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S/M No. : OC9A4T7001




Service Manual
Microwave Oven
Model: KOC-9A4T7S




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




June. 2006
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.




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.......................................................................................................................................36




1
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.
(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.




2
2. SPECIFICATIONS
MODEL KOC-9A4T7S
POWER SUPPLY 230V~50Hz, SINGLE PHASE WITH EARTHING
MICROWAVE 1450W
POWER GRILL 1250W
CONSUMPTION CONVECTION 2650W
COMBINATION 2950W
MICROWAVE ENERGY OUTPUT 900W (IEC 705)
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 542X329X520mm(21.3X13.0X20.5 in.)
CAVITY DIMENSIONS (W X H X D) 350X230X355mm(13.8X9.1X14.0 in.)
NET WEIGHT Approx. 19Kg (41.9 lbs.)
TIMER 60 minutes
FUNCTION SELECTIONS Microwave / Grill / Convection / Combination
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.0 Cu. Ft
* SPECIFICATION ARE SUBJECT TO CHANGE WITHOUT NOTICE.




3
3. EXTERNAL VIEW
1. OUTER DIMENSION




542 520




329




4
2. FEATURE DIAGRAM



2 34 56




7
1




e w q 09 8

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.




5
4. 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 13 amperes, 230V, 50Hz.
Power supply cord is about 1.0 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.




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 wire with 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 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.




6
5. CONTROL PANEL

1 Display : Cooking time, power level, indicators and
present time are displayed.
MW : When blinking, the oven is operating in
MICROWAVE COOK.
Grill : When blinking, the oven is operating in GRILL.
Combi : When blinking, the oven is operating in
COMBI.
Defrost Weight : When blinking, the oven is
operating in WEIGHT DEFROST.
Time : When blinking, the oven is operating in TIME
DEFROST.
Auto-cook : When blinking, the oven is operating
AUTO COOK.
Lock : When lighting, the oven is CHILD LOCK.
Con-vection : When blinking, the oven is operating
in CONVECTION.
g : When blinking, the oven is operating in weight
input mode.



2 Auto cook : Used to cook or reheat.




3 Combi : Used to select combi.
4 Weight Defrost : Used to defrost foods.

5 Grill : Used to select grill.



6 MW : Used to set power level of micro wave.
7 Time Defrost : Used to defrost foods.

8 Convection : Used to select convection and
selected temp.



9 Clock : Used to set clock.



q START/SPEEDY COOK : Used to start a
programmed, also for speedy start(each press adds
30 seconds microwave cooking time).


w STOP/CLEAR : Used to stop the oven operation or
to delete the cooking data.



0 Dial knob : Used to set time, weight and quantity.



Note : Please remove the protection film on the control
panel before using the oven first time




7
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 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.




8
1. To remove cabinet
1) Remove four 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 assemby.


NOTE: After replacing the door assembly, perform a check
of correct alignment with the hinge and cavity front
plate.




9
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).


3. To remove door parts.




REF NO. PART CODE PART NAME DESCRIPTION Q'TY REMARK
A01 3511614610 DECORATOR DOOR STS430 T0.5 1
A02 3512209220 FRAME DOOR ABS XR-401 SR-0320 1
A03 3517009900 BARRIER-SCREEN*O TEMP GLASS T3.2 1
A04 3515204900 STOPPER HINGE*T AS SCP-1 T2.0 1
A05 3516602200 DOOR PLATE SBHG-3A T0.7 1
A06 3512302410 GASKET DOOR LU POL 2300 1
A07 3513101200 HOOK POM 1
A08 3515102300 SPRING HOOK PW1 1
A09 7001401211 SCREW MACHINE PAN M4XL12 MFZN 2
A10 3512606020 HANDLE DOOR AL 1
A11 3511615600 DECORATOR BADGE SUS 55mm 1

(1) Remove the gasket door from door plate.
(2) Remove the door frame from door plate.
(3) Remove screws from door frame.
(4) Remove the handle from door frame.
(5) Remove the decorator door from door frame.
(6) Remove the stopper hinge top from door plate.
(7) Remove the spring and the hook.
(8) Remove barrier screen outer from door frame.
(9) Reverse the above steps for reassembly.




10
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part `A'.