Sharp R-677W User manual

R-677 - 1
TABLE OF CONTENTS Page
CAUTION, MICROWAVE RADIATION.................................................................................................... 2
WARNING.................................................................................................................................................3
SERVICING ............................................................................................................................................. 4
PRODUCT SPECIFICATIONS .................................................................................................................7
GENERAL INFORMATION.......................................................................................................................7
APPEARANCE VIEW .............................................................................................................................. 8
OPERATION SEQUENCE........................................................................................................................9
FUNCTION OF IMPORTANT COMPONENTS ..................................................................................... 11
TROUBLESHOOTING GUIDE ...............................................................................................................13
TEST PROCEDURE.............................................................................................................................. 14
CONTROL PANEL ASSEMBLY ............................................................................................................20
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE.................................................. 24
TEST DATA AT A GLANCE .................................................................................................................. 29
MICROWAVE MEASUREMENT ........................................................................................................... 30
WIRING DIAGRAM................................................................................................................................ 31
PICTORIAL DIAGRAM .......................................................................................................................... 34
CONTROL PANEL CIRCUIT ..................................................................................................................35
PRINTED WIRING BOARD ....................................................................................................................36
PARTS LIST .......................................................................................................................................... 37
CABINET AND UNIT CHASSIS PARTS.................................................................................................40
CONTROL PANEL/DOOR PARTS.........................................................................................................41
MISCELLANEOUS/PACKING AND ACCESSORIES.............................................................................42
S30331R677EHW
SERVICE MANUAL
SHARP CORPORATION
MICROWAVE OVEN WITH
TOP AND BOTTOM GRILL
MODELS
Ininterestsofuser-safetytheovenshouldberestoredtoitsoriginal
conditionandonlypartsidenticaltothosespecifiedshouldbeused.
R-677(W)
R-677(W)F
R-677(AL)D
R-677(AL)
R-677(W)D
®

R-677 - 2
CAUTION
MICROWAVE RADIATION
Personnel should not be exposed to the microwave energy which may radiate from the
magnetron or other microwave generating devices if it is improperly used or connected.
All input and output microwave connections, waveguides, flanges and gaskets must be
secured.
Never operate the device without a microwave energy absorbing load attached.
Never look into an open waveguide or antenna while the device is energized.
VARNING
MICKROVAGSSTRALING
Personal får inte utsättas för mikrovågsenergi som kan ustrala från magnetronen eller
andre mikrovågsalstrande anordningar om dessa är felanslutna eller används på fel sätt.
Alla in-och utgångsanslutningar för mikrovågor, vagledare, flänsar och packningar måste
vara fast anslutna.
Mikrovågsgeneratorn får inte arbeta utan att absorberande belastning är ansluten. Titta
aldrig in i ën öppen vågledare eller antenn när mikrovågsgeneratorn är påkopplad eller
laddad.
VAROITUS
MIKROAALTOSÄTELYÄ
Käyttäjä ei saa joutua alttiiksi mikroaaltoenergialle, jota voi säteillä magnetronista tai
muusta mikroaaltoja kehittävästä laitteesta, jos sitä käytetään tai jos se kytketään väärin.
Kaikkien mikroaaltoliitäntöjen sekä syöttö-että ulostulopuolella, aaltoputkien laippojen ja
tiivisteiden tulee olla varmistettuja.
Mikroaaltouunnia ei koskaan saa käyttää ilman kuormaa jossa mikroaaltoenergiaa kuluu.
Avoimeen aaltoputkeen tai antenniin ei koskaan saa katsoa virran ollessa kytkettynä.
ADVARSEL
MIKROBØLGESTRÅLING
Personell må ikke utsettes for mikrobølge-energi som kan utståles fra magnetronen eller
andre mikrobølge-generende deler dersom apparatet feilbetjenes eller blir feiltikoplet.
Alle inn-og ut-tilkoplinger i forbindelse med mikrobølge-strålingen, bølgeledere, flenser og
tetningsringer/pakninger må festes ordentlig.
Aldri bruk apparatet med mindre en mikrobålge-absorberende last er plassert i
ovnsrommet.
Aldri se direkte inn i en åpen bølgeleder eller antenne imens apparatet er strømførende.
ADVARSEL
MIKROBØLGEBESTRÄLING
Man bør ikke udsætte sig for mikrobølgebestråling fra magnetronen eller andre
mikrobølgefrembringende anordninger, hvilket kan ske hvis apparatet er forkert tilsluttet
eller bruges forkert. Alle mikrobølgeindgange og-udgange, bølgeledere, flanger og
tætningsstrimler må være forsvarligt udført.
Anvend aldrig ovnen uden en mikrobølgesabsorberende anordning. Se aldrig ind i en
åben bølgeleder eller antenne, mens ovnen er i brug.
CAUTION

R-677 - 3
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 not any other visible damage with the oven.
Servicing and repair work must be carried out only by trained service engineers.
Removal of the outer wrap gives access to potential above 250V.
Allthe parts marked"∆" on thepartslist may causeundue microwave exposure,bythemselves, or whenthey are
damaged, loosened or removed.
Never operate the Grill and/ or Bottom heater with the oven outer cabinet removed. (Because air flow is
eliminated, and the excess heat generated on adjacent components). It can cause permanent damage or fire.
SHARP CORPORATION
OSAKA, JAPAN
SERVICE MANUAL
®
MICROWAVE OVEN WITH TOP AND BOTTOM GRILL
R-677(W)/ R-677(AL)/ R-677(W)F R-677(W)D R-677(AL)D
GENERAL IMPORTANT INFORMATION
This Manual has been prepared to provide Sharp Corp. Service engineers with Operation and Service Information.
Itisrecommendedthatserviceengineerscarefullystudytheentiretextofthismanual,sotheywillbequalifiedtorender
satisfactory customer service.
WARNING
Note: The parts marked "*" are used in voltage more than 250V. (Parts List)
Anm: Delar märket med "*" har en spänning överstigande 250V.
Huom: Huolto-ohjeeseen merkitty "tähdella" osat joissa jännite on yli 250 V.
Bemerk: Deler som er merket "asterisk" er utsatt for spenninger over 250V til jord.
Bemærk: "Dele mærket med stjerne benyttes med højere spænding end 250 volt.

R-677 - 4
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
WARNING: AGAINST THE CHARGE OF THE HIGH-
VOLTAGE CAPACITOR
The high-voltage capacitor remains charged about 60 sec-
onds after the oven has been switched off. Wait for 60
seconds and then short-circuit the connection of the high-
voltagecapacitor(that is, ofthe connecting leadof the high-
voltage rectifier) against the chassis with the use of an
insulated screwdriver.
Sharp recommend that wherever possible fault-finding is
carried out with the supply disconnected. It may in, some
cases, be necessary to connect the supply after the outer
casehasbeenremoved,inthiseventcarryout3Dchecksand
then disconnect the leads to the primary of the power trans-
former. Ensure that these leads remain isolated from other
components and the oven chassis. (Use insulation tape if
necessary.) When the testing is completed carry out 3D
checks and reconnect the leads to the primary of the power
transformer.
SERVICING
WARNING TO SERVICE PERSONNEL
GB Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts will
result in electrocution.
High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage harness.
REMEMBER TO CHECK 4R
1) Reconnect all leads removed from components during
testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. 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
powertoHIGHandsetthemicrowavetimerfortwo(2)minutes.
When the two minutes has elapsed (timer at zero) carefully
check that the water is now hot. If the water remains cold carry
out 3D checks and re-examine the connections to the compo-
nent being tested.
When all service work is completed, and the oven is fully
assembled,themicrowavepoweroutputshouldbecheckedand
a microwave leakage test carried out.
NL Magnetronovens bevatten circuits die een zeer hoge spanning en stroom kunnen voortbrengen. Contact met de
volgende onderdelen kan elektrocutie tot gevolg hebben.
Hoogspanningscondensator, hoogspanningstransformator, magnetron, hoogspanningsgelijkrichter, hoogspannings
kabelboom.
VERGEET DE VOLGENDE 3 STAPPEN NIET
1) Haal de stekker uit het stopcontact.
2) Open de deur en zorg ervoor dat hij niet dicht kan vallen.
3) Ontlaad de hoogspanningscondensator.
PAS OP VOOR DE ELECTRISCHE LADING VAN DE
HOOGSPANNINGSCONDENSATOR
De hoogspanningscondensator blijft nog ongeveer 60
seconden lang opgeladen, nadat de oven is uitgeschakeld.
Wacht 60 seconden voordat u de verbinding van de
hoogspannings-condensator (m.a.w. de verbindingsdraad
van de hoogspanningsgelijkrichter) met een geïsoleerde
schroevedraaier kortsluit tegen het chassis.
Sharp beveelt ten sterkste aan dat, voor zover mogelijk,
defecten worden opgespoord wanneer de stekker uit het
stopcontactisgehaald.Somsishetnodigomdestroomtoevoer
weer tot stand te brengen nadat de buitenmantel verwijderd
is. Herhaal dan de bovengenoemde 3 stappen en haal de
electrische draden uit de primaire zijde van de
vermogenstransformator. Zorg ervoor dat deze draden
geïsoleerd blijven van andere elementen en van het chassis
van de oven. (Gebruik zo nodig isolatieband.) Wanneer de
test is uitgevoerd, herhaalt u de bovenstaande 3 stappen en
verbindt u de electrische draden weer aan de primaire zijde
van de vermogenstransformator.
VERGEET DE VOLGENDE 4 STAPPEN NIET
1) Sluit de draden weer aan diezijn losgehaald voor de test.
2) Plaatsdebuitenmantelweeromhettoestelheen(kabinet).
3) Stop de stekker weer in het stopcontact.
4) Zet de oven aan. Controleer alle functies.
Magnetronovens mogen niet leeg aangezet worden. Om te
controleren of er microgolf-energie binnen de oven wordt
geproduceerd, plaatst u een mok met koud water op de
draaitafel van de oven, sluit de deur, zet de oven op HIGH en
steltdeklokvandemagnetroninoptwee(2)minuten.Wanneer
de twee minuten voorbij zijn (klok staat op nul), controleert u
voorzichtig of het water heet is. Indien het water nog steeds
koud is, herhaalt u de allereerste drie stappen en controleer
nogmaals de aansluitingen naar de geteste onderdelen.
Wanneer alle reparaties zijn uitgevoerd en de oven weer in
elkaar is gezet, moet de het magnetronvermogen worden
gecontroleerd en moet worden gecontroleerd of er geen
microgolflekkage is.

R-677 - 5
ELos hornos de microondas contienen circuitos eléctricos capaces de producir voltajes de alta tensión y descargas
eléctricas.Para evitarel riesgode electrocución, absténgase de tocar los siguientes componentes: condensador de alta
tensión, transformador de alta tensión, magnetrón, dispositivo del rectificador de alta tensión y arnés de alta tensión.
RECUERDE LA COMPROBACION 3D
1) Desconecte la alimentación.
2) Deje la puerta abierta y calzada.
3) Descargue el condensador de alto voltaje.
ADVERTENCIA SOBRE LA CARGA DEL
CONDENSADOR DEALTO VOLTAJE
El condensador de alto voltaje permanece cargado unos
60 segundos después de haber apagado el horno. Espere
60segundos y luego ponga en cortocircuito la conexión del
condensador de alto voltaje (esto es, del conductor de
conexión del rectificador de alto voltaje) al chasis con un
destornillador de mango aislado.
Se recomienda encarecidamente que siempre que sea
posiblela localizaciónde fallos se realice conla alimentación
desconectada. Puede ser que en algunos casos sea
necesarioconectarla alimentación despuésde haber retirado
lacarcasa exterior. Eneste caso,realice lascomprobaciones
3D y luego desconecte los conductores del primario del
transformador de alimentación. Asegúrese de que estos
conductores permanezcan aislados de otros componentes y
del chasis del horno. (Use cinta aislante si es necesario).
Cuando termine la prueba efectúe las comprobaciones 3D y
reconecte los conductores al primario del transformador de
alimentación.
RECUERDE LA COMPROBACION 4C
1) Conecte todos los componentes desconectados de los
componentes durante la prueba.
2) Coloque la carcasa exterior (cabina).
3) Conecte la alimentación.
4) Compruebe todas sus funciones despues de poner en
marcha el horno.
Los hornos de microondas no deben funcionar vacíos. Para
comprobar la presencia de energía de microondas dentro de
unacavidad, coloqueuna tazade aguafría enel platogiratorio
del horno, cierre la puerta y ponga la potencia en HIGH (alta)
y coloque el temporizador en dos (2) minutos. Cuando
transcurranlos dos minutos (temporizador a cero) compruebe
cuidadosamente que el agua se ha calentado. Si el agua
permaneciese fría, efectúe las comprobaciones 3D y vuelva a
examinar las conexiones de los componentes que han sido
probados.
Cuandohaya terminadola intervenciónen el equipo y el horno
haya sido ensamblado de nuevo completamente, deberá
comprobar la potencia de salida de microondas y realizar una
prueba de fugas de microondas.
SV Mikrovågsugnar innehåller kretsar som producerar mycket höga spänningar och strömmar.
Kontakt med följande komponenter kan leda till dödsfall:
Högspänningskondensator, transformator, magnetron, högspännings likriktare, högspännings kablage.
KOM IHÅG ATT KONTROLLERA 3 STEG
1) Koppla från strömkällan.
2) Öppna dörren på glänt.
3) Ladda ur högspänningskondensatorn.
VARNING FÖR LADDNINGEN I
HÖGSPÄNNINGSKONDENSATORN
Högspänningskondensatorn är laddad i 60 sekunder efter
det att ugnen stängts av. Vänta 60 sekunder och korislut
sedan kondensatoms anslutning (dvs anslutningen till
högspänningslikriktaren)tillchassietmedhjälpavenisolerad
skruvmejsel.
Sharp rekommenderar att felsökning sker med strömmen
fränkopplad. Ibland kan det var nödvändigt att koppla på
strömmen efter det att höljet avlägsnats, utför da 3 Steg
kontrollen och koppla sedan från ledarna till transformatorns
primärsida. Se till att ledarna är isolerade från andra
komponenter och chassiet. (Använd isoleringsband om det
behövs). När Du testat färdigt utför Du 3 Steg kontrollen och
ansluter ledningarna till transformatorns primärsida igen.
KOM IHÅG ATT KONTROLLERA 4 STEG
1) Anslut alla ledningar som använts vid testning
2) Sätt tillbaka ytterhöljet.
3) Anslut strömkällan på nytt.
4) Sätt på ugnen. Kontrollera alla funktioner.
Mikrovågsugnar får inte användas tomma. Kontrollera
mikrovågsstrålningen i olika delar av ugnen genom att placera
en kopp med kallt vatten på ugnens tallrik, stäng dörren, ställ
inHIGHochställin2minuterpåtimern.Närtvåminuterhargått
(timemvisar0)kontrollerarduomvattnetärvarmt. Omvattnet
fortfarande är kallt utför Du 3 steg kontroller och kontrollerar
anslutningarna till varje enskild komponent på nytt.
När all service är klar och ugnen ihopskruvad skall ugnens
uteffekt och eventuellt mikrovågsläckage kontrolleras.
SERVICING CONT...

R-677 - 6
IIforni a microonde contengono un circuito elettrico in grado di generare tensioni e correnti estremamente elevate.
L’eventuale contatto con i seguenti componenti può causare la folgorazione:
condensatore ad alta tensione; trasformatore ad alta tensione; magnetron; rettificatore alta tensione; cablaggio ad
alta tensione.
TRE OPERAZIONI IMPORTANTI PER
INCOMINCIARE
1) Scollegare l'alimentazione elettrica.
2) Verificare che la porta sia bloccata in posizione
aperta.
3) Scaricare il condensatore ad alta tensione.
ATTENZIONE AL CONDENSATORE AD ALTA
TENSIONE: PUO ESSERE CARICO
Il condensatore ad alta tensione rimane carico per circa
60secondidopolo spegnimentodel forno.Occorre quindi
spettare 60 secondi prima di cortocircuitare, utilizzando
un cacciavite con impugnatura isolata, il collegamento
del condensatore ad alta tensione (cioè del conduttore
di collegamento del raddrizzatore ad alta tensione) sul
telaio del forno.
Sharp raccomanda, nei limiti del possibile, che la ricerca
dei guasti avvenga in assenza di alimentazione elettrica.
In alcuni casi tuttavia, può essere necessario alimentare
l'apparecchio dopo aver rimosso la scatola esterna. In
questo caso eseguire i tre controlli sopra citati e quindi
scollegare i connettori dal primario del trasformatore.
Assicurarsiche tali connettori non vengano a contatto con
altri componenti, ne con il telaio del forno (fare uso, se
necessario, di nastro isolante).Al termine dell'intervento,
eseguirenuovamente itre controlliericollegare iconduttori
al primario del trasformatore.
QUATTRO VERIFICHE IMPORTANTI DA NON
DIMENTICARE
1) Ricollegaretutti i conduttori staccati dai vari componenti
durante l'intervento.
2) Rimontare la scatola esterna.
3) Ripristinare l'alimentazione elettrica.
4) Rimettere in funzione il forno. Controllare tutte le
funzioni.
I forni a microonde non devono mai funzionare a vuoto.
Perverificarelapresenza dienergia damicroondeall'interno
di una cavitá, mettere una tazza di acqua fredda sul piatto
rotante del forno, chiudere la porta, regolare la potenza su
HIGH ed impostate il temporizzatore su due (2) minuti.
Trascorsi i due minuti (temporizzatore a zero), controllare
accuratamente che ora l'acqua sia calda. Se l'acqua è
rimasta fredda, eseguire i tre controlli iniziali e verificare
nuovamente i collegamenti del componente in questione.
Dopo aver portato a termine le operazioni di manutenzione
erimontato ilforno,è necessario controllarela potenza delle
microonde emesse ed eseguire un test per verificare che
non vi sia alcuna dispersione.
SERVICING CONT...
Aspartofourpolicyofcontinuousimprovement,wereservetherighttoalterdesign
and specifications without notice

R-677 - 7
SPECIFICATION
ITEM DESCRIPTION
Power Requirements 230 Volts
50 Hertz
Single phase, 3 wire earthed
Power Consumption Microwave cooking 1.34 kW Approx. 6.0 A
Top Grill mode..................... 0.75 kW Approx. 3.3 A
Grill cooking Bottom Grill mode................ 0.45 kW Approx. 2.0 A
Top and Bottom mode........ 1.15 kW Approx. 5.0 A
Micro and Top Grill ................ 2.1 kW Approx. 9.5 A
Micro and Bottom Grill........... 1.8 kW Approx. 8.2A
Dual cooking Micro and Top and Bottom Grill
(Auto cook only) ............(2.5 kW Approx. 11.3 A (Max.)
Power Output 800 W nominal of RF microwave energy (measured by method of IEC 705)
Operating fequency 2450 MHz
Grill heating element Power Output (Top Grill) 700 W
Bottom heating element Power Output 400 W
Case Dimensions Width 450 mm
Height 298 mm including foot
Depth 380 mm
Cooking Cavity Dimensions Width 296 mm
Height 203 mm
Depth 297 mm
Turntable diameter 275 mm
Control Complement Touch Control System
Clock (1:00 - 12:59 or 0:00 - 23:59) / Timer (0 - 90 minutes)
Microwave Power for Variable Cooking
Repetition Rate;
100%.................................Full power throughout the cooking time
70%.................................................. approx. 70% of FULL Power
50%.................................................. approx. 50% of FULL Power
30%.................................................. approx. 30% of FULL Power
10%.................................................. approx. 10% of FULL Power
LESS/MORE buttons
PIZZA button, AUTO COOK button
AUTO DEFROST button, WATT button
COOKING MODE selector, STOP button
+ 1 min./START button, CLOCK setting button
TIME/WEIGHT dial
Net Weight Approx. 15 kg
GENERAL INFORMATION
WARNING
THIS APPLIANCE MUST BE EARTHED
IMPORTANT
THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW : EARTH
BLUE : NEUTRAL
BROWN : LIVE
PRODUCT DESCRIPTION

R-677 - 8
OVEN
9. Door seals and sealing surfaces
10.Ventilation openings
11.Outer cabinet
12.Power supply cord
13.Turntable
14.Rack
1. Control panel
2. Oven lamp
3. Grill heating element (Top Grill)
4. Door opening button
5. Waveguide cover
6. Oven cavity
7. Turntable motor shaft
8. Grill heating element
(Bottom Grill)
DIGITAL DISPLAY AND INDICATORS
1. LESS /MORE indicator
2. AUTO indicator light
It will light during automatic operation.
3. WEIGHT (KG) indicator
4. MICROWAVE (WATT) indicator
5. COOK SET/TIMER indicator
6. COOKING IN PROGRESS indicator
OPERATION BUTTONS
7. LESS/MORE buttons
8. PIZZA button
9. AUTO DEFROST button
10.COOKING MODE dial
Rotate the dial so that indicator points to
appropriate symbol:
: Microwave
: Microwave and Top Grill
: Microwave and Bottom Grill
: Top Grill
: Bottom Grill
: Top and Bottom Grills
11.WATT button
12.TIME/WEIGHT dial
13.STOP button
14. (START)+ 1 min./ button
15.CLOCK button
16.AUTO COOK button
CONTROL PANEL
APPEARANCE VIEW
1
2
3456
7
8
9
10
11
12
13
14
15
16
1
11
10
12
5
6
4
14
13
2
3
8
7
9

R-677 - 9
OPERATION SEQUENCE
OFF CONDITION
Closingthedooractivatestheprimarylatchswitchandthe
stop switch.
IMPORTANT:
When the oven door is closed, the contacts COM-NC
of the monitor switch must be open. When the micro-
waveovenispluggedinawalloutlet(230V/50Hz),the
line voltage is supplied to the noise filter.
Figure O-1 on page 32
1. The control unit is not energized. The display shows
nothing (Fig. O-1 (a)).
2. Openthedoor.Thecontacts(COM-NC)oftheprimary
latch switch are closed and the control unit is ener-
gized. Then contacts of relays RY1 and RY6 are
closed,andthe oven lampwilllightand the displaywill
flash (Fig. -1(b)).
3. Closethedoor.Thecontacts(COM-NC)oftheprimary
latch switch are opened and the oven lamp will be
turned off. The display will stop flashing (Fig. O-1(c)).
NOTE: Energy save mode
1. Ifthe oven has not been usedformorethan2minutes,
the contacts of the relay RY6 will be opened and the
control unit will be not energized. Open and close the
door, the control unit will resume.
2. Iftheclockisset,thisenergysavemodedoesnotwork.
MICROWAVE COOKING CONDITION
HIGH COOKING
Select the microwave cooking mode with the COOKING
MODE selector. Enter a desired cooking time by turning
the TIME/WEIGHT dial and start the oven by pressing
START button.
Function sequence Figure O-2 on page 33
CONNECTED COMPONENTS RELAY
Oven lamp, Turntable motor RY1
High voltage transformer RY2
Grill heating element (Top) RY3
Bottom heating element RY4
Fan motor RY5
Control unit RY6
1. The line voltage is supplied to the primary winding of
thehighvoltage transformer. The voltageisconverted
to about 3.3 volts A.C. output on the filament winding
and high voltage of approximately 2000 volts A.C. on
the secondary winding.
2. The filament winding voltage (3.3 volts) heats the
magnetronfilamentandthehighvoltage(2000volts)is
sentto the voltagedoubling circuit, whereit is doubled
to negative voltage of approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the
magnetron generates a wavelength of 12.24 cm. This
energyischannelledthroughthewaveguide(transport
channel)intotheoven cavity, where the foodisplaced
to be cooked.
4. Whenthecookingtimeisup,asignaltoneisheardand
the relays RY1 + RY2 + RY5 go back to their home
position. The circuits to the oven lamp, high voltage
transformer, fan motor and turntable motor are cut off.
5. Whentheovendoor is opened duringacookingcycle,
the switches come to the following condition.
Switch Contact Condition
During Oven Door
Cooking Open(No cooking)
COM-NO Closed Opened
Primary latch Switch COM-NC Opened Closed
Stop switch COM-NO Closed Opened
COM-NO Closed Opened
Monitor Switch COM-NC Opened Closed
The circuit to the high voltage transformer, fan motor and
turntable motor are cut off when the primary latch switch
and stop switch are made open. The oven lamp remains
oneven if theoven door isopened afterthe cooking cycle
has been interrupted, because the relay RY1 stays
closed. Shown in the display is remaining time.
6. MONITOR SWITCH CIRCUIT
The monitor switch SW3 is mechanically controlled by
the oven door, and monitors the operation of the
primary latch switch SW1.
6-1. When the oven door is opened during or after the
cycle of a cooking program, the contacts (COM-NO)
oftheprimarylatchswitch SW1andstop switchSW2
must open their contacts first. After that the contacts
(COM-NC)of the monitorswitch SW3 can beclosed.
6-2. When the oven door is closed, the contacts (COM-
NC)ofthemonitorswitchSW3mustbeopened.After
that the contacts (COM-NO) of the primary latch
switch SW1 and the stop switch SW2 are closed.
6-3. When the oven door is opened and the contacts
(COM-NO) of the primary latch switch SW1 remain
closed, the fuse F2 F8A will blow, because the moni-
tor switch is closed and a short circuit is caused.
MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW
COOKING
When the microwave oven is preset for variable cooking
power, the line voltage is supplied to the high voltage
transformer intermittently within a 32-second time base
through the relay contact which is coupled with the cur-
rent-limitingrelay RY2. Thefollowing levels ofmicrowave
power are given.
SETTING
800P100%
560P 70%
400P 50%
240P 30%
80P 10%
32 sec. ON Approx. 100%
24 sec. ON 8 sec. OFF Approx. 70%
18 sec. ON 14 sec. OFF Approx. 50%
12 sec. ON 20 sec. OFF Approx. 30%
6 sec. ON 26 sec. OFF Approx. 10%
Note: TheOn/Offtimeratiodoesnotexactlycorrespond
to the percentage of microwave power, because
approx. 3 seconds are needed for heating up the
magnetron filament.
GRILL COOKING CONDITION
The oven has three grill cooking condition. They are the
TOPGRILL mode, BOTTOM GRILL mode and TOP AND
BOTTOM GRILL mode.

R-677 - 10
TOP GRILL MODE
In this mode, the food is cooked by the grill heating
element (top grill). Select the TOP GRILL mode with the
COOKING MODE selector. Enter the cooking time by
rotating the TIME/WEIGHT dial. When the START button
is pressed, the following operations occur:
Figure O-3(a) on page 33
1. The relay RY1 + RY3 + RY5 are energized.
2. Thenumbersofthedigitalreadoutstartthecountdown
to zero.
3. Then the grill heating element (top), turntable motor,
oven lamp and fan motor are energized.
4. Now, the food is grilled by the grill heating element.
5. Uponcompletion of the selected cooking time, audible
signal sounds and the contacts of relays RY1 + RY3
are opened, then the grill heating element (top), turn-
table motor and oven lamp are de-energized.
6. TherelayRY5staysclosedforfive(5)minutes,andthe
fan motor operates.
BOTTOM GRILL MODE
In this mode, the food is cooked by the bottom heating
element.SelecttheBOTTOMGRILLmodewiththeCOOK-
INGMODEselector.Enterthecookingtimebyrotatingthe
TIME/WEIGHT dial. When the START button is pressed,
the following operations occur:
Figure O-3(b) on page 33
1. The relay RY1 + RY4 + RY5 are energized.
2. Thenumbersofthedigitalreadoutstartthecountdown
to zero.
3. Then the bottom heating element, turntable motor,
oven lamp and fan motor are energized.
4. Now,the food is grilled by thebottomheatingelement.
5. Uponcompletion of the selected cooking time, audible
signal sounds and the contacts of relays RY1 + RY4
areopened,then the bottom heatingelements,turnta-
ble motor and oven lamp are de-energized.
6. TherelayRY5staysclosedforfive(5)minutes,andthe
fan motor operates.
TOP AND BOTTOM GRILL MODE
In this mode, the food is cooked by both the grill heating
element(topgrill)and bottom heating element.Selectthe
TOP AND BOTTOM GRILL mode with the COOKING
MODE selector. Enter the cooking time by rotating the
TIME/WEIGHT dial. When the START button is pressed,
the following operations occur:
Figure O-3(c) on page 34
1. The relay RY1 + RY3 + RY4 + RY5 are energized.
2. Thenumbersofthedigitalreadoutstartthecountdown
to zero.
3. Then the grill heating element (top), bottom heating
element,turntablemotor,ovenlampandfanmotorare
energized.
4. Now, the food is grilled by the grill heating element
(top) and the bottom heating element.
5. Uponcompletion of the selected cooking time, audible
signal sounds and the contacts of relays RY1 + RY3 +
RY4 are opened, then the grill heating element (top),
bottom heating element, turntable motor and oven
lamp are de-energized.
6. TherelayRY5staysclosedforfive(5)minutes,andthe
fan motor operates.
DUAL COOKING CONDITION
The oven has two dual cooking mode. One is MICRO-
WAVE AND TOP GRILL mode and other one is MICRO-
WAVE AND BOTTOM GRILL mode. In both modes, the
relayRY2operatesintermittentlywithina48secondstime
base as shown below.
Power level ON time OFF time
100% 48 sec. 0 sec.
70% 36 sec. 12 sec.
50% 26 sec. 22 sec.
30% 16 sec. 32 sec.
10% 8 sec. 40 sec.
MICROWAVE AND TOP GRILL MODE (DUAL 1)
Inthismode,thefoodiscookedbymicrowaveandthegrill
heatingelement(top).SelecttheMICROWAVEANDTOP
GRILLmodewiththeCOOKINGMODEselectorandthen
select the power level with the WATT button. Enter the
cookingtimebyrotatingtheTIME/WEIGHTdial.Whenthe
START button is pressed, the following operations occur
(Fig. O-4(a)):
1. The relay RY1 + RY2 + RY3 + RY5 are energized.
2. Thenumbersofthedigitalreadoutstartthecountdown
to zero.
3. The grill heating element (top), high voltage trans-
former, turntable motor, oven lamp and fan motor are
energized.
4. Now, the food is cooked by the microwave and grill
heating element (top).
5. Uponcompletion of the selected cooking time, audible
signal sounds and the contacts of relays RY1 + RY2 +
RY3 are opened, then the grill heating element (top),
high voltage transformer, turntable motor and oven
lamp are de-energized.
6. TherelayRY5staysclosedforfive(5)minutes,andthe
fan motor operates.
MICROWAVE AND BOTTOM GRILL MODE (DUAL 2)
In this mode, the food is cooked by microwave and the
bottom heating element. Select the MICROWAVE AND
TOPGRILLmodewiththeCOOKINGMODE selectorand
thenselectthepowerlevelwiththeWATTbuttonEnterthe
cookingtimebyrotatingtheTIME/WEIGHTdial.Whenthe
START button is pressed, the following operations occur
(Fig . O-4(b)):
1. The relay RY1 + RY2 + RY4 + RY5 are energized.
2. Thenumbersofthedigitalreadoutstartthecountdown
to zero.
3. Thebottomheatingelement,highvoltagetransformer,
turntable motor, oven lamp and fan motor are ener-
gized.
4. Now,the food iscooked bythe microwave andbottom
heating element.
5. Uponcompletion of the selected cooking time, audible
signal sounds and the contacts of relays RY1 + RY2 +
RY4 are opened, then the bottom heating elements,
high voltage transformer, turntable motor and oven
lamp are de-energized.
6. TherelayRY5staysclosedforfive(5)minutes,andthe
fan motor operates.
OPERATION SEQUENCE CONT...

R-677 - 11
PIZZA COOKING
PIZZA automatically works out the correct cooking mode
and time for cooking. Chose menu with the PIZZA button
and enter the weight of the food with the TIME/WEIGHT
dial. Once the oven starts, it will cook according to the
special cooking sequence.
AUTO COOKING
AUTOCOOKautomaticallyworksoutthe correctcooking
mode and time for cooking. Chose menu with the AUTO
COOK button and enter the weight of the food with the
TIME/WEIGHT dial. Once the oven starts, it will cook
according to the special cooking sequence.
AUTO DEFROST
AUTO DEFROST automatically works out the correct
microwave power and time for defrosting. Chose menu
with the AUTO DEF button and to enter the weight of the
food with the TIME/WEIGHT dial. Once the oven starts, it
will cook according to the special cooking sequence.
LIMITATIONS OF POWER OUTPUT IN MANUAL
OPERATION
After the same cooking mode is carried out for more than
the specified cooking time, the power output is automati-
cally reduced by turning the control relays on and off
intermittently, as shown in the table below. This is to
protect the oven door against temperature rising.
Specified cooking Limited power Time base
Cooking mode time (minutes) output (%) (seconds)
Microwave (100%) 30 70 32
Top grill 30 50 48
Bottom grill 30 50 48
Top grill and 10 (Top) 50 48
Bottom grill 10 (Bottom) 50 48
Micro. (100%) 20 (Micro.) 70 48
+ Top grill 15 (Grill) 50 48
Micro. (100%) 20 (Micro.) 70 48
+ Bottom grill 15 (Heater) 50 48
NOTE:
1. In case of Automatic operations, the limitations of
power output are not carried out.
2. Incasethatthestopbuttonispressedortheovendoor
is opened during cooking, the limitations of power
output are not carried out after the total cooking time
beyond the specified cooking time.
3. In case of the two or more same cooking modes are
carried out, the limitations of power output are not
carried out after the total cooking time beyond the
specified cooking time.
4. Incaseofthetwoormoredifferentcookingmodes are
carried out, the specified cooking time is started to
countfromthepointwhenthecookingmodeischanged.
5. If the cooking mode has the power level display, the
power level is also displayed when the limitations of
power output are carried out.
D
U
A
L
FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM
Thedoorcanbeopenedbypushingtheopenbuttononthe
control panel. When the open button is pushed, the open
leverispusheslowerlatchheadonthedoorupward. The
latchheadislinkedwiththe lowerlatch head, so now, the
door can be opened.
PRIMARY LATCH SWITCH SW1
1. Whentheovendoorisclosed,thecontacts(COM-NO)
of the switch must be closed and the contacts (COM-
NC) must be opened.
2. When the oven door is opened, the contacts (COM-
NO) of the switch must be opened and the contacts
(COM-NC) must be closed.
MONITOR SWITCH SW3
1. Whenthedoorisclosed,thecontacts(COM-NC)must
be opened and the contacts (COM-NO) must be
closed.
2. When the door is opened, the contacts (COM-NC)
must be closed and the contacts (COM-NO) must be
closed.
3. Ifthe oven dooris openedand he contacts(COM-NO)
of the primary latch switch SW1 fail to open, the fuse
F2 F8A blows immediately after closing the contacts
(COM-NC) of the monitor switch SW3.
CAUTION: BEFORE REPLACING A BLOWN FUSE F2
F8A TEST THE PRIMARY LATCH SWITCH
SW1, MONITOR SWITCH SW3 AND MONI-
TOR RESISTOR (MOUNTED NOISE FIL-
TER) FOR PROPER OPERATION. (REFER
TO CHAPTER “TEST PROCEDURE”).
Figure D-1. Door Open Mechanism
STOP SWITCH SW2
1. Whentheovendoorisclosed,thecontacts(COM-NO)
of the switch must be closed.
2. When the oven door is opened, the contacts (COM-
NO) of switch must be opened.
OPERATION SEQUENCE CONT...
LATCH HOOK
STOP SWITCH
PRIMARY
(MONITORED)
LATCH SWITCH
MONITOR SWITCH
LATCH
HEADS
OPEN LEVER
DOOR OPEN BUTTON
DOOR

R-677 - 12
SPECIAL FUSE F1 20A
If the wire harness or electrical components are short-
circuited,thisfuseF1blowstopreventanelectricshockof
fire hazard.
FUSE F2 F8A 250V
1. If the wire harness or electrical components are short-
circuited,thisfuseblowstopreventanelectricshockor
fire hazard.
2. The fuse also blows when the primary (monitored)
latch switch remains closed with the oven door open
andwhenthemonitorswitchcontact(COM-NC)closes.
THERMAL CUT-OUT TC1 145˚C (HVT)
Thisthermalcut-outprotectsthehigh voltagetransformer
against overheating. The cut-out is incorporated into the
HVTprimary windings. Ifthe temperature goes up higher
than 145˚C because the fan motor is interrupted or the
ventilationopeningsareblocked,thethermalcut-out TC1
will open and line voltage to the high voltage transformer
will be cut off and the operation of the magnetron will be
stopped. The thermal cut-out will cut back in at 115˚C.
THERMAL CUT-OUT TC2 150˚C (OVEN)
This thermal cut-out protects the oven against overheat-
ing during grill cooking. The thermal cut-out is also de-
signed to prevent damage to the oven if the foods in the
oven catch fire due to over heating produced by improper
setting of the cooking time or failure of the control unit.
Underthenormaloperation,theoventhermalcut-outTC2
remains closed. However, when abnormally high tem-
peratureare reached within the oven cavity,oventhermal
cut-out TC2 will open at 150˚C causing the oven to shut
down. The thermal cut-out will cut back in at 130˚C.
TURNTABLE MOTOR TTM
The turntable motor drives the turntable roller assembly
to rotate the turntable.
FAN MOTOR FM
The fan motor drives a blade which draws external cool
air. This cool air is directed through the air vanes sur-
rounding the magnetron and cools the magnetron. This
airischannelledthroughtheovencavitytoremovesteam
and vapours given off from heating food. It is then ex-
hausted through the exhausting air vents of the oven
cavity.
NOISE FILTER
The noise filter assembly prevents radio frequency inter-
ference that might flow back in the power circuit.
GRILL HEATING ELEMENT (TOP GRILL) GH1
The grill heating elementGH1 is located on the top ofthe
oven cavity assembly. The grill heating element GH1
sends out heat to grill foods.
BOTTOM HEATING ELEMENT GH2
The bottom heating element GH2 is located on the floor
oftheovencavityassembly.Thebottomheatingelement
GH2 sends out heat to grill foods.
FUNCTION OF IMPORTANT COMPONENTS CONT...
TROUBLESHOOTING GUIDE
When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks.
Manyof thepossible causesof trouble will require that a specific test beperformed. Thesetests aregiven aprocedure
letter which will be found in the “Test Procedure” section.
IMPORTANT: If the oven becomes inoperative because of a blown fuse (F8A) in the monitored latch switch - monitor
switch circuit, check the monitored latch switch and monitor switch before replacing the fuse (F8A).

R-677 - 13
TROUBLESHOOTING GUIDE CONT...
CONDITION PROBLEM
MAGNETRON HIGH VOLTAGE TRANSFORMER H.V. RECTIFIER HIGH VOLTAGE CAPACITOR PRIMARY LATCH SWITCH MONITOR SWITCH STOP SWITCH THERMAL CUT-OUT 145˚C (HVT) THERMAL CUT-OUT 150˚C (OVEN) FUSE 20A (F1) FUSE F8A (F2) NOISE FILTER FAN MOTOR TURNTABLE MOTOR GRILL HEATING ELEMENT (TOP) BOTTOM HEATING ELEMENT POWER SUPPLY CORD OVEN LAMP OR SOCKET SHORTED WIRE HARNESS OPENED WIRE HARNESS MIS-ADJUSTMENT OF SWITCHES CONTROL PANEL TACT SWITCH RELAY RY1 RELAY RY2 RELAY RY3 RELAY RY4 RELAY RY5 RELAY RY6 FOIL PATTERN ON P.W.B. LIMITATION OF OPERATION
ABCDEEEFFGH I J JKK LMNNNNNNO
Fuse F1 15A blows when power
cord is plugged into wall outlet.
Fuse F2 F8A blows when the
door is opened.
Oven lamp does not light when
door is opened. (Display
operates.)
Home fuse blows when power
cord is plugged into wall outlet.
Nothing appear in display when
power cord is plugged into wall
outlet and open and close the
door.
Display does not operate
properly when STOP button is
pressed.
Oven does not start when the
START button is pressed.
(Display operates.)
Oven lamp does not light.
(Turntable motor operates.)
Fan motor does not operate.
(Oven lamp lights.)
Turntable motor does not
operate. (Oven lamp lights.)
Oven or electrical parts does
not stop when cooking time is 0
or STOP button is pressed.
Oven goes into cook cycle but
shuts down before end of
cooking cycle.
Oven seems to be operating but
little or no heat is produced in
oven load.
Oven does not operating
properly during variable cooking
condition except 100% cooking
condition.
Oven goes into cook cycle but
shuts down before end of
cooking cycle.
Grill heating element (top)
doesn't operate.
Bottom heating element doesn't
operate.
Oven seems to be operating but
little or no heat is produced in
oven load. (Microwave power
does not seem to be generated
properly.)
Grill heating element (top)
doesn't operate.
Bottom heating element doesn't
operate.
OFF
CONDITION
COOKING
CONDITION
(COMMON MODE)
MICROWAVE
COOKING
CONDITION
GRILL
COOKING
CONDITION
DUAL
COOKING
CONDITION
TEST PROCEDURE
POSSIBLE CAUSE
AND
DEFECTIVE PARTS

R-677 - 14
AMAGNETRON TEST
PROCEDURE
LETTER COMPONENT TEST
CARRY OUT 3D CHECKS.
Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal.
Totestforanopen circuit filament use anohmmeter tomake acontinuity testbetweenthemagnetron
filament terminals, the meter should show a reading of less than 1 ohm.
Totestforshortfilamenttoanodecondition,connectohmmeterbetweenoneofthefilamentterminals
and the case of the magnetron (ground). This test should be indicated an infinite resistance. If a low
or zero resistance reading is obtained then the magnetron should be replaced.
MICROWAVE OUTPUT POWER (IEC-705-1988)
The following test procedure should be carried out with the microwave oven in a fully assembled
condition (outer case fitted). Microwave output power from the magnetron can be measured by way
of IEC 705, i.e. it is measured by how much power the water load can absorb. To measure the
microwave output power in the microwave oven, the relation of calorie and watt is used. When P(W)
heating works for t(second), approximately P x t/4.187 calorie is generated. On the other hand, if the
temperature of the water with V(ml) rises ∆T (°C) during this microwave heating period, the calorie of
the water is V x ∆T.
Measuring condition:
1. Container
The water container must be a cylindrical borosilicate glass vessel having a maximum material
thickness of 3 mm and an outside diameter of approximately 190 mm.
2. Temperature of the oven and vessel
The oven and the empty vessel are at ambient temperature prior to the start the test.
3. Temperature of the water
The initial temperature of the water is (10±2)°C.
4. Selecttheinitialandfinalwatertemperaturesothatthemaximumdifferencebetweenthefinalwater
temperature and the ambient temperature is 5K.
5. Selectstirringdevicesandmeasuringinstrumentsinordertominimizeadditionorremoval ofheat.
6. The graduation of the thermometer must be scaled by 0.1°C at minimum and be an accurate
thermometer.
7. The water load must be (1000±5) g.
8. “t”ismeasured while the microwavegeneratorisoperating at full power.Magnetronfilamentheat-
up time is not included.
NOTE: Theoperation timeof themicrowave ovenis“t +3” sec.(3sec. ismagnetron filamentheat-uptime.)
Therefore total heating time = 55 sec.
Measuring method:
1. Measure the initial temperature of the water before the water is added to the vessel.
(Example: The initial temperature T1 = 11°C)
2. Add the 1 litre water to the vessel.
3. Place the load on the centre of the shelf.
4. Operate the microwave oven at HIGH for the temperature of the water rises by a value ∆T of
(10 ±2) K.
5. Stir the water to equalize temperature throughout the vessel.
6. Measure the final water temperature. (Example: The final temperature T2 = 21°C)
7. Calculate the microwave power output P in watts from above formula.
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL
WHILE THE OVEN IS IN OPERATION.
The formula is as follows;
P x t / 4.187 = V x ∆T P (W) = 4.187 x V x ∆T / t
Our condition for water load is as follows:
Room temperature ........... around 20°CPower supply Voltage.............. Rated voltage
Water load..................................1000 g Initial temperature.............................. 10±2°C
Heating time.............................. 52 sec.
P = 80 x ∆T
TEST PROCEDURES
Initial temperature .................................................................................................. T1 = 11°C
Temperature after (52 + 3) = 55 sec ...................................................................... T2 = 21°C
Temperature difference Cold-Warm ...................................................................... ∆T1 = 10C
Measured output power
The equation is “P = 80 x ∆T” ...................................................... P = 80 x 10°C = 800 Watts

R-677 - 15
PROCEDURE
LETTER
TEST PROCEDURES CONT...
COMPONENT TEST
JUDGMENT: The measured output power should be at least ±15 % of the rated output power.
CAUTION: 1°C CORRESPONDS TO 80 WATTS. REPEAT MEASUREMENT IF THE POWER IS
INSUFFICIENT.
1000g
1000g
1000g
T1˚CT2˚C
Heat up for 55 sec
BHIGH VOLTAGE TRANSFORMER TEST
WARNING: High voltage and large currents are present at the secondary winding and
filamentwindingofthehighvoltagetransformer.Itisverydangeroustowork
nearthispart when the oven is on. NEVER make any voltage measurements
of the high-voltage circuits, including the magnetron filament.
CHIGH VOLTAGE RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested
usinganohmmetersettoitshighestrange.ConnecttheohmmeteracrosstheterminalB+Cofthehigh
voltagerectifier and notethereadingobtained.Reversethe meter leadsandnotethissecondreading.
The normal resistance is infinite in one direction and more than 100 kΩin the other direction.
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF
THEMEASURINGINSTRUMENTMUSTHAVEAVOLTAGEATLEAST6VOLTS,BECAUSE
OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
CARRY OUT 3D CHECKS.
Disconnect the leads to the primary winding of the high voltage transformer. Disconnect the filament
and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a low
range, it is possible to check the continuity of all three winding. The following readings should be
obtained:- a. Primary winding ................................ approximately 2.5 Ω
b. Secondary winding .......................... approximately 160 Ω
c. Filament winding......................................... less than 1 Ω
If the readings obtained are not stated as above, then the high voltage transformer is probably faulty
and should be replaced.
CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
A. Isolate the high voltage capacitor from the circuit.
B. Continuity check must be carried out with measuring instrument which is set to the highest
resistance range.
C. Anormalcapacitorshowscontinuityforashorttime(kick)andthenaresistanceofabout10MΩafter
it has been charged.
D. A short-circuited capacitor shows continuity all the time.
E. An open capacitor constantly shows a resistance about 10 MΩbecause of its internal 10MΩ
resistance.
F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
G. Theresistanceacrossalltheterminalsandthechassismustbeinfinitewhenthecapacitoris normal.
If incorrect reading are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS.
DHIGH VOLTAGE CAPACITOR TEST

R-677 - 16
PROCEDURE
LETTER COMPONENT TEST
ESWITCH TEST
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described
in the following table.
COM; Common terminal,
NO; Normally open terminal
NC; Normally close terminal
If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.
CARRY OUT 4R CHECKS.
FTHERMAL CUT-OUT TEST
Table: Terminal Connection of Switch
Plunger Operation COM to NO COM to NC
Released Open circuit Short circuit
Depressed Short circuit Open circuit
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the thermal cut-out. Then using an ohmmeter, make a
continuity test across the two terminals as described in the below.
Table: Thermal Cut-out Test
Temperature of "ON" Temperature of "OFF" Indication of ohmmeter
Parts Name condition (closed circuit). condition (open circuit). (Whenroomtemperature
(˚C) (˚C) is approx. 20˚C.)
Thermal cut-out 145˚CCuts back in at 115˚C. Above 145˚CClosed circuit
Thermal cut-out 150˚CCuts back in at 130˚C. Above 150˚CClosed circuit
If incorrect readings are obtained, replace the thermal cut-out.
Anopencircuitthermalcut-out TC1 (HVT) indicates that thehigh voltagetransforner hasoverheated,
thismay be duetoresistrictedventilation,coolingfanfailureor a faultconditionwithinthehighvoltage
transformer or HV. circuit.
An open circuit thermal cut-out TC2 (OVEN) indicates that the food in the oven cavity may catch fire,
this may be due to over heating produced by improper setting of the cooking timer or failure of the
control panel.
CARRY OUT 4R CHECKS.
GBLOWN FUSE 20A (F1)
CARRY OUT 3D CHECKS.
Ifthefuse15A is blown, therecouldbea shorts or agroundinelectricalparts or wire harness.Check
them and replace the defective parts or repair the wire harness.
CARRY OUT 4R CHECKS.
CAUTION: Only replace fuse 20A with the correct value replacement.
HBLOWN FUSE F8A (F2)
CARRY OUT 3D CHECKS.
Ifthe fuseF8A (F2)isblownwhen thedoorisopened,check theprimarylatchswitch,monitor switch
and monitor resistor.
IfthefuseF8A (F2)isblownbyincorrectdoorswitchingreplacethedefectiveswitch(es)andthe fuse
F8A (F2).
CARRY OUT 4R CHECKS.
CAUTION: Only replace fuse with the correct value replacement.
TEST PROCEDURES CONT...

R-677 - 17
PROCEDURE
LETTER COMPONENT TEST
INOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnecttheleadsfromtheterminalsofnoisefilter.
Using an ohmmeter, check between the terminals as
described in the following table.
MEASURING POINTS INDICATION OF OHMMETER
Between N and L Approx. 680 kΩ
Between terminal N and WHITE Short circuit
Between terminal L and RED Short circuit
If incorrect readings are obtained, replace the noise filter unit.
CARRY OUT 4R CHECKS.
LINE BYPASS
CAPACITOR
4700p/250V
LINE BYPASS
CAPACITOR
4700p/250V
NOISE SUPPRESSION COIL
RESISTOR 680K/0.5W
10M/0.5W
LINE CROSS CAPACITOR
0.22µ/250V F1:
FUSE 15A
F2: FUSE F8A
NOISE 
FILTER
LN
WHT RED
JMOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals as described in the table below.
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 370 Ω
Turntable motor Approximately 14.9 kΩ
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
KGRILL HEATING ELEMENT (TOP) AND BOTTOM HEATING ELEMENT TEST
CARRY OUT 3D CHECKS.
Before carrying out the following tests make sure the heating element is cooled completely.
1. Resistance of heating element.
Disconnectthewireleadstotheheatingelementtobetested. Usingohmmeterwithlowresistance
range. Check the resistance across the terminals of the heating element as described in the
following table. Table: Resistance of heating element
Parts name Resistance
Grill heating element (top) Approximately 76 Ω
Bottom heating element Approximately 132 Ω
2. Insulation resistance.
Disconnect the wire leads to the heating element to be tested. Check the insulation resistance
between the element terminal and cavity using a 500V - 100MΩinsulation tester. The insulation
resistance should be more than 10 MΩin the cold element.
If the results of above test 1 and/or 2 are out of above specifications, the heating element is probably
faulty and should be replaced.
CARRY OUT 4R CHECKS.
TEST PROCEDURES CONT...

R-677 - 18
PROCEDURE
LETTER COMPONENT TEST
ThetouchcontrolpanelconsistsofcircuitsincludingsemiconductorssuchasLSI,ICs,etc.Therefore,
unlike conventional microwave ovens, proper maintenance can not be performed with only a
voltmeter and ohmmeter. In this service manual, the touch control panel assembly is in two units,
control unit and key/jog unit and troubleshooting by replacement is described according to the
symptoms indicated.
Control Panel.
The following symptoms indicate a defective control unit.
1. Tact Switch.
The following symptoms indicate a defective tact switch. Replace the tact switch.
a) When touching a tact switch, a certain tact switch produces no signal at all.
b) When touching a tact switch, sometimes a tact switch produces no signal.
2. In connection with tact switches.
a) When touching a tact switch, a certain group of tact switch do not produce a signal.
b) When touching a tact switch, no tact switch produce a signal.
3. Potentiometer problem
a) When rotating the potentiometer, the cooking mode can not be selected.
4. Encoder problem
a) When rotating the encoder, the cooking or the weight of food can not be entered.
5. Display problems.
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 up.
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) When touching a tact switch, the control unit does not respond.
6. Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Cooking is not possible.
LTOUCH CONTROL PANEL ASSEMBLY TEST
MTACT SWITCH TEST
1. Disconnect the oven from the power supply.
2. Discharge the high voltage capacitor.
3. Remove the control unit from the control panel.
4. By using an ohmmeter, check the tact switch operation.
5. When the tact switch is not depressed, an ohmmeter should indicate an open circuit. When the
tact switch is depressed, an ohmmeter should indicate a short circuit. If improper operation is
indicated, the tact switch is probably defective and should be checked.
NRELAY TEST
Removethe outercase andcheck voltage between Pin No. 1 and Pin No.3 ofthe 5pin connector(A)
on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, if not check oven circuit.
RY1, RY2, RY3, RY4, RY5 and RY6 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, grill
cooking or dual cooking
DC. voltage indicated.......... Defective relay.
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. 18.0V D.C. Oven lamp / Turntable motor
RY2 Approx. 18.0V D.C. High voltage transformer
RY3 Approx. 24.0V D.C. Top heating element
RY4 Approx. 30.0V D.C. Bottom heating element
RY5 Approx. 24.0V D.C. Fan motor
RY6 Approx. 24.0V D.C. Touch control transformer
TEST PROCEDURES CONT...

R-677 - 19
PROCEDURE
LETTER COMPONENT TEST
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary
onthe PWB,thisfoilpatternactsasa fuse. Ifthefoilpatternisopen, follow thetroubleshootingguide
given below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 The rated AC voltage is not present at Check supply voltage and oven power cord.
POWER terminal of CPU connector (CN-A).
2 The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.
side of low voltage transformer. Check and repair.
3 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
4Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".
(CARRY OUT 3D CHECKS BEFORE REPAIR)
NOTE: *At the time of these repairs, make a
visual inspection of the varistor for
burning damage and examine the
transformerwithatesterforthepres-
ence of layer short-circuit (check pri-
mary coil resistance). If any abnor-
malconditionisdetected,replacethe
defective parts.
CARRY OUT 4R CHECKS.
VRS1
a
b
c
d
CN - A
T1
1
(J1)
RY5
TEST PROCEDURES CONT...
O PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD (PWB) IS OPEN

R-677 - 20
LSI(IXA201DR)
The I/O signal of the LSI(IXA201DR) are detailed in the following table.
Pin No. Signal I/O Description
1-2 VL2-VL1 IN Power source voltage input terminal.
Standard voltage for LCD.
3-5 AN7-AN5 IN Terminal to change functions according to the Model.
DC voltage in accordance with the Model in operation is applied to set up its
function.
6AN4 OUT Terminal not used.
7AN3 IN Signal coming from potentiometer.
By inputting DC voltage corresponding to the cooking mode set by the
potentiometer,thisinputisconvertedintothecookingmodebytheA/Dconverter
built into the LSI.
8AN2 IN Input signal which communicates the door open/close information to
LSI.
Door closed; "H" level signal.
Door opened; "L" level signal.
9-10 P01-P00 OUT Terminal not used.
11 P57 IN Terminal not used.
Thetouchcontrolsectionconsistsofthefollowingunitsas
shown in the touch control panel circuit.
The principal functions of these units and the signals
communicated among them are explained below.
Tact Switch
Signalsgenerated in theLSIare sent tothe tact switches.
When a tact switch is touched, a signal is completed
throughthetactswitchandpassedbacktotheLSIthrough
to perform the function that was requested.
Control Unit
Control unit consists of LSI, power source circuit, relay
circuit, back light circuit, synchronizing signal circuit, ACL
circuit, buzzer circuit, encoder circuit, potentiometer cir-
cuit and indicator circuit.
1) LSI
ThisLSIcontrolsthetactswitchstrobesignal,encoder
signal, potentiometer signal, relay driving signal for
oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
Symbol Voltage Application
VC -5.0V LSI(IC1)
3) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit. It accompanies a very small error because it
works on commercial frequency.
CONTROL PANEL ASSEMBLY
4) ACL Circuit
A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.
5) Buzzer Circuit
ThebuzzerisresponsivetosignalsfromtheLSItoemit
audible sounds (tact switch touch sound and comple-
tion sound).
6) Door Sensing Switch
A switch to "tell" the LSI if the door is open or closed.
7) Relay Circuit
Todrivethemagnetron,fanmotor,turntablemotor,top
heatingelement, bottomheating elementand light the
oven lamp.
8) Indicator Circuit
This circuit consists of 4-digits, 12-segments and 3-
common electrodes using a Liquid Crystal Display.
9) Encoder
Theencoderconvertsthesignalgeneratedby LSI into
thepulsesignal,andthepulsesignalisreturnedtothe
LSI.
10) Potentiometer Circuit
The circuit makes setting of the cooking mode by
variable resistance.
11) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1-LD4).
12) Auto Indicator Circuit
A circuit to drive the light (Light emitting diodes LD5).
OUTLINE OF CONTROL PANEL
DESCRIPTION OF LSI