Daewoo KOC-872 Service Manual

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 micro-

wave 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.

partments, 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

NAMES AND FUNCTION OF PARTS

CONTROL PANEL

OPERATION

INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS

PRECAUTIONS FOR DISASSEMBLY AND REPAIR

DISASSEMBLY AND ASSEMBLY

TROUBLE SHOOTING GUIDE

MEASUREMENT

COMPONENT TEST PROCEDURE

WIRING DIAGRAM

SCHEMATIC DIAGRAM

EXPLODED VIEWS AND PARTS LIST

PRINTED WIRING BOARD

P.C.B. BOARD DIAGRAM

P.C.B. CIRCUIT DIAGRAM

P.C.B. ASS’Y PARTS LIST

PROPER USE AND SERVICE 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) 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 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.

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.

WARNING : This appliance must be earthed.

NOTE : This oven is designed for counter-top use only.

IMPORTANT

POWER SUPPLY 230V ~ , 50Hz 240V~, 50Hz

POWER CONSUMPTION 1,500W 1,550W

MICROWAVE OUTPUT POWER 900 W (IEC 705) 900W(IEC 705)

FREQUENCY 2,450 MHZ 2,450MHz GRILL POWER CONSUMPTION 1,250 W 1,300W CONVECTION POWER CONSUMPTION 1,650 W 1,700W COMBINATION HEATING POWER CONSUMPTION 2,700 W 2,750W OUTSIDE DIMENSIONS (W X D X H) 501 (19.7) X398 (15.7) X 320 (12.6) mm (inch) CAVITY DIMENSIONS (W X D X H) 310 (12.2) X 320 (12.6) X 229 (9.0) mm (inch) NET WEIGHT 17.6 kg (38.9 Ibs.) TIMER 60 minutes SELECT FUNCTION Microwave/Grill /Convection /Combination MICROWAVE POWER LEVEL 10 stages

* Specifications subject to change without notice.

332

294

320

501

210 398

GRILL COMBI TEMP

M/W DEFROST PIE

PROGRAM COOK

1. ROAST BEEF

2. ROAST PORK

3. ROAST CHICKEN

4. FISH FILLETS

5. VEGETABLE SPEEDY COOK

STOP/CLEAR START

PROGRAM COOK

KgTEMP

COOK

PIE

M/W GRILL COMBI

WEIGHT

DEFROST

TIME

Fig. 1 Front View Fig. 2 Side View

SPECIFICATIONS

EXTERNAL VIEWS

3 5 64

1 9 8

GRILL COMBI TEMP

M/W DEFROST PIE

PROGRAM COOK

1. ROAST BEEF

2. ROAST PORK

3. ROAST CHICKEN

4. FISH FILLETS

5. VEGETABLE SPEEDY COOK

STOP/CLEAR START

PROGRAM COOK

KgTEMP

COOK

PIE

M/W GRILL COMBI

WEIGHT

DEFROST

TIME

¤ DOOR SEALƒ¡

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

¤Ł DOOR HOOKƒ¡When door is closed, it will

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

¤Ø

DOOR SCREENƒ¡Allows viewing of food.

Microwave cannot pass through perforations in screen.

¤Œ GRILL HEATER ƒ¡Turns on when grill and

simulta-neous cooking is selected.

¤º OVEN LAMP ƒ¡Automatically turns on during

oven operating.

¤ SAFETY INTERLOCK SYSTEM ¤ CONTROL PANEL ¤ TURNTABLE TRAYƒ¡Rotates during cooking

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

¤ OVEN FRONT PLATE ¤ ROTATING BASE ƒ¡

This fits over the shaft in the center of the oven’s cavity floor. This is to remain in the oven for all cooking. It should only be removed for cleaning.

¤æ UNDER HEATER

NAMES AND FUNCTION OF PARTS

CONTROL PANEL

GRILL COMBI TEMP

M/W DEFROST PIE

PROGRAM COOK

1. ROAST BEEF

2. ROAST PORK

3. ROAST CHICKEN

4. FISH FILLETS

5. VEGETABLE SPEEDY COOK

STOP/CLEAR START

PROGRAM COOK

KgTEMP

COOK

PIE

M/W GRILL COMBI

WEIGHT

DEFROST

TIME

When blinking, the oven is operating in COMBI cooking.

When blinking, the oven is operating in WEIGHT DEFROST.

When blinking, the oven is operating in GRILL

When blinking, the oven is operating in MIROWAVE COOK

When blinking, the oven is operating in PROGRAM.

Microwave Power Level-

Used to select the variable microwave power level. If this button is pressed for more tan 1.3 seconds, number is scrolled up automatically.

DIAL KNOB -Used to enter the cooking time and weight input.

Stop/Clear Button -Used to pause or clear all information manually put into the oven.

When blinking, the oven is operating in TIME DEFROST.

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

Temperature Button Used to set desired temperature. If this button pressed for more than 1.3 seconds, number is scrolled up automatically.

Function Button - Used to select desired oven operation.

MICROWAVE GRILL WEIGHT DEFROST

TIME DEFROST CONVECTION

(TEMP COOK) COMBINATION

PIE PROGRAM COOK

Start Button - Used to start the selected cycle.

Speedy Cook Button - Used to quickly program cooking time in 30 seconds increments.

M/W

GRILL

DEFROST

COMBI

+1MIN

+10SEC

PROGRAM

COOK

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.

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.

NOTE : Oven stops operating when door open.

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

INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS

Mounting screw

Hook

Primary interlock switch

(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.

PRECA UTIONS FOR DISASSEMBLY AND REPAIR

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 war rubber gloves when servicing the high voltage side.

(3)Warning about the electric charge in the high voltage capacitor. When inspecting and repairing the high voltage side,

always short the capacitor terminals and make sure of discharge.

1. Check the earthing.

Do not operate on a 2-wire extension cord. The microwave oven is designed to be used when earthed. It is imperative, therefore, to makes 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 stops, 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 screw driver to discharge.

(4)When the 15 Amp fuse (normal blow type) is blown out due to the operation of the monitor switch; replace primary,

secondary interlock switch and monitor switch. Refer to 17 page for the necessary adjustment.

(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 repairing 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 - H.V. Transformer, magnetron, H.V. Diode, H.V. Capacitor.

1. T o remo ve cabinet. (Refer to Fig. 1)

1) Remove four screws on cabinet back.

2) Push the cabinet backward.

2. T o remo ve guide wind assembl y. (Refer to Fig. 2)

1) Release two screws ¤Ł.

2) Remove back-cover ¤Ø.

3) Pull the fan

¤ºto the motor shaft.

4) Release two screws

¤ which secure the motor shaded pole ¤Œ.

5) Reverse the above steps for reassembly.

DISASSEMBLY AND ASSEMBLY

Fig. 1

Fig. 2

3. To remove H.V. transformer . (Refer to Fig. 3)

1) Remove four screws ¤ which secure the

H.V. Transformer bracket to the base plate.

2) Remove the H.V. Transformer

¤Ł.

High voltage circuit wiring

Fig. 3

H.V. Trans

H.V. Copacitor

Mognetron

H.V.Diode

H.V.Fuse

4. T o remo ve magnetr on. (Ref er to Fig. 4)

1) Remove three screws ¤Łwhich secure the magnetron ¤ .

2) Remove the magnetron.

3) Reverse the above steps for reassembly.

Fig. 4

CAUTION : 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

for a fully assembled oven with door normally closed.

Magnetron antenna

Wave guide

Magnetron antenna

Metallic gasket plate

Cooling fin

Filament terminal

Fig. 5

Fig. 6

5. To remove control panel assembl y. (Refer to Fig. 5, 6)

(1) Remove a screw holding control panel assembly to the oven

front plate. At the same time, draw forward the control panel assembly from oven front plate.

(2) Remove ten screws

¤ , ¤ which secure the main and sub

PCB assembly

¤ , ¤ to control panel ¤ .

(3) Remove buttons

¤Ø, ¤Œ, ¤º.

(4) Remove the Window display ¤Ł.

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

1 3516716320 CONTROL PANEL ABS 1 2 3515501210 WINDOW DISPLAY PMMA 1 SMOG 3 3516905100 BUTTON FUNCTION ABS 1 4 3516906300 BUTTON FUNCTION ABS 2 5 3516906200 BUTTON FUNCTION ABS 1 6 3613404600 KNOB VOLUME ABS 1 7 3516314800 PCB SUB AS KOC-872T 1 8 7121030811 SCREW TAPPING T2S PAN 3X8 MFZN 6 9 3514314720 PCB MAIN AS KOC-872T 1

10 7121030811 SCREW TAPPING T2S PAN 3X8 MFZN 4

6. To remove door assembly. (Refer to Fig. 7)

1) Remove two screws 1 which secure to hinge.

2) Remove door assembly

3) Remove door above for reassembly taking case to replace fixing glue.

7. To remove door part. (Refer to Fig. 8)

(1) Remove the Gasket door 8. (2) Remove the Door seal Ass’y 1. (3) Remove the Hook

2 and Spring 3.

(4) Remove the Barrier Screen

(5) Remove the Handle

6 form the Frame door 5.

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

1 3511709000 DOOR SEAL AS KOC-871C0S 1 2 3513101300 HOOK POM 1 3 3515101300 SPRING HOOK PW1 1 4 3517004500 BARRIER-SCREEN *0 TEMPERED GLASS 3.2T 1 5 3512203530 FRAME DOOR ABS XR-401 1 6 3512601510 HANDLE DOOR ABS SG-175 1 7 3515203600 STOPPER HINGE *T AS KOC-970T1S 1 8 3512301300 GASKET DOOR PBT 1 9 7S341W40B1 SCREW TAPPING T2S PAN 4X12 PW SE 2

Fig. 7

Fig. 8

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