Viking Professional VMOS200 User manual

DMOS200
CDMOS200
VMOS200
CVMOS200
In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specified
should be used.
WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage and
current. Contact with the following parts may result in a severe, possibly fatal, electrical shock. (Inverter unit that includes
High Voltage Capacitor, High Voltage Power Transformer, High Voltage Rectifier and Heat sink etc., and Magnetron, High
Voltage Harness etc..)
TABLE OF CONTENTS Page
PRECAUTIONSTOBEOBSERVEDBEFOREANDDURINGSERVICINGTO
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ................... INSIDEFRONTCOVER
BEFORESERVICING ...................................................................................................... INSIDEFRONTCOVER
WARNINGTOSERVICEPERSONNEL ................................................................................................................2
MICROWAVEMEASUREMENTPROCEDURE.....................................................................................................3
FOREWORDANDWARNING................................................................................................................................5
PRODUCTSPECIFICATIONS...............................................................................................................................6
GENERAL INFORMATION ...................................................................................................................................6
OPERATION .........................................................................................................................................................8
TROUBLESHOOTINGGUIDE .............................................................................................................................12
TESTPROCEDURE ............................................................................................................................................14
TOUCHCONTROLPANELASSEMBLY .............................................................................................................24
COMPONENTREPLACEMENTANDADJUSTMENTPROCEDURE ..................................................................31
PICTORIALDIAGRAM ........................................................................................................................................37
POWERUNITCIRCUIT.......................................................................................................................................38
LSIUNITCIRCUIT...............................................................................................................................................39
PRINTEDWIRINGBOARD .................................................................................................................................40
PARTS LIST........................................................................................................................................................41
PACKINGANDACCESSORIES .........................................................................................................................45
S72M194DMOS2E
DMOS200
CDMOS200
VMOS200
CVMOS200
MICROWAVEOVEN
MODELS
SERVICE MANUAL
This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
COOK
RangeCorporation
111 Front St., Greenwood, MS 38930
Tel: [phone]
(DMOS200modelshown)

DMOS200
CDMOS200
VMOS200
CVMOS200
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) Makethefollowingsafetychecksonallovenstobeservicedbeforeactivatingthemagnetronorothermicrowave
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 microwave power for any service test or inspection within the microwave generating
compartments,checkthemagnetron,waveguideortransmissionline,andcavityforproperalignment,integrity,
and connections.
(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and
transmissionsystemsshallberepaired,replaced,oradjustedbyproceduresdescribedinthismanualbeforethe
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.
BEFORE SERVICING
Before servicing an operative unit, perform a microwave emission check as per the Microwave Measure-
ment Procedure outlined in this service manual.
If microwave emissions level is in excess of the specified limit, contact Viking Service immediately @
1-888-845-4641.
If the unit operates with the door open, service person should (1) tell the user not to operate the oven and
(2) contact VIKING, plus the Department Of Health, Canada and/or the Food and Drug Administration's
Center for Devices and Radiological Health immediately.
Service personnel should inform VIKING of any certified unit found with emissions in excess of 4mW/cm2.
Theowneroftheunitshouldbeinstructednottousetheunituntiltheovenhasbeenbroughtintocompliance.
DANGER CAUTION
HIGH VOLTAGE
Do not energize a microwave oven with the outer case cabinet removed, because a microwave oven
generates High Voltage in the circuit.
Ifyouintendtooperatetheovenemployingthehighfrequencyswitchingpowerconvertercircuit,youshould
take special precautions to avoid an electrical shock hazard.
The high voltage transformer, high voltage capacitor and high voltage diode have energized high voltage
potential approx. 8 KV.
Thealuminiumheatsinkisconnectedto theswitchingpowertransistorCollectorpole,andhasanenergized
high voltage potential approx. 650V peak.
DO NOT ACCESS THE HIGH VOLTAGE TRANSFORMER, HIGH VOLTAGE CAPACITOR, HIGH
VOLTAGEDIODEANDHEATSINKWHENTHEPOWERSUPPLYISCONNECTEDTOANELECTRICAL
OUTLET.

1
CDMOS200
DMOS200
VMOS200
CVMOS200
Notes

2
CDMOS200
DMOS200
VMOS200
CVMOS200
WARNINGTO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of pro-
ducing very high voltage and current, contact with
following parts
may result in a severe, possibly
fatal, electrical shock.
(Example)
HighVoltageCapacitor,HighVoltagePowerTrans-
former,Magnetron,HighVoltageRectifierAssem-
bly, High Voltage Harness etc..
Read the Service Manual carefully and follow all
instructions.
Before Servicing
1. Disconnect the power supply cord , and then
remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
WARNING:RISK OF ELECTRIC SHOCK.
DISCHARGE THE HIGH-VOLTAGE
CAPACITOR BEFORE SERVICING.
The high-voltage capacitor remains charged about 60
secondsaftertheovenhasbeenswitchedoff.Waitfor60
secondsandthenshort-circuittheconnectionofthehigh-
voltagecapacitor(thatis the connectingleadofthehigh-
voltage rectifier) against the chassis with the use of an
insulated screwdriver.
Whenever troubleshooting is performed the power supply
mustbedisconnected.Itmayin,somecases,benecessary
to connect the power supply after the outer case has been
removed, in this event,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power
transformer.
5. Ensure that the leads remain isolated from other
components and oven chassis by using insulation tape.
6. After that procedure, reconnect the power supply cord.
When the testing is completed,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power
transformer.
5. Reinstall the outer case (cabinet).
6. Reconnectthepowersupplycordaftertheouter case is
installed.
7. Run the oven and check all functions.
After repairing
1. Reconnect all leads removed from components during
testing.
2. Reinstall the outer case (cabinet).
3. Reconnectthepowersupplycordaftertheouter case is
installed.
4. Run the oven and check all functions.
Microwave ovens should not be run empty. To test for the
presence of microwave energy within a cavity, place a cup
of cold water on the oven turntable, close the door and set
the power to HIGH and set the microwave timer for two (2)
minutes.Whenthetwominuteshaselapsed(timeratzero)
carefullycheckthatthewaterisnowhot.Ifthewaterremains
coldcarryoutBeforeServicingprocedureandre-examine
the connections to the component being tested.
When all service work is completed and the oven is fully
assembled,themicrowavepoweroutputshouldbechecked
and a microwave leakage test should be carried out.
Don't Touch !
Danger High Voltage

3
CDMOS200
DMOS200
VMOS200
CVMOS200
MICROWAVE MEASUREMENT PROCEDURE (CANADA)
Afteradjustmentofthedoorswitchesarecompletedindividuallyorcollectively,switchtestandmicrowaveleakagetestmust
beperformedwithsurveyinstrumentandtestresultmustbeconfirmedtomeettherequirementoftheperformancestandard
formicrowaveovensasundermentioned.
A.Requirements:
Every microwave oven shall function in such a manner that when the oven is fully assembled and operating with its service
controls and user controls adjusted to yield the maximum output, the leakage radiation, at all points at least 5 cm. from the
external surface of the oven, does not exceed:
1) 1.0mW/cm2 with the test load of 275 ± 15 ml of water at an initial temperature 20 ±5oC.
2) 5.0mW/cm2 whentheouterenclosureisremovedwithatestloadof275±15mlofwaterataninitialtemperature20±5oC.
3) 5.0mW/cm2 without a test load.
B.Preparationfortesting:
Beforebeginningtheactualmeasurementofleakage,proceedasfollows:
1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:
SurveyinstrumentsthatcomplywiththerequirementforinstrumentationasprescribedbyCSAandNHWperformancestandard
for microwave ovens must be used for testing recommended instruments are , NARDA 8100 and NARDA 8200.
2) Place the oven tray in the oven cavity.
3) Place the load of 275±15 ml of tap water initially at 20±5oC in the center of the oven cavity.
The water container shall be a low form of 600 ml beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made
of an electrically nonconductive material such as glass or plastic.
Theplacingofthisstandardloadintheovenisimportantnotonlytoprotecttheoven,butalsotoinsurethatanyleakage
ismeasured accurately.
4) SetthecookingcontrolonFullPowerCookingMode,Closethedoorandselectacookcycleofseveralminutes.Ifthewater
begins to boil before the survey is completed, replace it with 275 ml of cool water.
C. Leakagetestwithenclosureinstalled:
1) Grasptheprobeofthesurveyinstrumentandholditperpendiculartothegapbetweenthedoorandthebodyoftheoven.
2) Move the probe slowly, not faster than 2.5 cm/sec. along the gap, watching for the maximum indication on the meter.
3) Checkforleakageatthedoorscreen,sheetmetalseamsandotheraccessiblepositionswherethecontinuityofthemetal
hasbeen breached (eg., around the switches, indicator, and vents).
Whiletestingforleakagearoundthedoorpullthedoorawayfromthefrontoftheovenasfarasispermittedbytheclosed
latch assembly.
4) Measurecarefullyatthepointofhighestleakageandmakesurethatthehighestleakageisnogreaterthan4mW/cm2,and
that the secondary interlock switch does turn the oven OFF before any door movement.
C. Leakagetestwithoutenclosure:
1) Removetheenclosure(cabinet).
2) Grasptheprobeof the surveyinstrumentandholdit perpendicular toallmechanicalandelectric parts oftheoventhatis
accessibletotheuseroftheovenincluding,butnotlimitedto,thewaveguide,cavityseams,magnetrongapbetweenthe
door and the body of the oven.
3) Move the probe slowly, not faster than 2.5 cm/sec. along the gap, watching for the maximum indication on the meter.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is under 5mW/cm2.
CAUTION:SpecialattentionshouldbegiventoavoidelectricalshockbecauseHIGHVOLTAGEisgeneratedduringthistest
NoLoadtest
1) Operate the oven without a load and measure the leakage by the same method as the above test procedure " Leakage
test with enclosure installed"
2. Make sure that the highest leakage should not exceed 5mW/cm2.
NOTE: After servicing, record data on service invoice and microwave leakage report.

4
CDMOS200
DMOS200
VMOS200
CVMOS200
MICROWAVE MEASUREMENT PROCEDURE (USA)
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven
shouldnotexceed1mW/cm2atanypoint5cmormorefromtheexternalsurfaceoftheoven,measuredpriortoacquisition
byapurchaser, andthereafter(throughtheusefullifeof theoven),5mW/cm2at anypoint5cmor morefromthe external
surface of the oven.
2) Safety interlock switches:
Primary interlock relay switch shall prevent microwave radiation emission in excess of the requirement as above
mentioned. Secondary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of
5 mW/cm2 at any point 5cm or more from the external surface of the oven.
B.Preparationfortesting:
Beforebeginningtheactualmeasurementofleakage,proceedasfollows:
1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for
microwaveovens,21CFR1030.10(c)(3)(i),mustbeusedfortesting.
2) Place the oven tray in the oven cavity.
3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5O C (68OF) in the center of the oven cavity.
Thewatercontainershallbea lowformof 600ml(20 oz)beakerwith aninsidediameter ofapprox.8.5cm(3-1/2in.)and
made of an electrically nonconductive material such as glass or plastic.
Theplacingofthisstandardloadintheovenisimportantnotonlytoprotecttheoven,butalsotoinsurethatanyleakage
ismeasured accurately.
4) Set the cooking control on Full Power Cooking Mode.
5) Closethedoorandselectacookcycleofseveralminutes.Ifthewaterbeginstoboilbeforethesurveyiscompleted,replace
it with 275 ml of cool water.
C. Leakagetest:
Closed-doorleakagetest(microwavemeasurement):
1) Grasptheprobeofthesurveyinstrumentandholditperpendiculartothegapbetweenthedoorandthebodyoftheoven.
2) Movethe probeslowly,notfasterthan1in./sec.(2.5cm/sec.)alongthe gap,watchingforthemaximumindicationonthe
meter.
3) Checkforleakageatthedoorscreen,sheetmetalseamsandotheraccessiblepositionswherethecontinuityofthemetal
hasbeen breached (eg., around the switches, indicator, and vents).
Whiletestingforleakagearoundthedoor,pullthedoorawayfromthefrontoftheovenasfarasispermittedbytheclosed
latch assembly.
4) Measurecarefullyatthepointofhighestleakageandmakesurethatthehighestleakageisnogreaterthan4mW/cm2,and
that the primary interlock switch/secondary interlock relay does turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.

5
CDMOS200
DMOS200
VMOS200
CVMOS200
VIKING RANGE CORPORATION
111 Front St., Greenwood, MS 38930
Tel: [phone]
SERVICE MANUAL
VIKING RANGE CORPORATION
MICROWAVEOVENS
FOREWORD
This Manual has been prepared to provide Viking Service Personnel with
OperationandServiceInformationfortheVikingMicrowaveOvens,DMOS200,
CDMOS200,VMOS200,CVMOS200.
It is recommended that service personnel carefully study the entire text of
this manual so that they will be qualified to render satisfactory customer
service.
Check the interlock switches and the door seal carefully. Special attention
should be given to avoid electrical shock and microwave radiation hazard.
WARNING
Never operate the oven until the following points are ensured:
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is no other visible damage with the oven.
Servicing and repair work must be carried out only by trained service
personnel. DANGER
Certaininitialpartsareintentionallynotgroundedandpresentariskof
electricalshockonlyduringservicing.Servicepersonnel-Donot
contactthefollowingpartswhiletheapplianceisenergized;
HighVoltageCapacitor,PowerTransformer,Magnetron,HighVoltage
RectifierAssembly, HighVoltageHarness;
Ifprovided,VentHood,Fanassembly,CoolingFanMotor.
All the parts marked “*” on parts list are used at voltages more than
250V.
Removal of the outer wrap gives access to voltage above 250V.
All the parts marked “∆” on parts list may cause undue microwave
exposure, by themselves, or when they are damaged, loosened or
removed.
PRODUCT DESCRIPTION
GENERALINFORMATION
OPERATION
TROUBLESHOOTINGGUIDEAND
TEST PROCEDURE
TOUCHCONTROLPANEL
COMPONENTREPLACEMENT
ANDADJUSTMENTPROCEDURE
WIRINGDIAGRAM
PARTSLIST
DMOS200
CDMOS200
VMOS200
CVMOS200

6
CDMOS200
DMOS200
VMOS200
CVMOS200
ITEM DESCRIPTION
PowerRequirements 120 Volts / 13.0 Amperes/1500Watts
60Hertz
Singlephase,3wiregrounded
PowerOutput 1100watts(IEC-705TESTPROCEDURE)
Operatingfrequencyof2450MHz
CaseDimensions Width 24"
Height 13-3/8"
Depth 19-1/8"
CookingCavityDimensions Width 17-3/8"
2.0 Cubic Feet Height 10-1/2"
Depth 18-5/8"
Tray Size 15"
ControlComplement Touch Control System
Clock ( 1:00 - 12:59 )
Timer (0 - 99 min. 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
P-HI ................................................. Full power throughout the cooking time
P-90....................................................................approx. 90% of Full Power
P-80....................................................................approx. 80% of Full Power
P-70....................................................................approx. 70% of Full Power
P-60....................................................................approx. 60% of Full Power
P-50....................................................................approx. 50% of Full Power
P-40....................................................................approx. 40% of Full Power
P-30....................................................................approx. 30% of Full Power
P-20....................................................................approx. 20% of Full Power
P-10....................................................................approx. 10% of Full Power
P-0.....................................................No power throughout the cooking time
Cavity Light Yes
SafetyStandard UL and CUL Listed FCC Authorized
DHHSRules,CFR,Title 21,Chapter1,SubchapterJ andCanadianStandards
Association.HealthCANADA.
SPECIFICATION
GENERAL INFORMATION
GROUNDING INSTRUCTIONS
This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed
and grounded in accordance with the National Electrical Code and local codes and ordinances.
Intheeventofanelectricalshortcircuit,groundingreducestheriskofelectricshockbyprovidinganescapewirefortheelectric
current.
WARNING: Improper use of the grounding plug can result in a risk of electric shock.
ElectricalRequirements
The electrical requirements are a 120 volt 60 Hz, AC only,
15or20amp.fusedelectricalsupply.Itisrecommendedthataseparatecircuitservingonlythisappliancebeprovided.When
installing this appliance, observe all applicable codes and ordinances.
A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord.
Whereatwo-prongedwall-receptacleisencountered,itisthepersonalresponsibilityandobligationofthecustomertocontact
a qualified electrician and have it replaced with a properly grounded three-pronged wall receptacle or have a grounding
Sensor option pads, Breakfast pad, Lunch pad, Add a minute pad, Frozen
food pads, Beverage pad, Number pad, Timer/Clock pad, Clock pad, Power
level pad, Stop/Clear pad, Start touch pad, preset recipes pad, 15 minute
dinners pad, warm/hold pad and Defrost pad.

7
CDMOS200
DMOS200
VMOS200
CVMOS200
adapterproperlygroundedand polarized. Iftheextensioncordmust be
used, it should be a 3-wire, 15 amp. or higher rated cord. Do not drape
overacountertoportablewhereitcanbepulledonbychildrenortripped
over accidentally.
CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR RE-
MOVE THE ROUND GROUNDING PRONG FROM THIS
PLUG.
OVEN DIAGRAM
1. One touch door open button.
Push to open door.
2. Door latches.
The oven will not operate unless the
door is securely closed.
3. Removable turntable support.
4. Removable turntable.
The turntable will rotate clockwise or
counterclockwise.
5. Oven lamp.
It will light when oven is operating or
door is opened.
6. Oven door with see-through window.
7. Ventilation openings. (Rear)
8. Auto-Touch control panel.
9. Time display: Digital display, 99
minutes 99 seconds.
10.Turn table motor shaft
11.Wave guide cover.
12.Power supply cord
TOUCH CONTROL PANEL
1
65
4
210
11
12
9
7
8
3
COOK
(VMOS200 model shown)
NOTE:
Thedirectedfeaturesaredisabled
afteroneminutewhentheovenis
not in use. These features are
automatically enabled when the
door is opened and closed or the
STOP/ CLEAR pad is pressed.

8
CDMOS200
DMOS200
VMOS200
CVMOS200 OPERATION
DESCRIPTION OF OPERATING SEQUENCE
Thefollowingisadescriptionofcomponentfunctionsduring
oven operation.
OFF CONDITION
Closing the door activates the door sensing switch and
secondary interlock switch. (In this condition, the monitor
switch contacts are opened.)
When oven is plugged in, 120 volts A.C. is supplied to the
control unit. (Figure O-1).
1. The display will show flashing"WELCOME,
PRESS CLEAR"
Tosetanyprogramorsettheclock,youmustfirsttouch
theSTOP/CLEAR pad. The display will clear, and " : "
will appear.
COOKING CONDITION
Program desired cooking time by touching the NUMBER
pads. Program the power level by touching the POWER
LEVEL pad and then a Number pad.
When the START pad is touched, the following operations
occur:
1. The contacts of relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Figure O-2)
RELAY CONNECTED COMPONENTS
RY-1 oven lamp/turntable motor/fan motor
RY-2 power transformer
2. 120 volts A.C. is supplied to the primary winding of the
power transformer and is converted to about 3.3 volts
A.C. output on the filament winding, and approximately
2370 volts A.C. on the high voltage winding.
3. Thefilamentwindingvoltageheatsthemagnetronfilament
andtheH.V.windingvoltage issenttoavoltagedoubler
circuit.
4. The microwave energy produced by the magnetron is
channelled through the waveguide into the cavity feed-
box, and then into the cavity where the food is placed to
be cooked.
5. Upon completion of the cooking time, the power
transformer, oven lamp, etc. are turned off, and the
generation of microwave energy is stopped. The oven
will revert to the OFF condition.
6. Whenthedoorisopenedduringacookcycle,themonitor
switch, secondary switch, door sensing switch, primary
switch and secondary interlock relay are activated with
the following results. The circuits to the turntable motor,
thecooling fan motor, and the high voltage components
are de-energized, the oven lamp remains on, and the
digital read-out displays the time still remaining in the
cook cycle when the door was opened.
7. Themonitor switchelectricallymonitorstheoperationof
the primary switch and primary and is mechanically
associated with the door so that it will function in the
followingsequence.
1) Whenthedooropensfromtheclosedposition,theprimary
switch, secondary switch, door sensing switch, and
secondary interlock relay open their contacts and the
monitor switch contacts close.
(2) When the door is closed from the open position, the
monitor switch contacts open first. Then the contacts of
the primary switch and door secondary switch close.
If the primary switch and the secondary switch primary
contacts are closed when the door is opened, the monitor
switchcontactsformashortcircuitthroughthemonitorfuse,
primary switch and secondary switch causing the monitor
fuse to blow.
POWER LEVEL P-0 TO P-90 COOKING
WhenVariableCookingPowerisprogrammed,the120volts
A.C. is supplied to the power transformer intermittently
throughthecontactsofrelay(RY-2)whichisoperatedbythe
controlunitwithina32secondtimebase.Microwavepower
operation is as follows:
VARI-MODE ON TIME OFF TIME
Power 10(P-HI) 32 sec. 0 sec.
(100% power)
Power 9(P-90) 30 sec. 2 sec.
(approx. 90% power)
Power 8(P-80) 26 sec. 6 sec.
(approx. 80% power)
Power 7(P-70) 24 sec. 8 sec.
(approx. 70% power)
Power 6(P-60) 22 sec. 10 sec.
(approx. 60% power)
Power 5(P-50) 18 sec. 14 sec.
(approx. 50% power)
Power 4(P-40) 16 sec. 16 sec.
(approx. 40% power)
Power 3(P-30) 12 sec. 20 sec.
(approx. 30% power)
Power 2(P-20) 8 sec. 24 sec.
(approx. 20% power)
Power 1(P-10) 6 sec. 26 sec.
(approx. 10% power)
Power 0(P-0) 0 sec. 32 sec.
(0% power)
Note: TheON/OFFtimeratiodoesnotcorrespondwiththe
percentageofmicrowavepower,becauseapprox.2
seconds are needed for heating of the magnetron
filament.

9
CDMOS200
DMOS200
VMOS200
CVMOS200
SENSOR COOKING CONDITION
UsingtheSENSOR function,foodiscookedwithoutfiguring
time,powerlevelorquantity. Whentheovensensesenough
steam from the food, it relays the information to its
microprocessor which will calculate the remaining cooking
timeandpowerlevelneededforbestresults. Whenthefood
is cooked, water vapor is developed. the sensor "senses"
the vapor and its resistance increase gradually. When the
resistance reaches the value set according to the menu,
supplementary cooking is started.
Thetimeofsupplementarycookingisdeterminedbyexperi-
mentwith each food category and inputted into the LSI. An
example of how sensor works: (Potatoes)
1. Potatoes at room temperature. Vapor is emitted very
slowly.
2.Heat Potatoes. Moisture and humidity is emitted very
rapidly. You can smell the aroma as it cooks.
3.Sensor detects moisture and humidity and calculates
cooking time and variable power.
Cooking Sequence.
1. Touch one of the SENSOR pads.
NOTE: The oven should not be operated on sensor
immediately after plugging in the unit. Wait two
minutes before cooking on SENSOR.
2. The coil of shut-off relay (RY-1) is energized, the
turntablemotorareturnedon,butthepowertransformer
is not turned on.
3. After about 16 seconds, the cook relay (RY-2) is
energized. The power transformer is turned on,
microwaveenergyisproducedandfirststageisstarted.
The 16 seconds is the cooling time required to remove
any vapor from the oven cavity and sensor.
NOTE: Duringthisfirststage,donotopenthedoorortouch
STOP/CLEAR pad.
4. When the sensor detects the vapor emitted from the
food,thedisplayswitchesovertotheremainingcooking
time and the timer counts down to zero.
At this time, the door may be opened to stir, turn or
season food.
5. Whenthetimerreacheszero,anaudiblesignalsounds.
Theshut-offrelayandcookrelayarede-energizedand
the power transformer, oven lamp, etc. are turned off.
6. Opening the door or touching the STOP/CLEAR pad,
the time of the day will reappear on the display and the
oven will revert to an OFF condition. When the timer
reaches zero, an audible signal sounds.

10
CDMOS200
DMOS200
VMOS200
CVMOS200
Figure O-2 Oven Schematic - Cooking Condition
Figure O-1 Oven Schematic - Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY
SCHEMATIC
3. VARIABLE COOKING CONTROL "HIGH"
2. COOKING TIME PROGRAMMED
1. DOOR CLOSED
NOTE: CONDITION OF OVEN
4. "START" PAD TOUCHED
OL
120V AC
60 Hz
MONIT OR
SWITCH
H.V. R E C TIFIE R
MAG NE T R ON
SECONDARY
SWITCH
MONIT OR FUSE
CAVITY TEMP. FUSE
MAG NE T R ON TEMP. FUSE
A1
A2
COM.
N.C.
(R Y-1)
CONTROL UNIT
SECONDARY
INT E R LOC K
RELAY
GRN
POWER
TRANSFORMER
CAPACITOR 1.0µF
AC 2300V
FM
TTM
(R Y-2)
N.O.COM.
N.O.
COM.
B1 B2
PRIMARY
SWITCH
H
N
NOIS E FILT E R UNIT
N.O. COM.
DOOR
SENSING
SWITCH
NOISE SUPPRESSION COIL
LINE CROSS CAPACITOR 0.22uF/AC 250V
0.0033uF/AC 125V 0.0033uF/AC 125V
LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR
N.O.
COM.
COM.
OL
120V AC
60 Hz
MONIT OR
SWITCH
H.V. R E C T IFIE R
MAG NE T R ON
SECONDARY
SWITCH
MONIT OR FUSE
CAVITY TEMP. FUSE
MAG NE T R ON TEMP. FUSE
A1
A2
COM.
N.C.
(R Y-1)
CONTROL UNIT
SECONDARY
INT E R LOC K
RELAY
GRN
POWER
TRANSFORMER
CAPACITOR 1.0µF
AC 2300V
FM
TTM
(R Y-2)
N.O.COM.
N.O.
COM.
B1 B2
PRIMARY
SWITCH
H
N
NOISE FILTER UNIT
N.O. COM.
DOOR
SENSING
SWITCH
NOIS E S UP PR E S S ION C OIL
LINE CROSS CAPACITOR 0.22uF/AC 250V
0.0033uF/AC 125V 0.0033uF/AC 125V
LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR
N.O.
COM.
COM.
AH S E NS OR

11
CDMOS200
DMOS200
VMOS200
CVMOS200
DESCRIPTION AND FUNCTION OF COMPONENTS
DOOR OPEN MECHANISM
Thedoorisopenedbypushingtheopenbuttononthecontrol
panel, refer to the Figure D-1. When the open button is
pushed,theopenbuttonpushesuptheswitchlever,andthen
the switch lever pushes up the latch head. The latch heads
are moved upward and released from latch hook. Now the
doorwillopen.
FigureD-1.Door OpenMechanism
PRIMARY SWITCH, SECONDARY SWITCH &
DOOR SENSING SWITCH
Theprimaryswitchandsecondaryswitchmountedparrallel
to each other horizontally in the lower positions of the latch
hook,thedoorsensingswitchismountedhorizontallyinthe
upper position of the latch hook. They are activated by the
latchheadonthedoor.Whenthedoorisopened,theswitches
interruptthepowertoallhighvoltagecomponents,exceptthe
oven lamp . A cook cycle cannot take place until the door is
firmly closed thereby activating all interlock switches. The
secondary interlock system consists of the door sensing
switch and the secondary interlock relay located on the
controlcircuitboard.
MONITOR SWITCH
Themonitorswitchisactivated(thecontactsopened)bythe
latchheadonthedoorwhilethedoorisclosed.Theswitchis
intendedtorendertheoveninoperative,bymeansofblowing
themonitorfuse,whenthecontactsoftheprimary switchfail
toopenwhenthedooris opened.
Functions:
1. Whenthedoorisopened,themonitorswitchcontactclose
(totheONcondition)duetotheirbeingnormallyclosed.At
thistimethesecondaryinterlockrelay,primaryswitchand
secondaryswitchareintheOFFcondition(contactsopen)
dueto their being normally open contact switches.
2. As the door goes to a closed position, the monitor switch
contactsarefirstopenedandthenthedoorsensingswitch,
primary switch and secondary switch contacts close. (On
openingthedoor,eachoftheseswitchesoperateinversely.)
3. Ifthedoorisopened,primaryswitch and contactsfailto
open, the monitor fuse blows simultaneously with closing
of the monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE, TEST MONITOR SWITCH AND PRI-
MARY SWITCH FOR PROPER OPERATION.
(REFERTOCHAPTER"TESTPROCEDURE").
NOTE: MONITOR FUSE, AND MONITOR SWITCH ARE
REPLACEDAS ANASSEMBLY.
TURNTABLE MOTOR
The turntable motor rotates the turntable located on the
bottomoftheovencavity,sothat the foods on the turntable
cookevenlyduringcooking.Theturntablemayturnineither
direction.
COOLING FAN MOTOR
Thecoolingfanmotordrivesabladewhichdrawsexternalcool
air.Thiscool airisdirectedthrough theairvanes surrounding
themagnetronandcoolsthemagnetron.Thisairischannelled
throughtheovencavitytoremovesteamandvaporsgivenoff
from the heating foods. It is then exhausted through the
exhausting air vents at the oven cavity.
MONITOR FUSE
1. Themonitorfuseblowswhenthecontacts(COM-NO)of
the primaryswitchremainclosedwiththeovendooropen
and when the monitor switch closes.
2. If the wire harness or electrical components are short-
circuited, this monitor fuse blows to prevent an electric
shock or fire hazard.
CAVITY TEMPERATURE FUSE
The cavity temperature fuse located on the top of the oven
cavity,isdesignedtopreventdamagetotheovenbyfire.Ifthe
foodloadisovercooked, byeithererrorincook timeordefect
in the control unit, the cavity temperature fuse will open.
Undernormaloperation,thecavitytemperaturefuseremains
closed. However, when abnormally high temperatures are
reachedwithintheovencavity,thecavitytemperaturefusewill
openat302oF(150oC)causingtheoventoshutdown.
NOTE: This is fuse. It does not reset.
MAGNETRON TEMPERATURE FUSE
Themagnetrontemperaturefuselocatednearthemagnetronis
designedtopreventdamagetothemagnetronifanoverheated
condition develops in the tube due to cooling fan failure,
obstructed air guide, dirty or blocked air intake, etc.
Under normal operation, the magnetron temperature fuse
remainsclosed.However,whenabnormallyhightemperatures
arereachedwithinthemagnetron,themagnetrontemperature
fusewillopenat302oF(150oC)causingtheoventoshutdown.
NOTE: This is fuse. It does not reset.
Door Sensing
Switch
Monitor Switch
Switch Lever Secondary
Switch
Latch Heads
Door
Primary
Switch

12
CDMOS200
DMOS200
VMOS200
CVMOS200 TROUBLESHOOTING GUIDE
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
Whentroubleshootingthemicrowaveoven,itishelpful tofollowthe SequenceofOperationinperformingthechecks.Many
ofthepossiblecausesoftroublewillrequirethataspecifictestbeperformed.Thesetestsaregivenaprocedureletterwhich
will be found in the "Test Procedure "section.
IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the primary switch, and monitor
switch, before replacing the monitor fuse. If the monitor fuse is replaced, the monitor switch must also be
replaced. Use part FFS-BA016/KIT as an assembly.
IMPORTANT: Whenevertroubleshootingisperformedwiththepowersupplycorddisconnected.Itmayin,somecases,be
necessary to connect the power supply cord after the outer case has been removed, in this event,
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Dischargehighvoltagecapacitor.
4. Disconnect the leads to the primary of the power transformer.
5. Ensurethat theleadsremainisolatedfromothercomponentsand ovenchassisbyusinginsulationtape.
6. Afterthatprocedure,reconnectthepower supply cord.
Whenthetestingiscompleted
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Dischargehighvoltagecapacitor.
4. Reconnect the leads to the primary of the power transformer.
5. Reinstalltheoutercase(cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.

13
CDMOS200
DMOS200
VMOS200
CVMOS200
AMAGNETRON ASSEMBLY TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
Home fuse or circuit breaker blows
when power cord is plugged into
wall receptacle
Monitor fuse blows when power
cordis pluggedintowall receptacle.
All letters and indicators do not
appear in display when power cord
isfirstpluggedintowalloutlet.
Display does not operate properly
when STOP/CLEAR key is
touched.(Buzzershouldsound and
":" or time of day should appear in
display.)
Ovenlampdoesnotlightwhendoor
is opened.
Oven lamp does not go out when
door is closed.
Oven lamp lights but fan motor
and turntable motor do not operate.
Oven does not go into cook cycle
when START pad is touched
Oven seems to be operating but
little or no heat is produced in oven
load. (Food incompletely cooked or
not cooked at all at end of cook
cycle.)
Oven goes into a cook cycle but
extremely uneven heating is
produced in oven load (food).
Oven does not cook properly when
programmed for Cooking Power 5
mode. (Operates properly on
Cooking Power 10 (HIGH) mode.)
OvengoesintoCOMPUDEFROST
but food is not defrosted well.
AH sensor does not end during
sensor cooking condition. (Oven
doesnotshutoffafteracupofwater
is boiling by sensor cooking)
Oven stops at 16 sec. after starting
OFF
CONDITION
PROBLEM
CONDITION
SHORT IN POWER CORD SHORT OR OPENED WIRING MAGNETRON POWER TRANSFORMER H.V. RECTIFIER ASSEMBLY HIGH VOLTAGE CAPACITOR CAVITY TEMPERATURE FUSE MAGNETRON TEMPERATURE FUSE PRIMARY OR DOOR SENSING SWITCH SECONDARY INTERLOCK SYSTEM MONITOR SWITCH MONITOR FUSE OVEN LAMP OR SOCKET COOLING FAN MOTOR TURNTABLE MOTOR TOUCH CONTROL PANEL WRONG OPERATION LOW VOLTAGE DIRTY OVEN CAVITY KEY UNIT RELAY (RY1) COMPU DEFROST FOIL PATTERN ON PWB. NOISE FILTER
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
TESTPROCEDURE
RE RE ABCDEEF FG H RE RE CK I CKCKCK J K L M N
COOKING
CONDITION
CK = Check / RE = Replace
COOKING
CONDITION
SENSOR

14
CDMOS200
DMOS200
VMOS200
CVMOS200
BPOWER TRANSFORMER TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the primary input terminals and measure the resistance of the transformer with an
ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x 1 scale, the resistance of
the primary coil should be less than 1 ohm and the resistance of the high voltage coil should be
approximately 90 ohms; the resistance of the filament coil should be less than 1 ohm.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
(HIGHVOLTAGESARE PRESENTATTHEHIGHVOLTAGETERMINAL,SO DONOTATTEMPT TO
MEASURE THE FILAMENT AND HIGH VOLTAGE.)
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
4. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check
across the magnetron filament leads should indicate less than 1 ohm.
5. Totestforashortedmagnetron,connecttheohmmeterleadsbetweenthemagnetronfilamentleads
and chassis ground. This test should indicate an infinite resistance. If there is little or no resistance
the magnetron is grounded and must be replaced.
6. Reconnect all leads removed from components during testing.
7. Reinstall the outer case (cabinet).
8. Reconnect the power supply cord after the outer case is installed.
9. Run the oven and check all functions.
MICROWAVE OUTPUT POWER
Thefollowingtestprocedureshouldbecarriedoutwiththemicrowaveoveninafullyassembledcondition
(outer case fitted).
HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD
BE OBSERVED.
Power output of the magnetron can be measured by performing a water temperature rise test. This test
shouldonlybeusedifabovetestsdonotindicateafaultymagnetronandthereisnodefectinthefollowing
componentsorwiring:siliconrectifier,highvoltagecapacitorandpowertransformer.Thistestwillrequire
a 16 ounce (453cc) measuring cup and an accurate mercury thermometer or thermocouple type
temperature tester. For accurate results, the following procedure must be followed carefully:
1. Fillthemeasuringcupwith16oz.(453cc)oftapwaterandmeasurethetemperatureofthewaterwith
athermometerorthermocoupletemperaturetester.Stirthethermometerorthermocouplethroughthe
water until the temperature stabilizes. Record the temperature of the water.
2. Place the cup of water in the oven. Operate oven at POWER 10(HIGH) selecting more than 60
secondscooktime.Allowthewatertoheatfor60seconds,measuringwithastopwatch,secondhand
of a watch or the digital read-out countdown.
3. Remove the cup from the oven and again measure the temperature, making sure to stir the
thermometer or thermocouple through the water until the maximum temperature is recorded.
4. Subtractthecold watertemperaturefromthehot watertemperature.Thenormal result shouldbe38
to 78oF(21 to 42.6oC) rise in temperature. If the water temperatures are accurately measured and
tested for the required time period the test results will indicate if the magnetron tube has low power
output(lowriseinwatertemperature)whichwouldextendcookingtimeorhighpoweroutput(highrise
in water temperature) which would reduce cooking time. Because cooking time can be adjusted to
compensate for power output, the magnetron tube assembly should be replaced only if the water
temperaturerisetestindicatesapoweroutputwellbeyondthenormallimits.Thetestisonlyaccurate
if the power supply line voltage is 120 volts and the oven cavity is clean.

15
CDMOS200
DMOS200
VMOS200
CVMOS200
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Ifthecapacitorisopen,nohighvoltagewillbeavailabletothemagnetron.Disconnectinputleadsand
check for short or open between the terminals using an ohmmeter.
Checkingwithahighohmscale,ifthehighvoltagecapacitorisnormal,themeterwillindicatecontinuity
for a short time and should indicate an open circuit once the capacitor is charged. If the above is not
thecase,check the capacitor with an ohmmeter to see if it is shorted between either of the terminals
and case. If it is shorted, replace the capacitor.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
DHIGH VOLTAGE CAPACITOR TEST
ECAVITY TEMPERATURE FUSE TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Acontinuitycheckacrossthecavitytemperaturefuseterminalsshouldindicateaclosedcircuitunless
thetemperatureofthe cavitytemperaturefusereachesapproximately302oF(150oC). Anopen cavity
temperaturefuseindicatesoverheatingoftheoven,exchangethe cavitytemperaturefuseandcheck
inside of oven cavity and for improper setting of cooking time or operation of control unit. Check for
restricted air flow through the vent holes of the oven cavity, especially the cooling fan and air guide.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
MAGNETRON TEMPERATURE FUSE TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Acontinuitycheckacrossthemagnetrontemperature fuse terminals should indicate a closed circuit
unlessthetemperatureofthemagnetrontemperaturefusereachesapproximately302oF(150oC).An
open magnetron temperature fuse indicates overheating of the magnetron. Check for restricted air
flow to the magnetron, especially the cooling fan air guide.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
CHIGH VOLTAGE RECTIFIER TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance
across the terminals and observe, reverse the leads to the rectifier terminals and observe meter
reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions,
the rectifier is probably defective and should be replaced.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
NOTE:Be suretouseanohmmeter thatwill supplya forwardbiasvoltageofmore than6.3 volts.

16
CDMOS200
DMOS200
VMOS200
CVMOS200
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Dischargehighvoltagecapacitor.
4. Beforeperformingthis test,makesurethatthe primaryswitchisoperatingproperly, accordingtothe
aboveSwitchTestProcedure.Disconnectthewireleadfromthemonitorswitch(COM)terminal.Check
themonitorswitchoperationbyusingtheohmmeterasfollows.Whenthedoorisopen,themetershould
indicateaclosedcircuit.Whenthemonitorswitchactuatorispushedbyascrewdriverthroughthelower
latchholeonthefrontplateoftheovencavitywiththedooropened(inthisconditiontheplungerofthe
monitorswitchispushedin),themetershouldindicateanopencircuit.Ifimproperoperationisindicated,
the switch may be defective. After testing the monitor switch, reconnect the wire lead to the monitor
switch (COM) terminal and check the continuity of the monitor circuit.
CAUTION: IF THE TEMPERATURE FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERA-
TURE, REPLACE TEMPERATURE FUSE.
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Dischargehighvoltagecapacitor.
4. Isolatetheswitchandconnecttheohmmetertothecommon(COM.)andnormallyopen(NO)terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the secondary interlock switch.
5. Reconnectallleadsremoved from componentsduringtesting.
6. Reinstalltheoutercase(cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
SECONDARYINTERLOCKSYSTEMTEST
DOORSENSINGSWITCH
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Dischargehighvoltagecapacitor.
4. Isolatetheswitchandconnecttheohmmetertothecommon(COM.)andnormallyopen(NO)terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the door sensing switch.
5. Reconnectallleadsremoved from componentsduringtesting.
6. Reinstalltheoutercase(cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
NOTE: Ifthedoorsensingswitchcontactsfailintheopenpositionandthedoorisclosed,thecoolingfan,
turntable and oven light will be activated by RY1.
SECONDARYINTERLOCKRELAY(RY2)
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Dischargehighvoltagecapacitor.
4. Disconnecttwo(2)wireleadsfromthemaletabterminalsoftheSecondaryInterlockRelay.Checkthe
stateoftherelaycontactsusingaohmmeter.Therelaycontactsshouldbeopen.Iftherelaycontacts
are closed, replace the circuit board entirely or the relay itself.
5. Reconnectallleadsremoved from componentsduringtesting.
6. Reinstalltheoutercase(cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
FPRIMARYANDSECONDARYSWITCHTEST
GMONITORSWITCHTEST

17
CDMOS200
DMOS200
VMOS200
CVMOS200
HBLOWNMONITORFUSETEST
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Dischargehighvoltagecapacitor.
4. If the monitor fuse is blown when the door is opened, check the primary switch and monitor switch
according to the "TEST PROCEDURE" for those switches before replacing the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY SWITCH AND
MONITORSWITCHFORPROPEROPERATION.
If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must
bereplacedwith"monitorfuseandmonitorswitchassembly"partnumberFFS-BA016/KIT,evenifthe
monitorswitchoperatesnormally.Themonitorfuseandmonitorswitchassemblyiscomprisedofa20
ampere fuse and switch.
5. Reconnectallleadsremoved from componentsduringtesting.
6. Reinstalltheoutercase(cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter
andohmmeter.Inthisservicemanual,thetouchcontrolpanelassemblyisdividedintotwounits,Control
Unit and Key Unit, and also the Control Unit is divided into two units, LSI Unit and Power Unit, and
troubleshooting by unit replacement is described according to the symptoms indicated.
Before testing,
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power transformer.
5) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.
6) After that procedure, re-connect the power supply cord.
1. Key Unit.
NOTE ;
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Check Key unit ribbon connection before replacement.
5) Reconnect all leads removed from components during testing.
6) Re-install the outer case (cabinet).
7) Reconnect the power supply cord after the outer case is installed.
8) Run the oven and check all functions.
ITOUCHCONTROLPANELASSEMBLYTEST
5. Reconnectallleadsremoved from componentsduringtesting.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all
functions.
Monitor
Switch
Primary Interlock Switch
Screw Driver
Ohmmeter
RED WHT/WHT
Secondary Interlock Switch

18
CDMOS200
DMOS200
VMOS200
CVMOS200
The following symptoms indicate a defective key unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
If the Key unit is defective.
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Replace the Key unit.
5) Reconnect all leads removed from components during testing.
6) Re-install the outer case (cabinet).
7) Reconnect the power supply cord after the outer case is installed.
8) Run the oven and check all functions.
2. Control Unit
Thefollowingsymptomsindicateadefectivecontrolunit.Beforereplacingthecontrolunit,performthe
Key unit test (Procedure J) to determine if control unit is faulty.
2-1 In connection with pads.
a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.
2-2 In connection with indicators
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
h) The following symptoms indicate a defective LSI unit.
• When touching the keys on the touch screen, a certain key produces no signal at all.
• When touching a number key on the touch screen, two figures or more are displayed.
• When touching the keys on the touch screen, sometimes a key produces no signal.
2-3 Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.
When testing is completed,
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Reconnect all leads removed from components during testing.
5) Re-install the outer case (cabinet).
6) Reconnect the power supply cord after the outer case is installed.
7) Run the oven and check all functions..
TEST PROCEDURES
PROCEDURE LETTER COMPONENT TEST
JKEY UNIT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable
ismakinggoodcontact,verifythatthedoorsensingswitch(stopswitch)operatesproperly;thatisthe
contactsareclosedwhenthedoorisclosedandopenwhenthedoorisopen.Ifthedoorsensingswitch
(stopswitch)isgood,disconnecttheflatribboncablethatconnectsthekeyunittothecontrolunitand
make sure the door sensing switch is closed (either close the door or short the door sensing switch
connecter).UsetheKeyunitmatrixindicatedonthecontrolpanelschematicandplaceajumperwire
betweenthepinsthatcorrespondtotheSTOP/CLEARpadmakingmomentarycontact.Ifthecontrol
unitrespondsbyclearingwithabeepthekeyunitisfaultyandmustbereplaced.Ifthecontrolunitdoes
not respond, it is faulty and must be replaced. If a specific pad does not respond, the above method
may be used (after clearing the control unit) to determine if the control unit or key pad is at fault.
5. Reconnect all leads removed from components during testing.