Daewoo KOR-181G2A Service manual

S/M No. : R180A2A001
Service Manual
Microwave Oven
Model: KOR-180A2A
KOR-181G2A
KOR-181H2A
DAEWOO ELECTRONICS CO., LTD.
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 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 ..............................................................................................................................................................10
OPERATIONS AND FUNCTIONS .................................................................................................................................11
DISASSEMBLY AND ASSMBLY...................................................................................................................................12
INTERLOCK MECHANISM AND ADJUSTMENT.........................................................................................................19
TROUBLE SHOOTING GUIDE ......................................................................................................................................20
MESUREMENT AND TEST............................................................................................................................................24
MEASUREMENT OF THE MICROWAVE POWER OUTPUT................................................................................24
MICROWAVE RADIATION TEST ...........................................................................................................................25
COMPONENT TEST PROCEDURE .......................................................................................................................26
WIRING DIAGRAM.........................................................................................................................................................27
PRINTED CIRCUIT BOARD...........................................................................................................................................28
CIRCUIT CHECK PROCEDURE.............................................................................................................................28
PCB CIRCUIT DIAGRAM ........................................................................................................................................31
P.C.B. LOCATION NO. ............................................................................................................................................32
EXPLODED VIEW AND PARTS LIST ...........................................................................................................................33
DOOR ASSEMBLY ..................................................................................................................................................33
CONTROL PANEL ASSEMBLY ..............................................................................................................................33
TOTAL ASSEMBLY .................................................................................................................................................33
2
SAFETY AND PRECAUTIONS
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.
3
SPECIFICATIONS
MODEL
KOR-180A2A/181G2A/181H2A
POWER SUPPLY
120V~60HZ, SINGLE PHASE WITH EARTHING
POWER
CONSUMPTION
MICROWAVE
1600 W
GRILL
COMBINATION
MICROWAVE ENERGY OUTPUT
1200 W
MICROWAVE FREQUENCY
2450MHz
OUTSIDE DIMENSIONS (W X H X D)
589X339X487mm (23.2X13.3X19.2 in.)
CAVITY DIMENSIONS (W X H X D)
399X278X451mm (15.7X10.9X17.8 in.)
NET WEIGHT
APPROX. 18.0kg (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.
4
EXTERNAL VIEW
1. OUTER DIMENSION
5
2. FEATURE DIAGRAM
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.
6
3. CONTROL PANEL
(1) KOR-180A2A
KOR-180A
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.
7
(2) KOR-181G2A
M/W DEF TIMER LOCK lb
MICROWAVE OVEN KOR-181G
1. BREAD
2. SOUP
3. BAKED POTATO
4. FRESH VEGETABLE
5. FROZEN VEGETABLE
POPCORN
MORE
FROZEN
PIZZA
LESS
AUTO
COOK
DINNER
PLATE
AUTO DEFROST
MEAT
POULTRY
POWER
DEFROST
FISH
1 2 3
4 5 6
7 8 9
0
KITCHEN
TIMER
CLOCK
STOP/
START/
CLEAR
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.
8
(3) KOR-181H2A
M/W DEF TIMER LOCK lb
MICROWAVE OVEN KOR-181H
POPCORN
BEVERAGE
MORE
FRESH
VEGETABLE
FROZEN
PIZZA
LESS
FROZEN
VEGETABLE
DINNER
PLATE
AUTO DEFROST
MEAT
POULTRY
POWER
DEFROST
FISH
1 2 3
4 5 6
7 8 9
0
KITCHEN
TIMER
CLOCK
STOP/
START/
CLEAR
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. More - Used to add time to cooking.
5. Less - Used to remove time from cooking.
6. Auto Defrost - Used to defrost foods.(for weight)
7. Power - Used to set power level.
8. Defrost - Used to defrost foods.(for time)
9. Kitchen Timer - Used as a minute timer, delay cooking, hold setting after cooking.
10. Clock - Used to set clock.
11. Stop/Clear - Used to stop the oven operation or to delete the cooking data.
12. Start/Easy cook - Used to start the oven and also used to set a reheat time.
9
INSTALLATION
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 14.5 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.
10
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. 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.
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 set.
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%
11
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 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.
12
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.
13
3. To remove door parts.
REF NO.
A01
A02
A03
A04
A05
A06
A07
A08
PART CODE
3512205100
3517007400
3515204400
3511715500
3517005200
3512301800
3513101400
3515101900
PART NAME
FRAME DOOR
BARRIER-SCREEN*O
STOPPER HINGE *T AS
DOOR AS
BARRIER-SCREEN*I
GASKET DOOR
HOOK
SPRING HOOK
DESCRIPTION
ABS SG-175, SG-0760D
SAN T1.5
KOR-162JOA
KOR-180A
PE T0.1
PP
POM
RW-1
(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.
14
Q’TY
1
1
1
1
1
1
1
1
REMARK
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part ‘A’.
• Loosen two screws on stopper hinge top, and then push the
door to contact the door seal to oven front surface.
• Tighten two screws.
(2) To reduce gap located on part ‘B’.
• Loosen two screws on stopper hinge under, and then push
the door to contact the door seal to oven front surface.
• Tighten two screws.
NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.
15
5. To remove control panel parts.
REF NO.
B01
B02
B03
B04
B05
B06
B07
PART CODE
3518522800
3518522810
3518522820
3516726000
3514325010
7122401211
3513702800
441G430171
3516909600
PART NAME
SWITCH MEMBRANE
SWITCH MEMBRANE
SWITCH MEMBRANE
CONTROL PANEL
PCB AS
SCREW TAPPING
LEVER DOOR OPEN
BUTTON SPRING
BUTTON DOOR OPEN
DESCRIPTION
KOR-180A0A
KOR-181G2A
KOR-181H2A
ABS AF-348, VT-0826
KOR-180A2A
T2S TRS 4X12 MFZN
PP
SWP DIA 0.7
ABS AF-348, VT-0826
Q’TY
1
1
1
1
1
3
1
1
1
REMARK
(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.
16
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/cm2 for a fully assembled oven with door normally closed.
17
8. To remove wind guide assembly.
1) Remove a screw which secure the wind guide assembly.
2) Draw forward the wind guide assembly.
3) Pull the fan from the motor shaft.
4) Remove two screws which secure the motor shaded pole.
5) Remove the motor shaded pole.
6) Reverse the above steps for 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.
18
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. 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/cm2, readjust interlock mechanism.
19
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 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 : When electric parts are checked, be sure the power cord is not inserted the wall outlet.
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
RESULT
Check continuity of interlock
monitor switch with door closed
Continuity
Fuse blows.
CAUSE
Malfunction of
interlock
monitor switch
REMEDY
Replace
NOTE 1
No Continuity
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
Continuity
0Ω or infinite
Approx.
150~310
(normal)
Normal
Disconnect one side of the lead
wire connected form high
voltage transformer to the high
voltage capacitor and operate
the unit
Fuse again
blows
20
Shorted
contacts of
primary
interlock switch.
Defective low
voltage
transformer
Defective high
voltage capacitor
Defective high
voltage
transformer
Replace
NOTE 1
Replace
Replace
Replace
CONDITION
Outlet has
proper
voltage Fuse
does not
blow.
CHECK
RESULT
CAUSE
REMEDY
No
Continuity
Defective
magnetron
Replace
Check continuity of magnetron
Check continuity of
power supply cord
No
Continuity
Open power
supply cord
Replace
Normal
Defective touch
control circuit
Replace
Malfunction of
secondary
interlock switch
Replace
Display do not shown
countdown
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.
CONDITION
CHECK
RESULT
CAUSE
REMEDY
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
Check continuity of secondary
interlock switch
No
Continuity
Malfunction of
secondary
interlock
switch
Adjust or
replace
Check D.C. voltage being
supplied to RELAY (RY2) coil
0V
Defective touch
control circuit
Replace
Approx.
15 VDC
Faulty contacts of
RELAY (RY2) or
open relay coil
21
Replace
(TROUBLE 3) No microwave oscillation even though fan motor rotates.
CONDITION
No
microwave
oscillation
CHECK
RESULT
CAUSE
REMEDY
Check continuity of high
voltage capacitor terminals
with wires removed
Continuity
Defective high
voltage
transformer
Replace
Check continuity of high voltage
rectifier in forward and backward
direction with DC megger
Continuity in
backward
direction
Defective high
voltage rectifier
Replace
Connect megger leads to
magnetron terminal and
magnetron body
Continuity
Defective
magnetron
Replace
Defective high
voltage
transformer
Replace
0 Ω or ∞
Check resistance of primary and
secondary coil of high voltage
transformer
No
Continuity
Check continuity of magnetron
with wires removed
No
Continuity
Check continuity of filament
terminal of high voltage
transformer
Defective
magnetron
Defective high
voltage
transformer
0V
Check D.C. voltage being
supplied to RELAY (RY1) coil
Defective touch
control circuit
Approx
15 VDC
22
Faulty
contacts or
RELAY (RY1)
or open
relay coil
Replace
Replace
Replace
Replace
(TROUBLE 4) The following visual conditions inditions 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 is not on when it should be.
M/W
DEF TIMER LOCK
lb
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.(in case of setting present time)
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
Display does
not show
programming
at all, even if
keyboard is
touched.
Check each pad for
continuity of the membrane
keyboard for the following
keyboard check procedure
RESULT
Normal
Abnormal
CAUSE
REMEDY
Malfunction
of touch
control circuit
of control box
sub-assembly
Replace
control box
sub-assembly
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.
23
MEASUREMENT AND TEST
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 ± 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). If 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 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:
P = 4187 X ∆ T/t
• ∆ T is difference between initial and ending temperature.
• t is the heating time.
The power measured 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)
70
64
60
56
52
49
47
44
42
40
38
35
B (W)
600
650
700
750
800
850
900
950
1000
1050
1100
1200
24
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.
PROCEDURE
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 600 cc glass beaker with an inside diameter of approx. 95
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.
5. Measure the leakage by using Microwave Energy Survey Meter
with dual ranges, set to 2450MHz.
1) Measured radiation leakage must not exceed the value
prescribed below. Leakage for a fully assembled oven with
door normally closed must be less than 4mW/cm2.
2) When measuring the leakage, always use the 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.
25
3. COMPONENT TEST PROCEDURE
• High voltage is present at the high voltage terminal of the high voltage transformer during any cooking cycle.
• It is neither necessary nor advisable to attempt measurement of the high voltage.
• Before touching any oven components or wiring, always unplug the oven from its power source and discharge the
capacitor.
1. High voltage transformer
1) Remove connections from the transformer terminals and check continuity.
2) Normal readings should be as follows :
Secondary winding ... Approx. 110 Ω±10%
Filament winding ... Approx. 0 Ω
Primary winding ... Approx. 1 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 10MΩ once the capacitor 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 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.
26
WIRING DIAGRAM
27
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: 120V / Frequency: 60Hz
Terminal Voltage
LOAD
NO LOAD
4-7
AC 12.6 V
AC 14.7 V
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 ± 5% of nominal voltage.
2. Voltage Check
- Key check point
NO
CHECK POINT
1
IC1 PIN 2, 21, 30, 34
2
IC1 PIN 35
REMARK
-5VDC
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
DC -5V±0.25V
Replace VL1, EC1
NO LOAD
2
MP2
DC -12V±2.0V
Replace EC2, D12,13,14
NO LOAD
NOTE
Each measure point must be measured with GND points.
28
MP1
MP2
Mesure point
29
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
POINT
A
B
RELAY 2 ON
-5VDC
GND
RELAY 2 OFF
GND
-12VDC
STATE
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
A
B
RELAY 1 ON
-5VDC
GND
RELAY 1 OFF
GND
-12VDC
STATE
4. When the door is opened during operation the count down timer does not stop.
→ refer to Circuit Diagram (point 1)
- Check method
POINT
A
B
1) DOOR OPEN
OPEN
-5VDC
2) DOOR CLOSED
CLOSE
GND
STATE
CHECK NO
1
HETHOD
REMEDY
Check the stage(ON, OFF) of the secondary interlock
switch by resistance measurement.
Replace door open monitor switch.
5. When the digital clock does not operate properly.
→ refer to Circuit Diagram (point 5)
POINT
A
WAVE FORM
T: 16.67 ms(60Hz)
❈ If clock does not keep exact time, you must check resistor R15,16, zener diode ZD1.
30
2. PCB CIRCUIT DIAGRAM
31
3. P.C.B. LOCATION NO.
NO
NAME
SYMBOL
SPECIFICATION
PART CODE
Q’TY
3515600100
1
1
BUZZER
BZ1
BM-20K
2
C ARRAY
CA1
7P(6) 102 M 50V
CN6XB-102M
1
3
CAPACITOR ELEC
EC1
50V RS 1µF
CEXE1H109V
1
4
CPAPCITOR ELEC
EC2
25V RSS 1000µF
CEXF1E102V
1
5
CONNECTOR WAFER
CN1
YW396-02AV
3519150520
1
6
CONNECTOR WAFER
CN3
YW396-05AV
3519150510
1
7
CONNECTOR WAFER
CN2
FCZ254-11
441M367160
1
8
DIODE RECTIFY
D1~6, 9~12,15
1N4148
DZN4148---
11
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 330 5%
RD-AZ331J-
7
16
RESISTOR
R8, 10, 12, 14, 22
1/6W 1K 5%
RD-AZ102J-
5
17
RESISTOR
R11, 20, 21
1/6W 100K 5%
RD-AZ104J-
3
18
RESISTOR
R13
1/6W 100 5%
RD-AZ101J-
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-102M
TZRA102M--
8
25
TRANSISTOR
Q6
KTA-1266Y
TZTA1266Y-
1
26
TRANS POWER
LVT1
DMR-631FS
5EPV035303
1
27
WIRE COPPER
J1~3,5~8,10~12,17~21
1/0.52 TIN COATING
85801052GY
15
28
WIRE COPPER
SJ2, 3, 5
1/0.52 TIN COATING
85801052GY
2
29
IC MICOM
IC1
TMP47C440BN-3FC2
13GS181GH0
1
30
RESONATOR CERA
CR1
CRT 4.00MS
5P4ROOMTS-
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
C1, C3~C5, C7
104 50V Z AXIAL
CCZF1H104Z
5
35
RESISTOR
R23
1/6W 4.7K 5%
RD-AZ472J-
1
32
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
33
REF NO
PART CODE
A00
3511715500
DOOR AS
KOR-180A0A (KOR-180A2A)
1
3511715510
DOOR AS
KOR-181H2A (KOR-181G2A / KOR-181H2A)
1
3516726410
CONTROL-PANEL AS
KOR-180A2A
1
3516726420
CONTROL-PANEL AS
KOR-181G2A
1
3516726430
CONTROL-PANEL AS
KOR-181H2A
1
F01
3510802400
CABINET
SECC T0.6
1
F02
3516004100
SPECIAL SCREW
T1 TRS LR4 POLE 4X10 SE MFZN
3
F03
3516113110
CAVITY AS
KOR-180A2A
1
F04
7122401211
SCREW TAPPING
T2S TRS 4X12 MFZN
1
F05
7122401211
SCREW TAPPING
T2S TRS 4X12 MFZN
1
F06
7122401011
SCREW TAPPING
T1 TRS 4X10 MFZN
1
F07
35113UANT5
CORD POWER AS
3X14AWG 40X40 120-RTML
1
F08
7122401211
SCREW TAPPING
T2S TRS 4X12 MFZN
1
FUSE
65TS 125V 20A
1
B00
F09
PART NAME
DESCRIPTION
Q'TY
F10
7121403011
SCREW TAPPING
T2S PAN 4X30 MFZN
2
F11
3963822200
MOTOR SHADED POLE
120V 30W OEM-15DWX1-B07
1
F12
3512522100
GUIDE WIND
PP J640A
1
F13
3511800100
FAN
PP+20%GLASS
1
F14
3518003500
MAGNETRON
RM 259(JF)
1
F15
3516004000
SPECIAL SCREW
T2 BOLT FLANGE 5X12 DACRO
1
F16
7272400811
SCREW TAPTITE
TT3 TRS 4X8 MFZN
1
F17
3513003200
HOLDER HV CAPACITOR
SECC T0.6
1
F18
3518302300
CAPACITOR HV
2100VAC 1.1UF #187
1
F19
3518400110
DIODE HV
HVR-1X-70B 10KV #187
1
F20
HARNESS B
1
F21
3518117610
TRANS HV
DT-N12A0-18T
1
F22
3516003700
SPECIAL SCREW
TT3 HEX 4X8 FLANGE MFZN
4
F23
3510311800
BASE
SBHG T0.8
1
F24
7112401011
SCREW TAPPING
T1 TRS 4X8 MFZN
5
F25
3512101400
FOOT
PP DASF-310
4
F26
7272400811
SCREW TAPTITE
TT3 TRS 4X8 MFZN
1
F27
3515204500
STOPPER HINGE *U AS
KOR-162J0A
1
F28
3512706120
HARNESS MAIN
KOR-180A2A
1
F29
4415A17352
SW MICRO
VP-533A-OF SPNO #187 200G
1
F30
4415A66600
SW MICRO
VP-532A-OF SPNO #187 200G
1
F31
3518571000
SWITCH PUSH
MP101C
1
F32
3513702600
LEVER LOCK
POM
1
34
REF NO
PART CODE
PART NAME
DESCRIPTION
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
3966830700
MOTOR SYNCRO
120V 3W SM012
1
F37
3518905300
THERMOSTAT
OFF:75 ON:65 H #187 NB
1
F38
3513003400
HOLDER THERMOSTAT
PP (NATURAL)
1
F39
7272400811
SCREW TAPTITE
TT3 TRS 4X8 MFZN
1
F40
3511406220
COVER WAVE GUIDE
PP J640A WHITE
1
F41
3517402000
COUPLER
QUESTRA
1
F42
3514700710
ROLLER
TEFRON
3
F43
3512517200
GUIDE ROLLER
PP
1
F44
3517207700
TRAY
GLASS
1
F45
3518903400
THERMOSTAT
OFF: 150 ON: 60 V #187
1
F46
7121300811
SCREW TAPPING
T2S PAN 3X8 MFZN
2
35
Q'TY
VISION CREATIVE, INC.
DAEWOO ELECTRONICS CO., LTD.
686, AHYEON-DONG MAPO-GU SEOUL, KOREA
C.P.O. BOX 8003 SEOUL, KOREA
TELEX: DWELEC K28177-8
CABLE: “DAEWOOELEC”
S/M NO.:R180A2A001
PRINTED DATE: Aug, 2001