Daewoo KOC-621Q0S Schematic

S/M NO. : C621Q0S001

Service Manual

Microwave Oven

Model: KOC-621Q0S

DAEWOO ELECTRONICSCO.,LTD.

http://svc.dwe.co.kr

Dec. 2001

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.

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
1. SAFETY AND PRECAUTIONS....................................................................................................................................	2
2. SPECIFICATIONS ........................................................................................................................................................	3
3. EXTERNAL VIEW .........................................................................................................................................................	3
3-1. OUTER DIMENSION ..........................................................................................................................................	3
3-2. FEATURE DIAGRAM .........................................................................................................................................	4
4. INSTALLATION ............................................................................................................................................................	5
5. CONTROL PANEL .......................................................................................................................................................	6
6. DISASSEMBLY AND ASSEMBLY ..............................................................................................................................	7
7. INTERLOCK MECHANISM AND ADJUSTMENT.....................................................................................................	15
8. TROUBLE SHOOTING GUIDE ..................................................................................................................................	16
9. MEASUREMENT AND TEST.....................................................................................................................................	22
9-1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT ........................................................................	22
9-2. MICROWAVE RADIATION TEST ....................................................................................................................	23
9-3. COMPONENT TEST PROCEDURE................................................................................................................	24
9-4. COMPONENT ACTION....................................................................................................................................	25
10. WIRING DIAGRAM...................................................................................................................................................	26
11. EXPLODED VIEW AND PARTS LIST ..................................................................................................................	27
11-1. DOOR ASSEMBLY.........................................................................................................................................	27
12-2. CONTROL PANEL ASSEMBLY.....................................................................................................................	27
13-3. TOTAL ASSEMBLY........................................................................................................................................	27
12. PRINTED CIRCUIT BOARD ....................................................................................................................................	29
13. P.C.B CIRCUIT DIAGRAM.......................................................................................................................................	33

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. SPECIFICATIONS

MODEL		KOC-621Q0S

POWER SUPPLY		230V~50HZ, SINGLE PHASE WITH EARTHING

	MICROWAVE	1250W

POWER	GRILL	1250W

CONSUMPTION	OVEN	1650W

	COMBINATION	2500W

MICROWAVE ENERGY OUTPUT		800W(IEC705)

MICROWAVE FREQUENCY		2450MHz

OUTSIDE DIMENSIONS (W X H X D)		470X285X376mm (18.5X11.2X14.8 in.)

CAVITY DIMENSIONS (W X H X D)		295X167X300mm (11.6X6.6X11.8 in.)

NET WEIGHT		APPROX. 15kg (33.1 lbs.)

TIMER		Oven: 99 minutes, M/W: 60 minutes, Grill: 30 minutes

FUNCTION SELECTIONS		MICROWAVE/ GRILL/ OVEN/ COMBINATION

POWER SELECTIONS		10 LEVELS

CAVITY VOLUME		0.6 Cu. Ft

*Specifications are subject to change without notice.

3.EXTERNAL VIEW

3-1.	OUTER DIMENSION
	470	376
		285

3-2. FEATURE DIAGRAM

1 2

4 5

M/W Def. Grill Temp g

Auto Cook
1. Roast Beef	2. Roast Pork
3. Roast Chicken	4. Fish Fillets
5. Vegetable
M/W	Defrost
Grill	1000g 10m.	6
Combi	100g 1m.	6
Temp	10s.
Clock	Auto Cook
Stop/	Start/
Clear	Speedy cook

Combi

KOC-621Q

e w

q 7

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.TOP HEATER

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

14.OVEN LAMP

Automatically turns on during oven operating.

15.SAFETY INTERLOCK SYSTEM

16.CONTROL PANEL

17. UNDER HEATER

18. METAL RACK

19.TURNTABLE TRAY

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

10.TRAY GUIDE

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

11.COUPLER

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

12.OVEN FRONT PLATE

13.DOOR SEAL

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

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 12 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 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 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.

5. CONTROL PANEL

M/W Def. Grill Temp g

	Auto Cook
	1. Roast Beef	2. Roast Pork
	3. Roast Chicken	4. Fish Fillets
	5. Vegetable
1	M/W	Defrost
3	Grill	1000g 10m.
4	Combi	100g 1m.
5	Temp	10s.
9	Clock	Auto Cook
q	Stop/	Start/
q	Clear	Speedy cook

Combi

KOC-621Q

BUTTONS

1.m/w - Press to select microwave power level.

2.defrost - Press to select weight/time defrost mode.

3.grill - Press to select grill.

4.combi - Press to select combi cooking mode.

5.temp - Press to select temperature.

6.10m. - Press to set time and weight.

7.1m. - Press to set time and weight.

8.10s. - Press to set time.

9.clock - Use to set clock.

10.auto cook - Press to select auto cook menu.

11.stop/clear - Press once to stop a programme, and twice to cancel a programme.

12.start/speedy cook - Press to start a programme, also for speedy start (each press adds 30 seconds microwave cooking time).

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 15A fuse is blown out due to the operation of the monitor switch; replace primary interlock switch, secondary interlock switch SHORT 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.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 replacting the door assembly, perform a check of correct alignment with the hinge and cavity front plate.

3. To remove door parts.

REF NO.	PART CODE	PART NAME	DESCRIPTION	Q’TY	REMARK
A01	3512203410	FRAME DOOR	ABS	1
A02	3517004800	BARRIER-SCREEN *O	TEMP GLASS T3.2	1
A03	3515203000	STOPPER HINGE *T AS	KOC-621S5J	1
A04	3511709400	DOOR PAINTING AS	KOC-621S5J	1
A05	3517004700	BARRIER-SCREEN *I	TEMP GLASS T3.0	1
A06	3512301100	GASKET DOOR	PBT	1
A07	3513101000	HOOK	POM	1
A08	3515101700	SPRING HOOK	PW1	1

(1)	Remove the gasket door(A06) from door plate.
(2)	Remove the door frame (A01) from door plate(A04).
(3)	Remove the stopper hinge top(A03) from door plate(A04).
(4)	Remove the spring(A08) and the hook(A07).
(5)	Remove the barrier screen outer(A02) from door frame(A01).
(6)	Reverse the above steps for reassembly.
4. Method to reduce the gap between the door seal and the		A
oven front surface.
(1)	To reduce gap located on part ‘A’.
	• Loosen two screws on stopper hinge top, and then push the door	3.1. Roast Chicken 4. Fish Fillets
			Auto Cook
		Roast Beef 2. Roast Pork
	to contact the door seal to oven front surface.	5. Vegetable
	to contact the door seal to oven front surface.	Grill	1000g 10m.
		M/W	Defrost
	• Tighten two screws.	Temp	10s.
		Combi	100g 1m.
(2)	To reduce gap located on part ‘B’.	Clock	Auto Cook
(2)	To reduce gap located on part ‘B’.	Stop/	KOC-621Q
		Stop/	Start/
		Clear	Speedy cook
		Combi
	• Loosen two screws on stopper hinge under, and then push the
	door to contact the door seal to oven front surface.	B
	• Tighten two screws.	B
	• Tighten two screws.

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

5. To remove control panel parts.

REF NO.	PART CODE	PART NAME	DESCRIPTION	Q’TY	REMARK
B01	3518523500	SWITCH MEMBRANE	KOC-621Q0S	1
B02	3516715810	CONTROL-PANEL	ABS	1
B03	3514325720	PCB AS	KOC-621Q0S	1
B04	7112401211	SCREW TAPPING	T1 TRS 4X12 MFZN	4

(1)Remove four screws(B04) which secure the PCB AS(B03).

(2)Pull out the PCB AS(B03) from control panel(B02).

(3)Reverse the above steps for reassembly.

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