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S/M No.:R633R0S001
Service Manual
Microwave Oven
MODEL : KOR-633R0S
KOR-863R0S
DAEWOO ELECTRONICS CO., LTD
http : //svc.dwe.co.kr MAR. 2000
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 as necessary: (1) Interlock operation, (2) Proper door closing, (3) Seal and sealing
surfaces (arcing, wear, and other damage), (4) Damage to or loosening of hinges and latches, (5) Evidence of
dropping or abuse.
(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 ........................................................................................................ 2
1. FOR SAFE OPERATION ............................................................................................................. 2
2. FOR SAFE SERVICE PROCEDURES ........................................................................................ 2
SPECIFICATIONS ............................................................................................................................ 3
EXTERNAL VIEW ............................................................................................................................ 4
1. OUTER DIMENSION .................................................................................................................... 4
2. FEATURE DIAGRAM ................................................................................................................... 5
3. CONTROL PANEL ....................................................................................................................... 6
INSTALLATION ................................................................................................................................ 7
OPERATIONS AND FUNCTIONS ................................................................................................... 8
DISASSEMBLY AND ASSEMBLY .................................................................................................. 9
INTERLOCK MECHANISM AND ADJUSTMENT ........................................................................... 16
TROUBLE SHOOTING GUIDE ........................................................................................................ 17
MEASUREMENT AND TEST ........................................................................................................... 21
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT ..................................................... 21
2. MICROWAVE RADIATION TEST ................................................................................................ 22
3. COMPONENT TEST PROCEDURE ............................................................................................ 23
WIRING DIAGRAM .......................................................................................................................... 24
PRINTED CIRCUIT BOARD ............................................................................................................ 25
1. CIRCUIT CHECK PROCEDURE ................................................................................................. 25
2. P.C.B CIRCUIT DIAGRAM ........................................................................................................... 29
3. P.C.B LOCATION NO .................................................................................................................. 30
EXPLODED VIEW AND PARTS LIST ............................................................................................. 32
1. DOOR ASSEMBLY ...................................................................................................................... 32
2. CONTROL PANEL ASSEMBLY ................................................................................................... 32
3. TOTAL ASSEMBLY ...................................................................................................................... 32
1
SAFETY AND PRECAUTIONS
1. FOR SAFE OPERATION
Damage that allows the microwave energy (that cooks or heats the food) to escape will result in poor cooking and
may cause serious bodily injury to the operator.
IF ANY OF THE FOLLOWING CONDITIONS EXIST, OPERATOR MUST NOT USE THE APPLIANCE.
(Only a trained service personnel should make repairs.)
(1) A broken 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 surface should be kept clean.
No greas,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 micrwave oven has concealead 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 manafacterer immediately.
IMPORTANT
The wire in this mains lead coloured in accordance with the following code.
Green-and-yellow : Earth
Blue : Neartral
Brown. : live
As the colours of the wires in the manins lead of this appliance may not correspond with the coloured makings
identifying the terminals in your plug, proceed as follows.
The wire which is coloured green-and-yellow must be connected to the terminal in the plug which is marked with
the letter ` , earth symbol or coloured green-and-yellow.
E'
The wire which is coloured blue must be connected to the terminals which is marked with the letter ` or coloured black.
N'
The wire which is coloured brown must be connected to the terminal which is marked with the letter ` or coloured red.
L'
NOTE
The oven is desigend for counter-top use only.
2
SPECIFICATIONS
MODEL KOR-633R KOR-863R
POWER SUPPLY 230V ~ 50Hz, SINGLE PHASE WITH EARTHING
POWER MICROWAVE 1200W 1350W
CONSUMPTION
GRILL
COMBINATION
MICROWAVE ENERGY OUTPUT 800W 900W
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS(W X H X D) 465 x 279 x 365 mm 495 x 294 x 392 mm
(18.3 x 11.0 x 14.4 in.) (19.5 x 11.6 x 15.4 in.)
CAVITY DIMENSIONS (W X H X D) 290 x 220 x 306 mm 320 x 244 x 338 mm
(11.4 x 8.7 x 12.0 in) (12.6 x 9.6 x 13.3 in)
NET WEIGHT APPROX. 13Kg(28.7 lbs.) APPROX. 15Kg(33.1 lbs.)
TIMER 59min. 00 sec.
FUNCTION SELECTIONS MICROWAVE
POWER SELECTIONS 5 LEVELS
CAVITY VOLUME 0.7 Cu.Ft. 0.9 Cu.Ft.
* SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.
3
EXTERNAL VIEW
1. OUTER DIMENSION(KOR-633R/KOR-863R)
465/495 365/392
279/294
4
EXTERNAL VIEW
2. FEATURE DIAGRAM
5 4 1
9
3 2 6 7 8
1. Safety interlock system
2. Door screen - Allows viewing of food. The screen is transparent to light, but prevents microwaves escaping.
3. Door hook - When the door is closed, it will automatically shut off. If the door is opened while the oven operating,
the magnetron tube will immediately stop operating.
4. Oven cavity
5. Door seal - Door seal surfaces prevent microwave escaping from the oven cavity.
6. Glass cooking tray - Made of special heat resistant glass. The tray can be easily removed for cleaning. Make sure it is
correctly positioned(indentation) before operating. Place food in a suitable container(dish) on the tray.
7. Roller guide - Supports the glass cooking tray.
8. Coupler - This fits over the shaft in the center of the ovens cavity floor. This is to remain in the oven for all cooking.
9. Control panel
5
EXTERNAL VIEW
3. Control panel
1
2
3
4
5
6
7
8
-
1. Auto cook - Used to cook using a program or to reheat.
2. Defrost - Used to defrost foods by weight or time.
3. Power - Used to set power level.
4. Clock - Used to set clock.
5. Display - Cooking time, power level, indicators and present time are displayed.
6. Stop/Clear - Used to stop the oven operation or to erase all entries.
7. Strat/Easy cook - Used to start the oven operation and also increase the reheat time by 30 seconds.
8. Dial Knob - Used to set the time and weight.
6
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.
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. Position the oven as far from them as possible.
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 requires a current of approximately 6 amperes, 230Volts, 50Hz.
Power supply cord is about 0.8 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 amprer fuse other than those specified.
This appliance is supplied with cable of special type, which, if samaged, 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 applicance 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 accpt 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.
7
OPERATIONS AND FUNCTIONS
1. Connect the main lead to an electrical 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. Close the door securely.
4. When the oven door is opened, the light turns off.
5. 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 button.
6. Each time a button is touched, a BEEP will sound to acknowledge the touch.
7. The oven automatically cook on full power unless set to a lower power level.
8. The display will show " when the oven is plugged in.
:0"
9. Time clock returns to the present time when the cooking time ends.
10. When the Stop/Clear button 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 button once more. If the oven door is opened during
the oven operation, all information is retained.
11. If the Start button 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 door is completely closed or the program has been reset.
Make sure the oven is properly installed and plugged into the electrical outlet.
Wattage output chart
The power level is set by pressing the Power button. The chart shows the display, the power level and the percentage of power.
Touch Power button Power level (Display) Approximate Percentage of power
Once P-HI 100 %
Twice P-80 80 %
3 times P-60 60 %
4 times P-40 40 %
5 times P-20 20 %
8
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 safety 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 scredriver and ware rubber gloves when servicing the high voltage side.
3. Discahrge the high voltage capacitor before touching any oven components or wiring.
(1) Check the earthed.
Do not operate on a two-wire extension cord.
The microwave oven is designed to be used with earthed.
It is imperative, therefore, to make sure it is grounded properly
before beginning repair work.
(2) Warning about the electric charge in the high voltage capacitor.
For about 30 seconds after the operation stopped and 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 12A fuse is blown out due to the operation of the monitor switch;
replace primary interlock switch, secondary interlock switch and interlock
monitor switch. SHORT
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 th appliance, need a care of 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, HVFuse.
9
DISASSEMBLY AND ASSEMBLY
1. To remove cabinet
1) Remove three screws on cabinet back.
2) Push the cabinet backward.
2. To remove door assembly
1) Remove 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.
10
DISASSEMBLY AND ASSEMBLY
3. To remove door parts.
A06
A05
A04
A03
A02
A01
A07
A08
(1) KOR-633R0S
REF NO. PART CODE PART NAME DESCRIPTION Q'
TY REMARK
A01 3512203860 FRAME DOOR ABS SG-175 1
A02 3517005630 BARRIER-SCREEN*O SAN 1
A03 3515204100 STOPPER HINGE*T AS KOR-63150S 1
A04 3511705500 DOOR WELD AS KOR-61150S 1
A05 3517002800 BARRIER-SCREEN*I POLYESTER T0.1 1
A06 3512300200 GASKET DOOR PP 1
A07 3513100700 HOOK POM 1
A08 3515101300 SPRING HOOK PW1 1
(2) KOR-863R0S
REF NO. PART CODE PART NAME DESCRIPTION Q'TY REMARK
A01 3512204170 FRAME DOOR ABS SG-175 1
A02 3517005740 BARRIER-SCREEN *O ACRYL 1
A03 3515204100 STOPPER HINGE *T AS KOR-63150S 1
A04 3511705620 DOOR WELD AS KOR-81250S 1
A05 3517002900 BARRIER-SCREEN *I POLYESTER T0.1 1
A06 3512300400 GASKET DOOR PP 1
A07 3513100700 HOOK POM 1
A08 3515101300 SPRING HOOK PW1 1
11
DISASSEMBLY AND ASSEMBLY
(1) Remove the gasket door from door plate.
(2) Remove the barrier screen inner from door plate.
(3) Remove the door frame from door plate.
(4) Remove the stopper hinge top from door plate.
(5) Remove the spring and the hook.
(6) Remove the supporter barrier screen outer from door frame.
(7) Remove the barrier screen outer from door frame.
(8) Reverse the above steps for reassembly.
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part `
A'
Loosen two screws on stopper hinge top, and then push A
the door to contact the door seal to oven front surface.
Tighten a screw.
(2) To reduce gap located on part `
B'
Loosen two screws on stopper hinge under, and then
push the door to contact the door seal to oven front surface.
Tighten a screw. B
NOTE
A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2
12
DISASSEMBLY AND ASSEMBLY
5. To remove control panel parts.
B01 B02 B03 B04 B05 B06 B07 B08 B09
(1) KOR-633R0S
REF NO. PART CODE PART NAME DESCRIPTION Q'TY REMARK
B01 3515501540 WINDOW DISPLAY PMMA 1
B02 3516723730 CONTROL PANEL ABS SG-175 1
B03 3516907530 BUTTON FUNCTION * A ABS SG-175 1
B04 3516907540 BUTTON FUNCTION * B ABS SG-175 1
B05 3513405240 KNOB VOLUME ABS 1
B06 3514321430 PCB SUB AS KOR-633R0S 1
B07 7621301011 SCREW TAPPING T2 PAN 3X10 PW MFZN 4
B08 3514321350 PCB MAIN AS KOR-633R0S 1
B09 7122401211 SCREW TAPPING T2S TRS 4X12 MFZN 3
(2) KOR-863R0S
REF NO. PART CODE PART NAME DESCRIPTION Q'TY REMARK
B01 3515501540 WINDOW DISPLAY PMMA 1
B02 3516723730 CONTROL PANEL ABS SG-175 1
B03 3516907530 BUTTON FUNCTION * A ABS SG-175 1
B04 3516907540 BUTTON FUNCTION * B ABS SG-175 1
B05 3513405240 KNOB VOLUME ABS SG-175 1
B06 3514321430 PCB SUB AS KOR-633R0S 1
B07 7621301011 SCREW TAPPING T2 PAN 3X10 PW MFZN 4
B08 3514321570 PCB MAIN AS KOR-863R0S 1
B09 7122401211 SCREW TAPPING T2S TRS 4X12 MFZN 3
13
DISASSEMBLY AND ASSEMBLY
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 thee control panel.
3) Remove four screws which secure the PCB assembly.
4) Disconnect membrane tail from theconnector 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.
6. 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.
High voltage circuit wiring
7. 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/cm 2
for a fully assembled oven with door normally closed.
14
DISASSEMBLY AND ASSEMBLY
8. To remove wind guide assembly.
1) Remove a screw for earthing.
2) Remove the noise filter from the wind guide.
3) Remove a screw which secure the wind guide assembly.
4) Draw forward the wind guide assembly.
5) Pull the fan from the motor shaft.
6) Remove two screws which secure the motor shaded pole.
7) Remove the motor shaded pole.
8) Reverse the above steps for reasembly.
9. To remove H.V. transformert.
1) Remove four screws holding the H.V.transformer.
2) Remove the H.V.transformer.
3) Reverse the above steps for reassembly.
15
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.
Hook
Primary
interlock
switch
Button
Interlock
monitor
switch
Lock lever Secondary
interlock
Door open switch(front)
Mounting screw
monitor
switch(rear)
Condition : DOOR CLOSE Condition : DOOR OPEN
(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 microswitch. Then the button of the primary interlock switch
bring it under ON 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 and presses the button of the secondary interlock switch to bring it under ON
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.
3. Adjustment steps
a) Loosen the one mounting screw.
b) Adjust interlock switch assembly position.
c) Make sure that lock lever moves smothly after adjustment is completed.
d) Tighten completely one mounting screw.
NOTE
Microwave emission test should be performed after adjusting interlock mechanism.
If the microwave emission exceed 4mW/cm2 , readjust interlock mechanism.
16
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 transformer, disconnect one lead 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 connected of the terminals and power cord before check the parts listed below.
(TROUBLE 1) Door shut, timer set, but no cooking takes place.
CONDITION CHECK RESULT CAUSE REMEDY
Fuse blows. Check continuity of Malfunction Replace
interlock monitor switch Continuity of interlock NOTE 1
with door closed monitor
(COM NC) switch
No Continuity
Check continuity of both No Continuity Malfunction of Replace
primary and secondary interlock switch NOTE 1
interlock switch with door
closed Continuity
Check continuity of primary Continuity Shorted contacts Replace
interlock switch contact of primary NOTE 1
with door partially open interlock switch.
until interlock monitor switch
contact close
(COM NO )
Check continuity of 0 Or Defective low Replace
primary winding of low voltage
voltage transformer Approx. transformer
150~310
(normal)
Disconnect high voltage Fuse again Defective high Replace
fuse and operate the unit blows voltage transformer
17
TROUBLE SHOOTING GUIDE
CONDITION CHECK RESULT CAUSE REMEDY
Outlet has Check continuity of No Defective Replace
proper voltage magnetron Continuity magnetron
Fuse does not
blow. Check continuity of No Replace
Defective line
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
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 thouh desired program and time are
set and start pad is tapped.
CONDITION CHECK RESULT CAUSE REMEDY
Check continuity of No Malfunction Adjust or
Turn table
motor and primary interlock switch Continuity of primary replace
oven lamp do interlock
not turn on switch
Check continuity of No Malfunction Adjust or
secondary interlock and Continuity of secondary replace
D.O.M. switches interlock and
D.O.M. switch
Check D.C. voltage 0V Defective Replace
being supplied to touch control
RELAY (RY2) coil circuit
Approx. Faulty Replace
15 VDC contacts of
RELAY
(RY2) or open
relay coil
18
TROUBLE SHOOTING GUIDE
(TROUBLE 3) No microwave oscillation even though fan motor rotates.
CONDITION CHECK RESULT CAUSE REMEDY
No microwave Check continuity of high No Continuity
oscillation voltage fuse
Replace high voltage fuse
Check continuity of high Continuity Defective Replace
voltage capacitor high voltage
terminals with wires transformer
removed
Check continuity of high Continuity in Defective Replace
voltage rectifier in backward high voltage
forward and backward direction rectifier
direction with DC
megger
Connect megger leads to Continuity Defective Replace
magnetron terminal and magnetron
magnetron body
Check resistance of 0 or oo Defective Replace
primary and secondary high voltage
coil of high voltage transformer
transformer
Check continuity of No Defective Replace
magnetron with wires Continuity magnetron
removed
Check continuity of No Defective Replace
filament terminal of high Continuity high voltage
voltage transformer transformer
Check D.C. voltage 0V Defective Replace
being supplied to touch control
RELAY (RY1) coil circuit
Approx Faulty Replace
15 VDC contacts or
RELAY
(RY1) or open
relay coil
19
TROUBLE SHOOTING GUIDE
(TROUBLE 4) The following visual conditions indicate a profective 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) " does not display when power is on.
:0"
2. A distinct change in the display are not on when they numbers is the display.
M/W DEF. Lock g
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
Check each pad for Normal Malfunction Replace
Display does
continuity of the of touch control box
not show membrane keyboard
programming control circuit sub-assembly
for the following
at all, even if of control box
keyboard check
keyboard is procedure sub-assembly
touched.
Abnormal Malfunction of Replace the
the membrane membrane
keyboard keyborad
NOTE
Before following the particular steps listed above in the trouble shooting guide for the membrane keyboard' failure, please
s,
check for the continuity of each wire-harness between the membrane keyboard and P.C.B. assembly.
20
MEASUREMENT AND TEST
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT
Microwave output power can be checked by indirectly measuring the temperature rise of a certain amount of water exposed
to the microwave as directed below.
PROCEDURE
1. Microwave power output measurement is made 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 190mm.
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 (50 + 3.6 ). It 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 power output P in watts is calculated
from the following formula :
P = 4187 X T/t
T is difference between initial and ending temperature.
t is the heating time.
The power measured should be B (Refer to SPECIFICATIONS) W _
+ 10.0%.
CAUTION
1. Water load should be measured exactly to 1 liters.
2. Input power voltage should be exactly specified voltage (Refer to SPECIFICATIONS)
_
3. Ambient temperature should be 20 + 2 (68 _
+ 3.6 )
* Heating time for power output :
A(second) 70 64 60 56 52 49 47 44 42 40 38
B(W) 600 650 700 750 800 850 900 950 1000 1050 1100
21
MEASUREMENT AND TEST
2. MICROWAVE RADIATION TEST
WARNING
1. Make sure to check the microwave leakage before and after repair of adjustment.
2. Always start measuring of an unknown field to assure safety for operating personnel from microwave energy.
3. Do not place your hands into any suspected microwave radiation field unless the safe density level is known.
4. Care should be taken not to place the eyes in direct line with the source of microwave energy.
5. Slowly approch the unit under test until the radiometer readds an appreciable microwave leakage from the unit
under the test.
PROCEDURES
1. Prepare Microwave Energy Survey, 600cc glass
beaker, and glass thermometer 100 (212 ).
_ _ _
2. Pour 275cc + 15cc of tap water initially at 20 + 5 (68 + 9 ) in
the 600cc glass breaker with an inside diameter of approx.
95mm(3.5in.).
3. Place it at the center of the tray and set in a cavity.
4. Close the door and operate the oven.
5. Measure the leakage by using Microwave Energy Survey
Meter with dual ranes, set to 2450MHz.
1) Measured radiation leakage must not exceed the value
prescribed below. Leakage for a fully assembled oven with
door normally closed must be less than 4mW/cm2 .
2) When measuring the leakage, always use the 5cm(2 in.)
space cone with probe. Hold the probe perpendicular to
the cabinet and door. Place the space cone of the prove
on the door, cabinet, door seem, door viewing screen, the
exhaust air vents and the suction air vents.
3) Measuring should be in a counter-clockwise direction at a
rate of 1 in./sec. If the leakage of the cabinet door seem is
unknown, move the probe more slowly.
4) 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 closer than 2 in. from any metal. If it does not, erroneous reading may result.
22
MEASUREMENT AND TEST
3. COMPONENT TEST PROCEDURE
High voltage is present at the high voltage terminal of the high voltage transformer during any cooking cycle.
It is neither necessary nor advisable to attempt measurement of the high voltage.
Before touching any oven components or wiring, always unplug the oven from its power source and discharge the capacitor.
1. High voltage transformer
(1) Remove connections from the transformer terminals and check continuity.
(2) Normal readings should be as follows:
Secondary winding ........................ Approx. 110 _
+ 10%
Filament winding ............................................... Approx. 0
Primary winding ................................................ Approx. 0
2. High voltage capacitor
(1) Check continuity of capacitor with meter on the hightest OHM scale.
(2) A normal capacitor will show continuity for a short time, and then indicate 10M once the capacitor is charged.
(3) A shorted capacitor will show continuous continuity.
(4) An open capacitor will show constant 10M .
(5) Resistance between each terminal and chassis should be infinite.
3. High voltage diode
(1) Isolate the diode from the circuit by disconnecting the leads.
(2) With the ohmmeter set on the highest resistance 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 amy be read in both directions.
A normal diode' resistance will be infinite in one direction and several hundred K
s in the other direction.
4. Magnetron
For complete magnetron diagnosis, refer to "Measurement of the Microwave Power Output ".
Continuity checks can only indicate and open filament or a shorted magnetron.
To diagnose for an open filament or a shorted magnetron.
(1) Isolate magnetron from the circuit by disconnecting the leads.
(2) A continuity check across magnetron filament terminals should indicate 0.1 or less.
(3) A continuity check between each filament terminal and magnetron case should read open.
5. Fuse
If the fuse in the primary and monitor switch circuit is blown when the door is opened, check the primary and monitor
switch before replacing the blown fuse.
In case the fuse is blown by an improper switch operation, replace the defective switch and fuse at the same time.
Replace just the fuse if the switches operate normally.
23
WIRING DIAGRAM
24
PRINTED CIRCUIT BOARD
1. CIRCUIT CHECK PROCEDURE
1. Low voltage transformer check
The low voltage transformer is located on the P.C.B.
Measuring condition : Input voltage : 230V / Frequency : 50Hz
Terminal Voltage LOAD NO LOAD
4-7 AC 12.6 AC 14.7V
NOTE
1. Refer to Circuit Diagram (point 4).
2. Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source voltage.
_
3. The allowable tolerance of the secondary voltage is within + 5% of normal voltage.
2. Voltage Check
- Key check point
NO CHECK POINT REMARK
1 IC 1 PIN 2, 21, 30, 34 -5VDC
2 IC 1 PIN 35
T : 20ms(50Hz)
3 IC 1 PIN 31 OR 32
T : 250 ns(4MHz)
- Check method
NO MEASURE POINT WAVE FORM REMEDY REMARK
1 MP1 DC - 5V 0.25V Replace VL1, EC1 NO LOAD
2 MP2 DC - 12V 2.0V Replace EC2, D10,11,12 NO LOAD
NOTE
Each measure point must be measured with GND points.
25
PRINTED CIRCUIT BOARD
26
PRINTED CIRCUIT BOARD
27
PRINTED CIRCUIT BOARD
3. When there is no microwave oscillation
1) When touching START pad, oven lamp does not turn on.
Fan motor do not rotate, but cook indicator in display comes on.
* Cause : RELAY 2 does not operate. refer to Circuit Diagram (Point 3)
- Check method
POINT
A B
STATE
RELAY 2 ON - 5V DC GND
RELAY 2 OFF GND - 12VDC
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. refer to Circuit Diagram (Point 2)
- Check method
POINT
A B
STATE
RELAY 2 ON - 5V DC GND
RELAY 2 OFF GND - 12VDC
4. When the door is opened during operation, the count down timer does not stop.
refer to Circuit Diagram (Point 1)
- Check method
POINT
A B
STATE
1) DOOR OPEN OPEN -5VDC
2) DOOR CLOSED CLOSE GND
CHECK NO METHOD REMEDY
1 Check the stage(ON, OFF) of the door open monitor switch Replace door open monitor switch.
by resistance measurement.
5. When the digital clock does not operate properly.
refer to Circuit Diagram (Point 5)
POINT WAVE FORM
A
T : 20 ms (50Hz)
* If clock does not keep exact time, you must check resistor R5, 6 zener diodeZD2.
28
PRINTED CIRCUIT BOARD
2. P.C.B. CIRCUIT DIAGRAM
1
5
4
2
3
2
4
19
16
18
17
9
8
7
5
6
2
4
3
1
4
2
3
3
0
2
10
14
8
15
1
1
20
7
29
PRINTED CIRCUIT BOARD
3. P.C.B. LOCATION NO
(1) KOR-633R0S
NO. NAME SYMBOL SPECIFICATION PART CODE Q'
TY
1 BUZZER BZ1 BM-20K 3515600100 1
2 C ARRAY CA1 5P(4) 102M 50V CN4XB-102M 1
3 C ELECTRO EC1 16V RSS 100uF CEXF1C101V 1
4 C ELECTRO EC2 25V RSS 1000uF CEXF1E102V 1
5 CONNECTOR WAFER CN2 YW396-02AV 3519150520 1
6 CONNECTOR WAFER CN3 YW396-05AV 3519150510 1
7 CONNECTOR WAFER CN1 HLEM15S-1 4CW215SBD0 1
8 CONNECTOR WAFER CN101 HLEM15R-1 4CW215RBD0 1
9 DIODE D1~5, 7~10 1N4148 DZN4148--- 9
10 DIODE D11, 12 1N4004A DZN4004A-- 2
11 DIODE ZENER ZD2 UZ-5.1BSB DZUZ5R1BSB 1
12 DIODE ZENER ZD1 UZ-3.9BSB DZUZ3R9BSB 1
13 LED DISPLAY DP1 DDG-631H DDDG631H-- 1
14 PCB MAIN 169 90X197 3514321150 1
14 PCB SUB 170 70X197 3514321230 1
15 R ARRAY RA1 5P(4) 1/8 100K J RA-85X104J 1
16 R CARBON FILM R7~R9, R16~R19 1/6W 330 5% RD-AZ331J- 7
17 R CARBON FILM R1,10,15,13,21,101,102 1/6W 1K 5% RD-AZ102J- 7
18 R CARBON FILM R12 1/6W 100K 5% RD-AZ104J- 1
19 R CARBON FILM R2 1/6W 100 5% RD-AZ101J- 1
20 R CARBON FILM R3,5,6 1/6W 10K 5% RD-AZ103J- 3
21 R CARBON FILM R4 1/6W 1M 5% RD-AZ105J- 1
22 R CARBON FILM R20 1/4W 27 5% RD-4Z270J- 1
23 R CARBON FILM R14 1/6W 4.7K 5% RD-AZ472J- 1
24 IC REGULATOR VL1 MC7905C 1MC7905C-- 1
25 TRANSISTOR Q2~6, 8~10 KRA-106M TZRA106M-- 8
26 TRANSISTOR Q1 KTA-1266Y TZTA1266Y- 1
27 TRANS POWER LVT1 DMR-631FS 5EPV035303 1
28 WIRE COPPER J1-J8, J101 1/0.52 TIN COATING 85801052GY 9
29 WIRE FLAT WF1 1.25X15X90XCWH WSJ-159007 1
30 SW TACT SW101~106 KPT-1115AM 5S50101Z93 1
31 SW ROTARY SW107 SDB161PVB17F123636 5S10109002 1
32 IC MICOM IC1 TMP47C440BN-NG04 13GS631R00 1
33 RESONATOR CERA CR1 KBR-4.0MSTF 5PKBR40MKS 1
34 SW RELAY RY1 G5G-1A DC12V 5SC0101121 1
35 SW RELAY RY2 DJ-SS-112M-DC12V 5SC0101404 1
36 C CERA C4 102 50V Z AXIAL CCZB1H102K 1
37 C CERA C1~3, C5~C7 104 50V Z AXIAL CCZF1H104Z 6
30
PRINTED CIRCUIT BOARD
(2) KOR-863R0S
NO. NAME SYMBOL SPECIFICATION PART CODE Q'TY
1 BUZZER BZ1 BM-20K 3515600100 1
2 C ARRAY CA1 5P(4) 102M 50V CN4XB-102M 1
3 C ELECTRO EC1 16V RSS 100uF CEXF1C101V 1
4 C ELECTRO EC2 25V RSS 1000uF CEXF1E102V 1
5 CONNECTOR WAFER CN2 YW396-02AV 3519150520 1
6 CONNECTOR WAFER CN3 YW396-05AV 3519150510 1
7 CONNECTOR WAFER CN1 HLEM15S-1 4CW215SBD0 1
8 CONNECTOR WAFER CN101 HLEM15R-1 4CW215RBD0 1
9 DIODE D1~5, 7~10 1N4148 DZN4148-- 9
10 DIODE D11, 12 1N4004A DZN4004A-- 2
11 DIODE ZENER ZD2 UZ-5.1BSB DZUZ5R1BSB 1
12 DIODE ZENER ZD1 UZ-3.9BSB DZUZ3R9BSB 1
13 LED DISPLAY DP1 DDG-631H DDDG631H-- 1
14 PCB MAIN 169 90X197 3514321150 1
14 PCB SUB 170 70X197 3514321230 1
15 R ARRAY RA1 5P(4) 1/8 100K J RA-85X104J 1
16 R CARBON FILM R7~R9, R16~R19 1/6W 330 5% RD-AZ331J- 7
17 R CARBON FILM R1,10,15,13,21,101,102 1/6W 1K 5% RD-AZ102J- 7
18 R CARBON FILM R12 1/6W 100K 5% RD-AZ104J- 1
19 R CARBON FILM R2 1/6W 100 5% RD-AZ101J- 1
20 R CARBON FILM R3,5,6 1/6W 10K 5% RD-AZ103J- 3
21 R CARBON FILM R4 1/6W 1M 5% RD-AZ105J- 1
22 R CARBON FILM R20 1/4W 27 5% RD-4Z270J- 1
23 R CARBON FILM R14 1/6W 4.7K 5% RD-AZ472J- 1
24 IC REGULATOR VL1 MC7905C 1MC7905C-- 1
25 TRANSISTOR Q2~6, 8~10 KRA-106M TZRA106M-- 8
26 TRANSISTOR Q1 KTA-1270Y TZTA1266Y- 1
27 TRANS POWER LVT1 DMR-631FS 5EPV035303 1
28 WIRE COPPER J1-J8, J101,SJ1 1/0.52 TIN COATING 85801052GY 10
29 WIRE FLAT WF1 1.25X15X90XCWH WSJ-159007 1
30 SW TACT SW101~106 KPT-1115AM 5S50101Z93 1
31 SW ROTARY SW107 SDB161PVB17F123636 5S10109002 1
32 IC MICOM IC1 TMP47C440BN-NG04 13GS631R00 1
33 RESONATOR CERA CR1 KBR-4.0MSTF 5PKBR40MKS 1
34 SW RELAY