Sharp R-933 User manual

TABLE OF CONTENTS
Page
CAUTION, MICROWAVE RADIATION........................................................................ Indside front cover
WARNING.................................................................................................................................................1
SERVICING ............................................................................................................................................. 2
PRODUCT SPECIFICATIONS .................................................................................................................5
GENERAL INFORMATION.......................................................................................................................5
APPEARANCE VIEW .............................................................................................................................. 6
OPERATION SEQUENCE........................................................................................................................7
FUNCTION OF IMPORTANT COMPONENTS ..................................................................................... 10
TROUBLESHOOTING GUIDE ...............................................................................................................12
TEST PROCEDURE .............................................................................................................................. 14
CONTROL PANEL ASSEMBLY ............................................................................................................21
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE .................................................. 26
MICROWAVE MEASUREMENT ........................................................................................................... 32
TEST DATA AT A GLANCE .................................................................................................................. 32
WIRING DIAGRAM ................................................................................................................................ 33
PICTORIAL DIAGRAM .......................................................................................................................... 37
POWER UNIT CIRCUIT .........................................................................................................................38
CPU UNIT CIRCUIT ...............................................................................................................................39
INDICATOR CIRCUIT.............................................................................................................................40
JOG AND SWITCH CIRCUIT .................................................................................................................41
PRINTED WIRING BOARD OF POWER UNIT ......................................................................................42
PRINTED WIRING BOARD OF JOG AND SWITCH UNIT ....................................................................43
PARTS LIST .......................................................................................................................................... 44
S07283R933EHW
MICROWAVE OVEN WITH
GRILL AND CONVECTION
MODELS R-933(IN)
R-933(W)
In interests of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.
SERVICE MANUAL
SHARP CORPORATION
Grill Hot Air
STOP
R-933
/KG
+
1
min
D
FIE
NL
AUTO
REHEAT
Express
COOK
Express
DEFROST
AUTO
COOK
WATT
˚C

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.

1
SERVICE MANUAL
GRILL AND CONVECTION MICROWAVE OVEN
R-933(IN)/ R-933(W)
GENERAL IMPORTANT INFORMATION
This Manual has been prepared to provide Sharp Corp. Service
engineers with Operation and Service Information.
It is recommended that service engineers carefully study the entire
text of this manual, so they will be qualified to render satisfactory
customer service.
CAUTION
MICROWAVE RADIATION
DO NOT BECOME EXPOSED TO RADIATION FROM THE
MICROWAVE GENERATOR OR OTHER PARTS THAT CON-
DUCT MICROWAVE ENERGY.
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.
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.
All the parts marked "*" on parts list are used at voltage more than
250V.
Removal of the outer wrap gives access to potential above 250V.
All the parts marked "∆" on the parts list may cause undue
microwave exposure, by themselves, or when they are damaged,
loosened or removed.
SHARP CORPORATION
OSAKA, JAPAN
SERVICING
PRODUCT SPECIFICATIONS
GENERAL INFORMATION
APPEARANCE VIEW
OPERATING SEQUENCE
FUNCTION OF IMPORTANT
COMPONENTS
TROUBLESHOOTING GUIDE
AND TEST PROCEDURE
TOUCH CONTROL PANEL
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
MICROWAVE MEASUREMENT
TEST DATA AT A GLANCE
WIRING DIAGRAM
PARTS LIST

2
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-
voltage capacitor (that is, of the connecting lead of 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
case has been removed, in this event carry out 3D checks and
then disconnect the leads to the primary of the High voltage
transformer. 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 High
voltage 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, High voltage 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
power to HIGH and set the microwave timer for two (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, the microwave power output should be checked and
a microwave leakage test should be 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.Somsishetnodig om de stroomtoevoer
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) Plaats de buitenmantel weer om het toestel heen (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
stelt de klok van de magnetron in op twee (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.

3
E Los hornos de microondas contienen circuitos eléctricos capaces de producir voltajes de alta tensión y descargas
eléctricas. Para evitar el riesgo de 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 DE ALTO VOLTAJE
El condensador de alto voltaje permanece cargado unos
60 segundos después de haber apagado el horno. Espere
60 segundos 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
posible la localización de fallos se realice con la alimentación
desconectada. Puede ser que en algunos casos sea
necesario conectar la alimentación después de haber retirado
la carcasa exterior. En este caso, realice las comprobaciones
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
una cavidad, coloque una taza de agua fría en el plato giratorio
del horno, cierre la puerta y ponga la potencia en HIGH (alta)
y coloque el temporizador en dos (2) minutos. Cuando
transcurran los 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.
Cuando haya terminado la intervención en 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)tillchassietmed hjälp av enisolerad
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
in HIGH och ställ in 2 minuter på timern. När två minuter har gått
(timem visar 0) kontrollerar du om vattnet är varmt. Om vattnet
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

4
I I forni 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
60 secondi dopo lo spegnimento del 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.
Assicurarsi che 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,
eseguire nuovamente i tre controlli e ricollegare i conduttori
al primario del trasformatore.
QUATTRO VERIFICHE IMPORTANTI DA NON
DIMENTICARE
1) Ricollegare tutti 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. Per
verificare la presenza di energia da microonde all'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
e rimontato il forno, è necessario controllare la potenza delle
microonde emesse ed eseguire un test per verificare che
non vi sia alcuna dispersione.
SERVICING

5
PRODUCT DESCRIPTION
SPECIFICATION
ITEM DESCRIPTION
Power Requirements 230 Volts / 50 Hertz / Single phase, 3 wire earthed
Power Consumption Microwave cooking 1.5 kW Approx. 6.7 A
Convection cooking 2.65 kW Approx. 11.5 A
Grill cooking 2.65 kW Approx. 11.5 A
Micro and Grill ........................ 2.8 kW Approx. 12.4 A
Dual cooking Micro and Convection............. 2.8 kW Approx. 12.4 A
Power Output
900 W nominal of RF microwave energy (measured by method of IEC 60705)
Operating fequency 2450 MHz
Grill heating element Power Output 1300 W (650 W x 2)
Convection heating element Power Output 1300 W
Case Dimensions Width 550 mm Height 368 mm (including foot) Depth 537 mm
Cooking Cavity Dimensions Width 375 mm Height 272 mm Depth 395 mm
Turntable diameter 362mm
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;
HIGH ................................. Full power throughout the cooking time
MEDIUM HIGH ................................ approx. 70% of FULL Power
MEDIUM .......................................... approx. 50% of FULL Power
MEDIUM LOW ................................. approx. 30% of FULL Power
LOW................................................. approx. 10% of FULL Power
Convection temperature control range:
250˚C, 230˚C, 220˚C, 200˚C, 180˚C, 160˚C, 130˚C, 100˚C, 70˚C and 40˚C
LESS(")/ MORE(') buttons , LANGUAGE button
INFORMATION button, EXPRESS COOK button
EXPRESS DEFROST button, AUTO REHEAT button
AUTO COOK button, COOKING MODE dial , CONVECTION button
MICROWAVE POWER LEVEL button, TIME/WEIGHT dial
CLOCK setting button, STOP button , +1min / START button
Net Weight Approx. 23 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
As part of our policy of continuous improvement, we reserve the
right to alter design and specifications without notice

6
APPEARANCE VIEW
CONTROL PANEL
Digital display and indicators:
1. COOKING IN PROCESS indicator
2. GRIL indicator
3. CONVECTION indicator
4. MICROWAVE indicator
5. INFO indicator
Operating buttons:
6. INFORMATION button
7. LANGUAGE button
8. AUTO REHEAT button
9. EXPRESS DEFROST button
10. AUTO COOK button
11.COOKING MODE dial
Rotate the dial so that indicator points to appropriate
symbol.
for microwave cooking
for microwave cooking with GRILL
for microwave cooking with CONVECTION
for GRILL
for CONVECTION
12. CONVECTION buttonbutton
Press to change the convection temperature.
13. TIME/WEIGHT knob
Rotate the knob to enter either the cooking/defrosting
time or weight food.
14. 1 min / START button (See note)
NOTE:
This features is disabled after three minutes
when the oven is not in use. This feature is
automatically enabled when the door is
opened and closed or the STOP button is
pressed.
15. STOP button
16. CLOCK SETTING button
17. MICROWAVE POWER LEVEL button
Press to change the microwave power setting.
18. EXPRESS COOK button
19. LESS / MORE buttons
14.Turntable support
15.High Rack
16.Low Rack
17.Baking tin
OVEN
1. Grill heating element
2. Oven lamp
3. Control panel
4. Shelf runners
5. Waveguide cover
6. Oven cavity
7. Coupling
8. Door seals and sealing surfaces
9. Door opening handle
10.Air-vent openings
11.Outer cabinet
12.Power cord
13.Turntable
15
3
214
12
11
10
13
8
9
14 16
7 6 5
17
Grill .Hot Air
STOP
R-933
/KG
+ 1 min
D
FI
E
NL
AUTO
REHEAT
Express
COOK
Express
DEFROST
AUTO
COOK
WATT
˚C
2
1
18
17
16
15
19
3
4
5
6
8
10
11
13
12
14
9
7

7
OPERATION SEQUENCE
OFF CONDITION
Closing the door activates the monitored latch switch and
the stop switch.
IMPORTANT:
When the oven door is closed, the contacts COM-NC
of the monitor switch must be open. When the micro-
wave oven is plugged in a wall outlet (230V / 50Hz), the
line voltage is supplied to the noise filter.
Figure O-1 on page 33
1. The control unit is not energized. The display shows
nothing (Fig. O-1 (a)).
2. Open the door. The contacts (COM-NC) of the monitored
latch switch are closed and the control unit is energized.
Then contacts of relays RY1 and RY5 are closed, and
the oven lamp will light and the display will show "SE-
LECT LANGUAGE" in 5 languages. (Fig. O-1(b)).
NOTE: Once the language is selected using the LAN-
GUAGE button, the display will show "ENERGY
SAVE MODE TO GO OUT OF ENERGY SAVE
MODE SET CLOCK" when the oven is plugged in.
3. Close the door. The contacts (COM-NC) of the moni-
tored latch switch are opened and the contacts of relay
RY1 are opened and the oven lamp will be turned off.
The display will show " . 0". (Fig. O-1(c)).
NOTE: Energy save mode
1. If the oven has not been used for more than 3 minutes,
the contacts of the relay RY5 will be opened and the
control unit will be not energized. Open and close the
door, the control unit will resume.
2. If the clock is set, this energy save mode does not work.
3. If the display shows different messages from ENERGY
SAVE MODE, the oven may be set in demo mode. Close
the door, see operation manual to cancel demo mode.
MICROWAVE COOKING CONDITION
HIGH COOKING
Rotate the COOKING MODE dial to the micro setting.
And press the POWER LEVEL button once. And enter the
cooking time by rotating the TIME/WEIGHT dial. And start
the oven by pressing START button.
Function sequence Figure O-2 on page 34
CONNECTED COMPONENTS RELAY
Oven lamp, Turntable motor RY1
High voltage transformer RY2
Fan motor RY6
1. The line voltage is supplied to the primary winding of
the high voltage transformer. The voltage is converted
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
magnetron filament and the high voltage (2000 volts) is
sent to the voltage doubling circuit, where it 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
energy is channelled through the waveguide (transport
channel) into the oven cavity, where the food is placed
to be cooked.
4. When the cooking time is up, a signal tone is heard and
the relays RY1 + RY2 + RY6 go back to their home
position. The circuits to the oven lamp, high voltage
transformer, fan motor and turntable motor are cut off.
5. When the oven door is opened during a cooking cycle,
the switches come to the following condition.
Switch Contact Condition
During Oven Door
Cooking Open(No cooking)
COM-NO Closed Opened
Monitored 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 is cut off when
the contacts of relay RY2, and the contacts (COM-NO) of
the monitored latch switch SW1 and monitor switch SW3
are made open. The circuit to the fan motor is cut off when
the relay RY6 is made open. The circuit to the turntable
motor is cut off when the contacts (COM-NO) of the
monitored latch switch SW1 are made open. The oven
lamp remains on even if the oven door is opened after the
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
monitored latch switch SW1.
6-1. When the oven door is opened during or after the
cycle of a cooking program, the monitored latch
switch SW1 and stop switch SW2 must open their
contacts (COM-NO) first. And the contacts (COM-
NC) of the monitored latch switch SW1 are made
closed . After that the contacts (COM-NC) of the
monitor switch SW3 can be closed and the contacts
(COM-NO) of monitor switch SW3 are made open.
6-2. When the oven door is closed, the contacts (COM-
NC) of the monitor switch SW3 must be opened and
the contacts (COM-NO) of monitor switch SW3 must
be closed. After that the contacts (COM-NO) of the
monitored latch switch SW1 and the stop switch SW2
are made closed. And the contacts (COM-NC) of the
monitored latch switch SW1 are made open .
6-3. When the oven door is opened and the contacts
(COM-NO) of the monitored latch switch SW1 remain
closed, the fuse F2 F8A will blow. Because the relay
RY1 and monitor switch SW3 are 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-limiting relay RY2. The following levels of microwave
power are given.
100% (HIGH)
32 sec. ON
70%(MEDIUM
HIGH) Approx. 70%
100%
24 sec. ON 8 sec. OFF
14 sec. OFF
20 sec. OFF
26 sec. OFF
50%(MEDIUM) Approx. 50%
18 sec. ON
30% (MEDIUM
LOW) Approx. 30%
12 sec. ON
10%(LOW) Approx. 10%
6 sec. ON

8
Note: The On/Off time ratio does not exactly correspond
to the percentage of microwave power, because
approx. 3 seconds are needed for heating up the
magnetron filament.
GRILL COOKING CONDITION
TOP GRILL (Figure O-3a)
In this condition the food is cooked by the top grill heating
element . Rotate the COOKING MODE dial to GRILL
setting. And enter the desired cooking time by rotating the
TIME/WEIGHT dial. When the START button is pressed,
the following operations occur:
1. The numbers on the digital readout start the count
down to zero.
2. The oven lamp, cooling fan motor and turntable motor
are energized.
3. The relay RY3 is energized and the main supply
voltage is applied to the top grill heating elements.
4. Now, the food is cooked by the top grill heating ele-
ments.
NOTE: The convection cooking condition will be carried
out simultaneously until the temperature of the
oven cavity rise to 220˚C.
CONVECTION COOKING CONDITION
PRE-HEATING (by 40˚C - 130˚C)
Rotate the COOKING MODE dial to the convection
setting. And programme the desired convection tem-
perature of 40˚C - 130˚C by touching CONVECTION
button. When the START button is touched, the following
operations occur:
1. The relays RY1, RY6 and RY7 are energized, the oven
lamp, turntable motor, fan motor and convection motor
are turned on.
2. The relay RY4 is energized and the main supply
voltage is applied to the convection heating element.
3. After the temperature of oven cavity rises to the se-
lected one, the oven will continue to turned the
convection heating element on and off to maintain the
temperature for 30 minutes.
PRE-HEATING (by 160˚C _250˚C)
Rotate the COOKING MODE dial to the convection
setting. And programme the desired convection tem-
perature of 160˚C - 250˚C by touching CONVECTION
button. When the START button is touched, the following
operations occur:
1. The relays RY1, RY6 and RY7 are energized, the oven
lamp, turntable motor, fan motor and convection motor
are turned on.
2. The relay RY4 and RY3 are is energized and the main
supply voltage is applied to the convection heating
element and the grill heating elements.
3. After the temperature of oven cavity rises to the se-
lected one, the oven will continue to turned the
convection heating element on and off to maintain the
temperature for 30 minutes. And simultaneously the
grill heating element will be operated at 10% power
output.
CONVECTION COOKING (by 250˚C)
Rotate the COOKING MODE dial to the convection
setting. And enter the cooking time by rotating the TIME/
WEIGHT dial. And select the desired cooking tempera-
ture 250˚C by pressing the CONVECTION button. When
the START button is pressed, the following operations
occur:
1. The relays RY1, RY6 and RY7 are energized, the oven
lamp, turntable motor, fan motor and convection motor
are turned on.
2. The relay RY4 and RY3 are energized and the main
supply voltage is applied to the convection heating
element and the grill heating element.
3. The oven will continue to turn the convection heating
element on and off to maintain the temperature for the
programmed cooking time. And simultaneously the
grill heating elements will be operated at 10% power
output.
CONVECTION COOKING (by 40˚C _230˚C)
Rotate the COOKING MODE dial to the convection
setting. And enter the cooking time by rotating the TIME/
WEIGHT dial. And select the desired cooking temperature
40˚C - 230˚C by pressing the CONVECTION button.
When the START button is pressed, the following opera-
tions occur:
1. The relays RY1, RY6 and RY7 are energized, the oven
lamp, turntable motor, fan motor and convection motor
are turned on.
2. The relay RY4 is energized and the main supply
voltage is applied to the convection heating element.
3. The oven will continue to turned the convection heating
element on and off to maintain the temperature for the
programmed cooking time.
DUAL COOKING CONDITION
MICROWAVE AND CONVECTION (Figure O-5a)
Rotate the COOKING MODE dial to DUAL 1 setting.
And enter the desired cooking time by rotating the TIME/
WEIGHT dial. And press POWER LEVEL button to set the
desired microwave power. And press the CONVECTION
button to set the cooking temperature. When the START
button is pressed, the following operations occur:
NOTE: The 100% microwave power level can not be
selected.
When the START button is touched, the following opera-
tions occur:
1. The numbers on the digital read-out start the count
down to zero.
2. The oven lamp, fan motor, turntable motor and con-
vection motor are energized.
3. The relay RY4 will be energized and the main supply
voltage is applied to the convection heating element.
4. The relay RY2 is energized and the microwave energy
is generated by magnetron.
5. Now, the food is cooked by microwave and convection
energy simultaneously.
MICROWAVE AND TOP GRILL (Figure O-5b)
Rotate the COOKING MODE dial to DUAL 2 setting.
And enter the desired cooking time by rotating the TIME/
WEIGHT dial. And press POWER LEVEL button to set the
desired microwave power. When the START button is
pressed, the following operations occur:
1. The numbers on the digital read-out start the count
OPERATION SEQUENCE

9
down to zero.
2. The oven lamp, fan motor and turntable motor are
energized.
3. The relay RY3 is energized and the main supply
voltage is applied to the grill heating elements.
4. The relay RY2 is energized and the microwave energy
is generated by magnetron.
5. Now, the food is cooked by microwave and grill simul-
taneously.
ON/OFF TIME RATIO
In dual cooking, the magnetron operate within a 48 second
time base. The following table is the ON / OFF time ratio
at each power output of the magnetron.
POWER OUTPUT 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.
AUTOMATIC COOKING
Auto Cook functions automatically work out the correct
cooking mode and cooking time and/or cooking tempera-
ture. They will cook according to the special cooking
sequence.
POWER OUTPUT REDUCTION
After the same cooking mode is carried out for more than
the basis cooking time, the power output is automatically
reduced by turning the control relays on and off intermit-
tently, as shown in the table below. This is to protect the
oven door against temperature rising.
FAN MOTOR OPERATION (in Grill, Convection
and Dual mode)
When oven is stopped during cooking, or after the cooking
is completed, the fan motor will operate if the oven cavity
temperature is above 120˚C, and the fan motor will stop if
the oven cavity temperature is below 105˚C.
CONVECTION MOTOR OPERATION
If the temperature of oven cavity is higher than 120˚C
after and when operated by 250˚C convection cooking,
250˚C dual convection cooking or 250˚C preheating, the
convection motor will operate for maximum 1 minute until
the oven cavity temperature drops below 105˚C.
ON/OFF TIME RATIO
In grill cooking, convection cooking or dual cooking, the
top heater, bottom heater or magnetron operate within a
48 second time base. The following table is the ON / OFF
time ratio at each power output of the top heaters, bottom
heater or magnetron.
Basis cooking Reduced power Time base
Cooking mode time (minutes) output (%) (seconds)
Microwave (100%) 20 70 32
Grill 15 70 48
Convection No reduction
Micro. (70%) 40 (Micro.) 50 48
+ Grill 15 (Grill) 50 48
Micro. (100%) 15 (Micro.) 50 48
+ Grill 15 (Grill) 50 48
Micro. (70%) 40 (Micro.) 50 48
+ Conv. No reduction
NOTE:
1. If the multiple sequence cooking is carried out in the
same mode, the basis cooking time is calculated from
the first.
2. Even if the cooking is stopped by the STOP button or
opening the door, the basis cooking time is calculated
from the first.
3. If the same cooking mode is repeated within 1 minute
and 15 seconds, the basis cooking time is calculated
from the first.
4. If the same menu of automatic cooking is repeated
within 1 minute and 15 seconds, the power output of
the microwave or the grill will be reduced to 70% after
20 minutes when the oven is started at first.
D
U
A
L
OPERATION SEQUENCE

10
Figure D-1. Door Open Mechanism
MONITORED LATCH SWITCH SW1
1. When the oven door is closed, the contacts (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.
STOP SWITCH SW2
1. When the oven door is closed, the contacts (COM-NO)
of the switch must be closed.
2. When the oven door is opened, the contacts (COM-
NO) of switch must be opened.
MONITOR SWITCH SW3
The monitor switch is activated (the contacts opened) by
the upper latch head on the door while the door is closed.
The switch is intended to render the oven inoperative by
means of blowing the fuse F2 F8A when the contacts of
the monitored latch switch SW1 fail to open when the door
is opened.
Function
1. When the door is opened, the contacts (COM-NC) of
monitor switch SW3 close (to the ON condition) due to
their being normally closed and contacts (COM-NO)
open. At this time the contacts (COM-NO) of monitored
latch switch SW1 is in the OFF condition (contacts
open)due totheir beingnormally opencontactswitches.
2. As the door goes to a closed position, the monitor
switch SW3 contacts (COM-NC) are opened and con-
tacts (COM-NO) closed and then contacts (COM-NO)
of monitored latch switch SW1 and stop switch SW2
areclosed.(On openingthe door,each ofthese switches
operate inversely.)
3. If the door is opened and the monitored latch switch
SW1 contacts (COM-NO) fail to open, the fuse F2
(F8A) blows immediately after closing of the monitor
switch SW3 (COM-NC) contacts.
CAUTION: BEFORE REPLACING A BLOWN FUSE F2
F8A, TEST THE MONITORED LATCH
SWITCH SW1 AND MONITOR SWITCH
SW3 FOR PROPER OPERATION. (REFER
TO CHAPTER “TEST PROCEDURE”).
FUSE F1 20A 250V
If the wire harness or electrical components are short-
circuited, this fuse F1 20A blows to prevent an electric
shock of fire hazard.
FUSE F2 F8A 250V
1. If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or
fire hazard.
2. The fuse also blows when the monitored latch switch
SW1 remains closed with the oven door open and
when the monitor switch SW3 contact (COM-NC)
closes.
3. The fuse also blows when the asymmetric rectifier,
H.V. rectifier,.H.V. wire harness, H.V. capacitor,
magnetron or secondary winding of high voltage trans-
former is shorted.
TC TRANSFORMER
T/C transformer converts A.C. line voltage into low voltage
to drive the control unit.
THERMAL CUT-OUT TC1 125˚C (MG)
This thermal cut-out protects the magnetron against over-
heat. If the temperature goes up higher than 125˚C be-
cause the fan motor is interrupted or the ventilation open-
ings are blocked, the thermal cut-out TC1 will open and
switch off all the electrical parts. The defective thermal
cut-out must be replaced with a new one.
THERMAL CUT-OUT TC2 170˚C (GRILL)
This thermal cut-out protects the oven against the over-
heat during grill cooking, convection cooking or dual
cooking. If the temperature rises above 170˚C because
the fan motor is interrupted, the air inlet duct is blocked or
the ventilation openings are obstructed, the thermal cut-
out TC2 opens and switches off all the electrical parts.
When the cools itself down to the operating temperature of
155˚C, the contacts of the thermal cut-out will close again.
THERMAL CUT-OUT TC3 170˚C (CONV.)
Thisthermalcut-out protects the convection motor against
the overheat. If the temperature of the thermal cut-out TC3
rises above 170˚C because the convection fan is inter-
rupted, the ventilation openings are obstructed or the
other abnormal matter occurs, the thermal cut-out opens
and switches off the convection heating element and the
other electrical parts. When the cools itself down to the
operating temperature of 155˚C, the contacts of the ther-
mal cut-out will close again.
FUNCTION OF IMPORTANT COMPONENTS
Latch hook
Door
SW2: Stop switch
Latch
Heads
SW3: Monitor switch
SW1: Monitored
latch switch
Tab
DOOR OPEN MECHANISM
The door can be opened by puiiing the door handle.
When the door handle is pulled, the latch head is moved
upward, and released from the latch hook now the door
can be opened.

11
ASYMMETRIC RECTIFIER
The asymmetric rectifier is solid state device that prevents
current flow in both directions. And it prevents the tem-
perature rise of the high voltage transformer by blowing
the fuse F2 F8A when the high voltage rectifier is shorted.
The rated peak reverse voltage of D1 of the asymmetric
rectifier is 6 KV. The rated peak reverse voltage of D2 of
the asymmetric rectifier is 1.7 KV. D1 and D2 of the
asymmetric rectifier or high voltage rectifier are shorted
when the each peak reverse voltage goes beyond the
each rated peak reverse voltage. (The process of the
blowing the fuse F2 F8A.)
1. The high voltage rectifier is shorted by some fault when
microwave cooking or dual cooking.
2. The peak reverse voltage of D2 of the rectifier goes
beyond the rated peak reverse voltage 1.7 KV in the
voltage doubler circuit.
3. D2 of the rectifier is shorted.
4. The large electric currents flow through the high volt-
age winding of the high voltage transformer.
5. The large electric currents beyond 8A flow through the
primary winding of the high voltage transformer.
6. The fuse F2 F8A blows by the large electric currents.
7. The power supplying to the high voltage transformer is
cut off.
NOISE FILTER
The noise filter assembly prevents radio frequency inter-
ference that might flow back in the power circuit.
TURNTABLE MOTOR TTM
The turntable motor rotates 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 surrounding
the magnetron and cools the magnetron. This air is chan-
nelled through the oven cavity to remove steam and
vapours given off from heating food. It is then exhausted
through the exhausting air vents of the oven cavity.
CONVECTION MOTOR CM
The convection motor drives the convection fan and
provides the heated air.
GRILL HEATING ELEMENT GH
The grill heating elements are provided to brown the food
and are located on the top of the oven cavity.
CONVECTION HEATING ELEMENT CH
The convection heating element situated at the rear of the
oven cavity. It is intended to heat air driven by the
convection fan. The heated air is kept in the oven and
force-circulated and reheated by the convection heating
element.
D2 D1
ASYMMETRIC
RECTIFIER HIGH VOLTAGE
RECTIFIER
CONVECTION COOKING SYSTEM
This oven is designed with a hot air heating system where
food is heated by forced circulation of the hot air produced
by the grill heaters. The air heated by the grill heating
elements is circulated through the convection passage
provided on the outer casing of the oven cavity by means
of the convection fan which is driven by the convection
motor. It is then enters the inside of the oven through the
vent holes provided on the back side of the oven. Next, the
hot air heats the food on the turntable and leaves the oven
cavity through the vent in the oven cavity rear wall. In this
way, the hot air circulates inside the oven cavity to raise its
temperature and, at the same time, comes into contact
with the food being cooked. When the temperature inside
the oven cavity reaches the selected temperature, the
heating elements are de-energized. When the tempera-
ture inside the oven cavity drops below the selected
temperature, the heating elements are energized again. In
this way, the inside of the oven cavity is maintained at
approximately the selected temperature. When the con-
vection time reaches “0”, the heating elements are de-
energized and the convection fan stops operating and the
oven shuts off. At that time if the cavity air temperature has
raisen above 120˚C, the fan motor remains rotating.
Automatically the fan motor will be shut down at low
temperature (less than 105˚C).
Figure D-2. Convection Cooking System
FIRE SENSING FEATURE
The oven will stop its operation when there is a fire in the
oven cavity in microwave cooking condition.
LSI measures the voltage across the temperature meas-
urement circuit intermittently within 32-seconds time base
since the oven is started in microwave cooking condition.
The oven will stop its operation when the difference of the
voltage is more than 0.39 volts in microwave cooking
condition.
1. Within a 32-seconds base, the thermistor is energized
for 2 seconds. At that time, the voltage across the
temperature measurement circuit is measured.
2. The oven carries out the procedure above again. If the
second voltage is 0.39V higher than first voltage, LSI
judges it is a fire in the oven cavity and stop the oven.
3. When LSI judges it is a fire in the oven cavity, LSI will
switch off the relays to high voltage transformer and fan
motor and LSI stops counting down.
Door Oven Cavity Grill Heating Elements Convection
Passage
Cooling
Fan
Convection
Motor
Convection
Fan
Turntable
Turntable Motor
Roller Stay
Convection
Heating Element
FUNCTION OF IMPORTANT COMPONENTS

12
OPEN JUDGE BY THERMISTOR
1. If the temperature of the thermistor does not rise to
more than 40˚C after 4 minutes and 15 seconds from
when the oven is started in convection, grill or dual
cooking mode, the oven is turned off.
2. When the thermistor or the wire harness to the ther-
mistor is opened, the oven is turned off after 4 minutes
and 15 seconds because this condition is same as
above.
DAMPER OPEN-CLOSE MECHANISM
Damper position is set automatically by damper motor
DM, damper switch and motor cam.
These components are operated by a signal that judges
if microwave cooking or convection cooking operation is
selected by the CPU unit.
Microwave Cooking:
Damper is in the open position, because a portion of
cooling air is channelled through the cavity to remove
steam and vapours given off from the heating foods.
It is then exhausted at the top of the oven cavity into a
condensation compartment.
Convection Cooking:
Damper is in the closed position, so that no hot air will be
allowed to leak out the oven cavity.
Damper Operation
1. When power supply cord is plugged in or when the
control unit resumes after energy save mode finishes:
1-1. When power supply cord is plugged in, a signal is
sensed in the control unit, and operates shut-off
relay (RY8).
1-2. Contacts of shut-off relay (RY8) close, the damper
motor DM is energized, opening the damper door.
1-3. When the damper is moved to the open position by
the damper cam, damper switch SW4 is closed (ON
position).
1-4. The signal of damper switch SW4 is re-sensed in the
control unit and shut-off relay (RY8) is turned off.
1-5. The rated voltage to the damper motor DM is stopped
and the motor turns off.
2. When oven is microwave cooking:
Damper is in the open position
3. When oven is convection cooking:
3-1 Damper motor DM is energized right after the oven is
started.
3-2. When damper is in the closed position (damper
switch SW4 is OFF), its signal is sensed by the control
unit, and shut-off relay (RY8) is de-energized.
3-3. The damper is held in the closed position during the
convection cooking operation.
3-4. At the end of the convection cooking, when the fan
motor FM stops, shut-off relay (RY8) is energized,
and the damper is returned to the open position.
NOTE: If the damper door is not in the proper position,
closed during convection, grill or dual, or open
during microwave, the control unit will stop oven
operation after 1 minute.
4. Operation of damper is shown below.
Cooking Mode Operation of Damper
Microwave cooking Open
Convection cooking Closed
Grill; during backed up with
convection heating element Closed
Grill; after convection heating
element backed up has stopped Open
Dual (Microwave and Convection) Closed
Dual (Microwave and Grill) Open
Fire sensing condition Closed
When troubleshooting the microwave oven, it is helpful to
followthe SequenceofOperation in performingthe checks.
Many of the possible causes of trouble will require that a
specific test be performed. These tests are given a proce-
dure letter which will be found in the “Test Procedure”
section.
TROUBLESHOOTING GUIDE
IMPORTANT: If the oven becomes inoperative because
of a blown fuse F2 (F8A) in the monitored
latch switch SW1 - monitor switch SW3
circuit, check the monitored latch switch
SW1 and monitor switch SW3 before re-
placing the fuse F2 (F8A).
OPERATION SEQUENCE
THERMISTOR
Sensing
Voltage
ON
OFF
ON
OFF
30 32 (sec.)
Sensing the voltage across temperature measurement circuit.

13
Fuse F2 (F8A) blows when the door is opened. Home fuse blows when power cord is plugged into wall outlet. Fuse F1 20A blows when power cord is plugged into wall outlet. Nothing appears in display when power cord is plugged into wall outlet and the door is opened and closed. Display does not operate properly when STOP button is pressed. Oven lamp does not light when door is opened. (Display operates.) Oven does not start when the START button is pressed. (Display operates.) Oven lamp does not light and turntable motor does not operate. Fan motor does not operate. (Oven lamp lights.) Convection fan motor does not operate. (Fan motor operates.) Turntable motor does not operate. (Oven lamp lights.) Oven or any electrical parts (except fan motor) does not stop when cooking time is 0 or STOP button is pressed. Oven stops after 4 minutes and 15 seconds since START button is pressed. (Except Microwave mode and Dual cook mode) Display operates properly but all electrical parts do not operate. Oven goes into cook cycle but shuts down before end of cooking cycle. After cooking, the temperature of oven cavity is higher than 120˚C but
fan motor does not operate. The oven stops 1 minute after starting. Oven seems to be operating but little or no heat is produced in oven load. (Microwave power control is set at 100%) Oven does not seem to be operating properly during variable cooking condition except 100% cooking condition.
Oven goes into cook cycle but shuts down before end of cooking cycle. Convection cooking mode does not heat. Oven seems to be operating but the temperature in the oven cavity is lower or higher than preset one. Grill heating element does not operate. 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. (Microwave power does not seem to be generated properly) Oven seems to be operating but the temperature in the oven cavity is lower or higher than preset one. Convection heating elements do not heat. Grill heating element does not heat.
OFF
CONDITION
COOKING
CONDITION
(COMMON MODE)
MICROWAVE
COOKING
CONDITION
GRILL COOKING
CONDITION
CONVECTION
COOKING
CONDITION
DUAL COOKING
CONDITION
(COMMON MODE)
DUAL COOKING
CONDITION
(MICRO./CONV.)
DUAL COOKING
CONDITION
(MICRO./GRILL)
CONDITION
PROBLEM
BLOCKED COOLING FAN
BLOCKED CONVECTION FAN
NO POWER AT WALL OUTLET
HOME FUSE OR BREAKER
MIS-ADJUSTMENT OF SWITCHES
BLOCKED VENTILATION OPENINGS
OPENED WIRE HARNESS
SHORTED WIRE HARNESS
OVEN LAMP OR SOCKET
POWER SUPPLY CORD
FOIL PATTERN ON P.W.B.
RELAY RY8
RELAY RY7
RELAY RY6
RELAY RY5
RELAY RY4
RELAY RY3
RELAY RY2
RELAY RY1
KEY UNIT
TOUCH CONTROL PANEL
TC TRANSFORMER
CONVECTION HEATING ELEMENT
GRILL HEATING ELEMENT
FUSE F2 F8A
FUSE F1 20A
NOISE FILTER
DAMPER MOTOR DM
CONVECTION FAN MOTOR
FAN MOTOR FM
TURNTABLE MOTOR TM
THERMAL CUT-OUT 170˚C TC3
THERMAL CUT-OUT 170˚C TC2
THERMAL CUT-OUT 125˚C TC1
THERMISTOR
DAMPER SWITCH SW4
MONITOR SWITCH SW3
STOP SWITCH SW2
MONITORED LATCH SWITCH SW1
HIGH VOLTAGE CAPACITOR
H.V. HARNESS
H.V. RECTIFIER ASSEMBLY
HIGH VOLTAGE TRANSFORMER
MAGNETRON
ABC DEEEEFGGGHHH H
TEST PROCEDURE
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
I J K L L MN OOOOO OOO P
TROUBLESHOOTING GUIDE

14
AMAGNETRON TEST
CARRY OUT 3D CHECKS.
Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal.
To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron
filament terminals, the meter should show a reading of less than 1 ohm.
To test for short filament to anode condition, connect ohmmeter between one of the filament terminals
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 60705, 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. Select the initial and final water temperature so that the maximum difference between the final water
temperature and the ambient temperature is 5K.
5. Select stirring devices and measuring instruments in order to minimize addition or removal of heat.
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”is measured while the microwave generator is operating at full power. Magnetron filament heat-
up time is not included.
NOTE: The operation time of the microwave oven is “t + 3”sec. (3 sec. is magnetron filament heat-
up time.)
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.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
The formula is as follows;
P x t / 4.187 = V x ∆T+ 0.55 x mc (T2-T0) P (W) = 4.187 x V x ∆T / t + 0.55 x mc (T2-T0)/t
Our condition for water load is as follows:
Room temperature (T0) ... around 20°C Power supply Voltage .............. Rated voltage
Water load..................................1000 g Initial temperature (T1) ...................... 10±1°C
Heating time .............................. 47 sec. Mass of container (mc) ......................... 330 g
T2 ............................ Final Temperature P = 90 x ∆T + 0.55 x mc (T2-T0)/47

15
Room temperature ....................... To = 21˚C Initial temperature ..................... T1 = 11°C
Temperature after (47 + 3) = 50 sec. ..................................................................... T2 = 21°C
Temperature difference Cold-Warm.................................................................... ∆T1 = 10°C
Measured output power
The equation is “P = 90 x ∆T”...................................................... P = 90 x 10°C = 900 Watts
JUDGMENT: The measured output power should be at least ±15 % of the rated output power.
CAUTION: 1°C CORRESPONDS TO 90 WATTS. REPEAT MEASUREMENT IF THE POWER IS
INSUFFICIENT.
1000g
1000g
1000g
T1˚CT2˚C
Heat up for 50 sec
BHIGH VOLTAGE TRANSFORMER TEST
WARNING: High voltage and large currents are present at the secondary winding and
filamentwindingofthehighvoltagetransformer. It is very dangerous to work
near this part 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
using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C of the high
voltage rectifier and note the reading obtained. Reverse the meter leads and note this second reading.
The normal resistance is infinite in one direction and more than 100 kΩin the other direction.
CARRY OUT 4R CHECKS.
ASYMMETRIC RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The asymmetric rectifier can be tested
using an ohmmeter set to its highest range across the terminals A+B of the asymmetric rectifier and
note the reading obtained. Reverse the meter leads and note this second reading. If an open circuit is
indicated in both directions then the asymmetric rectifier is good. If the asymmetric rectifier is shorted
ineitherdirection,then the asymmetric rectifier is probably faulty and must be replaced with high voltage
rectifier. When the asymmetric rectifier is defective, check whether magnetron, high voltage rectifier,
high voltage wire or filament winding of the high voltage transformer is shorted.
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF
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 Ω
b. Secondary winding .......................... approximately 127 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.
AB
C
D2 D1
ASYMMETRIC
RECTIFIER
HIGH VOLTAGE RECTIFIER
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST

16
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 TC1 125˚C This is not resetable Above 125˚C Closed circuit
Thermal cut-out TC2 170˚C Below 155˚C. Above 170˚C Closed circuit
Thermal cut-out TC3 170˚C Below 155˚C. Above 170˚C Closed circuit
If incorrect readings are obtained, replace the thermal cut-out.
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. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ
after 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. The resistance across all the terminals and the chassis must be infinite when the capacitor is
normal.
If incorrect reading are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS.
ESWITCH TEST
Table: Terminal Connection of Switch
Plunger Operation COM to NO COM to NC
Released Open circuit Short circuit
Depressed Short circuit Open circuit
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.
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in
the following table.
F THERMISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect theconnector B from CPU unit. Measure the resistance of the thermistor with an ohmmeter.
Connect the ohmmeter leads to Pin No's C1 and C3 of the thermistor harness.
Room Temperature Resistance
20˚C - 30˚C Approximately 359.9 kΩ- 152 kΩ
If the meter does not indiicate above resistance, replace the thermistor.
CARRY OUT 4R CHECKS.
THE MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6 VOLTS, BE-
CAUSE OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIREC-
TIONS.
D HIGH VOLTAGE CAPACITOR TEST
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
GTHERMAL CUT-OUT TEST

17
An open circuit thermal cut-out (MG) TC1 indicates that the magnetron has overheated, this may be
due to resistricted ventilation, cooling fan failure.
An open circuit thermal cut-out (GRILL) TC2 indicates that the oven cavity has overheated, this may
be due to no load operation..
An open circuit thermal cut-out (CONV.) TC3 indicates that the convection fan winding has overheated,
this may be due to resistricted ventilation or locked cooling fan or locked convection fan motor.
CARRY OUT 4R CHECKS.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
HMOTOR 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.
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 293 Ω
Turntable motor Approximately 15 kΩ
Convection fan motor Approximately 288 Ω
Damper motor Approximately 11 kΩ
JBLOWN FUSE F1 20A
INOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of noise filter.
Using an ohmmeter, check between the terminals as
described in the following table.
CARRY OUT 3D CHECKS.
If the fuse F1 20A is blown, there is a shorts or grounds in electrical parts or wire harness. Check them
and replace the defective parts or repair the wire harness.
CARRY OUT 4R CHECKS.
CAUTION: Only replace fuse with the correct value replacement.
KBLOWN FUSE F2 F8A
CARRY OUT 3D CHECKS.
1. If the fuse F2 F8A is blown when the door is opened, check the monitored latch switch SW1 and
monitor switch SW3.
2. If the fuse F2 F8A is blown by incorrect door switching replace the defective switch(es) and the fuse
F2 F8A.
Cx
Cy
R2
R1
L
L
WHT
RED
20A
F8A
N
L
F1
F2
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 absorbed, replace the noise filter unit.
CARRY OUT 4R CHECKS.
L (min) Cx ±20% Cy ±20% R1 R2
1.0mH 0.22µF 4700pF 10MΩ680kΩ

18
MCONTROL PANEL ASSEMBLY TEST
The control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike
conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and
ohmmeter.
In this service manual, the control panel assembly is divided into two units, Control Unit and Jog and
Switch Unit, and also the control unit is divided into two units, CPU unit and Power unit, and
troubleshooting by replacement is described according to the symptoms indicated.
1. Jog and Switch Unit Note : Check Jog and Switch unit wire harness connection before replacement.
The following symptoms indicate a defective Jog and Switch unit. Replace the Jog and Switch unit.
1-1. Tact switch
a) When touching the buttons, a certain button produces no signal at all.
b) When touching the buttons, sometimes a button produces no signal.
1-2. Potentiometer
a) When rotating the potentiometer, the cooking mode can not be selected.
1-3. Encoder
a) When rotating the encoder, the cooking time or the weight of food can not be entered.
2. Control Panel
The following symptoms indicate a defective control unit. Before replacing the control unit.
perform the Jog and Switch unit test (Procedure N) to determine if control unit is faulty.
2-1 In connection with buttons
a) When touching the buttons, a certain group of buttons do not produce a signal.
b) When touching the buttons, no buttons 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 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.
3. If the fuse F2 F8A is blown, there could be shorts in the asymmetric rectifier or there is a ground
in wire harness. A short in the asymmetric rectifier may be occurred due to short or ground in H.V.
rectifier, magnetron, high voltage transformer or H.V. wire. Check them and replace the defective
parts or repair the wire harness.
CARRY OUT 4R CHECKS.
CAUTION: Only replace fuse F2 F8A with the correct value replacement.
LGRILL HEATING ELEMENTS (TOP) AND CONVECTION HEATING ELEMENT TEST
CARRY OUT 3D CHECKS.
Before carrying out the following tests make sure the heating element is cool completely.
1. Resistance of heating element.
Disconnect the wire leads to the heating element to be tested. Using ohmmeter with low resistance
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 elements GH (top) Approximately 44.4 Ω(22.2 Ωx 2)
Convection heating element CH Approximately 42.5 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 start.
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
PROCEDURE
LETTER COMPONENT TEST