Daewoo KOC-924T0S, KOC-924Т, KOC-924T, KOC-924T5S Service Manual

S/M No. : C910K0S001

Service Manual

Microwave Oven

Model: KOC-924T0S

KOC-924T5S

DAEWOO ELECTRONICS CO., LTD.

S/M No. : C924T0S001

http : //svc.dwe.co .kr Mar . 2002

✔

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).

1

PRECA UTIONS T O BE OBSERVED BEFORE AND
DURING SER VICING T O AVOID POSSIBLE
EXPOSURE T O EXCESSIVE MICROW AVE 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.

TABLE OF CONTENTS

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

2. SPECIFICATIONS ........................................................................................................................................................3

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

3-1. OUTER DIMENSION..........................................................................................................................................4

3-2. FEATURE DIAGRAM .........................................................................................................................................5

4. INSTALLATION............................................................................................................................................................6

5. CONTROL PANEL .......................................................................................................................................................7

6. DISASSEMBLY AND ASSEMBLY..............................................................................................................................8

7. INTERLOCK MECHANISM AND ADJUSTMENT.....................................................................................................17

8. TROUBLE SHOOTING GUIDE..................................................................................................................................18

9. MESUREMENT AND TEST .......................................................................................................................................23

9-1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT........................................................................23

9-2. MICROWAVE RADIATION TEST....................................................................................................................24

9-3. COMPONENT TEST PROCEDURE................................................................................................................25

9-4. COMPONENT ACTION....................................................................................................................................26

10. WIRING DIAGRAM...................................................................................................................................................27

11. EXPLODED VIEW AND PARTS LIST.....................................................................................................................28

11-1. DOOR ASSEMBLY.........................................................................................................................................28

11-2. CONTROL PANEL ASSEMBLY.....................................................................................................................28

11-3. TOTAL ASSEMBLY........................................................................................................................................28

12. PRINTED CIRCUIT BOARD ....................................................................................................................................31

13. P.C.B CIRCUIT DIAGRAM.......................................................................................................................................35

2

1. SAFETY AND PRECA UTIONS

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.

(1) inform the manufacturer, importer or assembler,

(2) repair the unit at no cost to the owner,

(3) attempt to ascertain the cause of the excessive leakage,

(4) 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 immediately.

IMPORTANT

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

Green-and-yellow : Earth
Blue : Neutral

Brown : Live
As the colours of the wires in the mains 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.

3

2. SPECIFICATIONS

MODEL KOC-924T0S
POWER SUPPLY 230V~50HZ, SINGLE PHASE WITH EARTHING

MICROWAVE 1500W
POWER GRILL 1150W
CONSUMPTION CONVECTION 2550W

COMBINATION 3000W
MICROWAVE ENERGY OUTPUT 1000W(IEC705)
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 542X329X515mm (21.3X13.0X20.3 in.)
CAVITY DIMENSIONS (W X H X D) 350X230X355mm (13.8X9.1X14.0 in.)
NET WEIGHT APPROX. 20kg (44.1 lbs.)
TIMER 60 minutes
FUNCTION SELECTIONS MICROWAVE/ GRILL/ CONVECTION/ COMBINATION
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.0 Cu. Ft

MODEL KOC-924T5S
POWER SUPPLY 230V~50HZ, SINGLE PHASE WITH EARTHING

MICROWAVE 1500W
POWER GRILL 1150W
CONSUMPTION CONVECTION 1450W

COMBINATION 1500W
MICROWAVE ENERGY OUTPUT 1000W(IEC705)
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 542X329X515mm (21.3X13.0X20.3 in.)
CAVITY DIMENSIONS (W X H X D) 350X230X355mm (13.8X9.1X14.0 in.)
NET WEIGHT APPROX. 20kg (44.1 lbs.)
TIMER 60 minutes
FUNCTION SELECTIONS MICROWAVE/ GRILL/ CONVECTION/ COMBINATION
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.0 Cu. Ft

* Specifications are subject to change without notice.

4

3. EXTERNAL VIEW

542

329

515

1. OUTER DIMENSION

- KOC-924T0S/KOC-924T5S

5

11.DOOR HOOK

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

12.DOOR VIEWING SCREEN

Allows viewing of food. The screen is designed so that light can pass through, but not the microwave.

13.METAL RACK

14.TOP HEATER

Turns on when convection, grill and combi cooking is selected.

15.OVEN LAMP

Automatically turns on during oven operating.

16.SAFETY INTERLOCK SYSTEM

17.CONTROL PANEL

18.TURNTABLE TRAY

Rotates during cooking and ensure even distribution of Microwaves.
It can also be used as a cooking utensil.

19.ROLLER GUIDE

This must always be used for cooking together with the turntable tray.

10. COUPLER

This fits over the shaft in the center of the ovens cavity floor. This is to remain in the oven for all cooking.

11. CONVECTION OUTLET & FAN

12. OVEN FRONT PLATE

13.DOOR SEAL

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

2. FEATURE DIAGRAM

6

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 15(KOC-924T0S)/
12(KOC-924T5S) amperes, 230V, 50Hz.

• Power supply cord is about 1.2 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 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 wire with a
earthing plug. The plug must be plugged into an outlet that is properly installed and earthed.

4. INSTALLATION

EARTHING INSTR UCTIONS

WARNING

Improper use of the earthing plug can result in a risk of electric shock.
Consult a qualified electrician of 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 plug, 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

5. CONTROL PANEL

1
2

3

4
5
6

7
8

9

10

11

12

13

14

16

17

18

15

19

2120

Defrost

MW

Auto

Cook

Auto Cook Menu

Weight
Defrost

Auto Cook

Combi

Grill

MW

Convection

Time

Defrost

Clock

STOP/CLEAR START/ SPEEDY COOK

1. Roast pork

2. Roast beef

3. Roast chicken

4. Baked fish

5. Fresh vegetable

Con-

vection

Lock

g

Grill Combi Weight Time

Indicators on the display window

11

COMBI - When blinking, the oven is operating in
COMBI mode.

22

GRILL - When blinking, the oven is operating in
GRILL mode.

33

MW - When blinking, the oven is operating in

MICROWAVE COOK mode.

44

Auto Cook - When blinking, the oven is operating in

AUTO COOK mode.

55

Lock - When lighting, the oven is in CHILD LOCK
mode.

66

Convection - When blinking, the oven is operating in

CONVECTION mode.

77

Defrost Weight - When blinking, the oven is

operating in WEIGHT DEFROST mode.

88

Defrost Time - When blinking, the oven is operating

in TIME DEFROST mode.

99

DISPLAY - Cooking time, power level, indicators and

time are displayed

00

g - When blinking, you can input the weight of food

for cooking.

Buttons on the control panel

qq

AUTO COOK - Press to select the auto cook menu.

ww

COMBI - Press to select the combi cooking mode.

ee

GRILL - Press to select the grill cooking mode.

rr

MW - Press to select a microwave power level.

tt

CONVECTION - Press to select convection

temperature.

yy

WEIGHT DEFROST - Press to select the weight
defrosting cooking.

uu

TIME DEFROST - Press to select the time defrosting

cooking.

ii

CLOCK - Press to set the clock.

oo

DIAL KNOB - Turn the dial knob to the cooking time,

the weight of food or the quantity of food.

pp

STOP/CLEAR - Press to stop the oven operation or

to delete programmed cooking data.

aa

START/SPEEDY COOK - Press to start a
programmed cooking or for the speedy start(In the
case, the microwave cooking time increases to 5
minutes by 30 seconds every pressing).

- KOC-924T0S/KOC-924T5S

8

6. 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 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, 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.

1. T o remo ve cabinet

1) Remove four screws on cabinet back.

2) Push the cabinet backward.

2. T o remo ve door assembl y

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 assemby.

9

NOTE: After replacing the door assembly, perform a check

of correct alignment with the hinge and cavity front
plate.

10

3. T o remo ve door parts.

KOC-924T0S/KOC-924T5S

A10 A09 A08 A07

A06A05

A04

A03

A02

A01

A11

A12

A13

REF NO. PART CODE PART NAME DESCRIPTION Q’TY REMARK

A01 3512603620 HANDLE DOOR S455C 1
A02 3511608300 DECORATOR DOOR*R SUS430 T0.5 H/L 1
A03 3512204820 FRAME DOOR ALLOY PC+ABS 1
A04 7001503011 SCREW MACHINE PAN 5*30 MFZN 2
A05 3515101800 SPRING HOOK PW1 1
A06 3513101200 HOOK POM 1
A07 3512302400 GASKET DOOR PBT 1
A08 3516602200 DOOR PLATE SBHG-3A T0.7 1
A09 3515304800 SUPPORTER HINGE*T SCP-1 T2.0 1
A10 3517007000 BARRIER-SCREEN*I TEMP GLASS T2.0 1
A11 3511608700 DECORATOR DOOR*T SUS430 T0.5 H/L 1
A12 3511608400 DECORATOR DOOR*L SUS430 T0.5 H/L 1
A13 3511608200 DECORATOR DOOR*U SUS430 T0.5 H/L 1

✔ 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)

11

(1) Remove the gasket door from door plate.
(2) Remove screws 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 handle door and barrier screen outer from door frame.
(7) Reverse the above steps for reassembly.

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

(1) To reduce gap located on part ‘A’.

• Loosen two screws on stopper hinge top, and then push the door

to contact the door seal to oven front surface.

• Tighten two screws.

(2) To reduce gap located on part ‘B’.

• Loosen two screws on stopper hinge under, and then push the
door to contact the door seal to oven front surface.

• Tighten two screws.

NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.