DAEWOO ELECTRONICS KOR-637V0A User manual

Service Manual
Microwave Oven
AUG. 2001
DAEWOO ELECTRONICS CO., LTD
http : //svc.dwe.co.kr
MODEL : KOR-637V0A
S/M No.:R637V0A001
✔ Caution
: In this Manual, some parts can be changed for improving, their
performance without notice in the parts list. So, if you need the
latest parts information,please refer to PPL(Parts Price List) in
Service Information Center (http://svc.dwe.co.kr).

1
TABLE OF CONTENTS
SAFETY AND PRECAUTIONS ........................................................................................................ 2
1.FORSAFEOPERATION.............................................................................................................2
2.FORSAFESERVICEPROCEDURES........................................................................................2
SPECIFICATIONS ............................................................................................................................ 3
EXTERNAL VIEW ............................................................................................................................ 4
1.OUTERDIMENSION....................................................................................................................4
2.FEATUREDIAGRAM...................................................................................................................5
3.CONTROLPANEL.......................................................................................................................6
INSTALLATION ................................................................................................................................ 7
OPERATIONS AND FUNCTIONS ................................................................................................... 8
DISASSEMBLY AND ASSEMBLY .................................................................................................. 9
INTERLOCK MECHANISM AND ADJUSTMENT ........................................................................... 17
TROUBLE SHOOTING GUIDE ........................................................................................................ 18
MEASUREMENT AND TEST ........................................................................................................... 23
1.MEASUREMENTOFTHEMICROWAVEPOWEROUTPUT.....................................................23
2.MICROWAVERADIATIONTEST................................................................................................24
3.COMPONENTTESTPROCEDURE............................................................................................25
WIRING DIAGRAM .......................................................................................................................... 26
PRINTED CIRCUIT BOARD ............................................................................................................ 27
1.CIRCUITCHECKPROCEDURE.................................................................................................27
2.P.C.BCIRCUITDIAGRAM...........................................................................................................31
3.P.C.BLOCATIONNO..................................................................................................................32
EXPLODED VIEW AND PARTS LIST ............................................................................................. 33
1.DOORASSEMBLY......................................................................................................................33
2.CONTROLPANELASSEMBLY...................................................................................................33
3.TOTALASSEMBLY......................................................................................................................33
PRECAUTIONSTO BE OBSERVEDBEFORE ANDDURING SERVICINGTO
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY
(a)Donotoperateorallowtheoventobeoperatedwiththedooropen.
(b)Makethefollowingsafetychecksonallovenstobeservicedbeforeactivatingthemagnetronorothermicrowave
source,andmakerepairsasnecessary:(1)Interlockoperation,(2)Properdoorclosing,(3)Sealandsealing
surfaces(arcing,wear,andotherdamage),(4)Damagetoorlooseningofhingesandlatches,(5)Evidenceof
droppingorabuse.
(c)Beforeturningonpowertothemicrowaveovenforanyservicetestorinspectionwithinthemicrowave
generatingcompartments,checkthemagnetron,waveguideortransmissionline,andcavityforproper
alignment,integrity,andconnections.
(d)Anydefectiveormisadjustedcomponentsintheinterlock,monitor,doorseal,andmicrowavegenerationand
transmissionsystemsshallberepaired,replaced,oradjustedbyproceduresdescribedinthismanualbeforethe
ovenisreleasedtotheowner.
(e)AmicrowaveleakagechecktoverifycompliancewiththeFederalperformancestandardshouldbeperformedon
eachovenpriortoreleasetotheowner.

2
SAFETY AND PRECAUTIONS
1. FOR SAFE OPERATION
Damagethatallowsthemicrowaveenergy(thatcooksorheatsthefood)toescapewillresultinpoorcookingand
maycauseseriousbodilyinjurytotheoperator.
IFANYOFTHEFOLLOWINGCONDITIONSEXIST,OPERATORMUSTNOTUSETHEAPPLIANCE.
(Onlyatrainedservicepersonnelshouldmakerepairs.)
(1)Abrokendoorhinge.
(2)Abrokendoorviewingscreen.
(3)Abrokenfrontpanel,ovencavity.
(4)Alooseneddoorlock.
(5)Abrokendoorlock.
Thedoorgasketplateandovensurfaceshouldbekeptclean.
Nogreas,soilorspattershouldbeallowedtobuilduponthesesurfacesorinsidetheoven.
DONOTATTEMPTTOOPERATETHISAPPLIANCEWITHTHEDOOROPEN.
Themicrwaveovenhasconcealeadswitchestomakesurethepoweristurnedoffwhenthedoorisopened.
Donotattempttodefeatthem.
DONOTATTEMPTTOSERVICETHISAPPLIANCEUNTILYOUHAVEREADTHISSERVICEMANUAL.
2. FOR SAFE SERVICE PROCEDURES
1)Iftheovenisoperativepriortoservicing,amicrowaveemissioncheckshouldbeperformedpriortoservicingthe
oven.
2)Ifanycertifiedovenunitisfoundtoservicing,amicrowaveemissioncheckshouldbeperformedpriortoservicing
theoven.
(a)informthemanufacturer,importerorassembler,
(b)repairtheunitatnocosttotheowner,
(c)attempttoascertainthecauseoftheexcessiveleakage,
(d)telltheowneroftheunitnottousetheunituntiltheovenhasbeenbroughtintocompliance.
3)Iftheovenoperateswiththedooropen,theservicepersonshouldtelltheusernottooperatetheovenandcontact
themanafactererimmediately.
Thewireinthismainsleadcolouredinaccordancewiththefollowingcode.
Green-and-yellow:Earth
Blue :Neartral
Brown. :live
Asthecoloursofthewiresinthemaninsleadofthisappliancemaynotcorrespondwiththecolouredmakings
identifying theterminalsinyourplug,proceedasfollows.
Thewirewhichiscolouredgreen-and-yellowmustbeconnectedtotheterminalintheplugwhichismarkedwith
theletter‘E’,earthsymbolorcolouredgreen-and-yellow.
Thewirewhichiscolouredbluemustbeconnectedtotheterminalswhichismarkedwiththeletter‘N’orcoloured black.
Thewirewhichiscolouredbrownmustbeconnectedtotheterminalwhichismarkedwiththeletter‘L’orcolouredred.
IMPORTANT
Theovenisdesigendforcounter-topuseonly.
NOTE

3
SPECIFICATIONS
* SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.
MODEL
KOR-637V
POWER SUPPLY 120V ~ 60Hz, SINGLE PHASE WITH EARTHING
POWER
CONSUMPTION
MICROWAVE 1200W
GRILL
COMBINATION
MICROWAVE ENERGY OUTPUT 800W
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS(W X H X D) 465 x 279 x 360 mm
(18.3 x 11.0 x 14.2 in.)
CAVITY DIMENSIONS (W X H X D) 290 x 220 x 306 mm
(11.4 x 8.7 x 12.0 in)
NET WEIGHT APPROX. 12.3Kg(27.2 lbs.)
TIMER 59min. 00 sec.
FUNCTION SELECTIONS MICROWAVE
POWER SELECTIONS 5 LEVELS
CAVITY VOLUME 0.7 Cu.Ft.
UV LAMP 10W

4
EXTERNAL VIEW
1. OUTER DIMENSION

5
EXTERNAL VIEW
2. FEATURE DIAGRAM
1. Safety interlock system
2. Door screen - Allows viewing of food. The screen is transparent to light, but prevents microwaves escaping.
3. Door latch - 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.
7. 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.
8. Roller guide - Supports the glass cooking tray.
9. Coupler - This fits over the shaft in the center of the ovens cavity floor. This is to remain in the oven for all cooking.
10. UV lamp
6. Shelf - Made of special heat resistant plastic. The shelf can be easily removed for cleaning. The shelf must be
placed on the glass cooking tray. Do not use when the oven is operating for microwave cooking.
11. Control panel

6
3. Control panel
1. Auto cook - Used to cook using a program or to reheat.
2. UV Purification - Used to purify baby bottle, cup, plate, etc.
3. Power/Def - Used to set power level andtodefrostfoodsbyweightortime.
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.
EXTERNAL VIEW

7
INSTALLATION
1. Steady, flat location
Thismicrowaveovenshouldbesetonasteady,flatsurface.
Thismicrowaveovenisdesignedforcountertopuseonly.
2. Leave space behind and side
Allairventsshouldbekeptaclearance.Ifallventsarecoveredduringoperation,theovenmayoverheatand,eventually,
causeovenfailure.
3. Away from Radio and TV sets
PoortelevisionreceptionandradiointerferencemayresultiftheovenislocatedclosetoaTV,Radio,antennaorfeeder
andsoon.Positiontheovenasfarfromthemaspossible.
4. Away from heating appliances and water taps
Keeptheovenawayfromhotair,steamorsplashwhenchoosingaplacetopositionit,ortheinsulationmightbeadversely
affectedandbreakdownsoccur.
5.Power supply
• Check your local power source.
This microwave oven requires a current of approximately 10 amperes, 120Volts, 60Hz grounded outlet.
• Power supply cord is about 0.8 meters long.
1. A short power-supply cord is provided to reduce the risks resulting from becoming entangled in or tripping over
a longer cord.
2. Longer cord sets or extension cords are available and may be used if care is exercised in their use.
3. If a long cord or extension cord is used:
1) The marked electrical rating of the cord set or extension cord should be at least as great as the electrical rat
ing of the appliance.
2) The extension cord must be a grounding type 3-wire cord.
3) The longer cord should be arranged so that it will not drape over the counter top or tabletop where it can be
pulled on by children or tripped over unintentionally.
6. Examine the oven after unpacking for any damagesuch 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.

8
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 “:0” when the oven is plugged in.
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.
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 %
Make sure the oven is properly installed and plugged into the electrical outlet.
12. When using the Purification mode ;
After purify metal tablewares, take out them certainly
.
If not so, touching other buttons, it can be happened to spark.
Do not use the glass tray for the Purification mode. Use the shelf only.
.

9
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.
5. After repair or replacement of parts, make sure that the screws are properly
tightened, and all electrical connections are tightened.
6. Do not operate without cabinet.
Service personnel should remove their watches whenever working close to or replacing the magnetron.
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.
CAUTION
WARNING

10
DISASSEMBLY AND ASSEMBLY
1. To remove cabinet
1)Removethreescrewsoncabinetback.
2)Pushthecabinetbackward.
2. To remove door assembly
1)Removescrewswhichsecurethestopperhingetop.
2)Removethedoorassemblyfromtopplateofcavity.
3)Reversetheaboveforreassembly.
Afterreplacingthedoorassembly,performacheckofcorrectalignmentwiththehingeandcavityfrontplate.
NOTE

11
3. To remove door parts.
DISASSEMBLY AND ASSEMBLY
NO PART CODE PART NAME DESCRIPTION Q'TY
A01 3512205230 FRAME DOOR ABS SG-175 SG-0760D 1
A02 3517005670 BARRIER SCREEN *O TEMP GLASS T3.2 1
A03 3515204100 STOPPER HINGE *T AS KOR-63150S 1
A04 3511706120 DOOR PAINTING AS KOR-634R0S 1
A05 3517002800 BARRIER SCREEN *I PET 0.1 1
A06 3512300200 GASKET DOOR PP 1
A07 3513100730 HOOK POM BLACK 1
A08 3515101320 SPRING HOOK HSW-3 1
A09 7112402011 SCREW TAPPING T1 TRS 4x20 MFZN 2
A10 3511606100 DECORATOR DOOR*R STS304 T0.5H/L 1
A11 3512603220 HANDLE DOOR CR T0.9 1
A12 3515307300 SUPPORTER HANDLE ABS SG-175 2
A13 3511605900 DECORATOR DOOR *U STS304 T0.5H/L 1
A14 3511606200 DECORATOR DOOR *L STS304 T0.5H/L 1
A15 3511605800 DECORATOR DOOR *T STS304 T0.5H/L 1
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the
latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr)

12
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
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.
A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm
NOTE
2
DISASSEMBLY AND ASSEMBLY

13
5. To remove control panel parts.
DISASSEMBLY AND ASSEMBLY
NO PART CODE PART NAME DESCRIPTION Q'TY
B01 3513404620 KNOB VOLUME ABS XR-401, H-2938 1
B02 3511604540 DECORATOR C-PANEL STS304 T0.5 H/L 1
B03 3516003980 SPECIAL DOUBLE TAPE SI-161 T0.15 1
B04 3515501530 WINDOW DISPLAT PMMA 1
B05 3516726200 CONTROL-PANEL ABS SG-175 SG-0760D 1
B06 3516907480 BUTTON FUNCTION ABS SG-175 SG-0760D 1
B07 3514321440 PCB SUB AS KOR-637V 1
B08 3514323330 PCB MAIN AS KOR-637V0A 1
B09 7122401211 SCREW TAPPING T2S TRS 4x12 MFZN 3
B10 7621301011 SCREW TAPPING T2 PAN 3x10 PW MFZN 5
B11 3516908520 BUTTON FUNCTION-C ABS SG-175 SG-0760D 2
B12 3511605120 DECORATOR RING ABS SG-175 SG-0760D 2
✔ Caution: In this Service Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the
latest parts information, please refer to PPL(Parts Price List) in Service information Center(http://svc.dwe.co.kr)

14
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.
DISASSEMBLY AND ASSEMBLY
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/
for a fully assembled oven with door normally closed.
NOTE
cm2

15
8. To remove wind guide assembly.
1) Remove a screw for earthing.
2) Remove a screw which secure the wind guide assembly.
3) Draw forward the wind guide assembly.
4) Pull the fan from the motor shaft.
5) Remove two screws which secure the motor shaded pole.
6) Remove the motor shaded pole.
7) 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.
DISASSEMBLY AND ASSEMBLY

16
10. To remove UV lamp assembly.
1) Remove the screw which secure the UV lamp assembly to the top-plate.
2) Remove the screw which hold the socket starter *O to the cover lamp.
3) Remove the socket starter *O from the cover lamp by pushing up two snap fits.
4) Remove the socket starter *I from the socket starter *O.
5) Remove the terminal starters from the socket starter *I.
6) Remove the starter glow from the socket starter *I.
7) Remove the lamp germicidal from the cover lamp.
DISASSEMBLY AND ASSEMBLY
8) Remove the socket lamp.
9) Remove the terminal lamp.
10) Reverse the above steps for reasembly.
11. To remove the ballast.
1) Remove two screws holding the ballast.
2) Remove the ballast.
3) Reversethe above steps for reasembly.

17
INTERLOCK MECHANISM AND ADJUSTMENT
Thedoorlockmechanismisadevicewhichhasbeenspeciallydesignedtocompletelyeliminatemicrowaveradiationwhenthedoor
isopenedduringoperation,andthustoperfectlypreventthedangerresultingfromtheleakageofmicrowave.
(1) Primary interlock switch
Whenthedoorisclosed,thehooklockstheovendoor.Ifthedoorisnotclosedproperly,theovenwillnotoperate.
Whenthedoorisclosed,thehookpushesthebuttonofthemicroswitch.Thenthebuttonoftheprimaryinterlockswitch
bringitunderONcondition.
(2) Secondary interlock switch and interlock monitor switch
Whenthedoorisclosed,thehookpushesthelockleverdownward.Thelockleverpressesthebuttonoftheinterlock
monitorswitchtobringitunderNOconditionandpressesthebuttonofthesecondaryinterlockswitchtobringitunderON
condition.
3. Adjustment steps
a)Loosentheonemountingscrew.
b)Adjustinterlockswitchassemblyposition.
c)Makesurethatlocklevermovessmothlyafteradjustmentiscompleted.
d)Tightencompletelyonemountingscrew.
Dooropen
monitor
switch(rear)
Hook Primary
interlock
switch
Interlock
monitor
switch
Secondary
interlock
switch(front)
LockleverCondition:DOORCLOSE Condition:DOOROPEN
Mountingscrew
Button
Interlockmonitorswitch
Whenthedoorisclosed,theinterlockmonitorswitchshouldbechanged(NOcondition)beforeotherswitchesareclosed.
Whenthedoorisopened,theinterlockmonitorswitchshouldbechanged(NCcondition)afterotherswitchesareopened.
ADJUSTMENT
Microwaveemissiontestshouldbeperformedafteradjustinginterlockmechanism.
Ifthemicrowaveemissionexceed4mW/cm,readjustinterlockmechanism.
NOTE
2

18
TROUBLE SHOOTING GUIDE
Following the procedure below to check if the oven is defective or not.
1.Checkgroundingbeforetroublechecking.
2.Becarefulofthehighvoltagecircuit.
3.Dischargethehighvoltagecapacitor.
4.Whencheckingthecontinuityoftheswitches,fuseorhighvoltagetransformer,disconnectoneleadwirefromtheseparts
andcheckcontinuitywiththeACplugremoved.Todootherwisemayresultinafalsereadingordamagetoyourmeter.
(TROUBLE 1) Doorshut,timerset,butnocookingtakesplace.
Continuity
NoContinuity
Continuity
0 OrApprox.
150~310
(normal)
Replace
NOTE1
Replace
NOTE1
Replace
Replace
Checkcontinuityof
primarywindingoflow
voltagetransformer
Malfunction
ofinterlock
monitor
switch
Defectivelow
voltage
transformer
Checkcontinuityof
interlockmonitorswitch
withdoorclosed
(COMC)
Checkcontinuityofprimary
interlockswitchcontact
withdoorpartiallyopen
untilinterlockmonitorswitch
contactclose
(COMNO)Shortedcontacts
ofprimary
interlockswitch.
Fuseagain
blows
Disconnecthighvoltage
fuseandoperatetheunitDefectivehigh
voltagetransformer
NoContinuityReplace
NOTE1
Checkcontinuityofboth
primaryandsecondary
interlockswitchwithdoor
closedMalfunctionof
interlockswitch
NoContinuity
Continuity
N
CHECK RESULTCAUSEREMEDY
CONDITION
Fuseblows.
Whenelectricpartsarechecked,besurethepowercordisnotinsertedthewalloutlet.
Checkwireharness,wiringandconnectedoftheterminalsandpowercordbeforecheckthepartslistedbelow.
NOTE

19
TROUBLE SHOOTING GUIDE
CONDITIONCHECK RESULTCAUSEREMEDY
Outlethas
propervoltage
Fusedoesnot
blow.Checkcontinuityof
magnetron No
ContinuityDefective magnetron Replace
No
Continuity
NormalDefectivetouch
controlcircuit
Openpower
supplycordReplace
Checkcontinuityof
powersupplycordAdjust
Checkcontinuityof
noisefilterboardNo
ContinuityDefectiveline
filterboardReplace
Alltheseswitchesmustbereplacedatthesametime,pleasereferto“InterlockMechanismAndAdjustment”.
NOTE
CONDITIONCHECK RESULTCAUSEREMEDY
Turntable
motorand
ovenlampdo
notturnon No
ContinuityAdjustor
replace
Adjustor
replace
Replace
Replace
Malfunction
ofprimary
interlock
switch
No
Continuity
0VApprox.
15VDC
Checkcontinuityof
primaryinterlockswitch
Checkcontinuityof
secondaryinterlockand
D.O.M.switches
CheckD.C.voltage
beingsuppliedto
RELAY(RY2)coil Malfunction
ofsecondary
interlockand
D.O.M.switch
Defective
touchcontrol
circuit
Faulty
contactsof
RELAY
(RY2)oropen
relaycoil
(TROUBLE 2) Displayshowsallfiguresselected,butovendoesnotstartcooking,eventhouhdesiredprogramandtimeare
setandstartpadistapped.