Service Manual

S/M No. :

R868G7S001

Service Manual

Microwave Oven

Model: KOR-868G7S

Caution

: In this 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).

DAEWOO ELECTRONICS CORP.

http : //svc.dwe.co.kr

Jun. 2003

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 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.

TABLE OF CONTENTS

SAFETY AND PRECAUTIONS ...........................................................................................................................................2

1. FOR SAFE OPERATION ..................................................................................................................................2

2. FOR SAFE SERVICE PROCEDURES .............................................................................................................2

SPECIFICATIONS ...............................................................................................................................................................3

EXTERNAL VIEW................................................................................................................................................................4

1. OUTER DIMENSION.........................................................................................................................................4

2. FEATURE DIAGRAM ........................................................................................................................................5

3. CONTROL PANEL ............................................................................................................................................6

INSTALLATION ...................................................................................................................................................................7

OPERATIONS AND FUNCTIONS.......................................................................................................................................8

DISASSEMBLY AND ASSEMBLY......................................................................................................................................9

INTERLOCK MECHANISM AND ADJUSTMENT.............................................................................................................16

TROUBLE SHOOTING GUIDE .........................................................................................................................................17

MEASUREMENT AND TEST ............................................................................................................................................21

1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT ........................................................................21

2. MICROWAVE RADIATION TEST ...................................................................................................................22

3. COMPONENT TEST PROCEDURE ...............................................................................................................23

WIRING DIAGRAM............................................................................................................................................................24

PRINTED CIRCUIT BOARD..............................................................................................................................................25

1. CIRCUIT CHECK PROCEDURE ....................................................................................................................25

2. PCB CIRCUIT DIAGRAM................................................................................................................................28

3. P.C.B. LOCATION NO ....................................................................................................................................29

EXPLODED VIEW AND PARTS LIST...............................................................................................................................30

1. DOOR ASSEMBLY .........................................................................................................................................30

2. CONTROL PANEL ASSEMBLY......................................................................................................................30

3. TOTAL ASSEMBLY.........................................................................................................................................30

1

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 the dealer immediately.

IMPORTANT

The wire in this mains lead coloured in accordance with the following code.

Green-and-yellow : Each

Blue : Neutral

Brown : Live

As the colours of the wires in the manins lead of this appliance may not correspond with the coloured markings identifying the terminals in your plug, proceed as follows.

The wire which is coloured green-and-yellow must be connected to the terminal in the plug which is marked with the letter ‘E’, earth symbol or coloured green-and-yellow.

The wire which is coloured blue must be connected to the terminal which is marked with the letter ‘N’ or coloured black.

The wire which is coloured brown must be connected to the terminal which is marked with the letter ‘L’ or coloured red.

NOTE

This oven is designed for counter-top use only.

2

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

KOR-868G7S

230V-50Hz, SINGLE PHASE WITH EARTHING

1350W

900W

2450MHz

495 x 294 x 384 mm (19.5 x 11.6 x 15.1 in)

320 x 237 x 343 mm (12.6 x 9.3 x 13.5 in)

APPROX. 13.5 kg (29.7 lbs)

59 min. 99 sec.

MICROWAVE

10 LEVELS

0.9 Cu. Ft.

* SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.

3

EXTERNAL VIEW

1. OUTER DIMENSION

4

2. FEATURE DIAGRAM

1

DOOR SEAL

Door seal maintains the microwave within the oven cavity and prevents microwave leakage.

2

DOOR HOOK

When the door is closed, it will automatically lock shut. If door is opened while oven is operating, magnetron tube will immediately stop operating.

3

DOOR SCREEN

Allows viewing of food. Microwave cannot pass through perforations in screen.

4

SPATTER SHIELD

Protects the microwave outlet from splashes of cooking foods.

5

OVEN LAMP

Automatically turns on during oven operating.

6

SAFETY INTERLOCK SYSTEM

7

CONTROL PANEL

8

GLASS COOKING TRAY

Made of special heat resistant glass. The tray must always be in proper position before operating. Do not cook food directly on the tray.

9

OVEN FRONT PLATE

0

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.

q

ROLLER GUIDE

Supports the glass cooking tray.

5

3. CONTROL PANEL

1

4

5

7

0

9

8

2

3

6

1

Display

Cooking time, power level, present time are displayed.

2

Auto Cook

Used to cook using a program or to reheat.

3

Auto defrost

Used to defrost foods (by weight)

4

Power

Used to set power level.

5

Defrost

Used to defrost foods.(by time)

6

Clock

Used to set clock.

7

Time set pad

Used to set the cooking time and the present time.

8

Reheat Meal

Used to reheat meal or dinner plate.

9

Stop/Clear

Used to stop the oven operation or to delete the cooking data.

0

Start/Speedy Cook

Used to start a selected operation and also increase the reheat time by 30 seconds.

6

INSTALLATION

1. Steady, flat location.

This microwave oven should be set on a steady, flat surface.

This microwave oven is designed for counter top use only.

2. Leave space behind and side.

All air vents should be kept a clearance. If all vents are covered during operation, the oven may overheat and, eventually, cause 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 12 amperes, 230 Volts, 50 Hz.

• Power supply cord is about 0.8 meters long.

• The voltage used must be the same as specified on this oven. Using a higher voltage may result in a fire or other accident causing oven damage. Using low voltage will cause slow cooking. We are not responsible for damage resulting from use of this oven with a voltage of ampere fuse other than those specified.

• This appliance is supplied with cable of special type, which, if damaged, must be repaired with cable of same type.

Such a cable can be purchased from DAEWOO and must be installed by a qualified person.

6. Examine the oven after unpacking for any damage such as:

A misaligned door, broken door or a dent in cavity.

If any of the above are visible, DO NOT INSTALL, and notify dealer immediately.

7. Do not operate the oven if it is colder than room temperature

(This may occur during delivery in cold weather.) Allow the oven to become room temperature before operating.

EARTHING INSTRUCTIONS

This appliance must be earthed. In the event of an electrical short circuit, earthing reduces the risk of the electric shock by providing an escape wire for the electric current. This appliance is equipped with a cord having a earthing plug. The plug must be plugged into an outlet that is properly installed and earthed.

WARNING

Improper use of the earthing plug can result in a risk of electric shock. Consult a qualified electrician or serviceman if the earthing instructions are not completely understood, or if doubt exists as to whether the appliance is properly earthed, and either : If it is necessary to use an extension cord, use only a 3-wire extension cord that has a 3-blade earthing plut, and a 3-slot receptacle that will accept the plug on the appliance. The marked rating of the extension cord should be equal to or greater than the electrical rating of the appliance, or Do not use an extension cord.

7

OPERATIONS AND FUNCTIONS

This section includes useful information about oven operation.

1. Plug power supply cord into a 230V 50Hz power 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. Shut the door. Make sure that it is firmly closed.

1

When the oven door is opened, the turns off.

2

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.

3

Each time a pad is touched, a BEEP will sound to acknowledge the touch.

4

The oven automatically cook on full power unless set to a lower power level.

5

The display will show ":0" when the oven is plugged in.

6

Time clock returns to the present time when the cooking time ends.

7

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.

8

If the START pad is touched and the oven does not operate, check the area between the door and door seal for obstructions and make sure the door is closed securely. The oven will not start cooking until the door is completely closed or the program has been reset.

Make sure the oven is properly installed and plugged into the electrical outlet.

Wattage output chart

The power-level is set by pressing the POWER pad. The chart shows the display, the power level and the percentage of power.

Touch Power 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%

8

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 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 while earthed.

It is imperative, therefore, to make sure it is earthed 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.

WARNING : When servicing the appliance, need a care of touching or replacing high potential parts because of electrical shock or exposing microwave. These parts are as follows - HV Transformer, Magnetron,

HV Capacitor, HV Diode, HV fuse.

9

1. To remove cabinet

1) Remove three screws on cabinet back.

2) Push the cabinet backward.

2. To remove door assembly

1) Remove one screw 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

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).

3. To remove door parts.

REF NO.

A01

A02

A03

A04

A05

A06

A07

A08

A09

PART CODE

3512207900

2TE16A27CL

3517008200

3515204100

3511711800

3517006000

3512302000

3513100700

3515101300

PART NAME

FRAME DOOR

DOUBLE TAPE

BARRIER-SCREEN*O

DESCRIPTION

ABS SG-175 SG-0760D

0.16T X 27MM CLEAR 550M

SAN T1.5

STOPPER HINGE*T AS KOR-63150S

DOOR PAINTING AS KOR-866T0S

BARRIER-SCREEN*I

GASKET DOOR

PE 0.1T

PP

HOOK

SPRING HOOK

POM

PW1

1

1

1

1

Q’TY

1

-

1

1

1

REMARK

11

4. Method to reduce the gap between the door seal and the oven front surface.

(1) To reduce gap located on part ‘A’

Loosen a 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 .

12

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).

5. To remove control panel parts.

REF NO.

PART CODE

B01 3516911300

B02

B03

3518522240

PART NAME

BUTTON DOOR OPEN

MEMBRANE

441G430171 SPRING BUTTON

B04

B05

3516729700

3516911100

CONTROL PANEL

BUTTON FUNCTION-A

B06 PKMPMSAQ20 MAIN PCB AS

B07 7122401211 SCREW TAPPING

B08

B09

3516911200

3513703100

BUTTON FUNCTION-B

LEVER DOOR OPEN

DESCRIPTION

ABS SG-175, SG-0760D

KOR-868G7S

SWP DIA 0.7

ABS SG-175 SG-0760D

ABS SG-175 SG-0760D

KOR-868G7S

T2S TRS 4X12 MFZN

ABS SG-175 SG-0760D

PP

1

5

1

1

Q’TY

1

1

1

1

1

REMARK

13

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.

Metallic gasket plate

Magnetron antenna

Cooling fin

Filament terminal

<MAGNETRON>

14

8. To remove wind guide assembly.

1) Remove a screw for earthing.

2) Remove the noise filter from the wind guide.

3) Remove a screw which secure the wind guide assembly.

4) Draw forward the wind guide assembly.

5) Pull the fan from the motor shaft.

6) Remove two screws which secure the motor shaded pole.

7) Remove the motor shaded pole.

8) 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.

15

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 “OFF” condition and 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 opened before other switches are closed.

When the door is opened, the interlock monitor switch should be closed after other switches are opened.

(3) Adjustment steps a) Loosen the mounting screw.

b) Adjust interlock switch assembly position.

c) Make sure that lock lever moves smoothly after adjustment is completed.

d) Tighten completely the mounting screw.

NOTE :

Microwave emission test should be performed after adjusting interlock mechanism. If the microwave smission exceed

4mW/cm 2 , readjust interlock mechanism.

16

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.

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.

(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

Check continuity of both primary and secondary interlock switch with door colosed

Check continuity of primary interlock switch contact with door partially open until interlock monitor switch contact close

(COM

NO)

Check continuity of primary winding of low voltage transformer

Disconnect high voltage fuse and operate the unit

RESULT

Continuity

No Continuity

No Continuity

Continuity

Continuity

0

Ω or infinite

Approx.

1160

(normal)

Fuse again blows

CAUSE

Malfunction of interlock monitor switch

Malfunction of interlock switch

Shorted contacts of primary interlock switch.

Defective low voltage transformer

Defective low voltage transformer

REMEDY

Replace

Replace

Replace

Replace

Replace

17

CONDITION

Outlet has proper voltage Fuse does not blow.

CHECK

Check continuity of magnetron

Check continuity of noise filter board

Check continuity of power supply cord

RESULT

No

Continuity

No

Continuity

No

Continuity

Normal

CAUSE

Defective magnetron

Defective magnetron

Open power supply cord

Defective touch control circuit

REMEDY

Replace

Replace

Replace

Replace

NOTE

All these switches must be replaced at the same time, please refer to “Interlock Mechanism And Adjustment”.

(TROUBLE 2) Display shows all figures selected, but oven does not start cooking, even though desired program and time are set and start button is pressed.

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

18

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

CONDITION

No microwave oscillation

CHECK

Check continuity of high voltage fuse

Replace high voltage fuse

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

RESULT

Continuity

Continuity

Continuity in backward direction

Continuity

0

Ω or

No

Continuity

Check continuity of filament terminal of high voltage transformer

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

No

Continuity

0 V

Approx

-15 VDC

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

19

(TROUBLE 4) The following visual conditions indicate a probable defective touch control circuit or membrane switch assembly.

1 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.

1 2. A distinct change in the display are not on when they numbers is the display.

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

M/W Def.

1 4. Display indicates a number different from one touched.

1 5. Specific numbers (for example 2 or 3) will not display when the button is touched.

1 6. Display does not count down or up with time cooking or clock operation.

1 7. Oven is programable and cooks normally but no display shows.

1 8. Display obviously jumps in time while counting down.

Lock g

1 9. Display counts down noticeably too fast while cooking.

10. Display does not show the time of day when cancel button 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

Display does not show programming at all, even if membrane 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 the P.C.B main-assembly

REMEDY

Replace the

P.C.B mainassembly

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.

20

MEASUREMENT AND TEST

1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT

Microwave output power can be checked by indirectly measuring the temperature rise of a certain amount of water exposed to the microwave as directed below.

PROCEDURE

1. Microwave power output measurement is made with the microwave oven supplied at rated voltage and operated at its maximum microwave power setting with a load of 1000±5cc of potable water.

2. The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190 mm.

3. The oven and the empty vessel are at ambient temperature prior to the start of the test.

The initial temperature of the water is 10±2˚C (50±3.6˚F)

It is measured immediately before the water is added to the vessel.

After addition of the water to the vessel, the load is immediately placed on the center of the shelf, which is in the lowest normal position.

4. Microwave power is switched on.

5. Heating time should be exactly A seconds. (Refer to table as following)

Heating time is measured while the microwave generator is operating at full power.

The filament heat-up time for magnetron is not included.

6. The initial and final temperature of water is selected so that the maximum difference between the ambient and final water temperature is 5K.

7. The microwave power output P in watts is calculated from the following formula :

P=4187 X

T/t

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%.

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

21

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.

PROCEDURES

1. Prepare Microwave Energy Survey Meter, 600cc glass beaker, and glass thermometer 100˚C(212˚F).

2. Pour 275cc±15cc of tap water initially at 20±5˚C(68±9˚F) in the 600cc glass beaker with an inside diameter of approx.

95mm(3.5in.).

3. Place it at the center of the tray and set it in a cavity.

4. Close the door and operate the oven.

5. Measure the leakage by using Microwave Energy Survey

Meter with dual ranges, set to 2450MHz.

1) Measured radiation leakage must not exceed the value prescribed below. Leakage for a fully assembled oven with door normally closed must be less than 4mW/cm 2 .

2) When measuring the leakage, always use the 5cm(2in.) space cone with probe. Hold the probe perpendicular to the cabinet and door. Place the space cone of the probe on the door, cabinet, door seem, door viewing screen, the exhaust air vents and the suction air vents.

3) Measuring should be in a counter-clockwise direction at a rate of 1 in./sec. If the leakage of the cabinet door seem is unknown, move the probe more slowly.

4) When measuring near a corner of the door, keep the probe perpendicular to the areas making sure the probe end at the base of the cone does not get closer than 2 in. from any metal. If it does not, erroneous reading may result.

22

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. 140

±10%

Filament winding....................................Approx. 0

Primary winding .....................................Approx. 2

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 is 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

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.

23

WIRING DIAGRAM

24

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 : 230V/Frequency : 50Hz

Terminal Voltage

4-7

LOAD

DC 12 V

NO LOAD

AC 30.5 V

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.

2. Voltage check

• Key check point

NO

1

2

CHECK POINT

IC 1 PIN 2, 21, 30, 34

IC 1 PIN 35

REMARK

-5 VDC

T:20ms(50Hz)

3 IC 1 PIN 31 OR 32

T:250ns(4MHz)

• Check method

NO MEASURE POINT

1

2

MP1

MP2

WAVE FORM

DC -5V±0.25V

DC -12V±2.0V

REMEDY

Replace VL1, EC1

Replace EC2, D12, D13, D14

REMARK

NO LOAD

NO LOAD

NOTE :

Each measure point must be measured with GND point.

25

MP2

MP1

Measure Point

26

3. When there is no microwave oscillation

1) When touching START pad, oven lamp does not turn on.

Fan motor does 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 -5 VDC

RELAY 2 OFF 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 -5VDC

RELAY 1 OFF GND

B

GND

-12 VDC

B

GND

-12 VDC

4. When the door is opened during operation, the count down timer does not stop.

→ refer to Circuit Diagram (Point 1)

-Check method

POINT

STATE

1) DOOR OPEN

2) DOOR CLOSED

A

OPEN

CLOSE

CHECK NO

1

METHOD

Check the stage (ON, OFF) of the door open monitor switch by resistance measurement.

B

-5VDC

GND

REMEDY

Replace door open monitor switch.

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 R26, R27, C5.

POINT

A

WAVE FORM

T:20ms(50Hz)

27

2. PCB CIRCUIT DIAGRAM

28

3. P.C.B. LOCATION NO.

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).

NO.

1 BUZZER

NAME

2 C ARRAY

3 CAPACITOR CERA

BZ1

CA1

C5

SYMBOL

4 CAPACITOR CERA

5 CAPACITOR ELEC

C1~4,6

EC1

6 CAPACITOR ELEC EC2

7 CONNECTOR WAFER CN1

8 CONNECTOR FILM CN2

9 CONNECTOR WAFER CN3

10 DIODE RECTIFY D1~7,9~12

11 DIODE RECTIFY

12 DIODE ZENER

D13,14

ZD1

13 DIODE ZENER

14 IC MICOM

15 IC REGULATOR

16 LED DISPLAY

17 PCB MAIN

ZD2

IC1

VL1

DP1

M304

18 R ARRAY

19 REGISTER

20 REGISTER

21 REGISTER

22 REGISTER

23 REGISTER

24 REGISTER

25 REGISTER

RA1

R8~10,16~19

R1,2,6,12,21

R3,22,23

R11

R13,14

R15

R7

26 REGISTER

27 REGISTER

R4

R20

28 RESONATOR CERA CR1

29 SW RELAY

30 SW RELAY

31 SW TACT

32 TRANSISTOR

RY1

RY2

SW1~3

Q1~5,8~10

33 TRANSISTOR

34 TRANS POWER

35 WIRE COPPER

36 WIRE COPPER

37 WIRE COPPER

38 WIRE COPPER

SPECIFICATION

BM-20K

7P(6) 1000PF M 50V

102 50V Z AXIAL

104 50V Z AXIAL

50V RS 1MF

25V RSS 1000MF

YW396-02V

FCZ 254-11

YW396-05AV

1N4148

KN4004A

UZ- 5.1BSB 1/2W

3519150510

DZN4148---

1

11

DZN4004A-2

DZUZ5R1BSB 1

UZ- 3.9BSB 1/2W DZUZ3R9BSB 1

TMP47C440BN-3J52 13GS632GH0 1

MC7905C

DDG-631H01

92X161

1MC7905C--

DDDG631H01

3514321190

1

1

1

7P(6) 1/8 100K J

1/6W 220 5%

1/6W 1K 5%

1/6W 100K 5%

1/6W 200 5%

1/6W 10K 5%

1/6W 510 5%

1/6W 1M 5%

1/6W 4.7K 5%

1/4W 51 5%

CRT 4.00MS

G5G-1A DC12V

CS11-12SH 1C 1P

JTS1230U(SEALED)

KRA-106M

Q6

LVT1

KTA-1266Y

DMR-631FS

J1,2,4,11,12,16~18,21 1/0.52 TIN COATING

J3,7,8,10,13~15,19,20 1/0.53 TIN COATING

J5,6,9

SJ1

1/0.54 TIN COATING

1/0.52 TIN COATING

PART CODE Q'TY REMARK

3515600100 1

CN6XB-102M 1

CCZB1H102K 1

CCZF1H104Z 5

CEXE1H109A 1

CEXF1E102V 1

3519150520 1

441M367160 1

RA-87X104J

RD-AZ221J-

RD-AZ102J-

RD-AZ104J-

RD-AZ201J-

RD-AZ103J-

RD-AZ511J-

RD-AZ105J-

RD-AZ472J-

RD-4Z510J-

TZTA1266Y-

5EPV035303

85801052GY

85801053GY

85801054GY

85801052GY

1

7

5

3

1

3

1

1

1

1

5P4R00MTS1

5SC0101121

5SC0101128

5S50101201

TZRA106M--

1

1

3

8

1

1

9

9

3

1

7.5MM

10MM

12.5MM

7.5MM

29

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

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).

REMARK

F38

F39

F40

F41

F42

F43

F44

F29

F30

F31

F32

F33

F34

F35

F36

F37

F45

F46

F47

F48

F22

F23

F24

F25

F26

F27

F28

F14

F15

F16

F17

F18

F19

F20

F21

F05

F06

F07

F08

F09

F10

F11

F12

F13

REF NO.

PART CODE

A00 3511712790

B00

F01

PKCPSWAQ20

3510805400

PART NAME

DOOR AS

CONTROL-PANEL AS

CABINET

F02

F03

F04

7112401011

3516109900

7112401011

SCREW TAPPING

CAVITY AS

SCREW TAPPING

7122401211

7122401211

4413A90012

7112401011

7122401211

4415D67620

3518606200

SCREW TAPPING

SCREW TAPPING

7112401011 SCREW TAPPING

35113AEQ0D CORD POWER AS

CLAMP POWER CORD

SCREW TAPPING

SCREW TAPPING

FUSE

NOISE-FILTER

7121402511

3963512310

3512517000

3511800300

3518003700

3516004000

7272400811

3513003200

3518302200

3518400400

3518701100

3518119340

3516003700

3510311900

7112401011

SCREW TAPPING

MOTOR SHADED POLE

GUIDE WIND

FAN

MAGNETRON

SPECIAL SCREW

TAPTITE SCREW

HOLDER HV CAPACITOR

CAPACITOR HV

DIODE HV AS

FUSE HV

TRANS HV

SPECIAL SCREW

BASE

SCREW TAPPING

DESCRIPTION

KOR-868G7S

KOR-868G7S

KOR-86150S

T1 TRS 4X10 MFZN

KOR-86150S

T1 TRS 4X10 MFZN

T2S TRS 4X12 MFZN

T2S TRS 4X12 MFZN

T1 TRS 4X10 MFZN

3X0.75 70X70 100-RTML

NYLON66

T1 TRS 4X10 MFZN

T2S TRS 4X12 MFZN

250V 10A

DWLF-M12

T2S PAN 4X25 MFZN

230V 20W MW10CA-M02

PP

PP+30%GLASS

2M218JFL

T2 BOLT FLANGE 5X12 DACRO

TT3 TRS 4X8 MFZN

SECC T0.6

2100VAC 0.98UF #187

HVR-1X-3AB 12KV #187

5KV 0.55A HV-41A55-02

DW-R90S0-86T A

TT3 HEX 4X8 FLG MFZN

SBHG T0.8

T1 TRS 4X10 MFZN

3512100900

7272400811

3515201101

4415A17352

4415A66910

4415A17352

3513702600

3513811700

3518571000

3513601600

7121400611

3966030900

3518905300

3513003400

7272400811

3511406200

3517400620

3514700900

3512509210

3517203500

FOOT

TAPTITE SCREW

STOPPER HINGE *U

SW MICRO

SW MICRO

SW MICRO

LEVER LOCK

LOCK

SWITCH PUSH

LAMP

SCREW TAPPING

MOTOR SYNCRO

THERMOSTAT

HOLDER THERMOSTAT

TAPTITE SCREW

COVER WAVE GUIDE

COUPLER

ROLLER

GUIDE ROLLER

TRAY

PP DASF-130

TT3 TRS 4X8 MFZN

SCP-1 T2.5

VP-533A-OF SPNO #187 200

VP-531A-OF /SZM-V16-FA-61

VP-533A-OF SPNO #187 200

POM

POM BLACK

MP101C

BL 240V 25W T25 C7A H187

T2S PAN 4X6 MFZN

220-240V 50/60HZ TYJ50-8A7

OFF:75 ON:65 H #187 NB

PP(NATURAL)

TT3 TRS 4X8 MFZN

PP J640A WHITE

XAREC

TEFLON

PP 5113MF6,A353B

GLASS

1

5

1

4

1

1

1

1

1

1

1

1

1

2

1

1

1

1

1

1

1

1

1

1

Q'TY

1

1

1

3

1

1

1

1

1

1

1

1

1

1

1

1

3

1

1

1

1

1

1

2

1

1

31

S/M No. : R868G7S001

DAEWOO ELECTRONICS CORP.

686, AHYEON-DONG MAPO-GU SEOUL, KOREA

C.P.O. BOX 8003 SEOUL, KOREA

TELEX: DWELEC K28177-8

CABLE: “DAEWOOELEC”

PRINTED DATE: Jun. 2003

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