Dacor DMO2420 Quick start guide

DMO2420
Microwave
Parts and Service Manual

1
DMO2420B
DMO2420R
DMO2420S
WARNING TO 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 (that istheconnecting lead ofthehigh-
voltage rectifier) against the chassis with the use of an
insulatedscrewdriver.
Whenever troubleshooting is performed the power supply
mustbedisconnected.Itmay,insomecases,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. Reconnectthe power supply cord after the outer caseis
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. Reconnectthe power supply cord after the outer caseis
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

2
DMO2420B
DMO2420R
DMO2420S
MICROWAVE MEASUREMENT PROCEDURE
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven
shouldnotexceed1mW/cm2atanypoint5cmormorefromtheexternalsurfaceoftheoven,measuredpriortoacquisition
bya purchaser,and thereafter(throughtheusefullife oftheoven),5mW/cm2at anypoint5cm ormore fromtheexternal
surface of the oven.
2) Safety interlock switches Primary interlock relay and door sensing switch shall prevent microwave radiation emission in
excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission
in excess of 5 mW/cm2at any point 5cm or more from the external surface of the oven.
B. Preparation for testing:
Before beginning the actual measurement of leakage, proceed as follows:
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
microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.
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±5½C (68½F) in the center of the oven cavity.
Thewatercontainershall bea lowform of600 ml(20 oz)beakerwithaninsidediameterofapprox.8.5 cm(3-1/2 in.)and
made of an electrically nonconductive material such as glass or plastic.
Theplacingofthisstandardload in the oven is important not only to protect the oven, but also to insure that any leakage
is measured accurately.
4) Set the cooking control on Full Power Cooking Mode.
5) Closethedoorandselectacookcycleofseveralminutes.Ifthewaterbeginstoboilbeforethesurveyiscompleted,replace
it with 275 ml of cool water.
C. Leakage test:
Closed-door leakage test (microwave measurement)
1) Grasptheprobeofthesurveyinstrumentandholditperpendiculartothegapbetweenthedoorandthebodyoftheoven.
2) Movetheprobeslowly,notfasterthan1in./sec.(2.5cm/sec.)alongthegap,watchingforthemaximumindicationonthe
meter.
3) Checkforleakageatthedoorscreen,sheetmetalseamsandotheraccessiblepositionswherethecontinuityofthemetal
has been breached (eg., around the switches, indicator, and vents).
Whiletestingforleakagearoundthedoorpullthedoorawayfromthefrontoftheovenasfarasispermittedbytheclosed
latch assembly.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2,
and that the secondary interlock switch does turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.

3
DMO2420B
DMO2420R
DMO2420S
SERVICE MANUAL
MICROWAVE OVEN
DMO2420B/DMO2420R/DMO2420S
FOREWORD
This Manual has been prepared to provide Dacor Service Personnel
with Operation and Service Information for the DACOR MICRO-
WAVE OVENS, DMO2420B, DMO2420R and DMO2420S.
Itisrecommendedthatservicepersonnelcarefullystudytheentiretext
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
radiationhazard.
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
Certaininitialpartsareintentionallynotgroundedandpresent
a risk of electrical shock only during servicing. Service
personnel - Do not contact the following parts while the
appliance is energized;
HighVoltageCapacitor,PowerTransformer,Magnetron,High
Voltage Rectifier Assembly, High Voltage Harness;
If provided, Vent Hood, Fan assembly, Cooling Fan Motor.
Allthepartsmarked“*”onpartslistareusedatvoltagesmorethan
250V.
Removal of the outer wrap gives access to voltage above 250V.
Allthepartsmarked“∆”onpartslistmaycauseunduemicrowave
exposure,bythemselves,orwhentheyaredamaged,loosenedor
removed.
PRODUCT DESCRIPTION
GENERAL INFORMATION
OPERATION
TROUBLESHOOTING GUIDE AND
TEST PROCEDURE
TOUCH CONTROL PANEL
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
WIRING DIAGRAM
PARTS LIST
distinctive appliances
950 SOUTH RAYMOND AVE.
PASADENA,CA 91105
distinctive appliances

4
DMO2420B
DMO2420R
DMO2420S
ITEM DESCRIPTION
Power Requirements 120 Volts / 13.8 Amperes
60 Hertz
Single phase, 3 wire grounded
Power Output 1200 watts (IEC TEST PROCEDURE)
Operating frequency of 2450MHz
Case Dimensions Width 24"
Height 13-3/8"
Depth 19-1/8"
Cooking Cavity Dimensions Width 17-3/8"
Height 10-1/2"
2.0 Cubic Feet Depth 18-5/8"
Control Complement Touch Control System
Clock ( 1:00 - 12:59 )
Timer (0 - 99 min. 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
100 PERCENT............................. Full power throughout the cooking time
90 PERCENT............................................... approx. 90% of Full Power
80 PERCENT............................................... approx. 80% of Full Power
70 PERCENT............................................... approx. 70% of Full Power
60 PERCENT............................................... approx. 60% of Full Power
50 PERCENT............................................... approx. 50% of Full Power
40 PERCENT............................................... approx. 40% of Full Power
30 PERCENT.............................................. approx. 30% of Full Power
20 PERCENT............................................... approx. 20% of Full Power
10 PERCENT............................................... approx. 10% of Full Power
0 PERCENT.............................. No power throughout the cooking time
Sensor Cooking pads, Breakfast pad, Lunch pad
15 Minute Dinner pad, Auto Defrost pad, Microwave Recipes pad
Beverage pad, Number selection pads, Timer/Clock pad
Keep Warm Plus pad, Easy Minute pad, Power Level pad
Stop/Clear pad, Start/Instant On pad
Oven Cavity Light Yes
SafetyStandard UL Listed FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
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. In the event of an electrical
short circuit, grounding reduces the risk of electric shock by providing an escape wire for the electric current.
WARNING: Improper use of the grounding plug can result in a risk of electric shock.
Electrical Requirements
The electrical requirements are a 120 volt 60 Hz, AC only, 15 or 20 amp. fused electrical supply. It is recommended that a
separate circuit serving only this appliance be provided. 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.

5
DMO2420B
DMO2420R
DMO2420S
Where a two-pronged wall-receptacle is encountered, it is the personal
responsibility and obligation of the customer to contact a qualified
electricianandhaveitreplacedwithaproperlygroundedthree-pronged
wall receptacle or have a grounding adapter properly grounded and
polarized. If the extension cord must be used, it should be a 3-wire, 15
amp.orhigherratedcord.Donotdrapeoveracountertoportablewhere
it can be pulled on by children or tripped 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.
Theturntablewillrotateclockwise
or counterclockwise.
5. Oven lamp.
Itwilllightwhenovenisoperating
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.Coupling.
11.Wave guide cover.
12.Power supply cord.
NOTE:
Thedirectedfeaturesaredisabled
afterthreeminuteswhentheoven
is not in use. These features are
automatically enabled when the
door is opened and closed or the
STOP/ CLEAR pad is pressed.
1
65
4
210 11
12
9
7
8
3
TOUCH CONTROL PANEL
3-Pronged
Plug
Grounded
Receptacle Box
Grounding Pin
3-Pronged Receptacle
DMO2420R DMO2420B DMO2420S

6
DMO2420B
DMO2420R
DMO2420S
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
Thefollowingisadescriptionofcomponentfunctionsduring
ovenoperation.
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 "Welcome".
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.
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 3.2 volts
A.C. output on the filament winding, and approximately
2360 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,doorsensing switch,secondaryinterlockswitch,
relay(RY1)andprimaryinterlockrelayareactivatedwith
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. Themonitorswitchelectricallymonitorstheoperationof
the secondary interlock switch and primary interlock
relayandismechanicallyassociatedwiththedoorsothat
it will function in the following sequence.
(1)When the door opens from the closed position, the
primary interlock relay (RY2) and secondary interlock
switch open their contacts. And contacts of the relay
(RY1)remainsclosed.Thenthemonitorswitchcontacts
close.
(2)When the door is closed from the open position, the
monitor switch contacts open first. Then the contacts of
the secondary interlock switch and door sensing switch
close. And contacts of the relay (RY1) open.
Ifthesecondaryinterlockswitchandprimaryinterlockrelay
(RY2)failwiththecontactsclosedwhenthedoorisopened,
the closing of the monitor switch contacts will form a short
circuitthroughthemonitorfuse,secondaryinterlockswitch,
relay (RY1) and primary interlock relay (RY2), causing the
monitor fuse to blow.
POWER LEVEL 0% TO 100% COOKING
When Variable Cooking Power is programmed, the 120
voltsA.C.issuppliedtothepowertransformerintermittently
throughthecontactsofrelay(RY-2)whichisoperatedbythe
controlunitwithina32secondtimebase.Microwavepower
operation is as follows:
VARI-MODE ON TIME OFF TIME
100% power 32 sec. 0 sec.
approx. 90% power 30 sec. 2 sec.
approx. 80% power 26 sec. 6 sec.
approx. 70% power 24 sec. 8 sec.
approx. 60% power 22 sec. 10 sec.
approx. 50% power 18 sec. 14 sec.
approx. 40% power 16 sec. 16 sec.
approx. 30% power 12 sec. 20 sec.
approx. 20% power 8 sec. 24 sec.
approx. 10% power 6 sec. 26 sec.
0% power 0 sec. 32 sec.
Note: TheON/OFFtimeratiodoesnotcorrespondwiththe
percentageofmicrowavepower,becauseapprox.2
seconds are needed for heating of the magnetron
filament.
SENSOR COOKING CONDITION
Using the SENSOR function, the food is cooked without
figuringtime,powerlevelorquantity.Whentheovensenses
enough 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 increases gradually. When the
resistance reaches the value set according to the menu,
supplementary cooking is started.

7
DMO2420B
DMO2420R
DMO2420S
Thetimeofsupplementarycookingisdeterminedbyexperi-
ment with 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. HeatPotatoes.Moistureandhumidityisemittedrapidly.
You can smell the aroma as it cooks.
3. Sensor detects moisture and humidity and calculates
cooking time and variable power.
Cooking Sequence.
1. TouchoneoftheSENSORpadsandthentouchtheStart
pad.
NOTE: The oven should not be operated on SENSOR
immediately after plugging in the unit. Wait two
minutes before cooking on SENSOR.
2. Thecoilofshut-offrelay(RY-1)isenergized,theturntable
motor, oven lamp and cooling fan motor are turned on,
but the power transformer is not turned on.
3. Afterabout16seconds,thecookrelay(RY-2)isenergized.
The power transformer is turned on, microwave energy
is produced and first stage is started.
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,thedisplayswitchesover totheremainingcooking
time and the timer counts down to zero.
At this time, the door may be opened to stir, turn, or
season food.
5. Whenthe timer reaches zero, an audiblesignalsounds.
The shut-off relay and cook relay are de-energized and
the power transformer, oven lamp, etc. are turned off.
6. OpeningthedoorortouchingtheSTOP/CLEARpad,the
timeof daywill reappearon thedisplayandtheoven will
revert to an OFF condition.
MICROWAVE
MICROWAVE
AH SENSOR

8
DMO2420B
DMO2420R
DMO2420S
Figure O-1. Oven Schematic-Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. CLOCK APPEARS ON DISPLAY.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME PROGRAMMED.
3. VARIABLE COOKING CONTROL "P-HI/ 100 PERCENT".
4. "START" PAD TOUCHED.
Figure O-2. Oven Schematic-Cooking Condition
120V AC
60 Hz
OVEN
LAMP TURN-
TABLE
MOTOR FAN
MOTOR
MONITOR
SWITCH
H.V. RECTIFIER MAGNETRON
SECONDARY
INTERLOCK
SWITCH
TTM
OL FM
MONITOR
FUSE 20A
CAVITY
TEMP.
FUSE
MAGNETRON
TEMP.
FUSE
A1
A2
COM.
COM.
COM.N.O.
N.C.
N.O.
DOOR
SENSING
SWITCH
(RY-1) (RY-2)
CONTROL UNIT
PRIMARY
INTERLOCK
RELAY
B1 B2
GRN
POWER
TRANSFORMER
CAPACITOR 1.0µF
AC 2300V
F3
F1 F2
AH SENSOR
120V AC
60 Hz
OVEN
LAMP TURN-
TABLE
MOTOR FAN
MOTOR
MONITOR
SWITCH
H.V. RECTIFIER MAGNETRON
SECONDARY
INTERLOCK
SWITCH
TTM
OL FM
CAVITY
TEMP.
FUSE
A1
A2
COM.
COM.
COM.N.O.
N.C.
N.O.
DOOR
SENSING
SWITCH
(RY-1) (RY-2)
CONTROL UNIT
PRIMARY
INTERLOCK
RELAY
B1 B2
GRN
POWER
TRANSFORMER
CAPACITOR 1.0µF
AC 2300V
MONITOR
FUSE 20A
MAGNETRON
TEMP.
FUSE
F3
F1 F2
NOTE: Indicates components with potential above 250 V.

9
DMO2420B
DMO2420R
DMO2420S
DESCRIPTION AND FUNCTION OF COMPONENTS
DOOR OPEN MECHANISM
Thedoorisopenedbypushingtheopenbuttononthecontrol
panel, refer to the Figure D-1. When the open button is
pushed, the open button pushes up the switch lever, and
then the switch lever pushes up the latch head. The latch
heads are moved upward and released from latch hook.
Now the door will open.
Figure D-1. Door Open Mechanism
DOOR SENSING AND SECONDARY INTERLOCK
SWITCHES
The secondary interlock switch is mounted in the lower
positionofthelatchhook andthe doorsensingswitchinthe
primaryinterlocksystemismountedintheupperpositionof
thelatchhook.Theyareactivatedbythelatchheads onthe
door. When the door is opened, the switches interrupt the
power to all high voltage components. A cook cycle cannot
take place until the door is firmly closed thereby activating
both interlock switches. The primary interlock system con-
sists of the door sensing switch and primary interlock relay
located on the control circuit board.
MONITOR SWITCH
Themonitorswitchisactivated(thecontactsopened)bythe
latch head on the door while the door is closed. The switch
is intended to render the oven inoperative, by means of
blowing the monitor fuse, when the contacts of the primary
interlock relay (RY2) and secondary interlock switch fail to
open when the door is opened.
Functions:
1. Whenthedoorisopened,themonitorswitchcontactclose
(totheONcondition)duetotheirbeingnormallyclosed.At
this time the primary interlock relay (RY2) and secondary
interlock switch are in the OFF condition (contacts open)
due to their being normally open contact switches.
2. As the door goes to a closed position, the monitor switch
contactsarefirstopenedandthenthedoorsensingswitch
and the secondary interlock switch contacts close. (On
openingthedoor,eachoftheseswitchesoperateinversely.)
3. If the door is opened, and the primary interlock relay
(RY2) and secondary interlock switch contacts fail to
open,themonitorfuseblowssimultaneouslywithclosing
of the monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE TEST THE DOOR SENSING SWITCH,
PRIMARYINTERLOCKRELAY(RY2),RELAY
(RY1), SECONDARY INTERLOCK SWITCH
AND MONITOR SWITCH FOR PROPER OP-
ERATION.(REFERTOCHAPTER"TESTPRO-
CEDURE").
NOTE: MONITOR FUSE AND MONITOR SWITCH ARE
REPLACED AS AN ASSEMBLY.
TURNTABLE MOTOR
The turntable motor rotates the turntable located on the
bottomofthe oven cavity, so that thefoodsonthe turntable
cookevenlyduringcooking.Theturntablemayturnineither
direction.
COOLING FAN MOTOR
Thecoolingfanmotordrivesabladewhichdrawsexternalcool
air.This coolair isdirectedthrough theair vanessurrounding
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
theprimaryinterlockrelay(RY2)andsecondaryinterlock
switchremain closedwith theoven dooropenandwhen
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
foodload is overcooked,byeither errorincook timeordefect
in the control unit, the cavity temperature fuse will open.
Undernormaloperation,thecavitytemperaturefuseremains
closed. However, when abnormally high temperatures are
reachedwithintheovencavity,thecavitytemperaturefusewill
open at 302½F(150½C) causing the oven to shut down.
NOTE: This is a fuse. It does not reset.
MAGNETRON TEMPERATURE FUSE
Themagnetrontemperaturefuselocatednearthemagnetron
is designed to prevent damage to the magnetron if an over
heatedconditiondevelopsinthetubeduetocoolingfanfailure,
obstructed air guide, dirty or blocked air intake, etc.
Under normal operation, the magnetron temperature fuse
remains closed. However, when abnormally high tempera-
tures are reached within the magnetron, the magnetron tem-
peraturefusewillopenat302½F(150½C)causingtheovento
shut down.
NOTE: This is a fuse. It does not reset.
Door Sensing
Switch
Monitor Switch
Switch Lever
Secondary Interlock
Switch
Latch Heads
Door

10
DMO2420B
DMO2420R
DMO2420S
TROUBLESHOOTING GUIDE
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
Whentroubleshootingthemicrowaveoven,itis helpfulto followthe 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 monitor switch, relay (RY1)
primary interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the
monitorfuse.Ifthemonitorfuseisreplaced,themonitorswitchmustalsobereplaced.UsepartFFS-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. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power transformer.
5. Ensurethatthe leadsremainisolatedfromothercomponentsand ovenchassis byusinginsulationtape.
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 all leads removed from components during testing.
5. Reinstall the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.

11
DMO2420B
DMO2420R
DMO2420S
CK = Check / RE = Replace
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 INTERLOCK SYSTEM SECONDARY INTERLOCK SWITCH 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) DEFROST CENTER FOIL PATTERN ON PWB. AH SENSOR
Home fuse or circuit breaker blows when
power cord is plugged into wall receptacle.
Monitor fuse blows when power cord is
plugged into wall receptacle.
Any letters or indicators do not appear in
display when power cord is first plugged
into wall outlet.
Display does not operate properly when
STOP/CLEAR key is touched. (Buzzer
should sound and ":" or time of day
should appear in display.)
Oven lamp does not light when door 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 P-50/ 50 PERCENT
mode. (Operates properly on P-HI/ 100
PERCENT mode.)
Oven goes into Defrost Center but food
is not defrosted well.
AH sensor does not end during Sensor
cooking condition. (Oven does not shut
off after a cup of water is boiling by
sensor cooking.)
Oven stops at 16 sec. after starting.
RE RE ABCDEEFFGHRE RE CK ICK CK CK JKLMN
TEST PROCEDURE
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
COOKING
CONDITION
CONDITION PROBLEM
OFF
CONDITION
SENSOR
COOKING
CONDITION

12
DMO2420B
DMO2420R
DMO2420S
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.
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. 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
a thermometer or thermocouple temperature tester. Stir the thermometer or thermocouple through
the water until the temperature stabilizes. Record the temperature of the water.
2. Placethecupofwaterintheoven.Operateovenat100PERCENTPOWER/P-HIselectingmorethan
60 seconds cook time. Allow the water to heat for 60 seconds, measuring with a stop watch, second
hand 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. Subtractthe coldwatertemperature fromthehot watertemperature.The normalresultshould be33
to62½F(18.6to34.5½C)riseintemperature.Ifthewatertemperaturesareaccuratelymeasuredand
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.
AMAGNETRON ASSEMBLY TEST

13
DMO2420B
DMO2420R
DMO2420S
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
the temperature of the cavity temperature fuse reaches approximately 302½F(150½C). An open
cavitytemperaturefuseindicatesoverheatingoftheoven,exchangethe cavitytemperaturefuseand
checkinsideofovencavityandforimpropersettingofcookingtimeoroperationofcontrolunit.Check
forrestrictedairflowthroughtheventholesoftheovencavity,especiallythecoolingfanandairguide.
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. Acontinuity check across the magnetron temperature fuseterminalsshouldindicatea closed circuit
unlessthetemperature of the magnetron temperature fuse reachesapproximately302½F(150½C).
An open magnetron temperature fuse indicates overheating of the magnetron. Check for restricted
air flow to the magnetron, especially the cooling fan air guide.
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:Besure tousean ohmmeterthatwill supplyaforward bias voltageof more than6.3 volts.
(HIGHVOLTAGES AREPRESENT ATTHEHIGH VOLTAGETERMINAL, SODONOTATTEMPTTO
MEASURE THE FILAMENT AND HIGH VOLTAGE.)

14
DMO2420B
DMO2420R
DMO2420S
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. Before performing this test, make sure that the secondary interlock switch and the primary interlock
relayareoperatingproperly,accordingtotheaboveSwitchTestProcedure.Disconnectthewirelead
fromthemonitor switch (COM) terminal. Check the monitor switchoperationbyusingthe ohmmeter
asfollows.Whenthedoorisopen,themetershouldindicateaclosedcircuit.Whenthemonitorswitch
actuatorispushedbyascrew driver through the lower latch hole on the front plate of the oven cavity
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.
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. Discharge high voltage capacitor.
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. 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.
PRIMARY INTERLOCK SYSTEM TEST
DOOR SENSING SWITCH
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. 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. 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: Ifthedoorsensingswitchcontactsfailintheopenpositionandthedoorisclosed,thecoolingfan,
turntable and oven light will be activated by RY1.
PRIMARY INTERLOCK RELAY (RY2)
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 two (2) wire leads from the male tab terminals of the Primary Interlock Relay. Check the
stateoftherelaycontactsusingaohmmeter.Therelaycontactsshouldbeopen.Iftherelaycontacts
are closed, replace the circuit board entirely or the relay itself.
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.
FSECONDARY INTERLOCK SWITCH TEST
GMONITOR SWITCH TEST

15
DMO2420B
DMO2420R
DMO2420S
HBLOWN MONITOR FUSE TEST
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. If the monitor fuse is blown when the door is opened, check the primary interlock relay, secondary
interlockswitchandmonitorswitchaccordingtothe"TESTPROCEDURE"forthoseswitchesbefore
replacing the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK
RELAY,SECONDARYINTERLOCKSWITCH,DOORSENSINGSWITCHANDMONITOR
SWITCH FOR PROPER OPERATION.
If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must
be replaced with "monitor fuse and monitor switch assembly" part number FFS-BA016/KIT, even if
the monitor switch operates normally. The monitor fuse and monitor switch assembly is comprised
of a 20 ampere fuse and switch.
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.
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
and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key
Unit,andalsothe Control Unit is divided into two units, LSI Unit andPowerUnit,andtroubleshootingby
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
insulationtape.
1. Key Unit.
NOTE ;
1) Check Key unit ribbon connection before replacement.
2) Reconnect all leads removed from components during testing.
3) Re-install the outer case (cabinet).
ITOUCH CONTROL PANEL ASSEMBLY TEST
withthedooropened(inthisconditiontheplungerofthemonitorswitchispushedin),themetershould
indicate an open circuit. If improper operation is indicated, 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.
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.
Monitor
Switch
Secondary Interlock Switch
Screw Driver
Ohmmeter
RED WHT/WHT

16
DMO2420B
DMO2420R
DMO2420S
4) Reconnect the power supply cord after the outer case is installed.
5) Run the oven and check all functions.
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
Thefollowingsymptoms indicateadefectivecontrolunit. Beforereplacingthecontrolunit,perform
the 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.
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.
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
notrespond,itisafaultyandmustbereplaced.Ifaspecificpaddoesnotrespond,theabovemethod
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST

17
DMO2420B
DMO2420R
DMO2420S
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
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.
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. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power transformer.
5. Ensurethattheseleadsremainisolatedfromothercomponentsandovenchassisbyusinginsulation
tape.
6. After that procedure, re-connect the power supply cord.
7. Remove the outer case and check voltage between Pin No. 1 of the 2 pin connector (A) and the
common terminal of the relay RY1 on the control unit with an A.C. voltmeter.
The meter should indicate 120 volts, if not check oven circuit.
RY1 and RY2 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated ......................... Defectiverelay.
DC. voltage not indicated.................... Check diode which is connected to the relay coil. If diode
is good, control unit is defective.
RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS
RY1 Approx. 24.0V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 Approx. 23.0V D.C. Power transformer
8.Disconnect the power supply cord, and then remove outer case.
9.Open the door and block it open.
10.Discharge high voltage capacitor.
11.Reconnect all leads removed from components during testing.
12.Re-install the outer case (cabinet).
13.Reconnect the power supply cord after the outer case is installed.
14.Run the oven and check all functions.
KRELAY TEST
WARNING : The oven should be fully assembled before following procedure.
(1) Place one cup of water in the center of the turntable tray in the oven cavity.
(2) Closethedoor, touchtheAutoDefrostpad andtouchthenumberpad 5.Andtouchthenumber pad
5 again. And then touch the Start pad.
(3) The oven is in Auto Defrost cooking condition.
(4) The oven will operate as follows.
LCOMPU DEFROST TEST
G 1 G 2 G 3 G 4 G 5 G 6 G 7 G 8
G 9
G10
G11
G12
G13
G14
FRESH
VEGETABLES
BEVERAGE
BREAKFAST LUNCH
POPCORN
SNACKS
MICROWAVE
RECIPES
START
INSTANT ON
FISH
SEAFOOD POWER LEVEL
KEEP
WARM
15
MINUTE
DINNER
AUTO
DEFROST
HELP
GUIDE
BAKED
POTATOES
REHEAT
EASY
MINUTE
VEGETABLES
RICE
1
6
2
7
3
8
4
9
5
0
POULTRY
GROUND
MEAT
ENTREES
TIMER
CLOCK
STOP
CLEAR

18
DMO2420B
DMO2420R
DMO2420S
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on
the PWB, this foil pattern acts as a fuse.
1. Foil pattern check and repairs.
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) Follow the troubleshooting guide given below for repair.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
2 Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".
5) Make a visual inspection of the varistor.
Checkforburndamageandexaminethe
transformerwithatesterforthepresence
of layer short-circuit (check the primary
coil resistance which is approximately
210ý±15%).Ifanyabnormalconditionis
detected, replace the defective parts.
6) Reconnect all leads removed from components during testing.
7) Re-install the outer case (cabinet).
8) Reconnect the power supply cord after the outer case is installed.
9) Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if indicator does not light up after above check and
repairs are finished.
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
insulationtape.
6) After that procedure, reconnect the power supply cord.
7) Follow the troubleshooting guide given below for repair.
STEPS OCCURRENCE CAUSE OR CORRECTION
The rated AC voltage is not present between
1 Pin No. 1 of the 2-pin connector (A) and the Check supply voltage and oven power cord.
common terminal of the relay RY1.
2The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.
side of low voltage transformer. Check and repair.
8) Disconnect the power supply cord, and then remove outer case.
9) Open the door and block it open.
MFOIL PATTERN ON THE PRINTED WIRING BOARD TEST
MENU 1ST STAGE 2ND STAGE
Steaks, chops or fish LEVEL TIME LEVEL TIME
0.5lb 70% 30sec. 40% 15sec.
(5) If improper operation is indicated, the control unit is probably defective and should be checked.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
T1AC
VRS1
OMIF DU
CN - A (J1)
abc
d
12
XA
VH

19
DMO2420B
DMO2420R
DMO2420S
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
10) Discharge high voltage capacitor.
11) Reconnect all leads removed from components during testing.
12) Re-install the outer case (cabinet).
13) Reconnect the power supply cord after the outer case is installed.
14) Run the oven and check all functions.
NAH SENSOR TEST
Checking the initial sensor cooking condition
WARNING : The oven should be fully assembled before following procedure.
(1) The oven should be plugged in at least two minutes before sensor cooking.
(2) Room temperature should not exceed 95½F (35½C).
(3) Theunitshouldnotbeinstalledinanyareawhereheatandsteamaregenerated.Theunitshouldnot
be installed, for example, next to a conventional surface unit. Refer to the “INSTALLATION
INSTRUCTIONS”of the operation manual.
(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity. To
permit adequate ventilation, be sure to install so as not to block these vents. There should be some
space for air circulation.
(5) Besuretheexteriorofthecookingcontainerandtheinterioroftheovenaredry.Wipeoffanymoisture
with a dry cloth or paper towel.
(6) The Sensor works with food at normal storage temperature. For example, chicken pieces would be
at refrigerator temperature and canned soup at room temperature.
(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The
sensor will detect the vapor given of by the spray and turn off before food is properly cooked.
(8) If the sensor has not detected the vapor of the food, ERROR will appear and the oven will shut off.
Water load cooking test
WARNING : The oven should be fully assembled before following procedure.
Make sure the oven has been plugged in at least two minutes before checking sensor cook operation.
The cabinet should be installed and screws tightened.
(1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
(2) Place the container on the center of tray in the oven cavity.
(3) Close the door.
(4) TouchtheTimer/Clockpadonce,thePowerLevelpadtwice,theStartpadonceandthenumberpad
1 once. Now, the oven is in the sensor cooking condition and "TEST", “SENSOR”and "COOK" will
appear in the display.
(5) The oven will operate for the first 16 seconds, without generating microwave energy.
NOTE: ERROR will appear if the door is opened or STOP/CLEAR pad is touched during first stage of
sensor cooking.
(6) After approximately 16 seconds, microwave energy is produced.
If ERROR is displayed, replace the AH sensor or check the control unit, refer to explanation below.
If the oven stops after 5 minutes and ERROR is displayed, check the parts except for the AH sensor.
TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT
Todetermineifthesensorisdefective,thesimplestmethodistoreplaceitwithanewreplacementsensor.
(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) Remove the AH sensor.
(5) Install the new AH sensor.
(6) Reconnect all leads removed from components during testing.
(7) Re-install the outer case (cabinet).
(8) Reconnect the power supply cord after the outer case is installed.
(9) Reconnect the oven to the power supply and check the sensor cook operation as follows:
9-1. Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
9-2. Place the container on the center of tray in the oven cavity.