Page 1
Service Manual
Microwave Oven
Model : KOR-180A0A
KOR-181G0A
DAEWOO ELECTRONICS CO., LTD.
http://svc.dwe.co.kr
S/M No.: R180A0A002
Page 2
PRECAUTIONS TO BE OBSERVED BEFORE AND
2
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 if 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........................................................................................................................................3
FOR SAFE OPERATION...........................................................................................................................................3
FOR SAFE SERVICE PROCEDURES .....................................................................................................................3
SPECIFICATIONS ............................................................................................................................................................4
EXTERNAL VIEW.............................................................................................................................................................5
OUTER DIMENSION .................................................................................................................................................5
FEATURE DIAGRAM.................................................................................................................................................6
CONTROL PANEL.....................................................................................................................................................7
INSTALLATION ............................................................................................................................................................... 8
OPERATIONS AND FUNCTIONS .................................................................................................................................. 9
DISASSEMBLY AND ASSMBLY...................................................................................................................................10
INTERLOCK MECHANISM AND ADJUSTMENT.........................................................................................................17
TROUBLE SHOOTING GUIDE ......................................................................................................................................18
MESUREMENT AND TEST............................................................................................................................................22
MEASUREMENT OF THE MICROWAVE POWER OUTPUT................................................................................22
MICROWAVE RADIATION TEST ...........................................................................................................................23
COMPONENT TEST PROCEDURE .......................................................................................................................24
WIRING DIAGRAM.........................................................................................................................................................25
PRINTED CIRCUIT BOARD...........................................................................................................................................26
CIRCUIT CHECK PROCEDURE.............................................................................................................................26
PCB CIRCUIT DIAGRAM ........................................................................................................................................29
P.C.B. LOCATION NO. ............................................................................................................................................30
EXPLODED VIEW AND PARTS LIST ...........................................................................................................................31
DOOR ASSEMBLY ..................................................................................................................................................31
CONTROL PANEL ASSEMBLY ..............................................................................................................................31
TOTAL ASSEMBLY .................................................................................................................................................31
Page 3
SAFETY AND PRECAUTIONS
3
CAUTION : This Device is to be Serviced Only by Properly Qualified Service Personnel. Consult the Service
Manual for Proper Service Procedures to Assure Continued Safety Operation and for Precautions
to be Taken to Avoid Possible Exposure to Excessive Microwave Energy.
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.
CAUTION
MICROWAVE RADIATION
PERSONNEL SHOULD NOT BE EXPOSED TO THE MICROWAVE ENERGY WHICH MAY RADIATE
FROM THE MAGNETRON OR OTHER MICROWAVE GENERATING DEVICE IF IT IS IMPROPERLY
USED OR CONNECTED. ALL INPUT AND OUTPUT MICROWAVE CONNECTIONS. WAVEGUIDES
FLANGES AND GASKETS MUST BE SECURED. NEVER OPERATE THE DEVICE WITHOUT A
MICROWAVE ENERGY ABSORBING LOAD ATTACHED. NEVER LOOK INTO AN OPEN WAVEGUIDE
OR ANTENNA WHILE THE DEVICE IS ENERGIZED.
Page 4
SPECIFICATIONS
4
MODEL KOR-180A, KOR-181G
POWER SUPPLY 120V~60HZ, SINGLE PHASE WITH EARTHING
POWER
CONSUMPTION
MICROWAVE ENERGY OUTPUT 1100 W
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 589X339X488mm (23.2X13.3X19.2 in.)
CAVITY DIMENSIONS (W X H X D) 399X278X451mm (15.7X10.9X17.8 in.)
NET WEIGHT APPROX. 18kg (39.7 lbs.)
TIMER 99min. 99sec.
FUNCTION SELECTIONS MICROWAVE
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.8 Cu. Ft
* Specifications are subject to change without notice.
MICROWAVE 1500 W
GRILL
COMBINATION
Page 5
EXTERNAL VIEW
488
5
1. OUTER DIMENSION
Page 6
2. FEATURE DIAGRAM
KOR-180A0A
6
1. DOOR SEAL
Door seal maintains the microwave within the oven cavity and prevents microwave leakage.
2. DOOR HOOK
When 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 resisant glass. The tray must always be in proper position before operating. Do not cook food
directly on the tray.
9. OVEN FRONT PLATE
10. 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.
11. ROLLER GUIDE
Supports the glass cooking tray.
Page 7
KOR-180A0A
3. CONTROL PANEL
7
(1) KOR-180A0A
1. Time set pad - Used to set the cooking time and the present time.
2. Display - Cooking time, power level, indicators and present time are displayed.
3. One touch - Used to cook or reheat specific quantities of food.
4. Auto cook - Used to cook or reheat.
5. More - Used to add time to cooking.
6. Less - Used to remove time from cooking.
7. Auto Defrost - Used to defrost foods.(for weight)
8. Power - Used to set power level.
9. Defrost - Used to defrost foods.(for time)
10. Kitchen Timer - Used as a minute timer, delay cooking, hold setting after cooking.
11. Clock - Used to set clock.
12. Stop/Clear - Used to stop the oven operation or to delete the cooking data.
13. Start/Easy cook - Used to start the oven and also used to set a reheat time.
Page 8
8
(2) KOR-181G0A
8
M/W DEF
1. BREAD
2. SOUP
3. BAKED POTATO
4. FRESH VEGETABLE
5. FROZEN VEGETABLE
AUTO
COOK
MEAT
TIMER LOCK lb
MICROWAVE OVEN KOR-181G
MORE
LESS
AUTO DEFROST
POULTRY FISH
123
POWER
456
789
DEFROST
STOP/
CLEAR
KITCHEN
TIMER
POPCORN
FROZEN
PIZZA
DINNER
PLATE
CLOCK
0
START/
SPEEDY COOK
1. Time set pad - Used to set the cooking time and the present time.
2. Display - Cooking time, power level, indicators and present time are displayed.
3. One touch - Used to cook or reheat specific quantities of food.
4. Auto cook - Used to cook or reheat.
5. More - Used to add time to cooking.
6. Less - Used to remove time from cooking.
7. Auto Defrost - Used to defrost foods.(for weight)
8. Power - Used to set power level.
9. Defrost - Used to defrost foods.(for time)
10. Kitchen Timer - Used as a minute timer, delay cooking, hold setting after cooking.
11. Clock - Used to set clock.
12. Stop/Clear - Used to stop the oven operation or to delete the cooking data.
13. Start/Easy cook - Used to start the oven and also used to set a reheat time.
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INSTALLATION
9
1. Steady, flat location.
This microwave oven should be set on a steady, flat surface.
2. Leave space behind and side.
All air vents should be kept a clearance. If all vents are covered during operation, the oven may be overheated
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. 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 3 amperes, 120Volts, 60Hz grounded outlet.
1. A short power-supply cord is provided to reduce the risks resulting from becoming entangled in or trippping over a
longer cord.
2. Longer cord sets or extension cords are available and may be used if care is exercised in their use.
3. If a long cord or extension cord is used:
1) The marked electrical rating of the cord set or extension cord should be at least as great as the electrical rating
of the appliance.
2) The extension cord must be a grounding type 3-wire cord.
3) The longer cord should be arranged so that it will not drape over the counter top or tabletop where it can be
pulled on by children or tripped over unintentionally.
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.
Page 10
OPERATIONS AND FUNCTIONS
10
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.
The oven door can be opened at any time during operation by touching the door release button on the control panel.
4.
The oven will automatically shut off. To restart the oven, close the door and then touch START.
5. Each time a pad is touched, a BEEP will sound to acknowledge the touch.
6. The oven automatically cook on full power unless set to a lower power level.
7. The display will show : 0 when the oven is plugged in.
8. Time clock returns to the present time when the cooking time ends.
9. 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.
10. 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 not completely closed or the program has not 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. Power level(Display) Approximate Percentage of Power
Once P-HI 100%
Twice P-90 90%
3 times P-80 80%
4 times P-70 70%
5 times P-60 60%
6 times P-50 50%
7 times P-40 40%
8 times P-30 30%
9 times P-20 20%
10 times P-10 10%
11 times P-00 0%
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DISASSEMBLY AND ASSEMBLY
11
- 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 wear 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 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 has stopped, 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 20A fuse is blown 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, take care when 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.
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1. To remove cabinet
12
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.
Page 13
3. To remove door parts.
13
REF NO. PART CODE PART NAME DESCRIPTION Q TY REMARK
A01
A02
A03
A04
A05
A06
A07
A08
(1) Remove the gasket door from door plate.
(2) Remove the barrier screen inner from door plate.
(3) Remove the door frame from door plate.
(4) Remove the stopper hinge top from door plate.
(5) Remove the spring and the hook.
(6) Remove the barrier screen outer from door frame.
(7) Reverse the above steps for reassembly.
3512205100
3512203900
3517007400
3517005320
3515204400
3511710500
3517005200
3512301800
3513101400
3515101900
FRAME DOOR
BARRIER-SCREEN*O SAN T1.5
STOPPER HINGE *T AS
DOOR PAINTING AS
BARRIER-SCREEN*I
GASKET DOOR
HOOK
SPRING HOOK
ABS SG-175, SG-0760D
KOR-162J0A
KOR-180A
PE T0.1
PP
POM
PW-1
1 KOR-180A
1
KOR-181G
KOR-180A
1
KOR-181G
1
1
1
1
1
1
1
Page 14
4. Method to reduce the gap between the door seal and the oven front surface.
14
(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.
Page 15
5. To remove control panel parts.
15
REF NO. PART CODE PART NAME DESCRIPTION Q TY REMARK
A01
A02
A03 PKMPMSXL00 PCB AS KOR-161G2A 1
A04 7122401211 SCREW TAPPING T2S TRS 4X12 MFZN 4
A05 3513702800 LEVER DOOR OPEN PP 1
A06 441G430171 BUTTON SPRING SWP DIA 0.7 1
A07 3516909600 BUTTON DOOR OPEN ABS AF-348, VT-0826 1
(1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly.
(2) Remove the door open lever from the control panel.
(3) Remove four screws which secure the PCB assembly to control panel.
(4) Disconnect membrane tail from the connector of the PCB assembly.
(5) Detach membrane from the control panel.
(6) Remove door open button and button spring from the control panel.
(7) Reverse the above steps for reassembly.
3518522800
3518522810 KOR-181G2A 1
3516726000 1
3516719100
SWITCH MEMBRANE
CONTROL PANEL
KOR-180A0A 1
ABS AF-348, VT-0826
1
KOR-180A
KOR-180G
Page 16
6. To remove high voltage capacitor.
16
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.
Page 17
8. To remove wind guide assembly.
17
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 reasembly.
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.
Page 18
INTERLOCK MECHANISM AND ADJUSTMENT
18
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. The lock lever 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 one mounting screw.
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 emission exceed 4mW/cm
2
, readjust interlock mechanism.
Page 19
TROUBLE SHOOTING GUIDE
19
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 tranformer, disconnect one load 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 :
Check wire harness, wiring and connection 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 CHECK
Fuse blows.
When electric parts are checked, be sure the power cord is not inserted the wall outlet.
Check continuity of interlock
monitor switch with door closed
Replace fuse
Check continuity of of primary
interlock switch contact with door
partially open until interlock
monitor switch contact close
Check continuity of primary
winding of low voltage
transformer
RESULT
Continuity
No Continuity
Continuity
0 or infinite
Approx.
150~310
(normal)
CAUSE REMEDY
Malfunction of
interlock
monitor switch
Shorted
contacts of
primary
interlock switch.
Defective low
voltage
transformer
Replace
NOTE 1
Replace
NOTE 1
Replace
Disconnect one side of the lead
wire connected form high
voltage transformer to the high
voltage capacitor and operate
the unit
Normal
Fuse again
blows
Defective high
voltage capacitor
Defective high
voltage
transformer
Replace
Replace
Page 20
CONDITION CHECK
20
RESULT
CAUSE REMEDY
Outlet has
proper
voltage Fuse
does not
blow.
NOTE1
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.
Check continuity of magnetron
Check continuity of
power supply cord
Display do not shown
countdown
No
Continuity
No
Continuity
Normal
Defective
magnetron
Open power
supply cord
Defective touch
control circuit
Malfunction of
secondary
interlock switch
Replace
Replace
Replace
Replace
CONDITION CHECK
Turn table
motor and
oven lamp
do not turn
on
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 Replace
Approx.
15 VDC
CAUSE REMEDY
Malfunction of
primary interlock
switch
Malfunction of
secondary
interlock
switch
Defective touch
control circuit
Faulty contacts of
RELAY (RY2) or
open relay coil
Adjust or
replace
Adjust or
replace
Replace
Page 21
(TROUBLE 3) No microwave oscillation even though fan motor rotates.
21
CONDITION CHECK RESULT
No
microwave
oscillation
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
Continuity
Continuity in
backward
direction
Continuity
0 or
No
Continuity
CAUSE
Defective high
voltage
transformer
Defective high
voltage rectifier
Defective
magnetron
Defective high
voltage
transformer
Defective
magnetron
REMEDY
Replace
Replace
Replace
Replace
Replace
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
Defective high
voltage
transformer
Defective touch
control circuit
Faulty
contacts or
RELAY (RY1)
or open
relay coil
Replace
Replace
Replace
Page 22
(TROUBLE 4) The following visual conditions inditions indicate a probable defective touch control circuit or
M/W DEF LOCK lbTIMER
22
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 programmable and cooks normally but no display shows.
8. Display obviously jumps in time while counting down.
9. Display counts down noticeable too fast while cooking.
10. Display does not show the time of day when the 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 if
keyboard is
Check rach pad for
continuity of the membrane
keyboard for the following
keyboard check procedure
Normal
Malfunction
of touch
control circuit
of control box
sub-assembly
Replace
control box
sub-assembly
touched.
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.
Page 23
MEASUREMENT AND TEST
23
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT
Microwave output power can be checked by indirectly mmeasuring 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 100
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
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 heatup 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:
3.6 F). If is measured immediately before the water is added to the vessel. After
T/t
T is difference between initial and ending temperature.
t is the heating time.
The power measured be B (Refer to SPECIFICATIONS) W
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
Heating time for power output:
A (second)
B (W)
70
600
64
650
2 3.6 F)
60
700
750
56
52
800
49
850
47
90044950
42
1000401050381100
Page 24
2. MICROWAVE RADIATION TEST
24
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.
PROCEDURE
1. Prepare Microwave Energy Survey Meter, 600cc glass beaker,
and glass thermometer 100
15cc of tap water initially at 20 5 9 F) in
mm(3.5 in.).
3. Place it at the center of the tray and set it in a cavity.
4. Close the door and operate the oven.
F).
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
2
door normally closed must be less than 4mW/cm
.
2) When measuring the leakage, always use the 5 cm (2 in.)
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.
Page 25
3. COMPONENT TEST PROCEDURE
25
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
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 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.
Page 26
WIRING DIAGRAM
26
Page 27
PRINTED CIRCUIT BOARD
27
1. CIRCUIT CHECK PROCEDURE
1. Low voltage transformer check
The low voltage transformer is located on the P.C.B.
Measuring condition: Input voltage: 120V / Frequency: 60Hz
Terminal Voltage
4-7
NOTE
1. Refer to Ciruit 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
2. Voltage Check
- Key check point
NO CHECK POINT REMARK
1 IC1 PIN 2, 21, 30, 34 -5VDC
2 IC1 PIN 35
LOAD
AC 12.6 V
NO LOAD
AC 14.7 V
T : 16.67ms(60Hz)
3 IC1 PIN 31 OR 32
T : 250 ns(4MHz)
- Check method
NO MEASURE POINT WAVE FORM REMEDY REMARK
1 MP1
2 MP2
NOTE
Each measure point must be measured with GND points.
Replace VL1, EC1 NO LOAD
Replace EC2, D12,13,14 NO LOAD
Page 28
MP1
28
MP2
Mesure point
Page 29
3. When there is no microwave oscillation
29
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
POINT
STATE
RELAY 2 ON -5VDC GND
RELAY 2 OFF 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
POINT
STATE
RELAY 1 ON -5VDC GND
RELAY 1 OFF 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
POINT
STATE
1) DOOR OPEN OPEN -5VDC
2) DOOR CLOSED CLOSE GND
AB
AB
AB
CHECK NO HETHOD REMEDY
1 Check the stage(ON, OFF) of the secondary interlock Replace door open monitor switch.
switch by resistance measurement.
5. When the digital clock does not operate properly.
refer to Circuit Diagram (point 5)
POINT WAVE FORM
A
If clock does not keep exact time, you must check resistor R15,16, zener diode ZD1.
T: 16.67 ms(60Hz)
Page 30
2. PCB CIRCUIT DIAGRAM
30
Page 31
3. P.C.B. LOCATION NO.
31
NO NAME SYMBOL SPECIFICATION PART CODE Q TY
1 BUZZER BZ1 BM-20K 3515600100 1
2 C ARRAY CA1 7P(6) 102 M 50V CN6XB-102M 1
3 CAPACITOR ELEC EC1 50V RS 1 F CEXE1H109V 1
4 CPAPCITOR ELEC EC2 25V RSS 1000 F CEXF1E102V 1
5 CONNECTOR WAFER CN1 YW396-02AV 3519150520 1
6 CONNECTOR WAFER CN3 YW396-05AV 3519150510 1
7 CONNECTOR WAFER CN2 FCZ 254-11 441M367160 1
8 DIODE RECTIFY
9 DIODE RECTIFY D13, 14 1N4004A DZN4004A-- 2
10 DIODE ZENER ZD1 UZ-5.1BSB DZUZ5R1BSB 1
11 DIODE ZENER ZD2 UZ-3.9BSB DZUZ3R9BSB 1
12 LED DISPLAY DP1 DDG-631H DDDG631H01 1
13 PCB MAIN M158 81.5X139.9 3514315410 1
14 R ARRAY RA1 7P(6) 1/8 100K J RA-87X104J 1
15 RESISTOR R1~R7 1/6W 220 5% RD-AZ221J- 7
16 RESISTOR
17 RESISTOR R11, 20, 21 1/6W 100K 5% RD-AZ104J- 3
18 RESISTOR R13 1/6W 200 5% RD-AZ201J- 1
19 RESISTOR R15~16 1/6W 10K 5% RD-AZ103J- 3
20 RESISTOR R17 1/6W 510 5% RD-AZ511J- 1
21 RESISTOR R18 1/6W 1M 5% RD-AZ105J- 1
22 RESISTOR R19 1/4W 51 5% RD-4Z510J- 1
23 REGULATOR VL1 MC7905C 1MC7905C-- 1
24 TRANSISTOR Q1~5, 9~11 KRA-106M TZRA106M-- 8
D1~6, 9~12,15
R8, 10, 12, 14, 22
1N4148 DZN4148--- 11
1/6W 1K 5% RD-AZ102J- 5
25 TRANSISTOR Q6 KTA-1266Y TZTA1266Y- 1
26 TRANS POWER LVT1 DMR-631P 5EPU035302 1
27 WIRE COPPER
28 WIRE COPPER SJ3, 5 1/0.52 TIN COATING 85801052GY 2
29 IC MICOM IC1 TMP47C440BN-NG14 13GS1A1AGH0 1
30 RESONATOR CERA CR1 KBR-4.0MSTF 5PKBR40MKS 1
31 SW RELAY RY1 G5G-1A DC 12V 5SC0101121 2
32 SW RELAY RY2 CS11-12SH 1C 1P 5SC0101128 1
33 CAPACITOR CERA C6 102 50V Z AXIAL CCZB1H102K 1
34 CAPACITOR CERA
J1~3,5~8,10~12,17~21
C1, C3~C5, C7
1/0.52 TIN COATING 85801052GY 15
104 50V Z AXIAL CCZF1H104Z 5
Page 32
EXPLODED VIEW AND PARTS LIST
32
1. DOOR ASSEMBLY
Refer to Disassembly and assembly
2. CONTROL PANEL ASSEMBLY
Refer to Disassembly and assembly
3. TOTAL ASSEMBLY
Page 33
REF NO PART CODE PART NAME DESCRIPTION Q’TY
33
A00
B00
F01
F02
F03
F04 7122401211
F05 7122401211
F06 7122401011
F07 35113TCN35
F08 7122401211
F09 FUSE
F10 7121403011 SCREW TAPPING
F11 3963822200 MOTOR SHADED POLE
F12 3512522100 GUIDE WIND
F13 3511800100 FAN
F14 3518002900 MAGNETRON
F15 3516004000 SPECIAL SCREW
F16 7272400811 SCREW TAPTITE
F17 3513003200 HOLDER HV CAPACITOR
F18 3518302200 CAPACITOR HV
F19 3518400900 DIODE HV 1
3511715500
3511715510
PKCPSWAC00 CONTROL-PANEL AS KOR-180A0A 1
PKCPSWAC50 CONTROL-PANEL AS KOR-181G0A 1
3510802400 1
3516004100
3516113100
3516112400
DOOR AS KOR-180A0A 1
DOOR AS KOR-181G0A 1
CABINET
SPECIAL SCREW
CAVITY AS
CAVITY JOINT AS
SCREW TAPPING
SCREW TAPPING
SCREW TAPPING
CORD POWER AS
SCREW TAPPING
SECC T0.6
T1 TRS LR4 POLE 4X10 SE MFZN
KOR-180A0A
KOR-180A0A
T2S TRS 4X12 MFZN
T2S TRS 4X12 MFZN
T1 TRS 4X10 MFZN
3X16AWG 40X40 120-RTML
T2S TRS 4X12 MFZN
65TS 125V 20A
T2S PAN 4X30 MFZN
120V 30W OEM-15DWX1-B07
PP J640A
PP+20%GLASS
2M218J(MF)P
T2 BOLT FLANGE 5X12 DACRO
TT3 TRS 4X8 MFZN
SECC T0.6
2100VAC 0.98UF #187
3
1
1
1
2
1
1
1
1
2
1
1
1
1
1
1
1
1
F20 HARNESS B 1
F21 3518113800 TRANS HV
F22 3516003800 SPECIAL SCREW
F23 3510311800 BASE
F24 7112401011 SCREW TAPPING
F25 3512101400 FOOT
F26 7272400811 SCREW TAPTITE
F27 3515202800 STOPPER HINGE *U AS
F28 3512706110 HARNESS MAIN
F29 4415A17352 SW MICRO
F30 4415A66600 SW MICRO
F31 3518571000 SWITCH PUSH
F32 3513701300 LEVER LOCK
DY-N95A0-16T
T2 FLANGE 5X8 MFZN
SBHG T0.7
T1 TRS 4X10 MFZN
PP DASF-310
TT3 TRS 4X8 MFZN
KOR-121M0A
KOR-180A0A
VP-533A-OF SPNO #187 200G
VP-532A-OF SPNO #187 200G
MP101C
POM
1
4
1
5
4
1
1
1
1
1
1
1
Page 34
REF NO PART CODE PART NAME DESCRIPTION Q’TY
34
F33 3513814300 LOCK POM BLACK 1
F34 3513601500 LAMP BL 125V 25W T25 C5A #187 1
F35 7121400611 SCREW TAPPING T2S PAN 4X6 MFZN 1
F36 3966820200 MOTOR SYNCRO 120V 2W GM-16-12F17 1
F37 3518905300 THERMOSTAT OFF:75 ON:65 H #187 NB 1
F38 3513003400 HOLDER THERMOSTAT PBT 1
F39 7272400811 SCREW TAPTITE TT3 TRS 4X8 MFZN 2
F40 3511406220 COVER WAVE GUIDE PP J640A WHITE 1
F41 3517400620 COUPLER XAREC 1
F42 3514700710 ROLLER TEFRON 3
F43 3512517200 GUIDE ROLLER PP 1
F44 3517207700 TRAY GLASS 1
Page 35
DAEWOO ELECTRONICS CO., LTD.
686,
AHYEON-DONG MAPO-GU SEOUL, KOREA
C.P.O BOX 8003 SEOUL, KOREA
TELEX: DWELEC K28177-8
CABLE:
“DAEWOOELEC”
PRINTED DATE: DEC, 2001
S/M NO. : R180A0A002
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