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Service Manual
Microwave Oven
KOG-261M, KOG-262M
KOG-281M, K OG-282M
D AEW OO ELECTRONICS CO ., LTD.
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1
PRECAUTIONS TO BE OBSERVED BEFORE
AND DURING SERVICING TO AVOID
POSSIBLE EXPOSURE T O EXCESSIVE
MICROWAVE ENERGY
(a) Do not operate or allow the oven to be operated with door open.
(b) Make the following safety checks on all ovens to be serviced before activating the mag-
netron or other microwave source, and make repairs as necessary : (1) Interlock operation,
(2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4)
damage to or loosening of hinges, (5) evidence of dropping or abuse.
(c) Before turning on microwave power for any service test or inspection within the microwave
gernerating compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, intergrity, and connections.
(d) Any defective or misadjusted components in the interlock, monitor, door seal, and
microwave gerneration and transmission systems shall be repaired, or adjusted by procedures described in this manual before the oven is released to the owner.
(e) A micrewave leakage check to verify compliance with the federal performance standard
should be performed on each oven prior to release to the owner.
PROPER USE AND SERVICE PRECAUTIONS................................................................................. 2
SPECIFICATIONS................................................................................................................................ 3
FEATURES DIAGRAM......................................................................................................................... 4
EARTHING INSTRUCTIONS............................................................................................................... 5
INSTALLATION..................................................................................................................................... 5
OPERATION PROCEDURE................................................................................................................. 6
CONTROLS .......................................................................................................................................... 7
INTERLOCK MECHINISM FUNCTIONS AND ADJUSTMENTS........................................................ 18
SAFETY PRECAUTIONS FOR DISASSEMBLY AND REPAIR.......................................................... 20
DISASSEMBLY AND ASSEMBLY....................................................................................................... 21
TROUBLE SHOOTING GUIDE............................................................................................................ 27
MEASUREMENT OF THE MICROWAVE OUTPUT POWER ............................................................ 34
MICROWAVE RADIATION TEST........................................................................................................ 34
WIRING DIAGRAM............................................................................................................................... 36
CIRCUIT DESCRIPTION...................................................................................................................... 37
COMPONENT TEST PROCEDURE.................................................................................................... 40
SAFETY INTERLOCK CONTINUITY TEST......................................................................................... 41
PRINTED CIRCUIT BOARD................................................................................................................. 42
CIRCUIT CHECK PROCEDURE...................................................................................................... 42
COMPONENT INFORMATION........................................................................................................ 47
PRINTED CIRCUITS BOARD.......................................................................................................... 48
P.C.B. CIRCUIT DIAGRAM.............................................................................................................. 49
P.C.B. LOCATION NO...................................................................................................................... 50
EXPLODED AND PARTS LIST............................................................................................................ 51
TABLE OF CONTENTS
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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 tok the operator.
IF ANY OF THE FOLLOWING CONDITIONS EXIST. OPERATOR MUST NOT USE THE APPLI-
ANCE. (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 servicing, a microwave emission check should be performed
prior to servicing the oven.
(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 and CDRH immediately.
2
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.
PROPER USE SERVICE PRECA UTIONS
CAUTIOU
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. WAVEGUIDE, FLANGES AND GASKETS MUST BE SECURE. NEVER OPERATE
THE DEVICE WITHOUT A MCROWAVE ENERGY ABSORNING LOAD ATTACHED. NEVER
LOOK INTO AN OPEN WAVEGUIDE OR ANTENNA WHILE THE DEVICE IS ENERGIZED.
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* Specifications subject to change without notice.
POWER SUPPLY
POWER CONSUMPTION
MICROWAVE ENERGY OUTPUT
MICROWAVE FREQUENCY
OUTSIDE DIMENSIONS (W x D x H)
CAVITY DIMENSIONS (W x D x H)
NET WEIGHT
TIMER
FUNCTION SELECTIONS
MICROWAVE POWER LEVELS
KOG-261M / 262M KOG-281M / 282M
120V~60Hz, SINGLE PHASE WITH EARTHING
920W 1200W
1050W 1050W
600W 800W
2450MHz
465 x 360 x 274 mm 495 x 382 x 289 mm
290 x 290 x 200 mm 320 x 330 x 225 mm
14kg 15kg
59 min. 99 sec.
MICROWAVE / GRILL
10 – LEVELS
3
SPECIFICATIONS
( ) : For KOG-281M/282M
MICROWAVE
GRILL
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1 Door latch–When the door is closed it will
automatically lock shut. If the door is
opened while the oven is operating. The
magnetron will automatically shut off.
2 Door seal–The door seal maintains the
microwave within the oven cavity and pre-
vents 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 fof food. The
Screen is designed so that light can pass
through, but not the microwaves.
10 Time set pad–Used to set the cooking
time and the present time
11 Display–Cooking time, power level, pre-
sent time are displayed.
12 Menu–Uesd to select foods.
13 Weight–Uesd to select quantity of foods.
14 Speedy–Touh to set the any desired
reheat setting.
15 Grill–Used to cook Grill.
16 Dinner plate–Used to reheat dinner plate.
17 Beverage–Used to reheat beverage.
18 Frozen pizza–Used to reheat frozen
pizza.
19 More–Used to add on one touch cooking.
20 Less–Used to add on one touch cooking.
21 Auto defrost–Used to defrost foods.
22 Power–Used to set power level.
23 Clock/A.start–Used to set clock & Used
to set auto start.
24 Stop/Clear–User to stop the oven opera-
tion or to delete the cooking data.
25 Start–Used to start a selected operation.
26 Feeding bottle–Used to disinfect bottle.
27 Reflector (Insulator Heater).
28 Heating Element.
29 Metal Rack.
30 Coupler.
4
FEATURES DIAGRAM
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This appliance must be earthed. In the event of an electrical short circuit, earthing reduces the risk of
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 ploug must be plugged into an outlet that is
properly installed and earthed.
5
EARTHING INSTRUCTIONS
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 extension to whether the appliance is properly earthed. If it
necessary to use an extension cord, use only a 3-wire extension cord that has a 3blade 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.
INSTALLATION
Steady, flat location
This oven should be set on a steady, flat surface.
This oven is designed for counter top use only.
Leave space behind and side
All air vents should be kept a clearance. lf all vents are covered during operation, the oven may
overheat and, eventually, oven failure.
Away from Radio and TV sets
Poor television reception and radio interference may result if the oven is located close to a TV,
Radio, or antenna, feeder and so on.
Position the oven as far from them as possible.
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.
Power supply
• Check uour local power source. This oven requires a current of approximately 10 amperes.
120V 60Hz.
• Power supply cord is about 1.1 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 thpe, 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.
Examine the oven after unpacking for any damage such as:
QA misaligned door, broken door, A dent in cavity.
If any of the above are visible, DO NOT INSTALL, and notify dealer immediately.
Do not operate the oven if it is colder than room termperature.
(This may occur during delivery in cold weather.) Allow the oven to become room temperature
before operating.
1
2
3
4
5
6
7
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This section includes useful information about oven operation.
1. Plug power supply cord into a 230V 50Hz power outlet.
2. After placing the food in a suitable container, open the oven door and put it on the glass tray.
The glass tray must always be in place during cooking.
3. Shut the door. Make sure that it is firmly closed.
Wattage output chart
The power-level is set by pressing the POWER pad. The chart shows the display, the power level and
the percentage of power.
6
OPERATION PROCEDURE
When the oven door is opened, the light
turns off.
The oven door can be opened at any time
during operation by touching the door
release button on the control panel. The
oven will automatically shut off. To restart
the oven. close the door and then touch
START.
Each time a pad is touched, a BEEP will
sound to acknowledge the touch.
The oven automatically cook on full power
unless set to a lower power level.
The display will show “ : 0” when the oven
is plugged in.
Time clock returns to the present time
when the cooking time ends.
When the STOP/CLEAR pad is touched
during the oven operation, the oven stops
cooking and all information retained. To
erase all information retained. To erase all
information (except the present time),
touch the STOP/CLEAR pad once more. lf
the oven door is opened during the oven
operation, all information is retained.
If the START pad is touched and the oven
does not operate, check the area between
the door and door is closed securely. The
oven will not start cooking until the door is
completely closed or the program has
been reset.
1
2
3
4
5
6
7
8
Make sure the oven is properly installed
and plugged into the electrical outlet.
Touch Power pad,
Once the touch
POWER
9
8
7
6
5
4
3
2
1
0
Power Level (Display)
P-HI
P-90
P-80
P-70
P-60
P-50
P-40
P-30
P-20
P-10
P- 0
Approximate Percentage
of Power
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
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When the oven is first plugged in, the display will flash “ : 0” and a tone will sound. If the AC power
ever goes off, the display will flash “ : 0” when the power comes back on.
DO THIS THIS HAPPENS...
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SETTING THE CLOCK
1. Touch CLOCK/
A.START pad.
This is a 12 hour clock system.
CLOCK/
A.STAR T
2. Touch CLOCK/
A.START pad once
more.
This is a 24 hour clock system.
CLOCK/
A.STAR T
4. Touch CLOCK/
A.START pad.
The display will stop blinking and the colon starts blinking.
If you selected 12 hour clock system this digital clock allows you to set
from 1:00 to 12:59.
If you selected 24 hour clock system, this digital clock allows you to
set from 0:00 to 23:59
CLOCK/
A.STAR T
3. Enter the correct time of
day by touching the numbers in sequence.
The display will then begin blinking.
1 2 3 0
NOTE : This oven is multiple
clock system. If you
want 12 hour clock
system, can be
omitted this step.
NOTE : If you attempt to enter an incorrect time, the time will not be set and a error signal tone will
sound. Touch the CLOCK/A.START pad re-enter the time.
CONTROLS
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WEIGHT DEFROST lets you easily defrost food by eliminating guesswork in determining defrosting
time. The minimum weight for WEIGHT DEFROST is 200 grams. The maximum weight for WEIGHT
DEFROST is 3000 grams. Follow the steps below for easy defrosting.
8
WEIGHT DEFROSTING
DO THIS THIS HAPPENS...
1. Touch AUTO
DEFROST pad.
The WEIGHT DEFROST indicator lights and “0” is displayed.
And the g indicator starts blinking.
AUTO
DEFROST
2. Touch number pads for
the defrosting weight
you want.
The display will show the numbers you pressed in the order
you tou ched.
5 0 0
3. Touch START pad.
WEIGHT DEFROSTING begins. The defrosting time is automatically
determined by the food category and weight entered.
The g indicator goes off and the WEIGHT DEFROST indicator blinks
and the defrosting time counts down in the display window. The oven
beeps during the defrosting cycle to signal that the food needs to be
turned or rearranged.
When the defrosting time ends, you will hear 3 beeps.
STAR T
NOTE : To prevent over defrosting thin areas or edges can be shielded with strips of aluminum foil.
Page 10
When TIME DEFROST is selected, the automatic cycle divides the defrosting time into periods of
alternating defrost and stand times by cycling on and off.
9
TIME DEFROSTING
DO THIS THIS HAPPENS...
1. Touch AUTO
DEFROST pad.
The WEIGHT DEFROST indicator lights and “0” is displayed.
And the g indicator starts blinking.
AUTO
DEFROST
2. Touch AUTO
DEFROST pad once
more.
The TIME DEFROST indicator
lights and “ : 0” is displayed.
AUTO
DEFROST
3. Touch number pads for
the defrosting time you
want.
The display will show the numbers you pressed in the order
you touched.
2 7 1 0
NOTE : Your oven can be
programmed for 59
minutes 99 sec-
4. Touch START pad.
When you touch START pad, the TIME DEFROST indicator starts
blinking to show the oven is in the TIME DEFROST mode. The display counts down the time to show you how much defrosting time is
left in the TIME DEFROST mode. The oven beeps during the defrosting cycle to signal that the food needs to be turned or rearranged.
When the defrosting time ends, you will hear 3 beeps.
STAR T
NOTE : To prevent over defrosting, thin areas or edges can be shielded with strips of aluminum foil.
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10
COOKING IN ONE STAGE
DO THIS... THIS HAPPENS...
1. Touch POWER pad.
The M/W indicator lights and
“P- ” is displayed.
POWER
4. Touch START pad.
When you touch START pad, the M/W indicator starts blinking to
show the oven is cooking.
The display counts down the time to show how much cooking time is
left. When the cooking time ends, you will hear 3 beeps.
STAR T
2. Touch the number
pad for the power
level you want.
The display will show what you
touched. This example shows
power level 3.
3
NOTE: If steps 1 and 2 are
omitted, the oven will
cook at full power.
3. Touch number pads
for the cooking time.
The display will show the numbers you pressed in the order
you touched.
3 05
NOTE: Your oven can be
programmed for 59
minutes 99 seconds.
(59:99)
NOTE: Using lower power levels increase the cooking time which is recommended for foods such as
cheese, milk and slow cooking of meats.
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11
GRILL COOKING
This function allows you to brown food quickly.
The heating element is located in the top of the oven.
There is no pre-heating the oven for grill cooking. Place food inside the oven when setting the controls.
DO THIS... THIS HAPPENS...
1. Touch GRILL pad.
The GRILL indicator lights and
“ :0” is displayed.
GRILL
3. Touch START pad.
When you touch START pad, the GRILL indicator starts blinking to
show the oven is cooking.
The display count down the time to show how much cooking time is
left. When the cooking time ends, you will hear 3 beeps.
STAR T
2. Touch number pads
for the cooking time.
The display will show the numbers you pressed in the order
you touched.
This example shows 25 min-
2 5 0 0
NOTE: Time can be set up
to 30 minutes.
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A UTO STAR T
Allows you to program cooking to start at a time you select.
The food will automatically start cooking at the desired time.
DO THIS... THIS HAPPENS...
1. Program the desired power level and cooking time.
12
2. Touch CLOCK/
A.START pad.
The AUTO START indicator
lights and “ :0” is displayed.
CLOCK/
A.STAR T
4. Touch START pad.
When you touch START pad, the present time appears in the display
and the cooking program indicators come on.
The AUTO START indicator and the colon start blinking.
When the selected start time arrives the oven bigins. Operating and
the oven light turns on. The AUTO START indicator goes off and the
next stage indicator begins to blink.
When the cooking is completed you will hear 3 beeps. The oven turns
off and the present time appears in the display.
STAR T
3. Enter the desired
start time by pressing the number pads.
The display will show the numbers you pressed in the order
you touched.
This example shows 11:30
1 1 3 0
NOTE: AUTO START can be used for time cooking, if clock is set. If the oven door is opened
after programming AUTO START, it is necessary to touch the START pad for the time of
day to appear in the readout so that the oven will automatically begin programmed cooking at the chosen AUTO START time. Before setting, check to make sure the clock is
showing the correct time of day.
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13
TO CHECK AUT O START TIME
Once you have correctly programmed the oven for AUTO START, the present time will appear on the
display.
DO THIS... THIS HAPPENS...
SPEEDY COOK
SPEEDY COOK allows you to reheat for 30 seconds at 100% (full power) by simply touching the
SPEEDY COOK pad.
By repeatedly touching the SPEEDY COOK pad, you can also extend reheating time to 5 minutes by
30 seconds.
DO THIS... THIS HAPPENS...
1. Touch CLOCK/
A.START pad.
The programmed AUTO START
time will appear on the display
for 3 seconds.
CLOCK/
A.STAR T
1. Touch SPEEDY
COOK pad.
When you touch SPEEDY
COOK, “ :30” is displayed.
After 1.5 seconds, the oven
starts reheating.
SPEEDY
COOK
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14
ONE TOUCH COOKING
One touch cook allows you to cook or reheat many of your favorite foods by touching just one pad. To
increase quantity, touch chosen pad until number in display is same as desired quantity to cook.
(except for DINNER PLATE)
DO THIS... THIS HAPPENS...
DO THIS... THIS HAPPENS...
1. Touch FROZEN
PIZZA pad.
When you touch FROZEN
PIZZA “200” is displayed.
After 1.5 seconds, the display
changed into cooking time of
quantity and the oven starts
cooking.
FROZEN
PIZZA
1. Touch BEVERAGE
pad.
When you touch BEVERAGE
pad, “1” is displayed.
After 1.5 seconds, the display
changed into cooking time of
quantity and the oven starts
cooking.
BEVERAGE
*
FORZEN PIZZA
*
• 200g: Touch FROZEN PIZZA once.
• 300g: Touch FROZEN PIZZA twice within 1.5 seconds.
NOTE: 1. Use only one frozen pizza at a time.
2. Use only frozen pizza for microwave oven.
3. If the cheese of frozen pizza does not melt sufficiently, cook a few seconds longer.
4. Some brands of frozen pizza may require more or less cooking time.
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DO THIS... THIS HAPPENS...
*
BEVERAGE * (250ml/cup)
• 1 cup (mug): Touch BEVERAGE once.
• 2 cups (mugs): Touch BEVERAGE twice within 1.5 seconds.
• 3 cups (mugs): Touch BEVERAGEthree times within 1.5 seconds.
NOTE: 1. This setting is good for restoring cooled beverage to a better drinking temperature.
2. Stir after cooking.
1. Touch DINNER
PLATE pad.
When you touch DINNER
PLATE pad, “300“ is displayed.
After the 1.5 seconds, the display changed into cooking time
of quantity and the oven starts
cooking.
DINNER
PLATE
NOTE: For best results, consult the cookbook.
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Auto cook allows you to cook or reheat many of your favorite foods by repeatedly touching menu pad.
After the menu selection, touch chosen pad until number in display is same as desired quantity to
cook.
DO THIS… THIS HAPPENS…
A UTO COOK (MENU & WEIGHT)
1. Touch MENU pad.
When you touch MENU pad,
“AC-1” is displayed.
The display will then begin blinking. By repeatedly touching this
pad, you can select other food
category as shown in the chart
below.
MENU
CATEGORY FOOD TOUCH PAD
AC-1 BAKED POTATO Touch MENU once.
AC-2 FRESH VEGETABLE Touch MENU twice.
AC-3 SOUP Touch MENU three times.
AC-4 FISH FILLETS Touch MENU four times.
AC-5 MEAT LOAF Touch MENU five times.
1. Touch WEIGHT pad.
“1” is displayed.
After the 1.5 seconds, the display changed into cooking time
of quantity and the oven starts
cooking.
WEIGHT
*
BAKED POTATO * (160~180g/ea.)
• 1 NO (ea.): Touch WEIGHT once.
• 2 NO (ea.): Touch WEIGHT twice within 1.5 seconds.
• 3 NO (ea.): Touch WEIGHT three times within 1.5 seconds.
*
FRESH VEGETABLE
*
• 200g: Touch WEIGHT once.
• 300g: Touch WEIGHT twice within 1.5 seconds.
*
SOUP
*
• 250g: Touch WEIGHT once.
• 350g: Touch WEIGHT twice within 1.5 seconds.
*
FISH FILLETS
*
• 300g: Touch WEIGHT once.
• 500g: Touch WEIGHT twice within 1.5 seconds.
*
MEAT LOAF
*
• 500g: Touch WEIGHT once.
• 700g: Touch WEIGHT twice within 1.5 seconds.
Page 18
17
FEEDING BOTTLE
This key is for feeding bottle disinfection effect.
At first, detach the nipple from the bottle and pour the 30cc water into each bottle, arrange the bottle
symmetrically on the glass tray and operate.
DO THIS... THIS HAPPENS...
MORE, LESS
MORE pad: adds for 10 seconds to 20 seconds.
LESS pad: remove for 10 seconds to 20 seconds.
These pad only work one touch cooking and feeding bottle mode. And always input previously.
CHILD SAFETY LOCK
The safety lock prevents unwanted oven operation such as by small children.
To set, press STOP/CLEAR for 3 seconds, LOCK indicator lights.
To cancel, press STOP/CLEAR for 3 seconds, LOCK indicator goes off.
TO STOP THE O VEN WHILE THE OVEN IS OPERATING
1. Press STOP/CLEAR pad.
• You can restart the oven by touching START pad.
• Touch STOP/CLEAR once more to erase all instructions.
• You must enter in new instructions.
2. Open the door.
• You can restart the oven by closing the door and touching START.
1. Touch FEEDING
BOTTLE pad.
When you touch FEEDING
BOTTLE pad, “2” is displayed.
After the 1.5 seconds, the display changed into sterilizing time
of quantity and the oven starts
sterilizing.
FEEDING
BOTTLE
*
FEEDING BOTTLE
*
• 2 NO (ea.): Touch FEEDING BOTTLE once.
• 4 NO (ea.): Touch FEEDING BOTTLE twice within 1.5 seconds.
• 6 NO (ea.): Touch FEEDING BOTTLE three times within 1.5 seconds.
NOTE: Oven stops operating when door is opened.
Page 19
18
The door lock mechamism is a device 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. Whem the door is closed, the hook pushes the button of the micro switch. Then
the button of the primary interlock switch bring it under on condition.
Adjustment 1.
When the door is closed, the switch button is
pushed by the hook.
The movement of the switch button should exceed
1.2mm measured at the top of the button.
INTERLOCK MECHANISM FUNCTIONS AND ADJUSTMENTS
Page 20
(2) Secondary interlock switch and interloc k monitor s witc h
When the door is closed, the hook pushes the push lever down ward, and push lever presses the
button of the interlock monitor swich to bring it under “off”, condition and presses the button of the
secondary interlock switch to bring it under “on”, condition.
Adjustment 2.
Interock monitor switch
When the door is closed, the interlock monitor switch should be opend before other switches close.
When the door is closed, the interlock monitor switch should be closed after other switches open.
Secondary interlock switch
The movent of the switch button should exceed 1.2mm measured at the top of the button.
(3) Adjustment steps
a) Loosen the two mounting screws.
b) Adjust interliock switch assembly position.
c) Confirm the gap (1.2mm) described above.
d) Make sure that push lever moves smoothly adjustments is completed.
e) Completly tighten the two mounting screws.
(4) Interlock switch resplacement
Whenever safety interlock switches are replaced:
1) Refer to the following diagram.
2) Check the connection of monitor switch after replacement.
3) Perform the electrical continuity check of interlock switches and microwave emission test men
tioned in this manual.
SYMBOL
RD
BL
BK
WH
GN
COLOR
RED
BLUE
BLACK
WHITE
GREEN
19
NOTE: Microwave emission test should be performed after adjusting interlock machanism. If the
microwave emission exceed 4mW/cm2, readjust interlock mechanism.
Page 21
20
– Cautions to be observed when trouble shooting.
Unlike many other appliances, the microwave oven is a high-voltage, high-current equipment. It is
com pletely safety during normal operation. However, carelessness in servicing the oven can result
in an electeric 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 which is attached to iron plate, and wear rubber gloves when servic-
ing 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 grounding.
Do not operate on a 2-wire extension cord.
The microwave oven is designed to be used
when grounded.
It is imperative, therefore, to makes sure it is
grounded properly vefore before begining
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 driber to discharge.
(4) When the 12 Amp. fuse is blown out to operation of the monitor switch; replace primary, and moni-
tor switch.
Refer to 19 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 opertate without cabinet.
CAUTION: Service personnel should remove their watches whenever working close to or repair-
WARNING: When servicing the appliance, need a care of touching or replacing high potential
parts because of electrical shock of exposing microwave. These parts are as follows–H.V. Thansformer, Magnetron, H.V. Capacitor, H.V. Diode.
Page 22
21
1. To remove cabinet.
Remove three screws (F02) on cabinet back.
2. To remove door assembly.
1) Remove two screws (F40) which secure
the top hinge seoppr (F37).
2) Remove the door assembly (F00) from the
top plate of cavity.
3) Reverse the above for reassembly.
3. To remove door parts.
NOTE: After replacing the door preform a
check of correct alignment with the
hinge and cavity front face.
Page 23
22
(1) Remove the gasket door (A06) from door plate (A04).
(2) Remove the barrier screen inner (A05) from door plate (A04).
(3) Remove the door frame (A02) from door plate (A04).
(4) Remove the top hinge stopper (A03) from door plate (A04).
(5) Remove the spring (A08) and the hook (A07).
(6) Remove the barrier screem outer (A01) from door frame (A02).
(7) Remove the above steps for reassenbly.
4. Method to reduce the gap between the
door seal and the oven front surface.
(1) To reduce gap located on part ‘A’
1) Loosen two screws on the top hinge
stopper, and then push the door to con
tact the door seal to oven front surface.
3) Tighten two screws.
(2) To reduce gap located on part ‘B’.
1) Loosen three screws in under hinge stopper, and then the door to contact the door seal to
oven front surface.
2) Tighten three screws.
(3) To reduce gap located on part ‘C’. (See Fig. A)
1) Loosen a screw on the interlock switch assembly located at the bottom of the oven body.
2) Draw the interlock switch assembly inward as possible with hook on the door bottom.
3) Tighten a screw.
(4) To reduce gap located on part ‘D’. (See Fig. B)
1) Loosen a screw on the interlock switch assembly located at the top of the oven body.
2) Follow step (3) 2) and 3).
NOTE: A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm
2
.
Page 24
23
Page 25
24
6. To remove high volta ge capacitor.
(1) Remove the screw (F13) which secure the
grounding ring terminal of diode (F16) and
capacitor holder (F14).
(2) Remove the capacitor holder (F14) with
capacitor (F15).
(3) Reverse the above steps for reassembly.
High voltage circuit wiring
7. To remove magnetron.
(1) Remove three screws (F07) which secure
magnetron (F06).
(2) Pull out the magntron (F06) from the wave
guide.
(3) Reverse the above steps for reassembly.
Page 26
25
8. To remove fan motor assembly.
(1) Remove two screws (F08) which secure the back cover (F10) from the cavity outer.
(2) Remove two screws (F09) which secure the fan motor (F11) from the back cover (F10).
(3) Pull out the fan (F12) from the motor (F11).
(4) Remove the above steps for reassembly.
9. To remove thransformer.
(1) Remove the four screws (F21) holding the
H.V. tramsformer (F20).
(2) Remove the transformer (F20).
(3) Reverse the above steps for reassembly.
CAUTION: Never install the magnetron without the metallic gasket plate which is packed with
each magnetron to prevent microwave.
Whenever repair work is carried out on magnetron, check the microwave leakage.
Page 27
10. To remove insulator Heater assembly.
(1) Remove the four HEX NUTS 1.
(2) Remove the insulator Heater assembly 2.
(3) Reverse the above steps for reassembly.
11. To remove Heater Part.
(1) Remove the HEX NUT 4.
(2) Remove the insulater Heater 1 and Heater 2.
(3) Remove the two screws 5.
(4) Reverse the above steps for reassembly.
NO PART NAME PART CODE Q’TY DESCRIPTION REMARK
26
1
2
3
4
5
6
7
INSULATOR HEATER
HEATER
SCREW MACHINE
NUT HEX
SCREW MACHINE
SPACER INSULATOR*
INUT HEX
3513301100
3512802300
7002500613
7392500008
7002400413
3515000700
3514000800
7392500411
1
1
1
1
2
2
2
2
SPP T0.8
120V1000W
TRS 5X6 MFCR
6N-2-5 SUS
TRS 4X4 MFCR
C3771BD
C3771BD
6N-2-5 MFZN
ONLY KOG-26xx
ONLY KOG-28xx
Page 28
27
Following the procedures below to c heck if the oven is defective or not.
1. Check grounding before checking trouble.
2. Be careful of the high voltage circuit.
3. Discharge the high voltage capacitor. (see page 20)
4. When checking the continuity of switches or of the high voltage transformer, disconnect one lead
wire from these parts and then check cintinuity with the AC plug removed. To do otherwise may
result in false reading ir damage to your meter.
5. Do not touch any part of the circuity on the touch control circuit since static electric discharge may
damage this control panel.
Always touch yourself to ground while working on this panel to discharge any static charge built up
in your body.
First of all operate the microwave oven following the correct operation described in pages 6~20 by
time cooking, in order to find the exact cause if any trouble.
(TROUBLE 1) The following visual conditions indicate a probable defective touch con-
trol circuit or membrane s witc h assemb l y.
TROUBLE SHOO TING GUIDE
1. Incomplete segments.
(A) Segments missing.
(B) Partical segments missing.
(C) Digit flickering other than normal fluores-
cent slight flickering.
(D) “:0” does not display when power is on.
2. A distinct change in the brightness of one or
more numbers in the display.
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. For example, touch 5 and 3 appears in the
display.
6. Specific numbers (for example 5 and 3 )will
not display when the panel is touched.
7. Display does not count down or up with time
cooking ot clock operation.
8. Oven is programmable and cooks normally
but no display shows.
9. Display obviously jumps in time while count-
ing down
10. Display counts down noticeably too fast
while cooking.
11. Display can not shift from the first stage coking to the third stage cooking while 3 phase
cooking (including defrost).
12. Display does not show the time of day when
dear pad is touched (in clock mode).
13. Oven lamp and fan motor and turn table
motor do not stop although cooking is finished.
Check if the RELAY “2” contacts close if
they are close, replace touch control circuit.
Page 29
28
(TROUBLE 2) Digital readout display does not sho w programming, even if the mem-
brane keyboard is programmed by touching proper pads.
MEMBRANE KEYBOARD CHECK PROCEDURE
1. Check the pad termination order and nomenc lature.
Fig. 4
Check Result
Cause Cause
Replace
control
box subassembly
Check each pad for
continuity of the
membrane keyboard
for the following
keyboard check
Condition
Display does not
show programming
at all, even if
keyboard is
touched
Normal
Malfunction
of touch
control
circuitry of
control box
Replace
the membrane
Abnormal
Malfunction
of the membrane keyboard
NOTE: Before following the particular steps listed above in the trouble shooting guide for the
membrane keyboard, failure, please check for the continuity of each wire-harness
between the membrane keyboard and control box assembly.
Page 30
29
2. T ype of encoding and pad names.
Fig. 8 Key Matrix
The membrane keyboard consists of 25 keys whose configurations are described above and provide
11 pad terminations to be connected to the touch control circuit as Fig. 7.
3. Key chec k pr ocedure.
To determine if the membrane keyboard is defective or not, check the continuity of each pad (KEY)
contacts with a multimeter.
1) 5 pad : Between A and F
2) 0 pad : Between A and G
3) POWER pad : Between A and H
4) SPEEDY COOK pad : Between A and I
5) MENU pad : Between A and K
6) 6 pad : Between B and F
7) 1 pad : Between B and G
8) GRILL pad : Between B and I
9) WEIGHT pad : Between B and K
10) 7 pad : Between C and F
11) 2 pad : Between C and
G
12) BEVERAGE pad : Between C and I
13) MORE pad : Between C and J
14) AUTO DEFROST pad : Between C and K
15) 8 pad : Between D and F
16) 3 pad : Between D and
G
17) DINNER PLATE pad : Between D and H
18) FROZEN PIZZA pad : Between D and I
19) LESS pad : Between D and J
20) CLOCK/A.START pad : Between D and K
21) 9 pad : Between E and F
22) 4 pad : Between E and G
23) FEEDING BOTTLE pad : Between A and J
24) START pad : Between E and J
25) STOP/CLEAR pad : Between E and K
Page 31
30
(TROUBLE3) The oven not operate at all; Display window does not display any figures
and any inputs can not be accepted.
Check Result
Cause Cause
Replace
Primary
Interlock Switch
and Secondary
Interlock Switch
and Monitor
Interlock Switch.
Check continuity
Interlock Monitor
switch with door
closed.
Condition
15A fuse
blows
Continuity
No
continuity
Malfunction of
Interlock monitor
switch
Replace Primary
Interlock Switch
and Monitor
Interlock Switch.
Check continuity
of both Primary
Interlock Switch
contact with door
partially open until
interlock monitor
switch contact
close.
Continuity
Shorted contacrs
of primary interlock switch.
(Replace 15A fuse)
Defective high
voltage trans-
Check continuity
of primary
winding of low
voltage transformer.
0 Ω or
infinite
Approx
80~100Ω
(normal)
Shorted of open
winding
Replace
Normal
Replace Low
Voltage
Transformer
Replace
15
A fuse
again blows
Defective high
voltage capacitor
Disconnect one
side of the lead
wire connected
from transformer
to the high voltage
capacitor and
operate the unit.
NOTE 1
NOTE 1
NOTE 1: All these switches must be replaced at the same time, please refer to page 18 and 19
for adjustment instructions.
Page 32
31
(TROUBLE 4) Display shows all figures selected, but oven does not start cooking,
even though desired program and time are and start pad is taped.
Check Result
Cause Cause
Replace
Check continuity
of oven
thermostat
Condition
No
Continuity
Defective oven
thermostat.
Replace
Check continuity
of power supply
cord.
No
Continuity
Open power
supply cord.
Replace
Normal
Defective touch
control circuit
Replace
Display do not
shown countdown
Malfunction of
secondary
interlock switch
Outlet has
proper
voltage
Fuse does
not open
Check Result
Cause Cause
Adjust or
replace
Check continuity
of parimary
interlock switch
Condition
No
Continuity
Malfunction of
Primary interlock
Replace
Check D.C. voltage
being supplied to
RELAY “2” coil.
OV
Defective touch
control circuit
Replace
Approx.
24VDC
Faulty contacts
of RELAY “2”
or open relay
coil
Turn table
motor
fan motor and
oven lamp do
Page 33
32
(TROUBLE 5) No microwave oscillation even though fan motor rotates.
Check Result
Cause Cause
Replace
Check continuity
of primary winding
of high voltage
transformer and
Condition
Turn table
motor,
fan motor and
oven lamp turn
on for a
second when
No
Conntinuity
Open winding
Replace
Normal
Defective touch
control circuit
Check Result
Cause Cause
Check continuity
of connecting wire
of magnetron.
Condition
No
microwave
Continuity
Replace
Check the isolation
of filament winding
No
Good
Defective
high voltage
transformer
Replace
Good
No
Continuity
Defective
magnetron
Replace
Check continuity
of filament of
magnetron.
No
Continuity
Defective
magnetron
Replace
Check the isolation
of filament terminal
No
Continuity
Defective
high voltage
transformer
Replace
Check the diode
for continuity
in the reverse
and normal
directions
Continuity
in the
reverse
direction
Defective
high voltage
diode
Continuity
Continuity
Page 34
(TROUBLE 6) Micrwave Output power is low .
First of all, check if output po wer is really low following “measurement
of the microwave output power” on page 34.
POWER
0
1
2
3
4
5
6
7
8
9
HI
RELAY “1” ON TIME
0
3 (Seconds)
5
8
11
14
17
20
23
26
29
RELAY “1” OFF TIME
29
26 (Seconds)
24
21
18
15
12
9
6
3
0
33
Check Result
Cause Cause
Customer
education
Check the power
source voltage
with magnetron
oscillating
Condition
Output
power is low.
Lower than
108 volts
Descrease in
power source
voltage
Normal
Replace
Check the timing
periods of the
RELAY “1” coil
Abnormal
NOTE 3
Defective touch
control circuit
Replace depending on the result of
output test
Normal
Aging change
of
magnetron
NOTE 2: The following chart shows the timing periods of the RELAY “1”.
NOTE 3: Interlock monitor switch must be replaced when fuse is blown out.
Page 35
34
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.
Proedure
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 1,000±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).
It is measured immediately before the water is added to the vessel. After addition of the water to
the vessel, the vessel, the Ioad is immediately placed on the center of the shelf which is in the
Iowest normal position.
4. Microwave power is switched on.
5. Heating time should be exactly 70(KOG26XX) or 52(KOG-28XX)seconds.
Heating time is measured while the
microwave generator is operatng at full
power.
The filament heat-up time for magnetrons is
not included.
6. The initial and final water temperatures are
selected so that the maximum difference
betwen the ambient and final water temperatures is 5K.
7. The microwave power output P in watts is calculated from the following formula:
• ▲▲ T is actual temperature rise.
• t is the heating time.
The power measured should be 600W(KOG-26XX) or 800W(KOG-28XX)±10.0%
WARNING
Make sure to check the micro wave leakage before and after repair or adjustment.
• Always, start measuring of an unknown field to assure. Safety for operating personnel from
microwave energy.
• Do not place you hands into any suspected microwave radiation field unless the safe density level is
known.
• Care should be taken not to place the eyes in direct line with the source of microwave energy.
• Slowly approach the unit under test until the radiometer reads an apperaciable microwave leakage
from the unit under the test.
MEASUREMENT OF THE MICRO WAVE OUTPUT POWER
MICROWAVE RADIATION TEST
P=4187X▲▲T.t
CAUTION:
1. Water load should be measured exactly to 1 liters.
2. Input power voltage should be exactly 120 volts as specified.
3. Ambient temperature should be 20±2°C
(68±3.6F)
Page 36
35
Procedure
A) Prepare Microwave Energy Survey Meter, 600cc glass breaker, glass thermometer100°C or
212°F.
B) Pour 275cc±15cc of tap water initially at 20±5°C (68±9°F) in the 600cc beaker with an inside diam-
eter of approx. 8.5 cm (3.5 in).
C) Place it at the center of the tray and set it in a cavity.
D) Close the door and operate the oven.
E) Measure the leakage by using microwave energy survery meter with dual ranges, set to 2,450
MHz.
– Measured radiation leakage must not exceed the values prescribed below.
• Leakage for a fully assembled oven with door normally closed must be less than 4mW/cm2.
– When measuring the leakage, always use the 5cm space cone with probe. Hold the probe per-
pendicular to the cabinet, door. place the
space cone of the probe on the door, cabinet, door seam,along the seam, the door
viewing window, the exhaust air vents, the
suction air vents.
– Measuring should be in a counter-clock-
wise direction at a rate of 1 inch/sec. If the
leakage of the cabinet door seam is
unknow, move the probe more slowly.
– When measuring near a corner of the door, keep the probe perpendicular to the areas making
sure the probe end at the base of the cone does not get closet than 2 inches from any metal.
If it does, erroneous reading may result.
Page 37
36
WIRING DIAGRAM
Page 38
38
Refer to the “WIRING DIAGRAM” on page 36.
MICROWAVE COOKING
TIME COOKING
1. When the food is placed inside the oven and door is closed.
1) The low voltage transformer supplies the necessary voltage to the touch control circuit when the
power cord is plugged in.
2) The contacts of the interlock monitor switch open.
This switch creates short circuit to blow 12A fuse and stop magnetron oscillation when door is
opened during operation under abnormal condition (i.e. the contacts of primary interlock switch
do not open the circuit).
3) The contacts of primary interlock switch close the primary circuit.
2. When cooking cycle, power and time are set by touching the function pads and the desired
numerical pads.
1) The function indicating bars are located on the digitron light to indicate that function have been
set.
2) The time you set appears in the display window.
3) The touch control circuit memorizes the cooking program you set.
3. When the start pad is touched.
*
The RELAY “1”, “2” are controlled by the touch control circuit.
1)
120VAC is applied to the high voltage transformer through the contacts of RELAY “1”.
2) Fan motor starts rotating and cools the magnetron by blowing the air coming form the intake on
the rear plate hold.
3) The oven lamp light the inside of the oven.
4) Indicator light turns on to indicate function operation. Cooking time starts count down.
5) 3.3 Volts Ac is generated from the filament winding of the high voltage transformer. This filament
voltage is applied to the magnetron to heat the magnetron filament through two noise prventing
choke coils.
6) A high voltage of 2000 Volts Ac is generated in the secondary of high voltage transformer and
this secondary voltage is increased by the action of the diode and the charging of the high voltage capacitor. This resultant DC voltage is then applied to the anode of the magnetron. As
shown in Fig. 2 the first half cycle of the high voltage produced in the high voltage transformer
secondary charges the high voltage capacitor. Current flow is in the direction of the dotted-line
during the second half cycle, the voltage produced by the transformer secondary, and the
charge of the high voltage capacitor are combined and applied to the magnetron as shown by
the solid line so that oscillations begin. The disturbance wave generated by the mangetron is
prevented by the choke coils of 3.2µH, filter capacitor of 16pF and the magnetron’s shielded
case so that TV and radio programs are not impaired by noise.
CIRCUIT DESCRIPTION
Page 39
39
Fig. 2
The touch control circuit controls the ON-OFF time of RELAY “1” in order to vary the output power of
the microwave oven from “power level 1“ to “HI (100%) power”.
One complete ON and OFF cycle of the RELAY “1” is 29 seconds. The relation between indications
on the control panel and the output of the microwave oven is as shown in Fig. 3
Page 40
Fig. 3
AUTO DEFROST CYCLE
When auto defrost is selected and the desired defrosting time is chosen, the automatic cycle divides
the defrosting time into 5 periods of alternating defrost and stand times, by cycling on and off.
4. When the door is opened during cooking.
1) The primary interlock switch is opened to cut off primary voltage to the high voltage transformer
to stop microwave oscillation.
2) The secondary interlock switch is opened to give the door open information to touch control circuit. The contacts of the RELAY “1” and “2” open, the display stops counting down.
3) Fan motor and turn table stop rotating.
4) The oven lamp turns off.
5) As soon as the door is opened, the interlock monitor switch contacts close and creats the short
circuit.
6) If the contacts of primary interlock switch malfunction the 12A fuse blows open due to the large
current surge caused by the short circuit activation, and this in turn stops magnetron oscillation
(Fig. 1).
5. When the STOP/CLEAR pad is touched during cooking.
1) The touch control circuit cuts the voltage supplied to the RELAY “1” coil and causes the magnetron to stop oscillating.
2) RELAY “2” turns off.
3) The display will show the time of day. If you don’t set the clock, the display will show a colon.
4) The oven lamp turns off.
5) Fan motor and turn table motor stop rotating.
0 0/29 (0%)
1 3/29 (10%)
2 5/29 (17%)
3 8/29 (28%)
4 11/29 (38%)
5 14/29 (48%)
6 17/29 (59%)
7 20/29 (69%)
8 23/29 (79%)
9 26/29 (90%)
HI 29/29 (100%)
POWER LEVEL
OUTPUT POWER
AGAINST FULL POWER
RELAY “1” TURN ON, OFF TIME
40
Page 41
41
1. High voltage is present at the high voltage terminal of the high voltage transformer during any cooking cycle.
2. It is neither necessary nor advisable to attempt measurement of the high voltage.
3. Before touching any oven components or wiring, always unplug the oven from its power source and
discharge the capacitor (see page 20).
5. Interlock monitor switch
The interlock switch can be checked with an ohmmeter. Isolate the switch and then connect the
meter leads to the common (COM) and normally close (NC) terminals of the switch. The meter
should indicate an open circuit with the door closed and a closed circuit with the door opened.
6. Primary and secondary interlock switch
The primary and secondary interlock switch can be checked with an ohmmeter. Isolate the switch
and connect the meter leads to the common (COM) and normally open (NO) terminals of the
switch.
The meter should indicate an openn circuit with the door opened and a closed circuit with the door
closed. In case improper operation is indicated, make the necessary switch adjustment or replacement.
COMPONENT TEST PROCEDURE
1. High voltage transformer
(A) Remove connections from the transformer
terminals and check continuity.
(B) Normal readings should be as follows:
Secondary winding..........Approx. 90Ω±10%
Filament winding.........................Approx. 0Ω
Primary winding..........................Approx. 0Ω
2. High voltage capacitor
(A) Check continuity of capacitor with meter on
the highest OHM scale.
(B) A normal capacitor will show continuity for a
short time, and then indicate 9MΩ once the
capacitor is charged.
(C) A shorted capacitor will show continuous
continuity.
(D) An open capacitor will show constant 9MΩ.
(E) Resistance between each terminal and
chassis should be infinite.
3. High voltage diode
(A) Isolate the diode from the circuit by discon-
necting the leads.
(B) With the ohmmeter set on the highest resis-
tance scale, measure the resistance across
the diode terminals.
Reverse the meter leads and again observe
the resistance reading. meter with 6V, 9V or
higher voltage batteries should be used to
check the front-back resistance of the diode,
otherwise an infinite resistance may be read
in both directions. A normal diodes resistance will be infinite in one direction and several hundred KΩ in the other direction.
4. Magnetron
For complete magnetron diagnosis, refer to
“Measurement of the Microwave Output
Power”. (Page 34) Continuity checks can
only indicate and open filament or a shorted
magnetron. To diagnose for an open filament or shorted magnetron.
(A) Isolate magnetron from the circuit by dis-
conecting the leads.
(B) A continuity check across magnetron fila-
ment terminals should indicate ohm or less.
(C) A continuity check between each filament
terminal and magnetron case should read
Page 42
42
• Disconnect the oven from the power supply.
• You can test continuity of safety interlocks and monitor switch by using switch tester or ohmmeter.
• The switch operation is checked by the lamp on/off of resistance zero/unlimited.
• The sequence of check is interlock monitor switch; primary and secondary interlock switches check.
• Make circuits like Fig. a, Fig. b, tests.
SAFETY INTERLOCK CONTINUITY TEST
1) In case of interlock monitor check.
(Lamp on or zero resistance)
(ohmmeter)
– Fig. a –
Condition: 1) Door is opened.
2) Common terminal of the monitor
switch disconnected.
*
(Schematic diagarm of S/W tester)
2) In case of primary interlock check.
(Lamp on or zero resistance)
(ohmmeter)
– Fig. b –
Condition: 1) Door is closed.
Page 43
1 MP1 DC -5V±0.25 Replace ZD2, EC1, EC2 NO LOAD
2 MP2 DC -30V±1.0 Replace R21, ZD3 NO LOAD
3 MP3 DC -27V±1.0 Replace R21, R22, EC5 NO LOAD
NO.
MEASURE POINT
Fig. 6
WAVE FORM REMEDY REMARK
NO. CHECK POINT REMARK
1 IC1 PIN 6, 10, 11 -5VDC
2 IC1 PIN 1 -20VDC
3 IC1 PIN 22
4 IC1 PIN 8 OR 9
5 DP1 PIN 1& 25 2.4VAC (DISPLAY FILAMENT VOLTAGE)
1. CIRCUIT CHECK PROCEDURE
1) Low Voltage Transformer (DMR-604P) Check.
The low voltage transformer is located on the P.C.B.
Measuring condition: Input voltage: 120V
Frequency: 60Hz
2) Voltage Check
Key check point
CHECK METHOD
6–7 24V 30V
8-10 2.4V 2.5V
Voltage
Terminal
LOAD NO LOAD
43
PRINTED CIRCUIT BOARD
NOTE 1: Secondary side voltage of the low voltage transformer changes in proportion to fluctua-
tion of power source voltage.
NOTE 2: The allowable tolerance of the secondary voltage is within ±5% of norminal voltage.
NOTE: Each measure point must be measured with GND points.
T:16.67ms (60HZ)
Page 44
LOCK doesn’t come on. GRID1 (G1), 21 30
GRILL, M/W don’t come on. GRID2 (G2), 17 29
WEIGHT DEFROST, NO/CUPS don’t come on. GRID3 (G3), 9 26
TIME DEFROST doesn’t come on. GRID4 (G4), 10 28
AUTO START, g don’t come on. GRID5 (G5), 4, 7 27
SEGMENT “a” doesn’t come on from G1 to G5. SEGMENT d, 19 39
SEGMENT “b” doesn’t come on from G1 to G5. SEGMENT e, 18 40
SEGMENT “c” doesn’t come on from G1 to G5. SEGMENT f, 16 41
SEGMENT “d” doesn’t come on from G1 to G5. SEGMENT a, 23 36
SEGMENT “e” doesn’t come on from G1 to G5. SEGMENT b, 22 37
SEGMENT “f” doesn’t come on from G1 to G5. SEGMENT c, 20 38
SEGMENT “g” doesn’t come on from G1 to G5. SEGMENT g, 15 42
LOCK, M/W, NO/CUPS, g don’t come on. UPPER BAR h, 5 33
GRILL, TIME DEFROST, LOWER BAR i, 34
WEIGHT DEFROST, AUTO START don’t come on. 6, 8, 9, 11
TROUBLE
DISPLAY NAME
& PIN NO.
MICOM OUTPUT
IN PIN NO.
3) Display problems
The display trouble shooting data
4) When there is no microwave oscillation.
(1) When touching “START” pad, oven lamp does not turn on.
Fan motor and turntable motor do not rotate, but cook indicator in display comes on.
*
Cause: RELAY “2” does not operate.
NO. CAUSE MEASUREMENT RESULT REMEDY
1 Poor contact between Check the voltage Fix the PIN 1 & 25
P.C.B. and display of PIN 1 & PIN 25. 2.4 VAC on the P.C.B.
filament.
2 Defective Display Refer to “The display Replace P.C.B.
trouble shooting data” assembly.
below.
3 Loss of vacuum in White Replace P.C.B.
the display spot is assembly
generated
on the
display
44
Page 45
45
Fig. 6 Measurement Point
Page 46
CHECK METHOD
(2) When touching “START” pad, oven lamp turns on.
Fan motor and turntable rotate and cook indicator in display comes on.
*
Cause: RELAY “1” does not operate.
CHECK METHOD
5) When the door is opened during operation, the Count down timer does not stop.
CHECK METHOD
CHECK
METHOD REMEDY
NO.
1 Check the stage (ON, OFF) of the secondary Replace secondary
Interlock switch by resistance measurement. interlock switch
POINT
A B
STAGE
1) DOOR OPEN OPEN –5VDC
2) DOOR CLOSED CLOSE GND
POINT
A B
STAGE
RELAY “1” ON –5VDC –24VDC
RELAY “1” OFF GND GND
POINT
A
STAGE
RELAY “2” ON –24VDC
RELAY “2” OFF GND
46
Page 47
POINT WAVEFORM
A
POINT
A B
STAGE
RELAY “4” ON –5VDC –24VDC
RELAY “4” OFF GND GND
5) When the digital clock does not operate properly.
If clock does not keep exact time, you must check resistor R11, R17.
7) When there is not grill heat.
When touching “START” pad, oven lamp turns on.
Fan Motor and turntable rotate and cook indicator in display comes on.
*
Cause: RELAY “4” does not operate.
CHECK METHOD
47
Page 48
2. COMPONENT INFORMATION
1) Transistor
2) Diode and Zener Diode
48
Page 49
49
3. PRINTED CIRCUITS BOARD
Page 50
50
4. P.C.B. CIRCUIT DIAGRAM
Page 51
5. P.C.B. LOCATION No.
REF No. PART CODE PART NAME DESCRIPTION REMARK
R10, 13, 18, 26 RD-AZ472J- RESISTOR 4.7 Kohm, 1/6W, 5%
R3 RD-AZ201J- RESISTOR 200 ohm, 1/6W, 5%
R5, 8 RD-AZ203J- RESISTOR 20 Kohm, 1/6W, 5%
R1 RD-AZ105J- RESISTOR 1 Mohm, 1//6W, 5%
R2, 4, 6, 9, 15, 20 RD-AZ102J- RESISTOR 1 Kohm, 1/6W, 5%
R24 RD-4Z510J- RESISTOR 51 ohm, 1/4vW, 5%
R11, 17 RD-AZ473J- RESISTOR 47 Kohm, 1/6w, 5%
R22, 25 RD-2Z560JS RESISTOR 56 ohm, 1/2W, 5%
R23, 14, 19 RD-2Z210JS RESISTOR 150 ohm, 1/2W, 5%
R21 RD-2Z122JS RESISTOR 1.2 Kohm, 1/2W, 5%
D1~7 DZN4148M-- DIODE SWITCHING 1N4148M
D9~15 DZN4002A-- DIODE RECTIFY 1N4002A
ZD1 DZTZ3R9B-- DIODE ZENER 3.9VB, 1/2W
ZD2 DZTZ5R1B-- DIODE ZENER 5.1VB, 1/2W
ZD3 DZTZ20B--- DIODE ZENER 20VB, 1/2W
Q5 TZTC3198GR TRANSISTOR KTC3198GR (1815GR)
Q1, 3, 4, 6 TZTA1270Y- TRANSISTOR KTA1270Y (562Y)
RA1 RA-87X104J RESISTOR ARRAY RGLD6X104J
C4 CCXF1H103Z CAPACITOR CERAMIC HIKF 50V 0.01uF Z
C1~3 CBXF1H104Z CAPACITOR CERAMIC HIKF 50V 0.1uF Z
EC5 CEXF1H471V CAPACITOR ELECTROLYTIC 470uF, 50V, RSS
EC1~2 CEXE1C470A CAPACITOR ELECTROLYTIC 47uF, 16V, RS
EC3 CEXE1H108A CAPACITOR ELECTROLYTIC 0.1uF, 50V, RS
EC4 CEXE1H229A CAPACITOR ELECTROLYTIC 2.2uF, 50V, RS
CA1 CN6XB-102M CAPACITOR ARRAY 1000pF, 2.54MM, M50V
BZ1 3515600100 BUZZER BM-20K
CR1 5PCST400MG RESONATOR CERA CST4.00MGW
CN2 441M36716 CONNECTOR FILM FCZ254-11
CN3 3519150510 CONNECTOR WAFER YW396-05VA
CN1 3519150520 CONNECTOR WAFER YW396-02V
DP1 DSVM5MS06- DIGITRON SVM-5MS06
DPH 3513000500 HOLDER VFD NYLON66
J1~7, 9~12,R16 85801052GY WIRE COPPER 1/0.52 TIN COATING
M145-1 3514311351 PCB MAIN 159.5X82
LVT 5EPV041304 TRANS POWER DMR-604FS
RY1, 4 5SC0101107 RELAY G5J-1-TP-M24V
RY2 5SC0101109 RELAY SW G5B-1 (DC24V) IC IP
IC1 147S811Q00 IC MICOM HD404314B09S
51
Page 52
1. Door Assembly
KOG-26XX
KOG-28XX
REF No. PART CODE PART NAME DESCRIPTION Q’TY REMARK
3511707300
DOOR ASSEMBLY
KOG-3615OS
1
ONLY KOG-261M
3511707310 KOG-3625OS ONLY KOG-262M
A01
3517003000
BARRIER-SCREEN *O PMMA 1
ONLY KOG-261M
3517003020 ONLY KOG-262M
A02
3512202000
FARME DOOR ABS 1
ONLY KOG-261M
3512202010 ONLY KOG-262M
A03 3515201000 STOPPER HINGE *T SCP-1 T2.5 1
A04 3511705510 DOOR WELD AS KOR-64150A 1
A05 3517002810 BARRIER-SCREEN *I PE T0.1 1
A06 3512300200 GASKET DOOR PP 1
A07 3513100700 HOOK POM 1
A08 3515101300 SPRING HOOK PW1 1
REF No. PART CODE PART NAME DESCRIPTION Q’TY REMARK
3511706402
DOOR ASSEMBLY
KOR-81150S
1
ONLY KOG-281M
3511706422 KOG-81250S ONLY KOG-282M
A01
3517003100
BARRIER-SCREEN *O PMMA T1.5 1
ONLY KOG-281M
3517003120 ONLY KOG-282M
A02
3512202200
FARME DOOR ABS 1
ONLY KOG-281M
3512202210 ONLY KOG-282M
A03 3515201500 STOPPER HINGE *T SCP-1 T2.5 1
A04 3511705600
DOOR WELD AS
KOR-814Q0A
1
ONLY KOG-281M
3511705620 KOR-81250S ONLY KOG-282M
A05 3517002900 BARRIER-SCREEN *I PE T0.1 1
A06 3512300400 GASKET DOOR PP 1
A07 3513100700 HOOK POM 1
A08 3515101300 SPRING HOOK PW1 1
52
EXPLODED AND PARTS LIST
Page 53
2. Control Panel Assembly
KOG-26XX
KOG-28XX
REF NO. PART CODE PART NAME DESCRIPTION Q’TY REMARK
CONTROL PANEL AS 1 ONLY KOG-261M
B01
3518514000
SWITCH MEMBRANE
KOG-261MOS
1
ONLY KOG-261M
3518514800 KOG-262MOS ONLY KOG-261M
B02
3516710900
CONTROL PANEL
KOG-361QOS ABS
1
ONLY KOG-261M
3516710710 KOG-262QOS ABS ONLY KOG-262M
B03 PKMPMSSA00 PCB MAIN AS KOG-261QOS 1
B04 7621401211 SCREW TAPPING T2S PAN 4X12 PW MFZN 3
B05 3513701400 LEVERL DOOR OPEN POM 1
B06 441B655072 SPRING DOOR BUTTON HSWR 1
B07
3516903600
BUTTON DOOR OPEN ABS 1
ONLY KOG-261M
3516903620 ONLY KOG-262M
53
REF No. PART CODE PART NAME DESCRIPTION Q’TY REMARK
PKCPSWTT00
CONTROL PANEL AS
KOG-281MOA
1
ONLY KOG-281M
ONLY KOG-282M
B01 3518514100 SWITCH MEMBRANE KOG-281MOS 1
ONLY KOG-281M
ONLY KOG-282M
B02
3516710900
CONTROL PANEL
KOG-281MOS
1
ONLY KOG-281M
3516710910 KOG-282MOS ONLY KOG-282M
B03 PKMPMSTA00 PCB MAIN AS KOG-281MOS 1
B04 7821401211 SCREW TAPPING T2SPAN 4X12 PW MFZN 3
B05 3513701400 LEVERL DOOR OPEN POM 1
B06 441B655072 SPRING DOOR BUTTON HSWR 1
B07
3518903600
BUTTON DOOR OPEN ABS 1
ONLY KOG-281M
3516903620 ONLY KOG-282M
Page 54
54
Page 55
REF No. PART CODE PART NAME DESCRIPTION Q’TY REMARK
F01
3510801300
CABINET PCM T0.6
1
ONLY KOG-26XX
3510801400
ONLY KOG-26XX
F02 7S312X4081 SCREW TAPPING T1 TRS 4X8 SE MFZN 3
F03
3516105010
CAVITY WELD AS
KOG-381QOS 1
ONLY KOG-26XX
3516104910 KOG-361QPS 1
ONLY KOG-26XX
F04 7S342X40B1 SCREW SPECIAL T2S TRS 4X12 SE MFZN 2
F05 7X342X40B1 SCREW SPECIAL T2S TRS 4X12 SE MFZN 1
F06 4413A90012 CLAMP POWER CORD 66 NYLON 1
F07 7112400811 SCREW TAPPING T1 TRS 4X8 MFZN 3
F08 35113NBND5 CORD POWER AS 3X0.75 60X60X200 RTML 1
F09 3518002200 MAGNETRON 2M218H(MF)I 1
F10 7112401011 SCREW TAPPING T1 TRS 4X10 MFZN 3
F11 7112400811 SCREW TAPPING T1 TRS 4X8 MFZN 2
F12 7172400811 SCREW TAPTITE TT1 TRS 4X8 MFZN 2
F13 3511402500 COVER*B SBHG T0.8 1
F14 3963820110 MOTOR SHADED POLE 120V 17W MW10XA-R01 1
F15 3511800300 FAN PP+30% GLASS 1
F16 7172400811 SCREW TAPTITE TT2 TRS 4X8 MFZN 1
F17 3513001900 HOLDER HV CAPACITOR SECC T0.8 1
F18
44IL267010
CAPACITOR HV
2100VAC 0.7µF 1
ONLY KOG-26XX
3518300800 2100VAC 0.82µF 1
ONLY KOG-26XX
F19 4416V24000 DIODE HV HVR-1X-32B(D5.3) 1
F20
3518106640
TRANS HV
JY-N60A0-61T
1
ONLY KOG-26XX
518106910 DH-N80A0-81T
ONLY KOG-28XX
F21 7112401011 SCREW TAPPING T1 TRS 4X10 MFZN 4
F22 3512100900 FOOT PP DASF-130 2
F23
3510308700
BASE SBHG T0.8 1
ONLY KOG-26XX
3510308900
ONLY KOG-26XX
F24 7172400811 SCREW TAPTITE TT2 TRS 4X8 MFZN 2
F25 7112401011 SCREW TAPPING T1 TRS 4X10 FMZN 6
F26 3515201100 STOPPER HINGE *U SCP-1 T2.5 1
F27 5S762S10G0 SW MICRO V16-FA-63 SPNO #187 1
F28 5S762M10G0 SW MICRO V16-FA-62 SPNC #187 1
F29 5S762S10G0 SW MICRO V16-FA-63 SPNO #187 1
F30 3513701300 LEVER LOCK POM 1
55
Page 56
56
REF No. PART CODE PART NAME DESCRIPTION Q’TY REMARK
F31 3513805700 LOCK POM BLACK 1
F32 3513601500 LAMP BL 125V 25W T25 C7A H1 1
F33 7121400811 SCREW TAPPING T2S PAN 4X8 MFZN 2
F34 3966820200 MOTOR SYNCRO 120V 2W GM-16-12F17 1
F35 3515201500 STOPPER HINGE *T AS KOR-61150OS 1
F36 3517400600 COUPLER PPS 1
F37 3511403500 COVER WAVEGUIDE MICA 1
F38 4078502031 BUTTOM LOCKING PP HONAM A 353 2
F39
3513301450
INSULATOR HEATER AS
KOG-261QOA 1
ONLY KOG-26XX
3513301430 KOG-281Q0A 1
ONLY KOG-28XX
F39-1 3512802300 HEATER 1000W 120V 1
F39-2 3513301100 INSULATOR HEATER SPP T0.8 1
F40 3514700900 ROLLER TEFLON 3
F41 3512509200 GUIDE ROLLER PP 1
F42
3517203600
TRAY
GLASS 1
ONLY KOG-28XX
3517203500 GLASS 1
ONLY KOG-28XX
F43 7172400811 SCREW TAPTITE TT2 TRS 4X8 MFZN 2
F44
3517204410
TRAY RACK AS
KOG-361QOS 100 MM 1
ONLY KOG-28XX
3517201800 KOR-1825OS 120MM 1
ONLY KOG-28XX
F45 7292500411 NUT SUS M5 2
F46 7279300611 SCREW TAPTITE TT2 TRS 3X6 MFZN 1
F47 3518902200 THERMOSTAT OFF:130 ON:115 1
F48 7S627W50X1 NUT HEX M5 FLANGE 2
F49 3512711310 HARNESS MAIN KOG-281QOA 1
F50 7172400811 SCREW TAPTITE TT2 TRS 4X8 MFZN 1
B00 CONTROL PANEL AS REFER TO EXPLODED VIEW page 54
A00 DOOR AS REFER TO EXPLODED VIEW page 53
Page 57
S/M NO.; G261AMU010
D AEW OO ELECTR ONICS CO ., LTD.
686, AHYEON-DONG, MAPO-GU,
SEOUL, KOREA
C.P.O. BOX 8003 SEOUL, KOREA
TELEX: DWELEC K28177-8
CABLE: “DAEWOOELEC”
FAX: 02) 364-5588/5305
TEL: 02) 360-7114/7315~7
PRINTED DATE: APR.1996
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