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Service Manual
Microwave Oven
Model: KOR-634R0S
DAEWOO ELECTRONICS CO., LTD.
http://svc.dwe.co.kr
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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 micro-
wave 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 gen-
erating 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 per-
formed 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
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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.
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MODEL KOR-634R0S
POWER SUPPLY 230V~50Hz, SINGLE PHASE WITH EARTHING
POWER CONSUMPTION MICROWAVE 1,200 W
MICROWAVE ENERGY OUTPUT 800W
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 465 x 279 x 360 mm (18.3 x 11.0 x 14.2 in)
CAVITY DIMENSIONS (W X H X D) 290 x 220 x 306 mm (11.4 x 8.7 x 12.0 in.)
NET WEIGHT Approx. 13 kg (28.7 Ibs.)
TIMER 59 min.
FUNCTION SELECTIONS MICROWAVE
POWER SELECTIONS 5 LEVELS
CAVITY VOLUME 0.7 Cu. Ft.
* SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.
SPECIFICATIONS
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EXTERNAL VIEW
1. OUTER DIMENSION
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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.
2. FEATURE DIAGRAM
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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.
3. CONTROL PANEL
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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.
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.
INSTALLATION
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.
EARTHING INSTRUCTIONS
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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 Power level (Display) Approximate Percentage of Power
Once P-HI 100%
3 times P-80 80%
5 times P-60 60%
7 times P-40 40%
9 times P-20 20%
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DISASSEMBLY AND ASSEMBL Y
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. T o remove door parts.
REF NO. PART CODE PART NAME DESCRIPTION Q’TY REMARK
A01 3512203850 FRAME DOOR ABS XR-401, H-2938 1
A02 3517005620 BARRIER-SCREEN*O TEMP GLASS T3.2 1
A03 3515204100 STOPPER HINGE*T AS KOR-63150S 1
A04 3511706120 DOOR PAINTING AS KOR-634R0S 1
A05 3517002800 BARRIER-SCREEN*I PE 0.1T 1
A06 3512300200 GASKET DOOR PP 1
A07 3513100730 HOOK POM BLACK 1
A08 3515101310 SPRING HOOK HSW-3 1
A09 7001503311 SCREW MACHINE PAN 5X33 MFZN 2
A10 3512603210 HANDLE DOOR STEEL NI + CR 1
A11 3511601500 DECORATOR LOGO AL T1.5 1
A12 3511604610 DECORATOR DOOR*U STS T0.6 1
A13 3511604600 DECORATOR DOOR*T STS T0.6 1
A14 3516003940 SPECIAL DOUBLE TAPE SI-161 T0.15 27MM 1
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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.
(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.
NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.
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5. T o remove control panel parts.
1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly.
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.
REF NO. PART CODE PART NAME DESCRIPTION Q’TY REMARK
B01 3513404620 KNOB VOLUME ABS XR-401, H-2938 1
B02 3511604510 DECORATOR C-PANEL STS T0.6 1
B03 3516003910 SPECIAL DOUBLE TAPE SI-161 T0.15 1
B04 3515501530 WINDOW DISPLAY PMMA T2.0 1
B05 3516721460 CONTROL PANEL ABS XR-401, H-2938 1
B06 3516907430 BUTTON FUNCTION ABS XR-401, COATING 1
B07 PKBPMSZY00 SUB PCB AS KOR-634R0S 1
B08 7121401611 SCREW TAPPING T2S PAN 4X16 MFZN 3
B09 PKMPMSZY00 MAIN PCB AS KOR-634R0S 1
B10 7621301011 SCREW TAPPING T2S TRS 4X12 MFZN 8
B11 3516906320 BUTTON FUNCTION ABS XR-401, COATING 2
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6. T o 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. T o 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.
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8. T o 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. T o 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.
(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.
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.
NOTE :
Microwave emission test should be performed after adjusting interlock mechanism. If the microwave smission exceed
4mW/cm
2
, readjust interlock mechanism.
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(TROUBLE 1) Oven does not operate at all ; any inputs can not be accepted.
TROUBLE SHOOTING GUIDE
Condition Check Result Cause Remedy
Fuse blows
Check continuity of interlock monitor switch
with door closed
(COM NC)
Check continuity of primary interlock switch contact with door partially
open until interlock monitor switch contact close
Check continuity of
primary winding of low
voltage transformer
Disconnect high voltage
fuse and operate the unit
Continuity
Continuity
Continuity
No
Continuity
0 Ω or
infinite
Fuse again
blows
Approx.
150~310
(normal)
Replace
Replace
Replace
Note 1.
Note 1.
Malfunction of
interlock
monitor switch
No
Continuity
Check continuity of primary interlock switch contact with door partially
open until interlock monitor switch contact close
(COM NO)
Replace
Note 1.
Shorted contacts of
primary interlock
switch.
Shorted contacts
of primary interlock
switch
Defective low voltage transformer
Defective high
voltage transformer
Replace
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.
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Condition Check Result Cause Remedy
Replace
Outlet has
proper voltage.
Fuse does not
blow.
Check continuity of
magnetron
No
Continuity
Defective magnetron
Replace
Defective line filter
board
Replace
Check continuity of
noise filter board
Replace
Defective touch control circuit
Check continuity of
power supply cord
Open power supply
cord
No
Continuity
No
Continuity
Normal
Condition Check Result Cause Remedy
Adjust or
Replace
Turn table
motor, and
oven lamp do
not turn on
Check continuity of
primary interlock
switch
No
Continuity
Malfunction of primary
interlock switch
Adjust or
Replace
Malfunction of secondary interlock and
D.O.M switch
Check continuity of
secondary interlock
and D.O.M. switchs
No
Continuity
Replace
Defective touch control circuit
Check D.C. voltage
being supplied to
RELAY (RY2) coil
0V
Replace
Faulty contacts of
RELAY (RY2) or open
relay coil
Approx
15 VDC
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.
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(TROUBLE 3) No microwave oscillation even though fan motor rotates.
Condition
No
microwave
oscillation
Check Result Cause Remedy
ReplaceCheck continuity
of high voltage
capacitor
terminals with
wires removed
Continuity Defective high
voltage
transformer
ReplaceCheck continuity of
high voltage rectifier in forward and
backward direction
with DC megger
Continuity in
backward
direction
Defective high
voltage rectifier
ReplaceConnect megger
leads to
magnetron
terminal and
magnetron body
Continuity Defective
magnetron
ReplaceCheck resistance
of primary and
secondary coil of
high voltage
transformer
Defective high
voltage
transformer
ReplaceCheck continuity
of magnetron
with wires
removed
No
Continuity
Defective
magnetron
ReplaceCheck continuity
of filament
terminal of high
voltage
transformer
No
Continuity
Defective high
voltage
transformer
ReplaceCheck D.C.
voltage being
supplied to
RELAY (RY1)
coil
0V Defective touch
control circuit
ReplaceApprox
15 VDC
Faulty contacts of
RELAY (RY1) or
open relay coil
0Ω or ∞
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Malfunction of
the membrane
keyboard
Replace the membrane keyboard
(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 opera-
tion.
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 Check Result Cause Remedy
Display does
not show
programming
at all, even it
keyboard is
touched
Check each pad
for continuity of the
membrane keyboard
for the following
keyboard check
procedure
Normal
Abnormal
Malfunction
of touch control
circuit of
control box
sub-assembly
Replace control box
sub-assembly
NOTE : Before following the particular steps listed above in the trouble shooting guide for the membrane key-
board’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 :
•
▲▲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%.
P=4187 X ▲▲T/t
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:
70
600
64
650
60
700
56
750
52
800
49
850
47
900
44
950
42
1000401050381100
A(second)
B(W)
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2. MICROWAVE RADIATION 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.
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.
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23
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. 110Ω±10%
Filament winding....................................Approx. 0Ω
Primary winding.....................................Approx. 1Ω
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 10MΩ once the capacitor is charged.
(3) A shorted capacitor will show continuous continuity.
(4) An open capacitor will show constant 10MΩ.
(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 KΩ 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 0.1Ω 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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24
WIRING DIAGRAM
Page 26
25
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
2. Voltage check
• Key check point
• Check method
PRINTED CIRCUIT BOARD
NO CHECK POINT REMARK
1 IC 1 PIN 2, 21, 30, 34 –5 VDC
2 IC 1 PIN 35
3 IC 1 PIN 31 OR 32
NOTE :
Each measure point must be measured with GND points.
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.
T
0V
–5V
T: 250 ns (4MHz)
0V
T
–5V
Terminal Voltage
4-7
LOAD
AC 25.8 V
NO LOAD
AC 28.4 V
NO MEASURE POINT WAVE FORM REMEDY REMARK
1 MP1 DC -5V±0.25V Replace VL1, EC1 NO LOAD
2 MP2 DC -12V±2.0V Replace EC2, D6, D11, D12 NO LOAD
T:20ms(50Hz)
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26
Measure Point
Page 28
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
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
4. When the door is opened during operation, the count down timer does not stop.
→ refer to Circuit Diagram (Point 1)
-Check method
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 R15, 16, zener diode ZD1.
27
STATE
POINT
A B
RELAY 2 ON -5VDC GND
RELAY 2 OFF GND -12VDC
STATE
POINT
A B
RELAY 1 ON -5VDC GND
RELAY 1 OFF GND -12VDC
STATE
POINT
A B
1) DOOR OPEN OPEN -5VDC
2) DOOR CLOSED CLOSE GND
CHECK NO METHOD REMEDY
1 Check the stage (ON, OFF) of the door open monitor switch by Replace door open monitor
resistance measurement. switch.
POINT WAVE FORM
1
T:20ms(50Hz)
0V
–5V
T
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2. PCB CIRCUIT DIAGRAM
Page 30
29
NAME NAME SYMBOL SPECIFICATION PART CODE Q'TY REMARK
1 PCB MAIN M166 82 X 146.8 3514321140 1 MAIN PCB
2 BUZZER BZ1 BM-20K 3515600100 1
3 C ARRAY CA1 5P(4) 1000PF M 50V CN4XB-102M 1
4 CAPACITOR CERA C6 102 50V Z AXIAL CCZB1H102K 1
5 CAPACITOR CERA C1~5, C7 104 50V Z AXIAL CCZF1H104Z 6
6 CAPACITOR ELEC EC1 16V RSS 100MF CEXF1C101V 1
7 CAPACITOR ELEC EC2 25V RSS 1000MF CEXF1E102V 1
8 CONNECTOR WAFER CN1 YW396-02V 3519150520 1
9 CONNECTOR WAFER CN2 HLEM15S-1 4CW215SBDO 1
10 CONNECTOR WAFER CN3 YW396-05AV 3519150510 1
11 DIODE SWITCHING D1~6, D8~10 1N4148 DZN4148--- 9
12 DIODE RECTIFY D11,12 KN4004A DZN4004A-- 2
13 DIODE ZENER ZD1 MTZ- 5.1VB 1/2W DZTZ5R1B-- 1
14 DIODE ZENER ZD2 MTZ- 3.9VB 1/2W DZTZ3R9B-- 1
15 IC MICOM IC1 TMP47C440BN-NGO4 13GS631R00 1
16 IC REGULATOR VL1 MC7905C 1MC7905C-- 1
17 LED DISPLAY DP1 DDG-631H DDDG631H-- 1
18 R ARRAY RA1 RGLD4X104J RA-85X104J 1
19 R CARBON FILM R19 1/4W 27 5% RD-4Z270J- 1
20 R CARBON FILM R13 1/6W 100 5% RD-AZ101J- 1
21 R CARBON FILM R1~R7 1/6W 330 5% RD-AZ331J- 7
22 R CARBON FILM R8,9,11,14,20 1/6W 1K 5% RD-AZ102J- 5
23 R CARBON FILM R15,16,17 1/6W 10K 5% RD-AZ103J- 3
24 R CARBON FILM R12 1/6W 100K 5% RD-AZ104J- 1
25 R CARBON FILM R18 1/6W 1M 5% RD-AZ105J- 1
26 RESONATOR CERA CR1 KBR-4.0MKSTF 5PKBR40MKS 1
27 SW RELAY RY1 G5G-1A 1C 1P DC12V 5SC0101121 1
28 SW RELAY RY2 OJ-SS-112LM DC 12V 5SC0101404 1
29 TRANSISTOR Q1~5, Q8~10 KRA-106M TZRA106M-- 8
30 TRANSISTOR Q6 KTA-1270Y TZTA1270Y- 1
31 TRANS POWER LVT1 DMR-631FS 5EPV035303 1
32 WIRE COPPER J1~J5,J8,J10~13,J15,J17 1/0.52 TIN COATING 85801052GY 12 7.5mm
33 WIRE COPPER J9,J14,J16 1/0.52 TIN COATING 85801052GY 3 10.0mm
34 WIRE COPPER J6,J7 1/0.52 TIN COATING 85801052GY 2 12.5mm
35 WIRE FLAT WF1 15/90 WH C WSJ-159007 1
1 PCB SUB M167 82 X 161 3514321220 1 SUB PCB
2 CONNECTOR WAFER CN101 HLEM15R-1 4CW215RBDO 1
3 R CARBON FILM R101, R102 1/6W 1K 5% RD-AZ102J- 2
4 SW ROTARY SW101 SDB161PVB17F123636 5S10109002 1
5 SW TACT SW102~SW107 KPT-1115AM 5S50101Z93 6
6 WIRE COPPER J101 1/0.52 TIN COATING 85801052GY 1 7.5mm
3. P.C.B. LOCATION NO.
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1. DOOR ASSEMBLY
Refer to Disassembly and assembly.
2. CONTROL PANEL ASSEMBLY
Refer to Disassembly and assembly.
3. TOTAL ASSEMBLY
EXPLODED VIEW AND PARTS LIST
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NAME PART CODE PART NAME DESCRIPTION Q'TY
A00 DOOR AS
Refer to disassembly and assembly
1
B00 CONTROL PANEL AS
Refer to disassembly and assembly
1
F01 3510801310 CABINET PCM T0.36 GE 1
F02 7112401011 SCREW TAPPING T1 TRS 4*10 MFZN 3
F03
3516109000 CAVITY WELD AS CAVITY WELD AS 1
3516109600 CAVITY JOINT AS CAVITY JOINT AS 1
F04 7112401011 SCREW TAPPING T1 TRS 4*10 MFZN 1
F05 7122401211 SCREW TAPPING T2S TRS 4*12 MFZN 1
F06 7122401211 SCREW TAPPING T2S TRS 4*12 MFZN 1
F08 35113AEQ0D CORD POWER AS 3X0.75 70X70 100-RTML 1
F09 4413A90012 CLAMP POWER CORD NYLON66 1
F10 7112401011 SCREW TAPPING T1 TRS 4*10 MFZN 1
F11 7122401211 SCREW TAPPING T2S TRS 4*12 MFZN 1
F12
4415D67620 FUSE 250V 12A 65TS 1
4415D67120 FUSE 250V 12A MDA 1
F13 3518606200 NOISE -FILTER DWLF-M12 1
F14 7121403011 SCREW TAPPING T2S PAN 4X30 MFZN 2
F15
3963513100 MOTOR SHADED POLE 120V 17W OEM-10DWC2-A07 1
3963512310 MOTOR SHADED POLE 230V 20W MW10CA-M02 1
F16 3512517000 GUIDE WIND PP 1
F17 3511800300 FAN PP+30%GLASS 1
F18 3518002200 MAGNETRON 2M218H(MF)I 1
F19 3516004000 SPECIAL SCREW T2 BOLT FLANGE 5X12 DACRO 1
F20 7272400811 TAPTITE SCREW TT2 TRS 4*8 MFZN 1
F21 3513003200 HOLDER HV CARACITOR SECC T0.6 1
F22 3518302200 CAPACITOR HV 2100VAC 0.98uF #187 1
F23 3518400400 DIODE HV HVR-1X-3AB 12KV #187 1
F24 3518701100 FUSE HV 5KV 0.55A HV-41A55-02 1
F25 3518113700 TRANS HV DY-N80S0-63T 1
F26 3516003700 SPECIAL SCREW TT3 HEX 4X8 FLG MFZN 4
F27 3510311700 BASE SBHG T0.8 1
F28 7112401011 SCREW TAPPING T1 TRS 4*10 MFZN 5
F29 3512100900 FOOT PP DASF-130 2
F30 7272400811 SECRW TAPTITE TT3 TRS 4X8 MFZN 1
F31 3515201101 STOPPER HINGE *U SCP-1 T2.5 1
F32 4415A17352 SW MICRO VP-533A-OF SPNO #187 200G 1
F33 4415A66910 SW MICRO VP-531A-OF/SZM-V16-FA-61 1
F34 4415A17352 SW MICRO VP-533A-OF SPNO #187 200G 1
F35 3513702610 LEVER LOCK POM 1
F36 3513811710 LOCK POM 1
F37 4415A17352 SW MICRO VP-533A-OF SPNO #187 200G 1
F38 3513601600 LAMP BL 240V 25W T25 C7A H187 1
F39 7121400611 SCREW TAPPING T2S PAN 4X6 MFZN 1
F40
3966310100 MOTOR SYNCRO 220V 2.5W GM-16-24FD12 1
3966310110 MOTOR SYNCRO 220V 2.5W M2LJ49ZT52 1
F41 3518905300 THERMOSTAT OFF:75 ON:65 H #187 NB 1
F42 3513003400 HOLDER THERMOSTAT PBT 1
F43 3516003700 SPECIAL SCREW TT3 HEX 4X8 FLG MFZN 1
F44 3511406200 COVER WAVE GUIDE HEATPROOF PP 1
F45 3517400620 COUPLER XAREC 1
F46 3514700710 ROLLER TEFLON 3
F47 3512517300 GUIDE ROLLER PP 5116MF6 A353B 1
F48 3517203600 TRAY GLASS 1
Page 33
S/M NO. :
DAEWOO ELECTRONICS CO., L TD.
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
PRINTED DATE: Oct. 1999
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