Daewoo KOG-875T0S Service Manual

Service Manual

Microwave Oven

Model : KOG-875T0S

DAEWOO ELECTRONICS CO., LTD.

OVERSEAS SERVICE DEPT.

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 microwave power 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
PROPER USE AND SERVICE PRECAUTIONS .......................................................................................................................	2
SPECIFICATIONS.......................................................................................................................................................................	3
NAMES AND FUNCTION OF PARTS........................................................................................................................................	4
CONTROL PANEL ......................................................................................................................................................................	5
OPERATION................................................................................................................................................................................	6
HOW TO SET THE OVEN CONTROLS.....................................................................................................................................	7
INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS ...........................................................................................	12
PRECAUTIONS FOR DISASSEMBLY AND REPAIR .............................................................................................................	14
DISASSEMBLY AND ASSEMBLY............................................................................................................................................	15
TROUBLE SHOOTING GUIDE ................................................................................................................................................	23
MEASUREMENT ......................................................................................................................................................................	29
COMPONENT TEST PROCEDURE ........................................................................................................................................	31
WIRING DIAGRAM ...................................................................................................................................................................	32
SCHEMATIC DIAGRAM ...........................................................................................................................................................	33
EXPLODED VIEWS AND PARTS LIST ...................................................................................................................................	35
PRINTED WIRING BOARD ......................................................................................................................................................	36
P.C.B. BOARD DIAGRAM ........................................................................................................................................................	41
P.C.B. CIRCUIT DIAGRAM ......................................................................................................................................................	43
MAIN P.C.B. ASS’Y PART LIST ...............................................................................................................................................	44
SUB P.C.B. ASS’Y PART LIST.................................................................................................................................................	45

1

PROPER USE AND SERVICE 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)This microwave oven weight 17.6kg (38.9 lbs.) and must be placed on a horizontal base strong enough to support this weight.

2)The oven should be placed as far from high temperature source and vapour as possible.

3)The power supply cord is about 1.1m (3.6ft) long. Earthing is required when connecting the power source.

4)Maximum power consumption of this oven is approximately 2.7Kw(230V). It is suggested that the unit is operated on such power line (about 13.0 amperes) that can provide more power than this rating.

5)Object must not be placed on the top enclosure so as not to obstruct air flow for ventilation.

WARNING : This appliance must be earthed.

IMPORTANT

The wires 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 the the terminal in the plug which is marked with the letter ‘E’ or by earth symbol or 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

POWER SUPPLY			230V ~ , 50Hz, single phase with earthing
		POWER CONSUMPTION	1,400 W
MICROWAVE		OUTPUT POWER	900 W (IEC 705)
		FREQUENCY	2,450 MHZ
GRILL POWER CONSUMPTION			1,400 W
COMBINATION HEATING POWER CONSUMPTION			2,750 W
OUTSIDE DIMENSIONS (W X D X H )			501 X 320 X 413 mm (19.7 X 12.6 X 16.2 in.)
CAVITY DIMENSIONS (W X D X H)			310 X 229 X 320 mm (12.2 X 9.0 X 12.6 in.)
NET WEIGHT			Approx. 17.6 kg (38.9 lbs.)
TIMER			60 min.
SELECT FUNCTION			Microwave/Grill /Combination Heating
MICROWAVE POWER LEVEL			10 stages
COMBINATION HEATING LEVEL			3-Levles (Grill + M/W 3-Power levels)

* Specifications subject to change without notice.

EXTERNAL VIEWS

Fig. 1 Front View	Fig. 2 Side View
	3

NAMES AND FUNCTION OF PARTS

1	2	6	3	4	5
									DEFROST
						M/W	GRILL	COMBI	WEIGHT	TIME
						PROGRAM			KG
						COOK
								WEIGHT		TIME
						M/W		DEFROST		DEFROST
						GRILL		COMBI		+1MIN.
					PROGRAM COOK
					1.	Roast Beef
					2.	Roast Pork
					3.	Roast Chicken
					4.	Fish Fillets
					5.	Vegetable
							SPEEDY
							COOK
					STOP/CLEAE				START/CLOCK
	9
					7
					8

1Door latch—When the door is closed it will automatically lock shut. If the door is opened while the oven is operating. The magnetron will automatically shut off.

2Door seal—The door seal maintains the microwave within the oven cavity and prevents microwave lekage.

3Oven cavity

4Spatter shield—Protects the microwave outlet from splashes of cooking foods.

5Safety interlock system—Prevents the oven from operating while the door is opened.

6Heater—Grill or Combi-Mode has need for the heater.

7Class 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.

8Roller guide—Supports the glass cooking tray.

9Door screen—Allows viewing of food. The screen is designed so that light can pass through, but not the microwaves.

4

CONTROL PANEL

When blinking, the oven is operating in COMBI cooking.

When blinking, the oven is
operating in GRILL
When blinking, the oven
is operating in		DEFROST
MICROWAVE COOK	M/W GRILL	COMBI WEIGHT	TIME
When blinking, the oven is	PROGRAM	KG
operating in PROGRAM	COOK
Microwave Power Level-		WEIGHT	TIME
	M/W	DEFROST	DEFROST
Used to select the variable
microwave power level.
If this button is pressed for more	GRILL	COMBI	+1MIN.
than 1.3 seconds, number is
scrolled up automatically.
	PROGRAM COOK
	1. Roast Beef
	2. Roast Pork
	3. Roast Chicken
	4. Fish Fillets
	5. Vegetable
	SPEEDY
	COOK
DIAL KNOB-
Used to enter the cooking
time and weight input.
	STOP/CLEAE	START/CLOCK
Stop/Clear Button-
Used to pause or clear all
information manually put into
the oven.

When blinking, the oven is operating in WEIGHT DEFROST

When blinking, the oven is operating in weight input mode.

Function Button-Used to select desired oven operation.

M/W MICROWAVE

GRILL

GRILL

WEIGHT

DEFROST WEIGHT DEFROST

COMBI

COMBINATION

TIME

DEFROST TIME DEFROST

+1MIN.

+1 MIN

PROGRAM

COOK PROGRAM COOK

When you touch this button. Cooking time is increased by the stop of 1 minute.

Speedy Cook Button-

Used to quickly program cooking time in 30 seconds increments.

Start/Clock Button-

Used to start operation and to set the clock.

5

OPERATION

TO STOP THE OVEN WHILE THE OVEN IS OPERATING

1.Press (STOP / CLEAR) button.

-The (STOP) indicator starts blinking.

-You can restart the oven by touching (START) button.

-Touch once more to erase all instruction except clock.

2.Open the door

-You can restart the oven by closing the door and touching button.

NOTE : Oven stops operating when door open.

ERASING INSTRUCTIONS

•Touch (STOP/CLEAR) button to erase all instructions you set previously.

•Opening the oven door during cooking dose not erase cooking instruction.

•If you touch button during operation, the cooking instructions is all erased.

6

HOW TO SET THE OVEN CONTROLS

TIPS :

•Be sure to read the cookbook’s introduction before operating the oven.

•Also remember to read this operating instruction for proper safety information and instruction before using the oven.

•See the cookbook for specific recipes.

•Prior to setting the controls, place one cup of water in the oven, in a heat-proof glass measuring cup, for testing purposes.

•When setting the controls, every time a button is pressed, a beep can be heard.

NOTE :

•The time setting has an interval of 10 seconds from 10 seconds to 5 minutes, 30 seconds from 5 minutes to 10 minutes, 1 minute from 10 minutes to 60 minutes.

•At the end of each cooking, the cooling fan will run for time five minutes to cool the oven.(The display will show “cool” then theSTOP/CLEAR button is pressed after cooking.) However, you can proceed with further cooking immediately even in this stage.

■MICROWAVE COOKING M/W

NOTE :

•To insure the best microwave and defrost results, be sure to start with a cool oven. This is important if grill, or combination was used prior to microwave cooking. The cooling fan will run for five minutes after the end of cooking.

•The variable power Level settings equal the following wattage.

DISPLAY	POWER LEVEL	DISPLAY	POWER LEVEL
P-HI	100%	P-90	90%
P-80	80%	P-70	70%
P-60	60%	P-50	50%
P-40	40%	P-30	30%
P-20	20%	P-10	10%

7

HOW TO SET THE OVEN CONTROLS

SETTING THE CONTROLS
M/W	button. The display will show “P-HI”.
1. Press
This oven has 10 power levels from P-HI to P-10.
2. Press the	M/W
	button to select
the desired microwave power		M/W
level.
For example: power level 80
M/W	button two times
Press
more.

3.Turn the DIAL KNOB for the desired cooking time.

For example: 18 minutes Turn right or left the DIAL KNOB. Then, 18:00 will show in the disply.

M/W

Time can be set up from 10 seconds to 60 munutes.

NOTE : If step 2 is omitted, the oven will cook at full power.

START/CLOCK

4.Press button.

The oven will now start microwave cook for 18 minutes at power level P-80.

5.Four beeps will sound at the end of the cooking time. The indicator light will go off. The display panel will return to the "0". The oven light will turn off and the turntable will stop turning.

NOTE : After the end of microwave cooking, the cooling fan will run for five minutes.

TIME

■ TIME DEFROST DEFROST

NOTE : After the defrosting operation, turn the food over after you hear 4 times of 4 beeps for complete defrost.

SETTING THE CONTROLS

TIME

1. Press DEFROST button.

2.Turn the DIAL KNOB for the desired defrosting time.

For example: 18 minutes

DEFROST
WEIGHT	TIME

Time can be set up from 10 seconds to 60 minutes.

3.Press START/CLOCK button.

4.Four beeps will sound at the end of the cooking time.

The indicator light will go off. The display panel will return to the "0". The oven light will turn off and the tunatable will stop turning.

8

WEIGHT

■ WEIGHT DEFROST DEFROST

NOTE : • This mode allows you to set weight from 0.1Kg 0.1Kg to 2.9Kg.

• During the defrosting operation turn over the food after 4 beeps ound 4 times for cpmplete defrosting.

SETTING THE CONTROLS
1.		WEIGHT
	Press DEFROST button.
2.	Turn the DIAL KNOB for the			DEFORST
	desired defrosting weight.
				WEIGHT	TIME
	For example : (2.3kg)
3.	Press	START/CLOCK
		button.
4. The		display will show	the	Kg
	defrosting time.

5.Four beeps will sound at the end of the cooking time. The indicator lights will go off. The display panel will return to the "0". The oven light will turn off and the turntable will stop turning.

■ GRILLING COOKING Grill

NOTE : • The grilling effect in this oven is similar to that of conventional oven.

• The heating element is located in the top of the oven.

SETTING THE CONTROLS
1.	Press	Grill
		button.
2. Turn the dial knob for the
	desired cooking time		GRILL
	For example : (25 minutes)
	Time can be set up from 10
	seconds to 60 minutes.

START/CLOCK

3.Press button.

4.Four beeps will sound at the end of the cooking time. The indicator light will go off. The display panel will return to the "0". The oven light will turn off and the turnatable will stop turning.

NOTE : When the selected operation is over, a cooling fan will run for five minutes.

9

PROGRAM

■ PROGRAM COOK

NOTE : • There is Pre-Programmed cooking of five menu (1-5)

• Don’t need to set cooking times, power or function.

SETTING THE CONTROLS

1.Press PROGRAM COOK button Then, “AC-1” will show in the display.

PROGRAM

COOK

AUTO

COOK

2.Select the desired cooking menu

For example : Roast pork.

Press PROGRAM COOK button roast pork. Press PROGRAM COOK button once again then “AC-2” will show in the display.

3. If you want to select other cooking, touch the button again, until display shows your desired menu.

4. Press	START/CLOCK
	button.

The oven will now start programmed cook for menu 2.

The cookingtime of the menu 2, roast pork, is 37 minutes.

5.The display will show the cooking time.

6.Four beeps will sound at the end of the cooking time. The indicator light wil go off. The display panel will return to the "0". The oven light will turn off and the turntable will stop turning.

NOTE : The menu of pre-programmed cooks equal to the following.

AC-1	ROAST BEEF (1.3Kg)
AC-2	ROAST PORK (1.3Kg)
AC-3	ROAST CHICKEN (1.3Kg)
AC-4	FISH FILLETS (450g)
AC-5	VEGETABLE (450g)

See the cooking guide for specific recipes.

■TO INTERRUPT THE COOKING CYCLE DURING OPERATION-open the door or press stop/clear button.

1.The oven will immediately stop.

2.The cooling fan will run for five minutes.

3.If not further cooking required, touch STOP/CLEAR button.

4.The "0" is displayed. If you press stop/clear button during cooling time, the "cool" is displayed.

5. To continue cooking, close the oven door and press	START/CLOCK
	button.

The oven will restart.

■ GENERAL COOKING HINTS

1.When cooking a roast with an excess amount of drippings, it is helpful to remove the dripping at turnover time to prevent spattering.

2.Prick the meats, fish or poultry with a fork to prevent bursting. Steam builds up pressure in meals, fish or poultry which is tightly covered by a skin or membrane.

3.Reduce suggested cooking times. It is always better to undercook foods rather than to overcook them. If a range of times is stated in a recipe, cook the food at the minimum suggested time, check for doneness, and then cook slightely longer if necessary.

10

SPEEDY

■ SPEEDY COOK COOK

NOTE : The cooking time increases by 30 seconds from 30 seconds to 5 minutes.

SETTING THE CONTROLS

START/CLOCK

1.Press button.

2.“30” will appear in the display window.

3.Whenever this button is pressed, cooking time is increased by 30 seconds.

M/W

4.Four beeps will sound at the end of the cooking time. The indicator light will go off. The display panel will return to the "0". The oven light will turn off and the turntable will stop turning.

■TIME PLUS

NOTE : • The cooking time can be increased during the oven operation by pressing buttons.

• This function is not valid in speedy cook mode.

•1 min

1.Press button.

Cooking time is increased by 1 minutes.

11

INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS

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 lever downward.

The lever press the button of the primary interlock switch to bring it under ‘ON’ condition.

Mounting screw

Hook

Primary interlock switch

12

(2) Monitor interlock switch

When the door is closed, the hook pushes the lever forward, and pushes the Latch Lever downward the lever press the button of the interlock monitor switch to bring it under ‘OFF’ condition. The latch Lever press the button on the secondary interlock switch to bring it under ‘ON’ condition.

- Adjustment

Interlock monitor switch

When the door is closed, the monitor switch should be opened before other switches close.

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

Adjustment steps :

a)Loosen the two mounting screws.

b)Adjust the interlock switch assembly position.

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

d)Completely tighten the two mounting screws.

13