Daewoo KOC-984T User manual

Service Manual
Microwave Oven
Model: KOC-984T
DAEWOO ELECTRONICS CO., LTD.
S/M No. : C972T0S002


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 doorhinge.
(2) A broken doorviewing screen.
(3) A broken front panel, oven cavity.
(4) A loosened door lock.
(5) A broken doorlock.
The door gasket plate and ovencavity surface should be kept clean.
No grease, soil or spatter should be allowed to build up on these surfacesor inside the oven.
DO NOTATTEMPT TO OPERATE THIS APPLIANCE WITH THE DOOROPEN.
The microwave oven has concealed switches to make sure the poweris turned off when the door is opened.
Do not attempt to defeat them.
DO NOTATTEMPT TO SERVICE THIS APPLIANCE UNTIL YOU HAVE READ THIS SERVICE MANUAL.
2. FOR SAFE SERVICE PROCEDURES
1. If the oven is operative priorto 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 emissioncheck 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.
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 terminalin the plug which is marked with the
letter 'E', earth symbolor 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 mustbe connected to the terminalwhich is marked with the letter 'L'or coloured red.
IMPORTANT
This oven is designed for counter-top use only.
NOTE


SPECIFICATIONS
SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUTNOTICE.
MODELKOC-984T
POWERSUPPLY230V~50Hz
POWER CONSUMPTION
MICROWAVE1450W
GRILL1200W
CONVECTION1550W
PROGRAMCOOK1850W
COMBINATION2600W(Simultaneous)
MICROWAVEENERGYOUTPUT1000W(IEC705)
MICROWAVEFREQUENCY2450MHz
OUTSIDEDIMENSIONS(WXHXD)526 x 345 x 496 mm (20.7 x 13.6 x 19.5 in.)
CAVITYDIMENSIONS(WXHXD)335 x 250 x 339 mm (13.2 x 9.8 x 13.3 in.)
NETWEIGHTAPPROX. 21 Kg (46.3 lbs.)
TIMER 60 minutes
FUNCTION SELECTIONS MICROWAVE/GRILL/CONVECTION/COMBI
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.0 Cu.Ft.
MODEL KOC-982T/983T/984T/985T1S KOC-982T/983T/984T/985T2S
POWER SUPPLY 230V~50Hz 230V~50Hz
POWER CONSUMPTION
MICROWAVE 1450W 1450W
GRILL 1200W 1200W
CONVECTION 1550W 1550W
PROGRAM COOK 1850W 1850W
COMBINATION 2600W (Simultaneous) 1550W (Sequential)
MICROWAVEENERGYOUTPUT
MICROWAVE FREQUENCY 2450MHz 2450MHz
OUTSIDEDIMENSIONS(WXHXD)
CAVITYDIMENSIONS(WXHXD)
NETWEIGHT
TIMER 60 minutes
FUNCTION SELECTIONS MICROWAVE/GRILL/CONVECTION/COMBI
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.0 Cu.Ft.


1. OUTER DIMENSION
KOC-972T
EXTERNAL VIEW KOC-984T

5
EXTERNAL VIEW
KOC-984T
1. Door seal - Door seal maintains the microwave energy within the oven cavity and prevents microwave leakage.
2. Door hook - When the door is closed, it will automatically shut. If the door is opened while the oven is operating,
the magnetron will immediately stop operating.
3.Door viewing screen - Allows viewing of food. The screen is designed so that light can pass through, but not the microwave.
4. Top heater - Turns on when convection, grill and combi cooking is selected.
5. Oven lamp - Automatically turns on during oven operating.
6. Safety interlock system
7. Control panel
8. Turntable tray - Rotates during cooking and ensure even distribution of Microwaves.
It can also be used as a cooking utensil.
9. Oven front plate
10. Rotating base - This fits over the shaft in the center of the ovens cavity floor.
This is to remain in the oven for all cooking. It should only be removed for cleaning.
11. Under heater
12. Metal rack
13. Convection outlet & Fan

6
INSTALLATION
1. Steady, flat location
This microwave oven should be set on a steady, flat surface.
This microwave oven is designed forcounter 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 resultif the oven is located close to a TV, radio, antenna or feeder and so on.
Position the oven as far from them aspossible.
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. Thismicrowave oven requires a current ofapproximately 13amperes, 230 Volts, 50 Hz.
Power supply cord is about 1.2 meters long.
The voltage used must be the same asspecified on this oven. Using a higher voltage may result in afire 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 cableof 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 iscolder than room temperature.
(This may occur during delivery in cold weather.) Allow the oven to become room temperature before operating.
This appliance must be earthed. In the event of an electrical short circuit, earthing reduces therisk of the electric shock bypro-
viding an escape wire for the electric current. This appliance is equipped with
acordhavinga earthing wire with a earthingplug. The plugmustbe plugged into an outletthat is properlyinstalledandearthed.
EARTHINGINSTRUCTIONS
Improper use of the earthing plug can result in a risk of electric shock.
Consult a qualified electrician orserviceman 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 ofthe extension cord should be equalto or greater than the electrical rating of the appliance,
or Do not use an extension cord.
WARNING

7
CONTROL PANEL
all information manually
put into the oven.
Stop/ClearButton-
Used topauseand clear
morethan1.3 sec, number
is scrolled up automatically.
this button(pad) is pressed for
time and weight.
Used toinput the cooking
Dial Knob-
Used to starttheselected
cooking cycle and to set
time.
Start/Clock Button-
(KOC-972T)
cooking cycle.
Used to starttheselected
Start Button-
increments.
cooking time in30 sec
Used to program quickly
Speedy Cook Button(pad)-
PROGRAM COOK
COMBI :COMBINATION
TEMP : CONVECTION
DEFROST : TIME or WEIGHT
PIE
DEFROST
cookingmode.
When blinking, the oven is
When blinking, the oven is
operating in "PROGRAM COOK"
operatingin "PIE"
When blinking, the oven is
operatingin "CONVECTION"
Used toselect the variable
Microwave Power Level-
microwave power level. If
cookingmode.
cookingmode.
cookingmode.
operating in "COMBI"
When blinking, the oven is
When blinking, the oven is
operatingin "GRILL"
When blinking, the oven is
operating in "MICROWAVE"
cookingmode.
cookingmode.
cooking function.
M/W : MICROWAVE
Used to select desired
Function Buttons(pads)-
scrolled up automatically.
1.3sec,number is
is pressed for more than
temperature. Ifthis button
Used to set desired
Temperature Button(pad)-
GRILL
mode.
When blinking, the ovenis
operating in "WEIGHT
DEFROST" cooking mode.
operating in "TIME
DEFROST" cooking mode.
When blinking, the ovenis
When blinking, the ovenis
operating in weght input
4.FISH FILLET
SPEEDY COOK
STOP/CLEAR
_
5.VEGETABLE
(START/CLOCK)
START
+
PROGRAM COOK
2.ROAST PORK
1.ROAST BEEF
3.ROAST CHICKEN
DEFROST
GRILL
M/W
PROGRAM
COOK PIE
MW GRILL
COMBI TEMP
PIE
KGTEMP
COOK
WEIGHT - TIMECOMBI
DEFROST

8
DISASSEMBLY ANDASSEMBLY
Cautions to be observed when trouble shooting.
Unlike many other appliances, the microwave oven is high-voltage, high-current equipment.
It is completely safety during normal operation.
However,carelessness in servicing the oven can result in an electric shock or possible danger from a short circuit.
Youare asked to observethe following precautions carefully.
1. Alwaysremove the power plug from the outlet before servicing.
2. Use aninsulated screwdriver and ware rubber gloves when servicing the high voltage side.
3. Discharge the high voltage capacitor before touching any oven components or wiring.
(1) Check the earthed.
Do not operate on a two-wire extension cord.
The microwave oven is designed to be used with earthed.
It is imperative, therefore, to make sure it is earthed properly before
beginning repair work.
(2) Warning about the electriccharge in the high voltage capacitor.
For about 30 secondsafter the operation stopped and electric charge
remains in the high voltage capacitor.
When replacing or checking parts, shortbetween oven chassis and
the negative high terminal of the high voltage capacitor,
by using a properly insulated screwdriver to discharge.
4. When the15A fuseis blownout dueto the operation of the monitor switch;
replace primaryinterlock 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.
Service personnelshould removetheirwatcheswheneverworking close toorreplacing the magnetron.
CAUTION
When servicing the appliance,needa care oftouching orreplacing highpotentialparts because ofelectricalshock or
exposing microwave.These parts are as follows -HV Transformer,Magnetron,HV Capacitor,HV Diode.
WARNING

9
DISASSEMBLY ANDASSEMBLY
1. To remove cabinet
(1) Remove four screws on cabinetback.
(2) Push the cabinet backward.
2. To remove guide wind assembly
(1) Remove two screws for earthingand for fixing to rear-plate.
(2) Remove the noise filter from theguide wind.
(3) Pull the fan from the motor shaft.
(4) Remove two screws which secure the motor shaded pole.
(5) Remove the motor shaded pole.
(6) Reverse the above steps for reassembly.

10
DISASSEMBLY AND ASSEMBLY
3. To remove H.V.transformer
(1) Remove four screws which secure
the H.V.transformer to the base plate.
(2) Remove the H.V.transformer.
(3) Reverse the above steps for reassembly.
4. To remove high voltage capacitor
(1) Remove a screw which securethe grounding ring
terminal of the H.V. diode and the capacitor holder.
(2) Remove the H.V. diode from the capacitor holder.
(3) Reverse the above steps for reassembly.
High voltage circuitwiring

11
DISASSEMBLY ANDASSEMBLY
5. To remove magnetron
(1) Remove three screws which secure the magnetron.
(2) Remove the magnetron.
(3) Reverse the above steps for reassembly.
Neverinstall 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
2
for a fully assembled oven with door normally closed.
CAUTION

12
DISASSEMBLY AND ASSEMBLY
(1) Remove a screw which securethe control panel assembly to
the oven front plate.
At the same time, draw forward the control panel assembly
from the oven front plate.
(2) Remove the dial knob.
(3) Remove ten screws which secure the main and
sub PCB assembly to control panel.
(4) Remove buttons.
(5) Remove the decorator panel.
REF NO. PART CODE PART NAME DESCRIPTION QTY REMARK
B01 3516719200 CONTROL-PANEL ABS XR-401 1
B02 3511602900 DECORATOR C/P *T STS304 T0.6 H/L 1
B03 3511603000 DECORATOR C/P *U STS304 T0.6 H/L 1
B04 3511603110 DECORATOR C-PANEL PMMA IF-850 1 SMOG
B05 3511602800 DECORATOR RING ABS XR-401 1 COATING
B06 3513404620 KNOB VOLUME ABS XR-401 1 COATING
B07 3516905120 BUTTON FUNCTION ABS XR-401 1 COATING
B08 3516907200 BUTTON FUNCTION ABS XR-401 1 COATING
B09 3516906320 BUTTON FUNCTION ABS XR-401 2 COATING
B10 PKBPMSYB00 PCB SUB AS KOC-984T 1
B11 7621301011 SCREW TAPPING T2S PAN 3x10 PW MFZN 6
B12 PKMPMSYB00 PCB MAIN AS KOC-984T1S 1
KOC-984T2S
B13 7122401211 SCREW TAPPING T2S TRS 4x12 MFZN 4


DISASSEMBLY ANDASSEMBLY
7. To remove door assembly
(1) Remove two screws which secure the stopper hinge top.
(2) Remove the door assembly fromtop plate of cavity.
(3) Reverse the above steps for reassembly.
8. To remove door parts
KOC-972T, KOC-982T
(1) Remove the gasket door. (4) Remove the barrier-screen *o.
(2) Remove the door seal assy. (5) Remove two screws.
(3) Remove the hook and spring. (6) Remove the handle from the frame door.
REF. NO. PART CODE PART NAME DESCRIPTION QTY REMARK
A01 3511708400 DOOR SEAL AS KOC-971C0S 1
A02 3513101100 HOOK POM 1
A03 3515101300 SPRING HOOK PW1 1
A04 3517004030 BARRIER-SCREEN *O TEMPERED GLASS T3.2 1
A05 3512203360 FRAME DOOR ABS XR-401 1
A06 3512601430 HANDLE DOOR ABS XR-401 1
A07 3515203600 STOPPER HINGE *T AS KOC-970T1S 1
A08 3512300800 GASKET DOOR PBT 1
A09 7621301011 SCREW TAPPING T2S PAN 3x10 MFZN 2
After replacing the door assembly, perform a check of
correct alignment with the hinge and cavity front plate.
NOTE

14
DISASSEMBLY AND ASSEMBLY
(1) Remove the gasket door.
(2) Remove a screw holding the handle.
(3) Remove the handle from the frame door.
(4) Remove the door seal ass’y.
(5) Remove the hook and spring.
(6) Remove the barrier-screen *o.
REF. NO. PART CODE PART NAME DESCRIPTION QTY REMARK
A01 3511708400 DOOR SEAL AS KOC-971C0S 1
A02 3513101100 HOOK POM 1
A03 3515101300 SPRING HOOK PW1 1
A04 3517004080 BARRIER-SCREEN *O TEMPERED GLASS T3.2 1MIRROR
A05 3512204000 FRAME DOOR ABS XR-401 1
A06 3511603200 DECORATOR DOOR *T STS304 T0.6 H/L 1
A07 3511603300 DECORATOR DOOR *U STS304 T0.6 H/L 1
A08 3515203600 STOPPER HINGE *T AS KOC-970T 1
A09 3512602400 HANDLE DOOR *T AS
ABS XR-401 WOOD GRAIN 1KOC-984T
A10 3512602300 HANDLE DOOR *U ABS XR-401 1
A11 7621300811 SCREW TAPPING T2S PAN 3x8 MFZN 1
A12 7122401211 SCREW TAPPING T2S TRS 4x12 MFZN 1
A13 3512300800 GASKET DOOR PBT 1

15
DISASSEMBLY ANDASSEMBLY
9. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gaplocated on part ‘A’
• Loosen two screws on stopper hinge top, and then push
the door to contact the door sealto oven front surface.
• Tighten two screws.
(2) To reduce gaplocated on part ‘B’
• Loosen two screws on stopper hinge under, and then push
the door to contact the door sealto oven front surface.
• Tighten two screws.
(3) To reduce gaplocated on part ‘C’
• Loosen a screw on interlock switchassembly
located bottom of oven body.
• Draw the interlock switch assembly inward as possible to engage with hook on the door bottom.
• Tighten a screw.
(4) To reduce gaplocated on part ‘D’
• Loosen a screw on interlock switchassembly located top of oven body.
• Following steps are same as step (3).
Small gap may be acceptable if the microwave leakage does notexceed 1mW/cm
2
.
NOTE
The door on a microwave oven is designed to actas an electronic seal preventing the leakage of microwave energy
from the oven cavity during the cook cycle. This function does notrequire thatthe door be air-tight, moisture (conden-
sation) Tight or light-tight. Therefore, the occasionalappearance of moisture, light or the sensing of gentle warm air
movement around the oven door is not abnormaland do not of themselves, indicate a leakage ofmicrowave energy
from the oven cavity. If such were the case, your oven could not be equipped with a bent, the very purpose of which
is to exhaustthe vapor-laden air from the oven cavity.
NOTE


DISASSEMBLY AND ASSEMBLY
10. To remove motor syncro and under heater
(1) Cut the syncro motor cover parts from the base plate.
(2) Remove two screws which secure the motor syncro and supporter to bracket syncro motor.
(3) Remove two screws and under heater assembly in cavity
11. To remove grill heater assembly
KOC-972T
(1) Remove a nut which secure the heater holder inserting the wire of grill heater to side plate.
(2) Remove two nuts and a screw which secure the heater bracket to grill heater.
(3) Remove two heater brackets.
(4) Pull the heater holder inward and then remove the grill heater.
(5) Reverse the above steps for reassembly.

17
DISASSEMBLY ANDASSEMBLY
(1) Remove two screws which secure the cover insulator *t to top plate.
(2) Remove the harness between heaters.
(3) Remove two screws for removing heater brackets.
(4) Remove heaters.
(5) Reverse the above steps for reassembly.
12.To removeconvection partassembly
(1) Remove cover *b and cover insulator *b protecting convection part assembly. - release two lances ofcover insulator *b.
(2) Remove four screws which secure the convection part assembly to the cavity rear plate.
(3) Remove a nut holding the convection fan and the pipe.
(4) Remove two screws which secure the bracket motor to cover insulator.
(5) Remove the cooling fan.
(6) Remove two screws which secure the motor shaded pole to the bracket motor.
(7) Reverse the above steps for reassembly.

18
INTERLOCK MECHANISM AND ADJUSTMENT
The door lock mechanism is adevice which has been speciallydesigned 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 thedoor is not closed properly, the oven will not operate.
When the door is closed, the hook pushes the button of the microswitch.
Then the button of the primary interlock switch bring it under “ON” condition.
2. Secondary interlock switch, door open monitor switch and interlock monitor switch
When the door is closed, the hook pushes the latch lever downward.
The latch lever presses the button of the interlock monitor switch to bring it under “OFF” conditionand
presses the button of the secondary interlock switch and door open monitor switch to bring it under “ON” condition.
3. Adjustment steps
(1) Loosen two mounting screws.
(2) Adjust interlock switch assembly position.
(3) Make sure that latch lever movessmoothly after adjustment is completed.
(4) Tighten completely two mounting screws.
Interlock monitor switch
When the door is closed, the interlock monitor switch should be opened before other switches are closed.
When the door is opened, the interlock monitor switch should be closed after other switches are opened.
ADJUSTMENT
Microwave emission test should be performed after adjusting interlock mechanism.
If the microwave emission exceed 4mW/cm2, readjust interlock mechanism.
NOTE

19
MEASUREMENT AND TEST
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT
Microwave output power can be checked by indirectly measuring the temperature rise of a certain
amount of water exposed to the microwave as directed below.
PROCEDURE
1. Microwave power output measurement is made wit the microwave oven supplied at rated voltage and operated at its
maximum microwave power setting witha load of 1000 ± 5cc of potable water.
2. The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and
an outside diameter of approximately 190 mm.
3. The oven and the empty vessel are at ambient temperature prior to the start of the test.
The initial temperatureof the water is 10 ± 2 °C (50 ± 3.6 °F).
It is measured immediately before the wateris added to the vessel.
After addition of the waterto the vessel, the load is immediately placed on the center ofthe shelf,
which is in the lowest normal position.
4. Microwave power is switched on.
5. Heating time should be exactlyAseconds.
Heating time is measured while the microwave generator is
operating at full power.
The filament heat-up time for magnetron is not included.
6. The initial and final temperature ofwater is selected so that the maximum
difference between the ambient and final water temperature is 5K.
7. The microwave power output P in watts is calculated from the following formula:
•
 Tis difference between initial and ending temperature.
•t is the heating time.
The power measured should be B(refer to Specifications)W ± 10.0 %.
Heating time for power output:
A (second) 7064605652494744424038
B (W) 600 650 700 750 800 850 900 950 1000 1050 1100
1. Water load should be measured exactly to 1 liters.
2. Input power voltage shouldbe exactly specified voltage(Refer to SPECIFICATIONS).
3. Ambient temperature should be 20 ± 2 °C (68 ± 3.6°F)
CAUTION
P = 4187  T/t

20
MEASUREMENT AND TEST
2. ELECTRICAL CONTINUITY CHECK OF INTERLOCK SWITCH
PROCEDURE
1. Primary interlock switch
(1)Disconnect two connectors from primary interlock switch.
(2)Connect the ohm-meter leads between the terminals of the primary interlock switch.
2. Read the value of resistance between the terminals of the switch, when the door is opened, and when the door is closed.
3. Secondary interlock switch
(1)Disconnect two connectors from secondary interlock switch.
(2)Connect the ohm-meter leads between the terminals of the secondary interlock switch.
(3)Read the value of resistance between theterminals of the switch, when the door isopened,
and when the door is closed.
3. Monitor interlock switch
(1)Disconnect the lead wire connecting the primary interlock switch and interlock monitor switch from
primary interlock switchterminal.
(2)Connect the ohm-meter leads between the lead wire connector disconnected as item1 and
the power supply neutral plug pin.
(3)Read the value of resistance between thelead wire connectorand the power supply neutral plug pin,
when the oven door is opened, and when the ovendoor is closed.
JUDGEMENT
•The value of resistance should be applied to the value specified below.
• When value obtained is not acceptable,the switch should be replaced or adjustedagain.
Switch Door Open Door Close
Primary interlock switch

0
Secondary interlock switch

0
Interlock monitor circuit 0

Remove the powerplug from the wall receptacle before testing.
NOTE