Daewoo KOC-870T0S, KOC-873T, KOC-870T5S, KOC-873T0S, KOC-873T5S Service Manual

Service Manual

Microwave Oven

Model: KOC-870T0S

KOC-870T5S

KOC-873T0S

KOC-873T5S

DAEWOO ELECTRONICS CO., LTD.

S/M No. : C870T0S004

http : //svc.dwe.co.kr Aug. 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).

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.......................................................................................................................................................................3

NAMES AND FUNCTION OF PARTS........................................................................................................................................4

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

OPERATION................................................................................................................................................................................7

INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS.............................................................................................8

PRECAUTIONS FOR DISASSEMBLY AND REPAIR.............................................................................................................10

DISASSEMBLY AND ASSEMBLY............................................................................................................................................11

TROUBLE SHOOTING GUIDE ................................................................................................................................................20

MEASUREMENT ......................................................................................................................................................................27

COMPONENT TEST PROCEDURE........................................................................................................................................29

WIRING DIAGRAM...................................................................................................................................................................30

SCHEMATIC DIAGRAM...........................................................................................................................................................31

EXPLODED VIEWS AND PARTS LIST ...................................................................................................................................34

PRINTED WIRING BOARD (KOC-870T) ................................................................................................................................37

P.C.B. CIRCUIT DIAGRAM (KOC-870T) .................................................................................................................................44

P.C.B. LOCATION NO (KOC-870T) ........................................................................................................................................45

PRINTED WIRING BOARD (KOC-873T) ................................................................................................................................47

P.C.B. CIRCUIT DIAGRAM (KOC-873T) .................................................................................................................................54

P.C.B. LOCATION NO (KOC-873T) ........................................................................................................................................55

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 19kg (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 2.6Kw(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

MODEL KOC-870T0S/873T0S KOC-870T5S/873T5S POWER SUPPLY 230V ~ , 50Hz 240V~, 50Hz 230V~, 50Hz MICROWAVE POWER CONSUMPTION 1,550 W 1,550 W 1,550 W

OUTPUT POWER 900 W (IEC 705) 900W(IEC 706) 900 W (IEC 705)

FREQUENCY 2,450 MHZ 2,450MHz 2,450MHz GRILL POWER CONSUMPTION 1,150 W 1,200 W 1,150 W CONVECTION POWER CONSUMPTION 1,550 W 1,600 W 1,550 W AUTO COOK POWER CONSUMPTION 2,600 W 2,650 W 1,550 W OUTSIDE DIMENSIONS (W X D X H ) 501 X 398 X 320 mm (19.7 X 15.7 X 12.6 in.) CAVITY DIMENSIONS (W X D X H) 310 X 310 X 229 mm (12.2 X 12.6 X 9.0 in.) NET WEIGHT 19 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

210 402

Grill

M/W

Combi +1 min

Pie Temp +10 sec

GRILL COMBI

WEIGHT

DEFROST

TIME

AUTO COOK

PIE TEMP

COOK

1. Roast Beef

2. Roast Pork

3. Roast Chicken

4. Fish Fillets

5. Vegetable

Auto Cook

TIME/WEIGHT

Speedy

Clock

Defrost

M/W

STOP/ CLEAR

START

Fig. 1 Front View Fig. 2 Side View

SPECIFICATIONS

EXTERNAL VIEWS

3 5 64

1 9 8

Grill

M/W

Combi +1 min

Pie Temp +10 sec

GRILL COMBI

WEIGHT

DEFROST

TIME

AUTO COOK

PIE TEMP

COOK

1. Roast Beef

2. Roast Pork

3. Roast Chicken

4. Fish Fillets

5. Vegetable

Auto Cook

TIME/WEIGHT

Speedy

Clock

Defrost

M/W

STOP/

CLEAR

START

DOOR SEAL -

Door seal maintains the microwave

within the oven cavity and prevents microwave leakage.

DOOR HOOK - When door is closed, it will automatically

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

DOOR SCREEN - Allows viewing of food. Microwave

cannot pass through perforations in screen.

GRILL HEATER - Turns on when grill and simultaneous cooking is selected.

OVEN LAMP - Automatically turns on during oven operating.

SAFETY INTERLOCK SYSTEM

CONTROL PANEL

TURNTABLE TRAY - Rotates during cooking and

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

OVEN FRONT PLATE

ROTATING BASE -

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.

UNDER HEATER

NAMES AND FUNCTION OF PAR TS

CONTROL PANEL

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 TIME DEFROST.

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

Cooking time is increased by 1 minute.

Cooking time is increased by 10 seconds.

FUNCTION BUTTON Used to select desired oven operation.;Grill, Combi, Pie Temp, Auto Cook, M/W, Defrost.

Stop/Clear Button-Used to select desired oven operation.;Grill, Combi, Pie Temp, Auto Cook, M/W,Defrost.

Start Button-Used to start the selectee cycle.

Speedy Cook ButtonUsed to set desired time. (Time increases by 30 seconds from 30 seconds to 5 minutes.)

Guide LampWhen blinking, it informs you to be ready to operate dial knob.

Dial KnobUsed to set the cooking time, time of day and weight input.

When blinking, the oven is operating in GRILL

When blinking, the onve is operating in MICROWAVE COOK

When blinking, the oven is operating in AUTO COOK.

When blinking, the oven is operating in PIE COOK.

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

Temp Button Used to set desired temperature. If this button pressed for more than

1.3 seconds, number is scrolled up automatically.

Clock Button-Used to set time.

When blinking, the oven is operating in CONVECTION (TEMP COOK)

Grill

M/W

Combi +1 min

Pie Temp +10 sec

GRILL COMBI

WEIGHT

DEFROST

TIME

AUTO COOK

PIE TEMP

COOK

1. Roast Beef

2. Roast Pork

3. Roast Chicken

4. Fish Fillets

5. Vegetable

Auto Cook

TIME/WEIGHT

Speedy

Clock

Defrost

M/W

STOP/

CLEAR

START

KOC-870T

CONTROL PANEL

KOC-873T

Defrost +1min

Auto

Cook

Temp Cook

Pie Kg

MW CombiGrill Weight

Defrost

Time

+10sec

KOC-873T0S

Clock Pie

Grill Combi

TIME WEIGHT/QUANTITY

STOP/CLEAR

START/SPEEDY COOK

Auto Cook Menu

1. Roast beef

2. Roast pork

3. Roast chicken

4. Fish Fillet

5. Vegetable

Auto

Cook

Temp

When blinking, the oven is operating in “Combi” cooking mode. When blinking, the oven is operating in “Grill” cooking mode.

When blinking, the oven is operating in “Microwave” cooking mode.

When blinking, the oven is operating in “Auto Cook” cooking mode.

When blinking, the oven is operating in “Pie” cooking mode.

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

Clock Button - Used to set time.

Microwave Button -

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

Dial Knob- Used to input the cooking time and quantity.

STOP/CLEAR Button - Used to pause and clear all information manually put into the oven.

When blinking, the oven is operating in “Weight Defrost” cooking mode. When blinking, the oven is operating in “Time Defrost” cooking mode.

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

When blinking, the oven is operating in “Convection” cooking mode.

Cooking time is increased by 1 minute.

Cooking time is increased by 10 seconds.

FUNCTION BUTTON-Used to select desired oven operation. ;Grill, Combi, Pie, Temp, Auto Cook, MW, Defrost.

START Button - Used to start the selected cycle.

SPEEDY COOK Button -

Used to program quickly cooking time in 30 seconds increments. (Time increases by 30 seconds from 30 seconds to 5 minutes.)

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.

OPERATION

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

INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS

Mounting screw

Upper 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 15Amp fuse(870T5S: 12Amp) is blown out due to the operation of the monitor switch; replace 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 three 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 ②.

2) Remove back-cover ③.

3) Pull the fan ⑤ to the motor shaft.

4) Release two screws ① which secure the motor shaded pole ④.

5) Reverse the above steps for reassembly.

DISASSEMBLY AND ASSEMBLY

Fig. 1

Fig. 2

54 3

3. T o remo ve H.V. transformer. (Refer to Fig. 3)

1) Remove four screws 1 which secure the

H.V. Transformer bracket to the base plate.

2) Remove the H.V. Transformer 2.

High voltage circuit wiring

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 one screws ② which secure the magnetron ① .

2) Remove the magnetron.

3) Reverse the above steps for reassembly.

Fig. 4

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 the Dial knob ⑪ (3) Remove nine screws ⑪ which secure the main and sub

PCB assembly ⑧

,⑨ to control panel ③. (4) Remove buttons ④,⑤,⑥,⑦. (5) Remove the Window display ②, and Decorator Panel ①.

Fig. 5

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.

Wave guide

Magnetron antenna

Metallic gasket plate

Magnetron antenna

Metallic gasket plate

Cooling fin

Filament terminal

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

1 3511602500 DECORATOR C-PANEL ABS 1

KOC-870T(ONLY)

2 3515501300 WINDOW DISPLAY PMMA 1

KOC-870T0S

3515501320 WINDOW DISPLAY PMMA 1

KOC-873T0S

3 3516716310 CONTROL-PANEL ABS 1

KOC-870T0S

3516716370 CONTROL-PANEL ABS 1

KOC-873T0S

4 3516906000 BUTTON FUNCTION(A) ABS 1

KOC-870T0S

3516909900 BUTTON FUNCTION(A) ABS 1

KOC-873T0S

5 3516905900 BUTTON FUNCTION(B) ABS 1

KOC-870T0S

3516909910 BUTTON FUNCTION(B) ABS 1

KOC-873T0S

6 3516905800 BUTTON FUNCTION(C) ABS 1

KOC-870T0S

3516909920 BUTTON FUNCTION(C) ABS 1

KOC-873T0S

7 3516906100 BUTTON FUNCTION(D) ABS 1

KOC-870T0S

3516909930 BUTTON FUNCTION(D) ABS 1

KOC-873T0S

8 PKBPMSQ200 PCB SUB ASS’Y KOC-970T1S 1

KOC-870T0S

PKBPM00000 PCB SUB ASS’Y KOC-873T0S 1

KOC-873T0S

9 PKMPMSP700 PCB MAIN ASS’Y KOC-870T0S 1

KOC-870T0S

PKMPMSP720 PCB MAIN ASS’Y KOC-870T5S 1

KOC-870T5S

PKMPM00000 PCB MAIN ASS’Y KOC-873T0S 1

KOC-873T0S

10 7121030811 SCREW TAPPING T2S PAN 3X8 MFZN 9

KOC-870T0S

7121030811 SCREW TAPPING T2S PAN 3X8 MFZN 7

KOC-873T0S

7122401211 SCREW TAPPING T2S PAN 4X12 MFZN 4

KOC-873T0S

11 3513403810 KNOB VOLUME ABS 1

KOC-870T0S

3513406600 KNOB VOLUME ABS 1

KOC-873T0S

Fig. 6

✔ 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)

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

1) Remove two screws 1 which secure to hinge.

2) Remove door assembly 2.

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 7. (2) Remove the Door seal Ass’y 5. (3) Remove the Hook 8 and Spring 9. (4) Remove the Supporter barri-s *0 3. (5) Remove the Barrier Screen 2. (6) Remove the Handle 0 from the Frame door 3.

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

1 3512203520 FRAME DOOR ABS XR-401 1 KOC-870T0S

3512205400 FRAME DOOR PC LUPOY GP-1000 1 KOC-873T0S

2 3517004510 BARRIER-SCREEN*O GLASS 3.2T 1 KOC-870T0S

3517007710 BARRIER-SCREEN*O GLASS 3.2T 1 KOC-873T0S

3 3515305300 SUPPORTER BARRI-S*O PBT 1

KOC-870T(ONLY) 4 3515203600 STOPPER HINGE*T AS KOC-970T1S 1 5 3511709000 DOOR SEAL AS KOC-871C0S 1 6 3517004400 BARRIER-SCREEN*I GLASS 3.0T 1 7 3512301300 GASKET DOOR PBT 1 8 3513101300 HOOK POM 1 9 3515101300 SPRING HOOK PW1 1

10 3512601500 HANDLE DOOR ABS XR-401 1

KOC-870T(ONLY)

11 7122401211 SCREW TAPPING T2S TRS 4X12 MFZN 2

KOC-870T(ONLY)

Fig. 7

Fig. 8

0 q

1 2 3 4 5 6 7

✔ Caution:

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

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

1) Remove the cabinet.

2) Loosen a screw on top door hinge, then push the door to contact the door seal to oven front surface.

3) Tighten a screw.

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

1) Loosen a screw on bottom hinge, then push the door to contact the door seal to oven front surface.

2) Tighten a screw.

(3) To reduce gap located on part ‘C’.

1) Remove the cabinet.

2) Loosen a screw on interlock switch assembly located bottom of oven body.

3) Draw the interlock switch assembly inward as possible to engage with hook on the door bottom.

4) Tighten a screw.

(4) To reduce gap located on part ‘D’.

1) Remove the cabinet.

2) Loosen a screw on interlock switch assembly located top of oven body.

3) and 4) are same as step (3).

A D

B C

Grill Combi +1 min

Pie Temp +10 sec

1. Roast Beef

2. Roast Pork

3. Roast Chicken

4. Fish Fillets

5. Vegetable

Auto Cook

TIME/WEIGHT

Speedy

Clock

Defrost

M/W

STOP/ CLEAR

START

NOTE : Small gap may be acceptable if the microwave leakage does not exceed 1mW/cm2.

NOTE : The door on a microwave oven is designed to act as an electronic seal preventing the leakage of microwave

energy from the oven cavity during the cook cycle. This function does not require that the door be air-tight, moisture (condensation) - Tight or light-tight. Therefore, the occasional appearance of moisture, light or the sensing of gentle warm air movement around the oven door is not abnormal and do not of themselves, indicate a leakage of microwave energy from the oven cavity. If such were the case, your oven could not be equipped with a vent, the very purpose of which is to exhaust the vapor-laden air from the oven cavity.

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