Page 1
Service Manual
Microwave Oven
Model : KOR-164HBA02
DAEWOO ELECTRONICS CO., LTD.
S/M No.:
Page 2
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
(a) Do not operate or allow the oven to be operated with the door open.
(b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave
source, and make repairs as necessary: (1) Interlock operation, (2) Proper door closing, (3) Seal and sealing
surfaces (arcing, wear, and other damage), (4) Damage to or loosening of hinges and latches, (5) Evidence of
dropping or abuse.
(c) Before turning on power to the microwave oven for any service test or inspection within the microwave
generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper
alignment, integrity, and connections.
(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and
transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the
oven is released to the owner.
(e) A microwave leakage check to verify compliance with the Federal performance standard should be performed on
each oven prior to release to the owner.
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE
EXPOSURE TO EXCESSIVE MICROWAVE ENERGY
TABLE OF CONTENTS
1
Page 3
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.
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.
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. WAVEGUIDE FLANGES AND GASKETS MUST BE
SECURE. NEVER OPERATE THE DEVICE WITHOUT A MICROWAVE ENERGY ABSORBING LOAD ATTACHED.
NEVER LOOK INTO AN OPEN WAVEGUIDE OR ANTENNA WHILE THE DEVICE IS ENERGIZED.
2
Page 4
SPECIFICATIONS
SPEC
IFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.
MODEL KOR-164HBA
POWER SUPPLY 120V~60Hz, SINGLE PHASE WITH GROUNDING
POWER
CONSUMPTION
MICROWAVE 1500W
GRILL
COM BIN ATIO N
MICROWAVE ENERGY OUTPUT 1100W
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 589 x 339 x 486 mm (23.2 x 13.3 x 19.1 in.)
CAVITY DIMENSIONS (W X H X D) 399 x 263 x 426 mm (15.7 x 10.4 x 16.8 in.)
NET W EIGHT APPROX. 18.5 Kg ( 40.8 lbs.)
TIMER 99 m in. 99 sec.
FUNCTION SELECTIONS MICROWAVE
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.6 Cu.Ft.
3
Page 5
EXTERNAL VIEW
1. OUTER DIMENSION
589 486
339
4
12 3
45 6
78 9
0
KICHEN
TIMER
CLOCK
POWER
STOP/CLEAR START
/SPEEDY COOK
MEAT
MORE
M/W DEF
Ons Touch & Easy Cook
TIMER LOCK Ib
BEVERAGE POPCORN
FRESH
VEGETABLE
FROZEN
VEGETABLE
FROZEN
PIZZA
DINNER
PLATE
LESS
POULTRY FISH
DEFROST
Page 6
EXTERNAL VIEW
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 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 cooking tray.
5
123
456
789
0
KICHEN
TIMER
CLOCK
POWER
STOP/CLEAR START
/SPEEDY COOK
MEAT
MORE
M/W DEF
Ons Touch & Easy Cook
TIMER LOCK Ib
BEVERAGE POPCORN
FRESH
VEGETABLE
FROZEN
VEGETABLE
FROZEN
PIZZA
DINNER
PLATE
LESS
POULTRY FISH
DEFROST
②
③
⑤
⑥
⑧
①
⑩
⑨
⑦
④
Page 7
EXTERNAL VIEW
3. CONTROL PANEL
- KOR-164H0A
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
- Use d to rem ove tim e from cooking.
6. Auto Defrost
- Used to defrost foods.(for weight)
7. Power
- U sed to set p o w er 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/Speedy cook
- Used to start the oven and also used to set a reheat time.
6
12 3
45 6
78 9
0
KICHEN
TIMER
CLOCK
POWER
STOP/CLEAR START
/SPEEDY COOK
MEAT
MORE
M/W DEF
Ons Touch & Easy Cook
TIMER LOCK g
BEVERAGE POPCORN
FRESH
VEGETABLE
FROZEN
VEGETABLE
FROZEN
PIZZA
DINNER
PLATE
LESS
POULTRY FISH
DEFROST
②
③
⑤
⑥
⑧
①
⑩
⑫⑪
⑨
⑦
④
Page 8
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 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 12 amperes, 120 Volts, 60 Hz grounded outlet.
Power supply cord is about 0.8 meters long.
1. A short power-supply cord is provided to reduce the risks resulting from becoming entangled in or tripping 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.
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Page 9
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 completely closed or the program has been reset.
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 tim e s P-00 0 %
Make sure the oven is properly installed and plugged into the electrical outlet.
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DISASSEMBLY AND ASSEMBLY
- Cautions to be observed when trouble shooting.
Unlike many other appliances, the microwave oven is high-voltage, high-current
equipment. It is completely safety during normal operation. However, carelessness in servicing the oven can result in an
electric shock or possible danger from a short
circuit. You are asked to observe the following precautions carefully.
1. Always remove the power plug from the outlet before servicing.
2. Use an insulated screwdriver and ware rubber gloves when servicing the high voltage side.
3. Discharge the high voltage capacitor before touching any oven components or wiring.
1) Check the grounding.
Do not operate on a two-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 15A fuse is blown out due to the operation of the monitor
switch; replace primary interlock switch, secondary interlock switch
and interlock monitor switch.
5. After repair or replacement of parts, make sure that the screws are
properly tightened, and all electrical connections are tightened.
6. Do not operate without cabinet.
CAUTION
Service personnel should remove their watches whenever working close to or replacing the magnetron.
CAUTION
When servicing the appliance, need a care of touching or replacing high potential parts because of electrical
shock or exposing microvave. These parts are as follows - HV Transformer, Magnetron, HV Capacitor, HV Diode.
9
Page 11
DISASSEMBLY AND ASSEMBLY
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.
10
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DISASSEMBLY AND ASSEMBLY
3. To remove door parts.
REF. NO PART CODE PART NAME DESCRIPTION QTY REMARK
A01 3512301800 GASKET DOOR PP 1
A02 3517005200 BARRIER-SCREEN *I PE T0.1 1
A03 3515204400 STOPPER HINGN *T AS KOR-162J0A 1
A04 3511710500 DOOR PAINTING AS KOR-161H0A 1
A05 3513101600 HOOK POM 1
A06 3515102000 SPRING HOOK PW1 1
A07 3517005350 BARRIER-SCREEN *O GLASS T3.2 1
A13 3511608000 DECORATOR DOOR *R SUS T0.5 1
A08 3512203930 FRAME DOOR ABS SG-175, SG-0760D 1
A09 7001401211 SCREW MACHINE PAN M14XL12 MFZN 2
A10 3511607700 DECORATOR DOOR *T SUS T0.5 1
A11 3511607900 DECORATOR DOOR *L SUS T0.5 1
A12 3511607800 DECORATOR DOOR *U SUS T0.5 1
A14 3512603630 HANDLE DOOR KOR-164HBA 2
(1) Remove the gasket door(A01) from door plate.
(3) Remove two screws(A09) from door plate.
(4) Remove the door handle (A15) and handle supporter (A14) from door plate.
(5) Remove the four door decorators (A10~A13) from door frame.
(2) Remove the door frame (A08) from door plate.
(6) Remove the stopper hinge top(A03) from door plate.
(7) Remove the spring(A06) and the hook(A05).
(8) Remove the barrier screen outer(A07) from door frame.
(9) Reverse the above steps for reassembly.
A04
A05
A02
A06
A01
A03
A11
A08
A07
A09
A10
A12
A13
A14
11
Page 13
123
456
789
0
KICHEN
TIMER
CLOCK
POWER
STOP/CLEAR START
/SPEEDY COOK
MEAT
MORE
M/W DEF
Ons Touch & Easy Cook
TIMER LOCK Ib
BEVERAGE POPCORN
FRESH
VEGETABLE
FROZEN
VEGETABLE
FROZEN
PIZZA
DINNER
PLATE
LESS
POULTRY FISH
DEFROST
DISASSEMBLY AND ASSEMBLY
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.
3) To reduce gap located on part "C".
Loosen a screw on interlock switch assembly located top of oven body.
Draw the interlock switch assembly inward as possible to engage with hook on the door bottom.
Tighten a screw.
4) To reduce gap located on part "D".
Loosen a screw on interlock switch assembly located bottom of oven body.
and (4) are same as step (3).
NOTE
A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.
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Page 14
DISASSEMBLY AND ASSEMBLY
5. To remove control panel parts.
REF.NO PART CODE PART NAME DESCRIPTION QTY REMARK
B01 3518520890 SWITCH MEMBRANE KOR-164H0A 1
3511608500 DECORATOR C-PANEL SUS T0.5 1
B02
3516719140 CONTROL-PANEL ABS SG-175, SG-0760D
B03
PKMPMSXL00 PCB MAIN MANUAL AS KOR-161G2A 1
1
B04
7112401211 SCREW TAPPING T2S TRS 4*12 MFZN 4
B05
(1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly.
(2) Remove four screws which secure the PCB assembly to control panel.
(3) Disconnect membrane tail from the connector of the PCB assembly.
(4) Detach membrane from the control panel.
(5) Pull out the decorator c-panel from the control panel.
(6) Reverse the above steps for reassembly.
13
B01
B02
B03
B04
B05
Page 15
DISASSEMBLY AND ASSEMBLY
6. To remove high voltage capacitor.
1) Remove a screw which secure the grounding ring terminal
of the H.V.diode and the capacitor holder.
2) Remove the H.V. diode from the capacitor holder.
3) Reverse the above steps for reassembly.
High voltage circuit wiring
7. To remove magnetron.
1) Remove a screw which secure the magnetron.
2) Remove the magnetron.
3) Reverse the above steps for reassembly.
NOTE
Never install the magnetron without the metallic gasket plate which is packed with each magnetron to prevent
microwave leakage. Whenever repair work is carried out on magnetron, check the microwave leakage. It shall
not exceed 4mW/cm
2
for a fully assembled oven with door normally closed.
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Page 16
DISASSEMBLY AND ASSEMBLY
8. To remove wind guide assembly.
1) Remove a screw which secure the wind guide assembly.
2) Draw forward the wind guide assembly.
3) Pull the fan from the motor shaft.
4) Remove two screws which secure the motor shaded pole.
5) Remove the motor shaded pole.
6) Reverse the above steps for reassembly.
9. To remove H.V.transformer.
1) Remove four screws holding the H.V.transformer.
2) Remove the H.V.transformer.
3) Reverse the above steps for reassembly.
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Page 17
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 pro perly, the oven will not op e rate.
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 c o ndition.
(3) Adjustm ent 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 emission exceed
4mW /cm
2
, readjust interlock mechanism.
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Page 18
TROUBLE SHOOTING GUIDE
Following the procedure below to check if the oven is defective or not.
1) Check grounding before trouble checking.
2) Be careful of the high voltage circuit.
3) Discharge the high voltage capacitor.
4) When checking the continuity of the switches, fuse or high voltage transformer, disconnect one lead wire from these parts
and check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to your meter.
(TROU BLE 1)
Oven does not operate at all : any inputs can not be accepted.
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.
CHECK RESULT CAUSE REMEDY
Fuse blows.
Continuity
No Continuity
Continuity
0 infinite
Ω
or
Approx.
150~310
(normal)
Replace
NOTE 1
Replace
NOTE 1
Replace
Replace
Check continuity of
primary winding of low
voltage transformer
Malfunction
of interlock
monitor
switch
Defective low
voltage
transformer
Check continuity of
interlock monitor switch
with door closed
Replace fuse
Check continuity of primary
interlock switch contact
with door partially open
until interlock monitor switch
contact close
Shorted contacts
of primary
interlock switch.
Fuse again
blows
Disconnect one side of the
lead wire connected form
high voltage transformer
to the high voltage capacitor
and operate the unit
DNormal efective high
voltage capacitor
Defective high
voltage transformer
Replace
CONDITION
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Page 19
TROUBLE SHOOTING GUIDE
( TR O UBLE 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
Outlet has
proper voltage
Fuse does not
blow.
Check continuity of
magnetron
No
Continuity
Defective
magnetron
Replace
Display do not
shown countdown
No
Continuity
Normal
Defective touch
control circuit
Open power
supply cord
Malfunction of
secondary
interlock switch
Replace
Check continuity of
power supply cord
Replace
Replace
NOTE
All these switches must be replaced at the same time, please refer to "Interlock Mechanism And Adjustment".
CONDITION
CHECK RESULT CAUSE REMEDY
Turn table
motor, and
oven lamp do
not turn on
No
Continuity
Check continuity of
primary interlock switch
Check continuity of
secondary interlock switch
Check D.C. voltage
being supplied to
RELAY (RY2) coil
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
Replace
No
Continuity
0 V
Approx
15 VDC
18
Page 20
TROUBLE SHOOTING GUIDE
(
TROUBLE 3 )
No m icrow ave oscillation ev e n tho ugh fan m otor rotates.
CONDITION
CHECK RESULT
Continuity
Continuity in
backward
direction
0 Ω
or
No
Continuity
No
Continuity
0 V
Approx
15 VDC
CAUSE
Defective
high voltage
transformer
Defective
high voltage
rectifier
Defective
magnetron
Defective
magnetron
Defective
high voltage
transformer
Defective
high voltage
transformer
Defective
touch control
circuit
Faulty
contacts of
RELAY
(RY1) or open
relay coil
REMEDY
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
No m icrowave
oscillation
Check continuity of high
voltage rectifier in
forward and backward
direction with DC
megger
Check continuity of high
voltage capacitor
terminals with w ires
rem oved
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
rem oved
Check continuity of
voltage transformer
Check D.C. voltage
being supplied to
RELAY (RY1) coil
Continuity
19
filament terminal of high
Page 21
TROUBLE SHOOTING GUIDE
( 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 diplay are not on when they
numbers is the display.
3. One or more digits in the diplay 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 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 if
keyboard is
touched.
Normal
Replace
control box
sub-assembly
Replace the
mem brane
keyboard
Malfunction
of touch
control circuit
of control box
sub-assembly
Abnormal
Check each pad for
continuity of the
mem brane keyboard
for the following
keyboard check
procedure
Malfunction of
the membrane
keyboard
NOTE
Before following the particular steps listed above in the trouble shooting guide for the membrane keyboardís, failure,
please check for the continuity of each wire-harness between the membrane keyboard and P.C.B. assembly.
20
Page 22
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 wit 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. Th e wa te r is contained in a cylindrical borosilicate glass ve ssel ha ving a maxim um 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 %.
Heating time for power output:
A (second) 70 64 60 56 52 49 47 44 42 40 38
B (W) 600 650 700 750 800 850 900 950 1000 1050 1100
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)
21
Page 23
MEASUREMENT AND TEST
2. MICROWAVE RADIATION 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.
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.
22
123
456
789
0
KICHEN
TIMER
CLOCK
POWER
STOP/CLEAR START
/SPEEDY COOK
MEAT
MORE
M/W DEF
Ons Touch & Easy Cook
TIMER LOCK Ib
BEVERAGE POPCORN
FRESH
VEGETABLE
FROZEN
VEGETABLE
FROZEN
PIZZA
DINNER
PLATE
LESS
POULTRY FISH
DEFROST
Page 24
MEASUREMENT AND TEST
3. COMPONENT TEST PROCEDURE
High voltage is present at the high voltage terminal of the high voltage transformer during any cooking cycle.
It is neither necessary nor advisable to attempt measurement of the high voltage.
Before touching any oven components or wiring, always unplug the oven from its power source and discharge the capacitor.
1. High voltage transformer
1) Remove connections from the transformer terminals and check continuity.
2) Normal readings should be as follows :
Secondary winding ... Approx. 110
±
10%
Filament winding ... Approx. 0
Primary winding ... Approx. 1
2. High voltage capacitor
1) Check continuity of capacitor with meter on the highest OHM scale.
2) A n orm al capacitor w ill sh o w co ntinuity for a short tim e, 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 ìMeasurement 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.
23
Page 25
WI RI NG DI AGRAM
24
Page 26
PRINTED CI RCUI T 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: 120 V / Frequency: 60Hz
2. Voltage Check
- Key check point
- Check method
Terminal Voltage LOAD NO LOAD
4 - 7 AC 12.6 V AC 14.7 V
NO CHECK POINT REMARK
1 IC1 PIN 2,21,30,34 -5VDC
2IC1 PIN 35
T : 1 6.67 m s(60 H z )
3 IC1 PIN 31 OR 32
T : 2 50 n s (4 M H z)
NO MEASURE POINT WAVE FORM REMEDY REMARK
1MP1 DC -5V
±
0.25V Replace VL1, EC1 NO LOAD
2MP2 DC -12V
±
2.0V Replace EC2, D12,13,14 NO LOAD
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.
NOTE
Each measure point must be measured with GND points.
25
Page 27
PRINTED CIRCUIT BOARD
Measure Point
26
MP1
MP2
Page 28
PRI NTED CI RCUIT BOARD
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 diodeZD1.
POINT
STATE
A B
RELAY 2
ON - 5VDC GND
RELAY 2
OFF GND - 12VDC
POIN T
STATE
A B
RELAY 1
ON -5VD C G ND
RELAY 1
OFF GND -12VDC
POINT
STATE
A B
1) DOOR OPEN OPEN -5VDC
2) DOOR CLOSED CLOSE GND
CHECK NO METHOD REMEDY
1
Check the stage(ON,OFF ) of the secondary interlock switch by resistance
measurem ent.
Replace secondary interlock switch.
POINT WAVE FORM
A T: 16.67 m s(6 0Hz)
27
Page 29
PRINTED CIRCUIT BOARD
2. PCB CIRCUIT DIAGRAM
28
Page 30
✔ Caution:
In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the
latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr)
PRINTED CIRCUIT BOARD
3. P.C.B. LOCATION NO.
NO NAME SYMBOL SPEC IFICATION PART CODE Q'TY
1 BUZZER B Z1 BM-20K 3515600100 1
2 C ARR AY CA1 7P(6) 102 M 50V CN6XB-102M 1
3 CAPACITOR ELEC EC1 16V RSS 100uF CEXF1C101V 1
4 CAPACITOR ELEC EC2 25V RSS 1000uF CEXF 1E102V 1
5 CON NE CTOR WAFE R CN1 YW396-02AV 3519150520 1
6 CON NE CTOR WAFE R CN2 YW396-05AV 3519150510 1
7 CON NE CTOR WAFE R CN3 FCZ254-11 441M367160 1
8 DIODE REC TIFY D1~6,9~12 1N4148 DZN4148--- 10
9 DIODE R ECTIFY D13,14 1N4002A DZN4002A-- 2
10 DIODE ZENER ZD1 MTZ 5.1VB 1/2W D ZTZ5R1B-- 1
11 DIODE ZENER ZD2 M TZ 3.9VB 1/2W DZTZ3R9B-- 1
12 LED DISPLAY DP1 DDG -631H DDD G631H -- 1
13 PCB MA IN 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% R D-AZ104J- 3
18 RESISTOR R13 1/6W 100 5% R D-AZ101J- 1
19 RESISTOR R15~17 1/6W 10K 5% RD-AZ103J- 3
20 RESISTOR R18 1/6W 1M 5% R D-AZ105J- 1
21 RESISTOR R19 1/4W 51 5% RD-4Z510J- 1
22 REGULATOR VL1 MC7905C 1MC 7905C-- 1
23 TRANSISTOR Q1~5,9~11 KRA -102M TZRA102M -- 8
24 TRANSISTOR Q 6 KTA-1270Y TZTA1270Y- 1
25 TRANS PO W ER LVT1 DMR -631P 5EPU 035302 1
26 WIRE COPPER J1-J21 1/0.52 TIN COATING 85801052GY 21
27 WIRE COPPER SJ2,3,5 1/0.52 TIN COATING 85801052GY 3
28 IC MICOM IC1 TMP47C 440BN 13GS631G H0 1
29 RESONATOR CERA CR1 KBR-4.0MSTF 5PKBR40MKS 1
30 SW R ELAY RY1 G5G -1A DC12V 5SC0101121 1
31 SW R ELAY RY2 G5B-1 DC12V 5SC0101110 1
32 CAPACITOR CER A C6 102 50V Z AXIAL CC ZB 1H102K 1
33 CAPACITOR CER A C1~5,C7 104 50V Z AXIAL CC ZF1H104Z 6
Page 31
EXPLODED VIEW AND PARTS LIST
1. DOOR ASSEMBLY
Refer to Disassembly and assembly.
2. CONTROL PANEL ASSEMBLY
Refer to Disassembly and assembly.
3. TOTAL ASSEMBLY
30
Page 32
EXPLODED VIEW AND PARTS LIST
REF NO PART CODE PART NAME DESCRIPTION Q'TY
A00 3511710460 DOOR AS KOR-161G2A 1
B00 PKCPSWKN20 CONTROL PANEL AS KOR-164HBA 1
F01 3510802420 CABINET SUS430T0.5
F02 7112401011 SCREW TAPPING T1 TRS 4*10 MFZN 3
F03 3516004100 SCREW TAPPING T2S TRS LR POLE 4*10 SEMFZN 4
F04 7112403011 SCREW TAPPING T1 TRS 4*30 MFZN 2
F05 3963822200 MOTOR SAHDED POLE 120V 30W OEM-15DWX1-B07 1
F06 3512514200 GUIDE WIND PP 1
F07 3511800500 FAN PP GF20 1
F08 3513003200 HOLDER CAPACITOR SECC T0.6 1
F09 7S422X4081 SPECIAL SCREW TT2 TRS 5*8 SE MFZN 1
F10 3518400400 DIODE HV HVR-1X-3AB 12KV #187 1
F11 3518302200 CAPACITOR HV 2100VAC 0.98UF #187 1
F12 3513601500 LAMP BL 125V 25W T25 C5A H187 1
F13 3513815900 LOCK PP 1
F14 4415A17352 SW MICRO VP-533A-OF SPNO #187 200G 1
F15 4415A66910 SW MICRO VP-531A-OF/SZM-V16-FA-6 1
F16 4415A17352 SW MICRO VP-533A-OF SPNO #187 200G 1
F17 4415A6660 SW MICRO VP-532A-OF SPNO *187 200G 1
F18 3513702600 LEV ER LOCK POM 1
F19 3512714650 HARNESS MAIN KOR-161H2A 1
F20 3516003800 SPECIAL SCREW T2 FLANGE 5*8 MFZN 1
F21 3518003500 MAGNETRON RM259(JF) 1
F22 3510311800 BASE SBHG T0.8 1
F23 3516003700 SPECIAL SCREW TT3 HEX 4*9 FLG MFZN 4
F24 3518114250 TRANS HV DWARLLAO-16T 1
F25 7121400611 SCREW TAPPING T2S PAN 4*6 MFZN 1
F26 3966820200 MOTOR SYNCRO 120V 2W GM-16-12F17 1
F27 3513003400 HOLDER THERMOSTAT PBT 1
F28 3518906400 THERMOSTAT OFF : 85 ON : 75 H #187 NB 1
F29 3512101400 FOOT DASF-310 4
F30 7112401011 SCREW TAPPING T1 TRS 4*10 MFZN 5
F31 7S422X4081 SPECIAL SCREW TT2 TRS 4*8 SE MFZN 1
F32 3515202800 STOPPER HINGE UNDER AS KOR-121M0A 1
F33 3517400600 COUPLER ZAREC 1
F34 3514700710 ROLLER TEFLON 3
F35 3512517200 GUIDE ROLLER PP 1
31
Page 33
F36 4419W88004 RT AY GLASS 1350G 1
F37 3515202900 STOPPER HINGE TOP AS KOR-121M0A 1
F38 3511403200 COVER WAVE GUIDE HEATPROOF PP 1
F39 3516003700 SPECIAL SCREW TT3 HEX 4*8 FLG MFZN 2
F40 3516109810 CAVITY AS KOR-161G2A 1
F41 7122401211 SCREW TAPPING T2S TRS 4*12 MFZN 2
F42 7122401211 SCREW TAPPING T2S TRS 4*12 MFZN 1
F43 4413A90012 CLAMP POWER CORD NYLON 66 1
F44 7112401011 SCREW TAPPING T1 TRS 4*10 MFZN 1
F45 35113UHWT5 CORD POWER AS 3*14AWG90*90120-RTML 1
REF NO PART CODE PART NAME DESCRIPTION Q'TY
EXPLODED VIEW AND PARTS LIST
32
Page 34
DAEWOO ELECTRONICS CO., LTD.
PRINTED DATE: DEC, 2006
686,
AHYEON-DONG MAPO-GU SEOUL, KOREA
C.P.O BOX 8003 SEOUL, KOREA
TELEX: DWELEC K28177-8
CABLE:
“DAEWOOELEC”
S/M NO. :
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