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S/M No. : G867T7S001
Service Manual
Microwave Oven & Toaster
Model: KOG-867T
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).
DAEWOO ELECTRONICS CORP.
http : //svc.dwe.co.kr Dec. 2003
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.
(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
SAFETY AND PRECAUTIONS........................................................................................................................................3
FOR SAFE OPERATION...........................................................................................................................................3
FOR SAFE SERVICE PROCEDURES .....................................................................................................................3
SPECIFICATIONS ............................................................................................................................................................4
EXTERNAL VIEW .............................................................................................................................................................5
OUTER DIMENSION .................................................................................................................................................5
FEATURE DIAGRAM.................................................................................................................................................6
CONTROL PANEL.....................................................................................................................................................7
INSTALLATION ................................................................................................................................................................8
OPERATION PROCEDURE(MICROWAVE OVEN)........................................................................................................9
IMPORTANT ...................................................................................................................................................................10
OPERATION PROCEDURE(TOASTER).......................................................................................................................11
DISASSEMBLY AND ASSMBLY...................................................................................................................................12
INTERLOCK MECHANISM AND ADJUSTMENT.........................................................................................................20
TROUBLE SHOOTING GUIDE ......................................................................................................................................21
MESUREMENT AND TEST............................................................................................................................................26
MEASUREMENT OF THE MICROWAVE POWER OUTPUT................................................................................26
MICROWAVE RADIATION TEST ...........................................................................................................................27
COMPONENT TEST PROCEDURE .......................................................................................................................28
WIRING DIAGRAM.........................................................................................................................................................29
PRINTED CIRCUIT BOARD...........................................................................................................................................30
CIRCUIT CHECK PROCEDURE.............................................................................................................................30
PCB CIRCUIT DIAGRAM ........................................................................................................................................33
P.C.B. LOCATION NO. ............................................................................................................................................34
EXPLODED VIEW AND PARTS LIST ...........................................................................................................................35
DOOR ASSEMBLY ..................................................................................................................................................35
CONTROL PANEL ASSEMBLY ..............................................................................................................................35
TOTAL ASSEMBLY .................................................................................................................................................35
2
SAFETY ANDPRECAUTIONS
CAUTION : This Device is to be Serviced Only by Properly Qualified Service Personnel. Consult the Service
Manual for Proper Service Procedures to Assure Continued Safety Operation and for Precautions
to be Taken to Avoid Possible Exposure to Excessive Microwave Energy.
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 have excessive emission level 5mW/cm2, the service person should:
(a) inform the manufacturer, importer or assembler,
(b) repair the unit at no cost to the owner,
(c) attempt to ascertain the cause of the excessive leakage,
(d) 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.
CAUTION
MICROWAVE RADIATION
PERSONNEL SHOULD NOT BE EXPOSED TO THE MICROWAVE ENERGY WHICH MAY RADIATE
FROM THE MAGNETRON OR OTHER MICROWAVE GENERATING DEVICE IF IT IS IMPROPERLY
USED OR CONNECTED. ALL INPUT AND OUTPUT MICROWAVE CONNECTIONS. WAVEGUIDES
FLANGES AND GASKETS MUST BE SECURED. NEVER OPERATE THE DEVICE WITHOUT A
MICROWAVE ENERGY ABSORBING LOAD ATTACHED. NEVER LOOK INTO AN OPEN WAVEGUIDE
OR ANTENNA WHILE THE DEVICE IS ENERGIZED.
3
SPECIFICATIONS
POWER SUPPLY 230V AC 50 Hz SINGLE PHASE WITH EARTHING
POWER CONSUMPTION 1350 W
OUTPUT POWER 900 W
FREQUENCY 2450 MHz
MICROWAVE OVEN TIMER 59 min. 90 sec.
POWER LEVELS 10 LEVELS
CAVITY DIMENSIONS 320 x 244 x 338 mm (12.6 x 9.6 x 13.3 inch)
CAVITY VOLUME 0.9 Cu.ft
TOASTER POWER CONSUMPTION 900 W
MICROWAVE + TOASTER POWER CONSUMPTION 2200 W
OUTSIDE DIMENSIONS (W x H x D) 583 x 301 x 421 mm (22.9 x 11.8 x 16.5 inch)
NET WEIGHT APPROX. 15.7 KG (34.3 lbs)
* Specifications are subject to change without notice.
IMPORTANT
The wires in this mains lead are colored in accordance with the following code.
Green-and-yellow : Earth
Blue : Neutral
Brown : Live
As the colors of the wires in the mains lead of this appliance may not correspond with the colored markings
identifying the terminals in your plug, proceed as follows: the wire which is colored green-and-yellow must be
connected to the terminal in the plug which is marked with the letter 'E', the earth symbol or colored green-
and-yellow. The wire which is colored blue must be connected to the terminal which is marked with the letter
'N' or colored black.
The wire which is colored brown must be connected to the terminal which is marked with the letter 'L' or
colored red.
WARNING: This appliance must be earthed.
4
EXTERNAL VIEW
1. OUTER DIMENSION
M/W TOAST DEF. TIMER g
BREAD BAGEL
TOAST
STOP
START
CLEAR
1.Beverage 2.Baked
Potato AUTO
M/W
DEFROST
AUTO
COOK
5.Dinner
Plate 3.Frozen KITCHEN
Pizza MEMORY
TIMER
4.Fresh
Vegetable
10 MIN 1 MIN 10 SEC
1 HOUR 10 MIN 1 MIN
CLOCK
MORE LESS
STOP START
CLEAR SPEEDY COOK
5
2. FEATURE DIAGRAM
MICROWAVE OVEN TOASTER
2 3 4 5 0
M/W TOAST DEF. TIMER g
BREAD BAGEL
TOAST
STOP
START
CLEAR
2.Baked
1.Beverage
Potato AUTO
M/W
DEFROST
AUTO
1
COOK
5.Dinner
Plate 3.Frozen KITCHEN
Pizza MEMORY
TIMER
4.Fresh
Vegetable
10 MIN 1 MIN 10 SEC
q
1 HOUR 10 MIN 1 MIN
CLOCK
MORE LESS
STOP START
CLEAR SPEEDY COOK
9 8 7 6 w
1. DOOR LATCH
When the door is closed it will automatically shut off. If the door is opened while the oven is operating, the
magnetron will automatically shut off.
2. DOOR SEAL
The door seal maintains the microwave within the oven cavity and prevents microwave leakage.
3. OVEN CAVITY
4. SPATTER SHIELD
Protects the microwave outlet from splashes of cooking foods.
5. SAFETY INTERLOCK SYSTEM
Prevents the oven from operating while the door is opened.
6. DOOR RELEASE BUTTON
Pushing this button stops oven operation and opens the door.
7. GLASS 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.
8. ROLLER GUIDE
Supports the glass cooking tray.
9. DOOR SCREEN
Allows viewing of food. The screen is designed so that light can pass through, but not the microwaves.
10. TOASTER DRAWER
11. TOASTER OPENING HANDLE
12. CRUMB TRAY(REFER. PAGE10)
6
3. CONTROL PANEL
2
M/W TOAST DEF. TIMER g
3 BREAD BAGEL 4
TOAST
STOP
5 CLEAR
START 6
w
2.Baked
q
1.Beverage
Potato AUTO
M/W
DEFROST
AUTO
8 COOK
5.Dinner
Plate
4.Fresh
3.Frozen
Pizza MEMORY
KITCHEN
TIMER e
Vegetable
7
10 MIN
1 HOUR
1 MIN
10 MIN
10 SEC
1 MIN 1
9 CLOCK r
MORE LESS
0
STOP START
t CLEAR SPEEDY COOK
y
1 Time set pad - Used to set the cooking time and the present time.
2 Display - Cooking time, power level, indicators and present time are displayed.
3 Toast Bread - Used to reheat bread.
4 Toast Bagel- Used to reheat bagel.
5 Toast Stop/Clear - Used to stop the toast operation or to clear the toast setting.
Used to transfer toaster mode to microwave mode.
6 Toast Start - Used to toast start.
7 Memory - Used to set favorite cooking mode.
8 Auto Cook - Used to cook or reheat.
9 More-Used to add time to cooking.
0 Less-Used to remove time from cooking.
q Auto Defrost - Used to defrost foods.(for weight and time)
w M/W - Used to select microwave power level.
e Kitchen Timer - Used as a minute timer, to delay the start of cooking, or to set a holding time after cooking.
r Clock - Used to set clock.
t Stop/Clear - Used to stop the Microwave operation or to delete the cooking data.
Used to transfer Microwave mode to toaster mode.
y Start/Speedy Cook - Used to start the oven and also used to set a reheat time.
7
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 oven failure. Position the oven as far from them as passible.
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.
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 and toaster requires a current of approximately 10 amperes, 230Volts, 50Hz grounded outlet.
Power supply cord is about 1.0 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 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 or 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.
8
OPERATION PROCEDURE(MICROWAVE OVEN)
This section includes useful information about Microwave oven operation.
1. Plug power supply cord into a standard 3-pronged 15Amp, 230V AC 50Hz poweroutput.
2. After placing the food in a suitable container, open the oven door and put it on the glass tray.
The glass tray and roller guide must always be in place during cooking.
3. Shut the Microwave oven door. Make sure that it is firmly closed.
1 The oven light is on only when the microwave oven 7
is operating.
When the Microwave STOP/CLEAR pad is touched
during the oven operation, the oven stops cooking and all
information retained. To erase all information(except the
present time), touch the STOP/CLEAR pad once more.
2 The oven by touching the door at any time during the
operation
door can be opened
release button on If the oven door is opened during the oven operation, all
control panel. The oven will automatically shut off. information is retained.
3 Each time a pad is touched, a BEEP sounds to
acknowledge the touch.
8 If the Microwave START pad is touched and the oven
does not operate, check the area between the door and
door seal for obstructions and make sure the door is
closed securely. The oven will not start cooking until the
4 Theto a lower power level. on full power unless
set
oven automatically cooks
door is completely closed or the program has been reset.
5 The display will show
in.
: 0 when the oven is plugged Make sure the oven is properly installed and
plugged into the electrical outlet.
6 Time clock returns to the present time when the
cooking time ends.
WATTAGE OUTPUT CHART
The power-level is set by pressing the MICROWAVE pad. The chart shows the display, the power level and the
percentage of power.
Touch MICROWAVE pad Power level (Display) Approximate Percentage of Power
once P-HI 100%
twice P-90 90%
3 times P-80 80%
4 times P-70 70%
5 times P-60 60%
6 times P-50 50%
7 times P-40 40%
8 times P-30 30%
9 times P-20 20%
10 times P-10 10%
11 times P-00 0%
9
IMPORTANT
Before using the toaster for the first time, operate the toaster without bread in order to burn off residues on the
heating elements. You will notice an odor that is characteristics of new heating elements. This is normal and will
soon disappear.
CLEANING THE TOASTER
Always unplug the Microwave oven & Toaster and allow the toaster to cool completely before cleaning.
Toaster drawer:
Wipe surface with a soft, clean, damp cloth. Never use abrasive cleaners, as they may scratch the surface. Do not
use fork or other sharp, metal object to clean inside of the Toaster drawer, or to remove toast, as it may damage
heating elements.
Crumb Tray :
After allowing the toaster to cool down and closing the door, gently slide out the crumb tray. Brush crumbs off the
tray and, if necessary, wipe it with a clean, damp cloth. Always dry the tray thoroughly. When sliding the crumb
tray into place, be sure you feel and hear it snap into position.
COOKING TIPS
WARNING!
Never place any object in the toaster for any reason!
DO NOT toast pastries with runny fillings or frosting.
DO NOT toast torn slices of bread or broken pastries.
DO NOT place buttered bread, wrapped food, or frozen pastries in the toaster.
DO NOT use this toaster to toast or warm small-size bread slices. These include melba size breads, slices of
mini-baguettes, breadsticks, etc.
DO NOT toast oversized bagel. Because thick bagel s surface may become closer to the heater, this may cause
overdone of surface and smoke.
NOTE : Different types of bread and their moisture levels may require different darkness settings. For
example, dry bread will brown more rapidly than moist bread and so will be toasted to your taste at a
lighter setting.
NOTE : 2 pieces of bread or bagel should be cooked with this toaster.
10
OPERATION PROCEDURE(TOASTER)
This section includes useful information about toaster operation.
1. Plug power supply cord into a standard 3-pronged 15Amp, 230V AC 50Hz poweroutput.
2. Put 2 pieces of toast bread or bagel between the toaster guides (wire rack) of the toaster drawer.
3. Shut the toaster drawer. Make sure that it is firmly closed.
1 The toaster drawer can be opened at any time during operation by pulling out the toaster handle on the toaster
drawer. The toaster will automatically shut off.
2 Touch the bread or bagel pad of toast menu and the degree of darkness will be displayed.
3 Each time a pad is touched, a BEEP sounds to acknowledge the touch.
4 Touch toaster start pad and thentoaster (not in the case ofistimeand the best cooking time isstarts. During the
according to the condition of the
the toast indicator linght on
toasting) and toast cooking
displayed
toast cooking, hot smoke or air may goes out from the gap of the toaster drawer.
5 When the toast STOP/CLEAR all information(except the present time), touch toaster stops cooking and all
information retained. To erase
pad is touched during the oven operation, the
the STOP/CLEAR pad once
more. If the toaster drawer is opened during the toaster operation, all information is retained.
6 If the toast START pad is not start cooking until thedoes notdrawer is completelytoaster drawer program has
securely. The toaster will
touched and the toaster
toaster
operate, check the
closed or the
is closed
been reset.
NOTE :
When the toaster drawer is opened after toast cooking, hot smoke or air will go out and the toaster guides
(wire rack) are very hot.
Take out food carefully not to touch hot surfaces of the toaster or hot air.
NOTE :
When the toaster is operated several times in series and is overheated, the safety thermal switch works
and the heating elements stop operating. So, though the toaster seems to operate normally, it does not
cook toast.
Open the toaster drawer and cool it for 5~6 min.
After then the toaster can cook toast normally.
NOTE :
When you start toast cooking (br-1~br-3 and bg-1~bg-3) within 1 min. in series after toast cooking, the
toaster starts cooking with cooling time automatically added to the cooking time.
NOTE :
When you start toast cooking, the best cooking time is displayed according to the condition of the toaster.
(br-1~br-3: 1 min. 20 sec.~2 min. 40 sec/ bg-1~bg-3: 1min. 20 sec.~2 min. 45 sec.)
11
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 earthed.
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 due to the operation of the monitor
switch; replace primary interlock 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.
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, HV Fuse.
12
1. To remove cabinet
1) Remove three 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 reassembly.
NOTE : After replacing the door assembly, perform a check of correct alignment with the hinge and cavity front plate.
13
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).
3. To remove door parts.
Door As : 3511724200
REF NO. PART CODE PART NAME DESCRIPTION Q'TY
A01 3517008600 BARRIER SCREEN*O SAN T1.5 1
A02 3511724400 DOOR SUB AS KOG-867T9 1
A03 3511711800 DOOR PAINTING AS KOR-86670S 1
A04 3515204100 STOPPER HINGE*T AS KOR-63150S 1
A05 3517006000 BARRIER SCREEN*I PE T0.1 1
A06 3512302000 GASKET DOOR PP 1
A07 3513100700 HOOK POM 1
A08 3515101300 SPRING HOOK PW-1 1
(1) Remove the gasket door from door plate.
(2) Remove the barrier screen inner from door plate.
(3) Remove the door sub assembly from door painting assambly.
(4) Remove the stopper hinge top assembly from door painting assambly.
(5) Remove the spring and the hook.
(6) Remove the barrier screen outer from door sub assembly.
(7) Reverse the above steps for reassembly.
14
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part A .
Loosen the screw on stopper hinge top, and then push the
door to contact the door seal to oven front surface. M/W TOAST DEF. TIMER g
BREAD BAGEL
Tighten the screw. STOP
CLEAR
1.Beverage
TOAST
2.Baked
Potato
M/W
START
AUTO
DEFROST
AUTO
COOK
5.Dinner
Plate 3.Frozen KITCHEN
Pizza MEMORY
TIMER
4.Fresh
Vegetable
10 MIN 1 MIN 10 SEC
1 HOUR 10 MIN 1 MIN
(2) To reduce gap located on part B . MORE
STOP
CLEAR
LESS
START
CLOCK
SPEEDY COOK
Loosen two screws on stopper hinge under, and then push
the door to contact the door seal to oven front surface.
Tighten two screws.
NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.
15
5. To take off the toaster assembly.
(1) Remove four screws on the toaster assembly.
(2) Lift up the toaster assembly and pull it out.
(3) Reverse the above for assembly.
NOTE : To assemble the toaster assembly, push two taps on the side of the toaster front plate into two rectomgular
holes of the front plate securely. And push two rectangular holes of the bottom of the toaster front plate into
two vertical taps of the base plate.
16
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).
6. To remove control panel parts.
REF NO. PART CODE PART NAME DESCRIPTION Q'TY
B01 3518524410 SWITCH MEMBRANE KOG-867T7S 1
B02 3516731110 CONTROL PANEL ABS SG-175 SG-0760D 1
B03 PKMPMSAY10 PCB AS KOG-867T7S 1
B04 7122401211 SCREW TAPPING T2S TRS 4X12 MFZN 4
B05 3513702700 LEVER DOOR LOCK PP 1
B06 441G430171 BUTTON SPRING SWP DIA 0.7 1
B07 3516912300 BUTTON DOOR OPEN ABS SG-175 SG-0760D 1
(1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly.
(2) Remove the door open lever from the control panel.
(3) Remove four screws which secure the PCB assembly to control panel.
(4) Disconnect membrane tail from the connector of the PCB assembly.
(5) Detach membrane from the control panel.
(6) Remove door open button and button spring from the control panel.
(7) Reverse the above steps for reassembly.
17
7. To remove high voltage capacitor.
1) Remove a screw which secure the 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.
8. High voltage circuit wiring
9. To remove magnetron.
1) Remove a screw which secure the magnetron.
2) Remove the magnetron.
3) Reverse the above steps for reassembly.
NOTE : 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/cm2 for a fully assembled oven with door normally closed.
Metallic Magnetron
gasket antenna
plate
Cooling fin
Filament
terminal
18
10. To remove wind guide assembly.
1) Remove a screw which secure the wind guide assembly.
2) Draw forward the wind guide assembly.
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 reasembly.
11. To remove H.V.transformer.
1) Remove four screws holding the H.V.transformer.
2) Remove the H.V.transformer.
3) Reverse the above steps for reassembly.
19
INTERLOCK MECHANISM AND ADJUSTMENT
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.
Toast Panel Top
GN
BK
RD
RD/RD
WH/BL
Spring
WH
BK
Condition : Toast Drawer Open
DOM SWITCH
GN
BL Toast interlock switch
BK/WH
WH/WH
Condition : DOOR CLOSE Condition : DOOR OPEN Condition : Toast Drawer Close
(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 button of the micro switch. Then the button of the primary interlock switch
bring it under NO condition.
(2) Secondary interlock switch and interlock monitor switch
When the door is closed, the hook pushes the lock lever downward. The lock lever presses the button of the interlock
monitor switch to bring it under NO condition. The lock lever presses the button of the secondary interlock switch to bring
it under NO condition.
(3) Toast interlock switch
When the toast drawer is closed, the lever pushes the button of the micro switch.
Then the button of the toast interlock switch bring it under NO condition.
ADJUSTMENT :
Interlock monitor switch
When the door is closed, the interlock monitor switch should be changed (NO condition) before other switches are closed.
When the door is opened, the interlock monitor switch should be changed (NC condition) after other switches are opened.
(4) Adjustment steps
a) Loosen the one mounting screw.
b) Adjust interlock switch assembly position.
c) Make sure that lock lever moves smoothly after adjustment is completed.
d) Tighten completely two mounting screws.
NOTE :
Microwave emission test should be performed after adjusting interlock mechanism.
If the microwave emission exceed 4mW/cm2, readjust interlock mechanism.
20
TROUBLE SHOOTING GUIDE
Following the procedure below to check if the oven is defective or not.
1) Check grounding before trouble checking.
2) Be careful of the high voltage circuit.
3) Discharge the high voltage capacitor.
4) When checking the continuity of the switches, fuse or high voltage tranformer, disconnect one load wire from these
parts and check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to
your meter.
NOTE : When electric parts are checked, be sure the power cord is not inserted the wall outlet.
Check wire harness, wiring and connection of the terminals and power cord before check the parts listed below.
(TROUBLE 1) Oven does not operate at all : any inputs can not be accepted.
CONDITION CHECK RESULT CAUSE REMEDY
Fuse blows. Replace
Check continuity of interlock Malfunction of
Continuity
monitor switch with door closed interlock NOTE 1
(COM NC) monitor switch
No Continuity
Check continuity of both
primary and secondary No Continuity Replace
interlock switch with door Malfunction of
NOTE 1
closed interlock switch
Continuity
Continuity Replace
Check continuity of primary Shorted contacts
interlock switch contact with door of primary NOTE 1
partially open until interlock interlock switch.
monitor switch contact close
(COM NC)
0 or infinite Replace
Check continuity of primary Defective low
winding of low voltage voltage
Approx.
transformer transformer
1160
(normal)
Replace
Defective high
Disconnect high voltage fuse Fuse again
voltage
and operate the unit blows
transformer
21
CONDITION CHECK RESULT CAUSE REMEDY
No Defective Replace
Outlet has
Check continuity of magnetron Continuity
proper magnetron
voltage Fuse
does not
blow. Check continuity of No Defective line Replace
noise filter board Continuity filter board
Check continuity of No Open power Replace
power supply cord Continuity supply cord
Normal Defective touch Adjust
control circuit
NOTE 1
All these switches must be replaced at the same time, please refer to Interlock Mechanism And Adjustment .
(TROUBLE 2) Display shows all figures selected, but oven does not start cooking, even though desired program and
time are set and start pad is pressed.
CONDITION CHECK RESULT CAUSE REMEDY
Turntable Check continuity of primary No Malfunction of Adjust or
motor and interlock switch Continuity primary interlock replace
oven lamp switch
do not turn
on
Check continuity of secondary No Malfunction of Adjust or
interlock and D.O.M. switches Continuity primary interlock replace
and D.O.M.
switch
Check D.C. voltage being 0V Defective touch Replace
supplied to RELAY (RY2) coil control circuit
Approx. Replace
Faulty contacts of
15 VDC RELAY (RY2) or
open relay coil
22
(TROUBLE 3) No microwave oscillation even though fan motor rotates.
CONDITION CHECK RESULT CAUSE REMEDY
No Check continuity of No Defective Replace
microwave high voltage fuse continuity high voltage
oscillation fuse
No microwave oscillation
Check continuity of Continuity Defective 1
high voltage capacitor terminals high voltage
with wires removed transformer
Check continuity of Continuity Defective high Replace
high voltage rectifier in forward in backward voltage rectifier
and backward direction
direction with DC megger
Connect megger leads to Continuity Defective 2
magnetron terminal and magnetron
magnetron body
Check D.C voltage 0V Defective Replace
being supplied to touch control
RELAY (RY1) coil circuit
Approx. Faulty contacts of Replace
15V DC RELAY
(RY1) or open
relay coil
1 Check resistance of primary 0 or Defective Replace
and secondary coil of high high voltage
voltage transformer transformer
1 Check continuity of filament No continuity Defective high Replace
terminal of high voltage voltage
transformer transformer
2 Check continuity of Defective Replace
No continuity
magnetron heater with wires magnetron
removed
23
(TROUBLE 4)
Toaster heater is not heated; bread or bagel will not toast.
CONDITION CHECK RESULT CAUSE REMEDY
Toaster Check continuity of No Adjust or
Malfunction of
heater is spring flat continuity replace
spring flat
not heated.
Check continuity of No Adjust or
Malfunction of replace
interlock switch continuity interlock switch
Check continuity of No Defective heater Replace
- heater assy continuity assy
Check D.C voltage 0V Defective touch Replace
being supplied to control circuit
RELAY (RY3) coil
Approx. Faulty contacts of Replace
15V DC RELAY
(RY3) or open
relay coil
(TROUBLE 5)
1) Fan motor does no rotate.
CONDITION CHECK RESULT CAUSE REMEDY
Check continuity of No Malfunction of Adjust or
primary interlock switch continuity primary Interlock replace
1)Fan switch
motor does
not rotate. Check continuity of No Malfunction of Adjust or
secondary interlock continuity secondary replace
switch interlock switch
Check continuity of No Replace
Defective motor
(heater or motor) continuity
Check D.C voltage 0V Defective touch Replace
being supplied to control circuit
RELAY (RY4) coil
Approx. Faulty contacts of Replace
15V DC RELAY
(RY4) or
open relay coil
24
(TROUBLE 6) The following visual conditions indicate a probable defective touch control circuit or membrane switch
assembly
1. Incomplete segments,
1) Segments missing.
2) Partical segments missing.
3) Digit flickering other than normal display slight flickering.
4) " :0" does not display when power is on.
2. A distinct change in the brightness of one or more numbers exists in the
display.
M/W TOAST DEF. TIMER
3. One or more digits in the display are not on when they should be.
4. Display indicates a number different from one touched.
5. Specific numbers (for example 2 or 3) will not display when the panel is touched.
6. Display does not count down or up with time cooking or clock operation.
7. Oven is programmable and cooks normally but no display shows.
8. Display obviously jumps in time while counting down.
9. Display counts down noticeably too fast while cooking.
10. Display does not show the time of day when clear pad is touched.
11. Oven lamp and turntable motor do not stop although cooking is finished. Check if the RELAY 2 contacts close if they
are close, replace touch control circuit.
CONDITION CHECK RESULT CAUSE REMEDY
Normal
Display does Check each pad for Replace pcb
not show continuity of the membrane assembly
Malfunction
programming keyboard for the following
of pcb assembly
at all, even if keyboard check procedure
keyboard is
touched.
Abnormal Malfunction Replace the
of the membrane membrane
keyboard keyboard
NOTE
Before following the particular steps listed above in the trouble shooting guide for the membrane keyboard's,
failure, please check for the continuity of each wire-harness between the membrane keyboard and P.C.B.
assembly.
25
MEASUREMENT AND TEST
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT
Microwave output power can be checked by indirectly mmeasuring the temperature rise of a certain amount of water
exposed to the microwave as directed below.
PROCEDURE
1. Microwave power output measurement is made with the microwave oven supplied at rated voltage and operated at
its maximum microwave power setting with a 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 temperature of
the water is 10 2 C (50 3.6 F). If is measured immediately before the water is added to the vessel. After
addition of the water to the vessel, the load is immediately placed on the center of the shelf, which is in the lowest
normal position.
4. Microwave power is switched on.
5. Heating time should be exactly A seconds.
(Refer to table as following)
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 of water is selected so
that the maximum difference between the ambient and
final water temperature is 5K.
7. The microwave powe