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

POWER SUPPLY

POWER

CONSUMPTION

MICROWAVE

GRILL

COMBINATION

MICROWAVE ENERGY OUTPUT

MICROWAVE FREQUENCY

OUTSIDE DIMENSIONS (W X H X D)

CAVITY DIMENSIONS (W X H X D)

NET WEIGHT

TIMER

FUNCTION SELECTIONS

POWER SELECTIONS

CAVITY VOLUME

* Specifications are subject to change without notice.

KOR-180A2A/181G2A/181H2A

120V~60HZ, SINGLE PHASE WITH EARTHING

1600 W

1200 W

2450MHz

589X339X487mm (23.2X13.3X19.2 in.)

399X278X451mm (15.7X10.9X17.8 in.)

APPROX. 18.0kg (39.7 lbs.)

99min. 99sec.

MICROWAVE

10 LEVELS

1.8 Cu. Ft

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

AUTO

COOK

MORE

LESS

POPCORN

FROZEN

PIZZA

DINNER

PLATE

MEAT

AUTO DEFROST

POULTRY FISH

POWER

DEFROST

1 2 3

4 5 6

7 8 9

KITCHEN

TIMER

0

CLOCK

STOP/

CLEAR

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.

8

(3) KOR-181H2A

M/W DEF TIMER LOCK lb

MICROWAVE OVEN KOR-181H

BEVERAGE

FRESH

VEGETABLE

FROZEN

VEGETABLE

MORE

LESS

POPCORN

FROZEN

PIZZA

DINNER

PLATE

MEAT

AUTO DEFROST

POULTRY FISH

POWER

DEFROST

1 2 3

4 5 6

7 8 9

KITCHEN

TIMER

0

CLOCK

STOP/

CLEAR

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. 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.

Once

Twice

3 times

4 times

5 times

6 times

7 times

8 times

9 times

10 times

11 times

Power level(Display)

P-HI

P-90

P-80

P-70

P-60

P-50

P-40

P-30

P-20

P-10

P-00

Approximate Percentage of Power

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

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.

PART CODE

A01 3512205100

A02

A03

3517007400

3515204400

A04

A05

A06

A07

A08

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

(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.

DESCRIPTION

ABS SG-175, SG-0760D

SAN T1.5

KOR-162JOA

KOR-180A

PE T0.1

PP

POM

RW-1

1

1

1

1

1

Q’TY REMARK

1

1

1

14

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/cm 2 .

15

5. To remove control panel parts.

REF NO.

PART CODE

3518522800

B01

B02

B03

B04

B05

B06

B07

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/cm 2 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/cm 2 , 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

Fuse blows.

CHECK

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

Disconnect one side of the lead wire connected form high voltage transformer to the high voltage capacitor and operate the unit

RESULT

Continuity

No Continuity

Continuity

0

Ω or infinite

Approx.

150~310

(normal)

Normal

Fuse again blows

CAUSE

Malfunction of interlock monitor switch

Shorted contacts of primary interlock switch.

Defective low voltage transformer

Defective high voltage capacitor

Defective high voltage transformer

REMEDY

Replace

NOTE 1

Replace

NOTE 1

Replace

Replace

Replace

20

CONDITION

Outlet has proper voltage Fuse does not blow.

CHECK

Check continuity of magnetron

Check continuity of power supply cord

Display do not shown countdown

RESULT

No

Continuity

No

Continuity

Normal

CAUSE

Defective magnetron

Open power supply cord

Defective touch control circuit

Malfunction of secondary interlock switch

REMEDY

Replace

Replace

Replace

Replace

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

Turn table motor and oven lamp do not turn on

CHECK

Check continuity of primary interlock switch

Check continuity of secondary interlock switch

Check D.C. voltage being supplied to RELAY (RY2) coil

RESULT

No

Continuity

No

Continuity

0 V

Approx.

15 VDC

CAUSE

Malfunction of primary interlock switch

Malfunction of secondary interlock switch

Defective touch control circuit

Faulty contacts of

RELAY (RY2) or open relay coil

REMEDY

Adjust or replace

Adjust or replace

Replace

Replace

21

(TROUBLE 3) No microwave oscillation even though fan motor rotates.

CONDITION

No microwave oscillation

CHECK

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

Check continuity of filament terminal of high voltage transformer

RESULT

Continuity

Continuity in backward direction

Continuity

0

Ω or

No

Continuity

No

∞

Continuity

0 V

Check D.C. voltage being supplied to RELAY (RY1) coil

Approx

15 VDC

CAUSE

Defective high voltage transformer

Defective high voltage rectifier

Defective magnetron

Defective high voltage transformer

Defective magnetron

Defective high voltage transformer

Defective touch control circuit

Faulty contacts or

RELAY (RY1) or open relay coil

REMEDY

Replace

Replace

Replace

Replace

Replace

Replace

Replace

Replace

22

(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.

3. One or more digits in the display are not on when they should be.

M/W DEF TIMER LOCK lb

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

Display does not show programming at all, even if keyboard is touched.

CHECK

Check each pad for continuity of the membrane keyboard for the following keyboard check procedure

RESULT

Normal

Abnormal

CAUSE

Malfunction of touch control circuit of control box sub-assembly

Malfunction of the membrane keyboard

REMEDY

Replace control box sub-assembly

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)

B (W)

70

600

64

650

60

700

56

750

52

800

49

850

47

900

44

950

42

1000

40

1050

38

1100

35

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/cm 2 .

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 10M

Ω once the capacitor charged.

3) A shorted capacitor will show continuous continuity.

4) An open capacitor will show constant 10M

Ω

.

5) Resistance between each terminal and chassis should be infinite.

3. High voltage diode

1) Isolate the diode from the circuit by disconnecting the leads.

2) With the ohmmeter set on the highest resistance scale measure the resistance across the diode terminals.

Reverse the meter leads and again observe the resistance reading. Meter with 6V, 9V or higher voltage batteries should be used to check the front-back resistance of the diode, otherwise an infinite resistance may be read in both directions. A normal diode's resistance will be infinite in one direction and several hundred k

Ω in the other direction.

4. Magnetron

For complete magnetron diagnosis, refer to "Measurement of the Microwave Power Output." Continuity checks can only indicate and open filament or a shorted magnetron. To diagnose for an open filament or a shorted magnetron,

1) Isolate magnetron from the circuit by disconnecting the leads.

2) A continuity check across magnetron filament terminals should indicate 0.1

Ω or less.

3) A continuity check between each filament terminal and magnetron case should read open.

5. Fuse

If the fuse in the primary and monitor switch circuit is blown when the door is opened, check the primary and monitor switch before replacing the blown fuse. In case the fuse is blown by an improper switch operation, replace the defective switch and fuse at the same time. Replace just the fuse if the switches operate normally.

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

4-7

LOAD

AC 12.6 V

NO LOAD

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

2

IC1 PIN 2, 21, 30, 34

IC1 PIN 35

-5VDC

REMARK

T : 16.67ms(60Hz)

3 IC1 PIN 31 OR 32

T : 250 ns(4MHz)

- Check method

NO

1

2

MEASURE POINT

MP1

MP2

WAVE FORM

DC -5V±0.25V

DC -12V±2.0V

REMEDY

Replace VL1, EC1

Replace EC2, D12,13,14

REMARK

NO LOAD

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

STATE

A

RELAY 2 ON

RELAY 2 OFF

-5VDC

GND

2) When touching START pad, oven lamp turns on.

Fan motor and turntable rotate and cook indicator in display comes on.

✻ Cause : RELAY 1 does not operate. → refer to Circuit Diagram (point 2)

- Check method

POINT

STATE

A

RELAY 1 ON

RELAY 1 OFF

-5VDC

GND

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

A

1) DOOR OPEN

2) DOOR CLOSED

OPEN

CLOSE

CHECK NO

1

HETHOD

Check the stage(ON, OFF) of the secondary interlock switch by resistance measurement.

B

GND

-12VDC

B

GND

-12VDC

B

-5VDC

GND

REMEDY

Replace door open monitor switch.

5. When the digital clock does not operate properly.

→ refer to Circuit Diagram (point 5)

POINT WAVE FORM

A

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

1

2

3

4

5

BUZZER

NAME

C ARRAY

CAPACITOR ELEC

CPAPCITOR ELEC

CONNECTOR WAFER

8

9

6

7

CONNECTOR WAFER

CONNECTOR WAFER

DIODE RECTIFY

DIODE RECTIFY

10 DIODE ZENER

11 DIODE ZENER

12 LED DISPLAY

13 PCB MAIN

14 R ARRAY

15 RESISTOR

16 RESISTOR

17 RESISTOR

18 RESISTOR

19 RESISTOR

20 RESISTOR

21 RESISTOR

22 RESISTOR

23 REGULATOR

24 TRANSISTOR

25 TRANSISTOR

26 TRANS POWER

27 WIRE COPPER

28 WIRE COPPER

29 IC MICOM

30 RESONATOR CERA

31 SW RELAY

32 SW RELAY

33 CAPACITOR CERA

34 CAPACITOR CERA

35 RESISTOR

SYMBOL

BZ1

CA1

EC1

EC2

CN1

SPECIFICATION

BM-20K

7P(6) 102 M 50V

50V RS 1µF

25V RSS 1000µF

YW396-02AV

CN3

CN2

YW396-05AV

FCZ254-11

D1~6, 9~12,15 1N4148

D13, 14 1N4004A

ZD1

ZD2

UZ-5.1BSB

UZ-3.9BSB

DP1

M158

RA1

R1~R7

DDG-631H

81.5X139.9

7P(6) 1/8 100K J

1/6W 330 5%

R8, 10, 12, 14, 22 1/6W 1K 5%

R11, 20, 21

R13

1/6W 100K 5%

1/6W 100 5%

R15~16

R17

R18

R19

1/6W 10K 5%

1/6W 510 5%

1/6W 1M 5%

1/4W 51 5%

VL1 MC7905C

Q1~5, 9~11 KRA-102M

Q6 KTA-1266Y

LVT1 DMR-631FS

J1~3,5~8,10~12,17~21 1/0.52 TIN COATING

SJ2, 3, 5

IC1

CR1

RY1

1/0.52 TIN COATING

TMP47C440BN-3FC2

CRT 4.00MS

G5G-1A DC 12V

RY2

C6

CS11-12SH 1C 1P

102 50V Z AXIAL

C1, C3~C5, C7 104 50V Z AXIAL

R23 1/6W 4.7K 5%

PART CODE Q’TY

3515600100 1

CN6XB-102M

CEXE1H109V

CEXF1E102V

3519150520

1

1

1

1

3519150510

441M367160

DZN4148---

DZN4004A--

DZUZ5R1BSB 1

DZUZ3R9BSB 1

1

1

11

2

DDDG631H01

3514315410

RA-87X104J

RD-AZ331J-

RD-AZ102J-

RD-AZ104J-

RD-AZ101J-

1

7

1

1

5

3

1

RD-AZ103J-

RD-AZ511J-

RD-AZ105J-

RD-4Z510J-

1MC7905C--

TZRA102M--

TZTA1266Y-

5EPV035303 1

85801052GY 15

85801052GY

13GS181GH0

2

1

5P4ROOMTS1

5SC0101121 2

5SC0101128

CCZB1H102K

CCZF1H104Z

RD-AZ472J-

5

1

1

1

1

1

3

1

1

8

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

F23

F24

F25

F26

F27

F28

F29

F30

F31

F32

F16

F17

F18

F19

F20

F21

F22

F09

F10

F11

F12

F13

F14

F15

F03

F04

F05

F06

F07

F08

REF NO PART CODE

A00

B00

F01

F02

3511715500

3511715510

3516726410

3516726420

3516726430

3510802400

3516004100

PART NAME

DOOR AS

DOOR AS

CONTROL-PANEL AS

CONTROL-PANEL AS

CONTROL-PANEL AS

CABINET

SPECIAL SCREW

7121403011

3963822200

3512522100

3511800100

3518003500

3516004000

7272400811

3513003200

3518302300

3518400110

3516113110

7122401211

7122401211

7122401011

CAVITY AS

SCREW TAPPING

SCREW TAPPING

SCREW TAPPING

35113UANT5 CORD POWER AS

7122401211 SCREW TAPPING

FUSE

SCREW TAPPING

MOTOR SHADED POLE

GUIDE WIND

FAN

MAGNETRON

SPECIAL SCREW

3518117610

3516003700

SCREW TAPTITE

HOLDER HV CAPACITOR

CAPACITOR HV

DIODE HV

HARNESS B

TRANS HV

SPECIAL SCREW

3510311800

7112401011

3512101400

7272400811

3515204500

3512706120

4415A17352

4415A66600

3518571000

3513702600

BASE

SCREW TAPPING

FOOT

SCREW TAPTITE

STOPPER HINGE *U AS

HARNESS MAIN

SW MICRO

SW MICRO

SWITCH PUSH

LEVER LOCK

DT-N12A0-18T

TT3 HEX 4X8 FLANGE MFZN

SBHG T0.8

T1 TRS 4X8 MFZN

PP DASF-310

TT3 TRS 4X8 MFZN

KOR-162J0A

KOR-180A2A

VP-533A-OF SPNO #187 200G

VP-532A-OF SPNO #187 200G

MP101C

POM

DESCRIPTION

KOR-180A0A (KOR-180A2A)

KOR-181H2A (KOR-181G2A / KOR-181H2A)

KOR-180A2A

KOR-181G2A

KOR-181H2A

SECC T0.6

T1 TRS LR4 POLE 4X10 SE MFZN

KOR-180A2A

T2S TRS 4X12 MFZN

T2S TRS 4X12 MFZN

T1 TRS 4X10 MFZN

3X14AWG 40X40 120-RTML

T2S TRS 4X12 MFZN

65TS 125V 20A

T2S PAN 4X30 MFZN

120V 30W OEM-15DWX1-B07

PP J640A

PP+20%GLASS

RM 259(JF)

T2 BOLT FLANGE 5X12 DACRO

TT3 TRS 4X8 MFZN

SECC T0.6

2100VAC 1.1UF #187

HVR-1X-70B 10KV #187

34

1

1

1

1

1

1

2

1

1

1

1

1

1

Q'TY

1

1

3

1

1

1

1

4

1

1

5

1

1

1

1

1

1

1

1

4

1

1

1

1

F40

F41

F42

F43

F44

F45

F46

REF NO PART CODE

F33

F34

F35

F36

F37

F38

F39

3513814300

3513601500

7121400611

3966830700

3518905300

3513003400

7272400811

3511406220

3517402000

3514700710

3512517200

3517207700

3518903400

7121300811

PART NAME

LOCK

LAMP

SCREW TAPPING

MOTOR SYNCRO

THERMOSTAT

HOLDER THERMOSTAT

SCREW TAPTITE

COVER WAVE GUIDE

COUPLER

ROLLER

GUIDE ROLLER

TRAY

THERMOSTAT

SCREW TAPPING

DESCRIPTION

POM BLACK

BL 125V 25W T25 C5A #187

T2S PAN 4X6 MFZN

120V 3W SM012

OFF:75 ON:65 H #187 NB

PP (NATURAL)

TT3 TRS 4X8 MFZN

PP J640A WHITE

QUESTRA

TEFRON

PP

GLASS

OFF: 150 ON: 60 V #187

T2S PAN 3X8 MFZN

3

1

1

1

1

1

2

Q'TY

1

1

1

1

1

1

1

35

VISION CREATIVE, INC.

S/M NO.:R180A2A001

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: Aug, 2001