LED DISPLAY
17 PCB MAIN
ZD2
IC1
VL1
DP1
M304
18 R ARRAY
19 REGISTER
20 REGISTER
21 REGISTER
22 REGISTER
23 REGISTER
24 REGISTER
25 REGISTER
RA1
R8~10,16~19
R1,2,6,12,21
R3,22,23
R11
R13,14
R15
R7
26 REGISTER
27 REGISTER
R4
R20
28 RESONATOR CERA CR1
29 SW RELAY
30 SW RELAY
31 SW TACT
32 TRANSISTOR
RY1
RY2
SW1~3
Q1~5,8~10
33 TRANSISTOR
34 TRANS POWER
35 WIRE COPPER
36 WIRE COPPER
37 WIRE COPPER
38 WIRE COPPER
SPECIFICATION
BM-20K
7P(6) 1000PF M 50V
102 50V Z AXIAL
104 50V Z AXIAL
50V RS 1MF
25V RSS 1000MF
YW396-02V
FCZ 254-11
YW396-05AV
1N4148
KN4004A
UZ- 5.1BSB 1/2W
3519150510
DZN4148---
1
11
DZN4004A-2
DZUZ5R1BSB 1
UZ- 3.9BSB 1/2W DZUZ3R9BSB 1
TMP47C440BN-3J52 13GS632GH0 1
MC7905C
DDG-631H01
92X161
1MC7905C--
DDDG631H01
3514321190
1
1
1
7P(6) 1/8 100K J
1/6W 220 5%
1/6W 1K 5%
1/6W 100K 5%
1/6W 200 5%
1/6W 10K 5%
1/6W 510 5%
1/6W 1M 5%
1/6W 4.7K 5%
1/4W 51 5%
CRT 4.00MS
G5G-1A DC12V
CS11-12SH 1C 1P
JTS1230U(SEALED)
KRA-106M
Q6
LVT1
KTA-1266Y
DMR-631FS
J1,2,4,11,12,16~18,21 1/0.52 TIN COATING
J3,7,8,10,13~15,19,20 1/0.53 TIN COATING
J5,6,9
SJ1
1/0.54 TIN COATING
1/0.52 TIN COATING
PART CODE Q'TY REMARK
3515600100 1
CN6XB-102M 1
CCZB1H102K 1
CCZF1H104Z 5
CEXE1H109A 1
CEXF1E102V 1
3519150520 1
441M367160 1
RA-87X104J
RD-AZ221J-
RD-AZ102J-
RD-AZ104J-
RD-AZ201J-
RD-AZ103J-
RD-AZ511J-
RD-AZ105J-
RD-AZ472J-
RD-4Z510J-
TZTA1266Y-
5EPV035303
85801052GY
85801053GY
85801054GY
85801052GY
1
7
5
3
1
3
1
1
1
1
5P4R00MTS1
5SC0101121
5SC0101128
5S50101201
TZRA106M--
1
1
3
8
1
1
9
9
3
1
7.5MM
10MM
12.5MM
7.5MM
29
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
30
✔
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).
REMARK
F38
F39
F40
F41
F42
F43
F44
F29
F30
F31
F32
F33
F34
F35
F36
F37
F45
F46
F47
F48
F22
F23
F24
F25
F26
F27
F28
F14
F15
F16
F17
F18
F19
F20
F21
F05
F06
F07
F08
F09
F10
F11
F12
F13
REF NO.
PART CODE
A00 3511712790
B00
F01
PKCPSWAQ20
3510805400
PART NAME
DOOR AS
CONTROL-PANEL AS
CABINET
F02
F03
F04
7112401011
3516109900
7112401011
SCREW TAPPING
CAVITY AS
SCREW TAPPING
7122401211
7122401211
4413A90012
7112401011
7122401211
4415D67620
3518606200
SCREW TAPPING
SCREW TAPPING
7112401011 SCREW TAPPING
35113AEQ0D CORD POWER AS
CLAMP POWER CORD
SCREW TAPPING
SCREW TAPPING
FUSE
NOISE-FILTER
7121402511
3963512310
3512517000
3511800300
3518003700
3516004000
7272400811
3513003200
3518302200
3518400400
3518701100
3518119340
3516003700
3510311900
7112401011
SCREW TAPPING
MOTOR SHADED POLE
GUIDE WIND
FAN
MAGNETRON
SPECIAL SCREW
TAPTITE SCREW
HOLDER HV CAPACITOR
CAPACITOR HV
DIODE HV AS
FUSE HV
TRANS HV
SPECIAL SCREW
BASE
SCREW TAPPING
DESCRIPTION
KOR-868G7S
KOR-868G7S
KOR-86150S
T1 TRS 4X10 MFZN
KOR-86150S
T1 TRS 4X10 MFZN
T2S TRS 4X12 MFZN
T2S TRS 4X12 MFZN
T1 TRS 4X10 MFZN
3X0.75 70X70 100-RTML
NYLON66
T1 TRS 4X10 MFZN
T2S TRS 4X12 MFZN
250V 10A
DWLF-M12
T2S PAN 4X25 MFZN
230V 20W MW10CA-M02
PP
PP+30%GLASS
2M218JFL
T2 BOLT FLANGE 5X12 DACRO
TT3 TRS 4X8 MFZN
SECC T0.6
2100VAC 0.98UF #187
HVR-1X-3AB 12KV #187
5KV 0.55A HV-41A55-02
DW-R90S0-86T A
TT3 HEX 4X8 FLG MFZN
SBHG T0.8
T1 TRS 4X10 MFZN
3512100900
7272400811
3515201101
4415A17352
4415A66910
4415A17352
3513702600
3513811700
3518571000
3513601600
7121400611
3966030900
3518905300
3513003400
7272400811
3511406200
3517400620
3514700900
3512509210
3517203500
FOOT
TAPTITE SCREW
STOPPER HINGE *U
SW MICRO
SW MICRO
SW MICRO
LEVER LOCK
LOCK
SWITCH PUSH
LAMP
SCREW TAPPING
MOTOR SYNCRO
THERMOSTAT
HOLDER THERMOSTAT
TAPTITE SCREW
COVER WAVE GUIDE
COUPLER
ROLLER
GUIDE ROLLER
TRAY
PP DASF-130
TT3 TRS 4X8 MFZN
SCP-1 T2.5
VP-533A-OF SPNO #187 200
VP-531A-OF /SZM-V16-FA-61
VP-533A-OF SPNO #187 200
POM
POM BLACK
MP101C
BL 240V 25W T25 C7A H187
T2S PAN 4X6 MFZN
220-240V 50/60HZ TYJ50-8A7
OFF:75 ON:65 H #187 NB
PP(NATURAL)
TT3 TRS 4X8 MFZN
PP J640A WHITE
XAREC
TEFLON
PP 5113MF6,A353B
GLASS
1
5
1
4
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
Q'TY
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
2
1
1
31
S/M No. : R868G7S001
DAEWOO ELECTRONICS CORP.
686, AHYEON-DONG MAPO-GU SEOUL, KOREA
C.P.O. BOX 8003 SEOUL, KOREA
TELEX: DWELEC K28177-8
CABLE: “DAEWOOELEC”
PRINTED DATE: Jun. 2003
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Table of contents
- 3 SAFETY AND PRECAUTIONS
- 3 1. FOR SAFE OPERATION
- 3 2. FOR SAFE SERVICE PROCEDURES
- 4 SPECIFICATIONS
- 5 EXTERNAL VIEW
- 5 1. OUTER DIMENSION
- 6 2. FEATURE DIAGRAM
- 7 3. CONTROL PANEL
- 8 INSTALLATION
- 9 OPERATIONS AND FUNCTIONS
- 10 DISASSEMBLY AND ASSEMBLY
- 17 INTERLOCK MECHANISM AND ADJUSTMENT
- 18 TROUBLE SHOOTING GUIDE
- 22 MEASUREMENT AND TEST
- 22 1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT
- 23 2. MICROWAVE RADIATION TEST
- 24 3. COMPONENT TEST PROCEDURE
- 25 WIRING DIAGRAM
- 26 PRINTED CIRCUIT BOARD
- 26 1. CIRCUIT CHECK PROCEDURE
- 29 2. PCB CIRCUIT DIAGRAM
- 30 3. P.C.B. LOCATION NO
- 31 EXPLODED VIEW AND PARTS LIST
- 31 1. DOOR ASSEMBLY
- 31 2. CONTROL PANEL ASSEMBLY
- 31 3. TOTAL ASSEMBLY