Sharp R-733W User manual

SHARP CORPORATION
SERVICE MANUAL
S04273R733EHW
In interests of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.
GRILL AND
MICROWAVE OVEN
TABLE OF CONTENTS
Page
CAUTION MICROWAVE RADIATION, WARNING ............................................................. INSIDE COVER
GENERAL IMPORTANT INFORMATION .................................................................................................. 1
SERVICING ................................................................................................................................................ 2
PRODUCT SPECIFICATIONS ................................................................................................................... 5
APPEARANCE VIEW ................................................................................................................................. 6
OPERATION SEQUENCE .......................................................................................................................... 7
FUNCTION OF IMPORTANT COMPONENTS .......................................................................................... 8
TEST PROCEDURE ................................................................................................................................. 10
TOUCH CONTROL ASSEMBLY .............................................................................................................. 18
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ..................................................... 22
TEST DATA AT A GLANCE ..................................................................................................................... 26
MICROWAVE MEASUREMENT .............................................................................................................. 27
SCHEMATIC DIAGRAMS ......................................................................................................................... 28
PICTORIAL DIAGRAM ............................................................................................................................. 30
CONTROL PANEL CIRCUIT .................................................................................................................... 31
PRINTED WIRING BOARD DIAGRAM ................................................................................................... 32
PARTS LIST ............................................................................................................................................. 33
EXPLODED VIEW OF OVEN ....................................................................................................................36
CONTROL PANEL /DOOR PARTS ...........................................................................................................37
MISCELLANEOUS/PACKING AND ACCESSORIES ................................................................................38
R
MODELS
R-733
COOK & DEFR
COOK & DEFR
OST
OST
KG
R-733(W/B)
R-733(Y/LB/LG/W)F

CAUTION
MICROWAVE RADIATION
Personnel should not be exposed to the mircowave energy which may radiate from the magnetron or
other microwave generating devices if it is improperly used or connected. All input and output micro-
wave connections, waveguides, flanges and gaskets must be secured. Never operate the device with-
out a microwave energy absorbing load attached.
Never look into an open waveguide or antenna while the device is energised.
VARNING
MIKROVAGSSTRALING
Personal får inte utsättas för mikrovågsenergi som kan utstrala 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 en
öppen vågledare eller antenn när mikrovågsgeneratorn är påkopplad eller laddad.
VAROITUS
MIKROAALTOSATEILYA
Käyttäjä ei saa joutua alttiiksi mikroaaltoenergialle, jota voi säteillä magnetronista tai muusta
mikroaaltoja kehittävästä laitteesta, jos sitä käytetään väärin tai jos se kytketään väärin. Kaikkien
mikroaaltoliitäntöjen sekä syöttö-että ulostulopuolella, aaltoputkien laippojen ja tiivisteiden tulee olla
varmistettuja.
Mikroaaltouunia ei koskaan saa käyttää ilman kuormaa jossa mikroaaltoenergiaa kuluu. Avoimeen
aaltoputkeen tai antenniin ei koskaan saa katsoa virran ollessa kytkettynä.
ADVARSEL
MIKRØBOLGESTRÅLING
Personell må ikke utsettes for mikrobølge-energi som kan utstråles 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
MIKRØBOLGEBESTRALING
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 mikrobølgeabsorberende anordning. Se aldrig ind i en åben bølgeleder
eller antenne, mens ovnen er i brug.

1
R-733 -
SERVICE MANUAL
GRILL AND MICROWAVE OVEN
R-733(W/B)/ 733(W/Y/LB/LG/)F
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.
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 voltages more than 250V.
Removal of the outer wrap gives access to potentials 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.
Never operate the Grill 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 a fire.
SHARP CORPORATION
OSAKA, JAPAN

2
R-733 -
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 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
WARNING :-BEWARE OF THE HIGH-VOLTAGE
CAPACITOR CHARGE
The high-voltage capacitor remains charged for about
60 seconds after the oven has been switched off. Wait for
60 seconds and then short-circuit the connection of the
high-voltagecapacitor(thatis, the connecting lead of the
high-voltagerectifier)against the chassis,usinga screw-
driver with an insulated handle.
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 power
transformer,before connecting the supply. 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.
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 component 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 carried out.
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.
NL
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 stopcontact is gehaald. Soms is het
nodig 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 deprimaire zijde vande
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
nogmaalsdeaansluitingennaardegetesteonderdelen.
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.
WARNING TO SERVICE PERSONNEL
SERVICING

3
R-733 -
SERVICING
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.
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.
E
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.
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) till chassiet
med hjälp av en isolerad skruvmejsel.
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.
Mikrovågsugnarfår inteanvändastomma. 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
kontrolleraranslutningarnatillvarje enskildkomponent
på nytt.
När all service är klar och ugnen ihopskruvad skall
ugnens uteffekt och eventuellt mikrovågsläckage
kontrolleras.

4
R-733 -
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.
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.
I
When troubleshooting the microwave oven, it is helpful
to follow the Sequence of Operation in performing the
checks. Many of the possible causes of trouble will
requirethata specific test beperformed.These tests are
given a procedure 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.
SERVICING

5
R-733 -
PRODUCT SPECIFICATIONS
ITEM DESCRIPTION
Power Requirements 230 Volts
50 Hertz
Single phase, 3 wire grounded
Power Consumption Microwave cooking 1.52 kW Approx. 7.1 A
Grill cooking 1.25 kW Approx. 5.3 A
Dual cooking 2.7 kW Approx. 12.4 A
Power Output 900W watts nominal of RF microwave energy
(measured by way of IEC 705) Operating frequency of 2450 MHz
Grill Heating Element Power Output 1200W (600W x 2)
Case Dimensions Width 520mm
Height 305mm including foot
Depth 413mm
Cooking Cavity Dimensions Width 342mm
Height 207mm
Depth 368mm
Turntable diameter 325mm
Control Complement Jog Touch Control
Clock(1:00-12:59 or 0:00-23:59)
Timer (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
FUNCTION KEYS:
AUTO COOK key
MODE key
STOP key,
ROTARY knob
MINUTE PLUS/START key
Set Weight Approx. 18.7 kg
SPECIFICATION
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
R-733 -
Low rack
1. Place the roller stay on the coupling.
2. Then place the turntable on it.
High rack
AUTO-TOUCH CONTROL PANEL
APPEARANCE VIEW
1. Display Window
2. Key Button
3. Start Button
4. Rotary Knob
5. Door Open Button
3
5
2
1
4
1. Door
2. Door hinges
3. Grill Guide
4. Lamp filter
5. Waveguide cover
6. Contol panel
7. Coupling
8. Door open button
9. Door latches
10. Oven cavity
11. Safety door latches
12. Ventilation openings
13. Outer case
14. Rear back plate
15. Power supply cord
KG
R-733F
COOK & DEFROST
KG
R-733
COOK & DEFROST
OVEN

7
R-733 -
OFF CONDITION
Closing the door activates all door interlock switches
(monitored latch switch and stop switch).
IMPORTANT
When the oven door is closed, the monitor switch contacts
COM - NC must be open.
When the microwave oven is plugged in a wall outlet
(230V 50Hz), the line voltage is supplied to the point
A1+A3 in the control unit.
Figure O-1 on page 28
1. The display flashes "88:88”.
2. To set any programmes or set the clock, you must first
touch the STOP pad.
3. “:”appears in the display.
NOTE: When the oven door is opened, the oven lamp
comes on at this time.
MICROWAVE COOKING CONDITION
HIGH COOKING
Enter a desired cooking time with the ROTARY knob and
start the oven by touching START button.
Function sequence Figure O-2 on page 28
CONDITION
DURING DOOR OPEN
SWITCH CONTACT COOKING (NO COOKING)
Monitored latch switch COM-NO Closed Open
Monitor switch COM-NC Open Closed
COM-NO Closed Open
Stop switch COM-NO Closed Open
The circuits to the power transformer, fan motor and
turntable motor are cut off when the primary latch
switch and stop switch 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 the remaining time.
6. MONITOR SWITCH CIRCUIT
The monitor switch SW2 is mechanically controlled by
oven door, and monitors the operation of the
monitored latch switch SW1
6-1 When the oven door is open during or after the
cycle of cooking program, the monitored latch and
stop switches SW1 + SW3 must open their contacts
first. After that the contacts (COM - NC) of the
monitor switch SW2 can be closed.
6-2 When the oven door is closed, the contacts
(COM - NC) of the monitor switch SW2 must be
opened. After that contacts of the monitored latch
and stop switches SW1 + SW3 are closed.
6-3 When the oven door is opened and the contacts of
the monitored latch switch SW1 remain closed, the
fuse F8A will blow, because the monitor 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 power
transformer intermittently within a 48-second time base
through the relay contact which is coupled with the
current-limiting relay RY3. The following levels of
microwave power are given.
SETTING
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.
CONNECTED COMPONENTS RELAY
Oven lamp, Fan motor, Turntable motor RY1
Grill heater RY2
Power transformer RY3
1. The line voltage is supplied to the primary winding of
the power 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 wave length 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 single tone is heard
and the relays RY1 + RY3 go back to their home
position. The circuits to the oven lamp, power
transformer, fan motor and turntable motor are cut off.
5. When the door is opened during a cook cycle, the
switches come to the following condition.
OPERATING SEQUENCE
48 sec. ON
36 sec. ON
26 sec. ON
16 sec. ON
8 sec. ON
12 sec. OFF
22 sec. OFF
32 sec. OFF
40 sec. OFF
HIGH
MEDIUM
HIGH
MEDIUM
MEDIUM
LOW
LOW
Approx. 70% = 630Watts
Approx. 50% = 450Watts
Approx. 30% = 270Watts
Approx. 10% = 90Watts
Approx100% = 900Watts

8
R-733 -
DOOR OPEN MECHANISM
The door can be opened by pushing the door open button
on the control panel. When the door open button is pushed,
the open lever is moved upward, operating the latch head.
The latch head is moved upward, and released from the
latch hook. Now, the door can be opened.
Figure D-1. Door Open Mechanism
MONITORED LATCH SWITCH SW1
STOP SWITCH SW3
1. When the oven door is closed, the contacts (COM - NO)
must be closed.
2. When the oven door is opened, the contacts (COM - NO)
must be opened.
MONITOR SWITCH SW2
1. When the oven door is closed, the contacts (COM - NC)
must be opened and the contacts (COM - NO) must be
closed.
2. When the oven door is opened, the contacts (COM - NC)
must be closed and the contacts (COM - NO) must be
closed.
3. If the oven door is opened and the contacts (COM - NO)
of the monitored latch switch SW1 fail to open, the fuse F1
F8Ablowssimultaneously with closing the contacts(COM
- NC) of the monitor switch SW2.
CAUTION: BEFORE REPLACING A BLOWN FUSE F1 F8
TEST THE MONITORED LATCH SWITCH SW1
AND MONITOR SWITCH SW2 FOR PROPER
OPERATION. (REFER TO CHAPTER ”TEST
PROCEDURE”.)
GRILL COOKING CONDITION
In this condition the food is cooked by grill heater energy.
Program desired cooking time and grill mode using MODE
button and ROTARY knob. When the START button is
touched, the following operations occur:
Figure O-3 on page 29
1. The relay RY1 and RY2 are energized.
2. The numbers of the digital readout start the count down
to zero.
3. Then the grill heating elements, turntable motor, oven
lamp and fan motor are energized.
4. Now , the food is grilled by the grill heater.
5. Upon completion of the selected cooking time, audible
signal sounds, and contacts of relays are opened, then
the activated components as item 4 are de-energized.
DUAL COOKING CONDITION
In this condition the food is cooked by both microwave
energy and grill heating elements energy simultaneously.
Figure O-4 on page 29
1. The contact of monitored latch switch SW1 are closed.
2. The relay RY1, RY2 and RY3 are energized.
3. The numbers of the digital readout start the count down
to zero.
4. Then following components are energized.
Power transformer Grill heating elements
Magnetron Turntable motor
H.V. capacitor Fan motor
H.V. rectifier Oven lamp
5. Now, the food is cooked by microwave and grill heating
elements energy simultaneously.
6. Upon completion of selected cooking time, audible signal
sounds, and contacts of relays are opened, then the
activated components as item 4 are de- energized.
7. When cooking in dual mode the microwave power is
limited to 70% (via the I.C.).
AUTO COOK PROGRAMME
Keep on touching the AUTO COOK pad until the desired
cooking programme appears in the display. Then using the
ROTARY knob, enter the weight and touch the START
button.The cookingmodesand cookingtimeare automatically
computed and selected based on the programmes.
OPERATING SEQUENCE
FUNCTION OF IMPORTANT COMPONENTS
LATCH
HEADS
LATCH HOOK MONITOR
SWITCH (SW2)
MONITORED
LATCH
SWITCH (SW1)
STOP
SWITCH
(SW3)
DOOR OPEN BUTTON
OPEN LEVER
DOOR

9
R-733 -
FUSE F1 F8A 250V
This fuse blows when monitored latch switch SW1 remains
closed with the oven door open and when the contacts
(COM + NC) of monitor switch SW2 closes.
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 blows when the asymmetric rectifier, H.V.
rectifier, H.V. wire harness, H.V. capacitor, magnetron or
secondary winding of power transformer is shorted.
SPECIAL FUSE F2 15A
If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or fire
hazard.
THERMAL CUT-OUT 125°C TC1 (MG)
The thermal cut-out protects the magnetron against
overheating. If this temperature goes up higher than 125°C
because the fan motor is interrupted, or the ventilation
openings are blocked, the thermal cut-out TC1 will open
and line voltages to the power transformer T1 will be cut off
and the operation of the magnetron MG will be stopped. The
defective thermal cut-out TC1 must be replaced with a new
one.
THERMAL CUT-OUT 160°C TC2 (OVEN)
The thermal cut-out located on the top the oven cavity is
designed to prevent damage to the oven if the foods in the
oven catch fire due to over heating produced by improper
setting of cook time or failure of control unit. Under normal
operation, the oven thermal cut-out remains closed.
However, when abnormally high temperatures are reached
within the oven cavity, the oven thermal cut-out will open at
160°C, causing the oven to shut down. The defective
thermal cut-out TC2 must be replaced with new one.
TURNTABLE MOTOR
The turntable motor drives the turntable roller assembly to
rotate the turntable.
FAN MOTOR
The fan motor drives a blade which draws in external cool
air.Thiscool air isdirectedthroughthe air vanessurrounding
the magnetron and cools the magnetron. This air is then
channeled through the oven cavity to remove steam and
vapoursgiven off from heating the food. It is then exhausted
through the exhaust air vents at the rear of the oven cavity.
NOISE FILTER
The noise filter prevents any radio frequency interference
that might flow back in the power circuit.
GRILL HEATING ELEMENT (GH)
The grill heating element GH is located on the top of the
oven cavity assembly. The grill heating element emits heat
to grill foods.
ASYMMETRIC RECTIFIER
The asymmetric rectifier is a solid state device that prevents
current flow in both directions. And it prevents the tempera-
ture rise of the power transformer by blowing the fuse F1
when the high voltage rectifier is shorted.
AB
C
D2 D1
ASYMMETRIC
RECTIFIER
HIGH VOLTAGE RECTIFIER
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
rectifieror high voltage rectifier are shorted when each peak
reversevoltagegoes beyondtheratedpeak reversevoltage.
The process of blowing the fuse F1 will blow during a
fault condition.
1. The high voltage rectifier is shorted circuited during
microwave cooking.
2. The peak reverse voltage of D2 of the rectifier goes
beyond the rated peak reverse voltage of 1.7 KV in the
voltage doubler circuit.
3. D2 of the rectifier then breaks down and short-circuits.
4. A large electric current then flows through the high
voltage winding of the power transformer.
5. A large electric current >10A flows through the primary
winding of the power transformer.
6. The fuse F1 blows due to its 8A current rating.
7. The power supply to the power transformer is cut off.
FUNCTION OF IMPORTANT COMPONENTS

10
R-733 -
PROBLEM
Fuse F2 15A blows when power
cord is plugged into wall outlet.
Fuse F8A blows when the door
is opened.
Oven lamp does not light when door
is opened. (Display appears.)
Home fuse blows when power
cord is plugged into wall outlet.
“88:88”does not appear in display
when power cord is plugged into
wall outlet.
Display does not operate properly
when STOP pad is touched.
Oven does not start when START
pad is touched. (Display appears.)
Oven lamp does not light.
(Turntable motor operates.)
Fan motor does not operate. (Oven
lamp light.)
Turntable motor assembly does not
operate. (Oven lamp light.)
Oven or electrical parts do not stop
when cooking time is 0 or STOP
pad is touched.
Oven goes into cook cycle but
shuts down before end of cooking
cycle.
Oven stops as soon as the START
pad is touched. (Except for Grill
Cooking)
Oven seems to be operating but
little or no heat is produced in oven
load. (Microwave power level is set
at ”HIGH”)
Oven does not operate properly
during the variable cooking condition
except ”HIGH”cooking condition.
(Oven operates properly at HIGH)
Oven goes into cook cycle but shuts
down before end of cooking cycle.
Grill Heating element does not
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 does not
operate.
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
TEST PROCEDURE
CONDITION
OFF
CONDITION
COOKING
CONDITION
(COMMON)
MICROWAVE
COOKING
CONDITION
GRILL
COOKING
CONDITION
H
.
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TEST PROCEDURES
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11
R-733 -
TEST PROCEDURES
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL
WHILE THE OVEN IS IN OPERATION.
PROCEDURE
LETTER COMPONENT TEST
AMAGNETRON TEST
CARRY OUT 3D CHECK
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 considered faulty and 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. the temperature of a water load is measured to see how much energy is absorbed in a
given time. To measure the microwave output power in the microwave oven, the relation between the
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.
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°C Power supply Voltage.........Rated voltage
Water load.........1000 g Initial temperature...........10 ±2°C Heating time ...47+3=50 sec.
P = 90 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 of 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 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 seconds is the 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.

12
R-733 -
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.
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 Approx.
JUDGMENT: The measured output power should be within at least ±15 % of the rated output
power.
CAUTION: 1°C CORRESPONDS TO 90 WATTS. REPEAT MEASUREMENT IF THE POWER IS
INSUFFICIENT.
CARRY OUT 3D CHECKS
Disconnect the leads to the primary winding of the power 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 windings. The following readings should be obtained:-
a. Primary winding ............ 1.9 ohms approximately
b. Secondary winding .......13 ohms approximately
c. Filament winding ...........less than 1 ohm
If the reading obtained are not stated above, then the power transformer is probably faulty and should
be replaced.
CARRY OUT 4R CHECKS
PROCEDURE
LETTER COMPONENT TEST
HIGH 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.
WARNING: High voltages and large currents are present at the secondary winding and
filament winding of the power transformer. 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.
BPOWER TRANSFORMER TEST
Heat up for 50 sec.
CHIGH VOLTAGE RECTIFIER ASSEMBLY TEST
1000g
1000g
1000g
T1˚CT2˚C
TEST PROCEDURES

13
R-733 -
PROCEDURE
LETTER COMPONENT TEST
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. Connect the ohmmeter 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 an
asymmetric rectifier is shorted in either direction, then the asymmetric rectifier is faulty and must be
replaced along with the high voltage rectifier. When the asymmetric rectifier is defective, check whether
the magnetron, high voltage rectifier, high voltage wire or filament winding of the power transformer is
is also damaged.
CARRY OUT 4R CHECKS
NOTE: FOR MEASURING THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF THE
MEASURING INSTRUMENT MUST HAVE A VOLTAGE OF AT LEAST 6 VOLTS, BECAUSE
OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
AB
C
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 very short time (kick) and then a resistance of about 10 MΩ
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 10 MΩ
resistance.
F. When the internal wire is opened in the high voltage capacitor, the 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 readings are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS
DHIGH VOLTAGE CAPACITOR 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
Table: Terminal Connection of Switch
Plunger Operation COM to NO COM to NC
Released Open circuit Short circuit
Depressed Short circuit Open Circuit
If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.
CARRY OUT 4R CHECKS.
AB
C
D2 D1
ASYMMETRIC
RECTIFIER
HIGH VOLTAGE RECTIFIER
TEST PROCEDURES

14
R-733 -
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
FTHERMAL CUT OUT TEST
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.
CARRY OUT 4R CHECKS
Table: Thermal Cut-out Test
PARTS NAME THERMAL CUT-OUT THERMAL CUT-OUT
Condition 125°C (MAG) 160°C (OVEN)
Temperature of ”ON”condition This is not resetable type This is not resettable type
(closed circuit)
Temperature of ”OFF”condition Above 125°C Above 160°C
(open circuit)
Indication of ohmmeter (When room Closed circuit Closed circuit
temperature is approx. 20°C.)
If incorrect readings are obtained replace the thermal cut-out.
An open circuit thermal cut-out (MG) indicates that magnetron has overheated, this may be due to
restricted ventilation, cooling fan failure or a fault condition within the magnetron or HV circuit.
An open circuit thermal cut-out (OVEN) indicates that the foods in the oven may catch fire, this may be
due to over heating produced by improper setting of the cooking timer or failure of the control panel.
An open circuit thermal cut-out (GRILL) indicates that the oven cavity has overheated, this may be due
to no load operation.
CARRY OUT 3D CHECKS
If the fuse F1 F8A is blown when the door is opened, check the monitored latch switch and monitor
switch.
If the fuse F1 F8A is blown by incorrect door switching replace the defective switch(s) and the fuse F1
F8A
BLOWN FUSE F1 F8A
If the fuse F1 is blown, there could be a short in the asymmetric rectifier or there is a ground in wire
harness. A short in the asymmetric rectifier may have occured due to short or ground in H.V. rectifier,
magnetron, power 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 with the correct value replacement.
CARRY OUT 3D CHECKS
If the fuse 15A is blown, there could be 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 15A with the correct value replacement
GBLOWN FUSE 15A F2
HBLOWN FUSE F8A F1

15
R-733 -
PROCEDURE
LETTER COMPONENT TEST
INOISE FILTER TEST
CARRY OUT 3D CHECKS
Disconnect the leads from the terminals of
the noise filter.
Using an ohmmeter, check between the
terminals as described in the following table.
MEASURING POINTS INDICATION OF OHMMETER
Between N and L Approx. 680K ohm
Between terminal N and WHITE Short circuit
Between terminal L and RED Short circuit
R1: 10M ohm ±20%
R2: 680K ohm ±20%
L(min) Cx ±20% Cv ±20%
1.0mH 0.22µF 0.0047µF
KMOTOR 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 300Ω
Turntable motor Approximately 14.5kΩ
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS
LGRILL HEATING ELEMENT TEST
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.
CARRY OUT 3D CHECKS
Before carrying out the following tests make sure the heating element is cool completely.
1. Resistance of heating element
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 10MΩin 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 sholud be replaced.
CARRY OUT 4R CHECKS
If incorrect readings are obtained, replace the noise filter unit.
CARRY OUT 4R CHECKS
Table: Resistance of heating element
Parts name Resistance
Grill heating element Approximately 22.5Ωx 2 = 45Ω
RED
WHT
L
L
R1
L
F8A
R2
N
Cx Cy
TEST PROCEDURES

16
R-733 -
PROCEDURE
LETTER
MTOUCH CONTROL PANEL ASSEMBLY TEST
COMPONENT TEST
The touch 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 touch control panel assembly is in one unit and troubleshooting by unit
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. 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.
4. Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Cooking is not possible.
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.
N TACT SWITCH TEST
ORELAY TEST
Remove the outer case and check voltage between Pin No. 1 and Pin No. 3 of the 3 pin connector (A)
on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, if not check oven circuit.
RY1, RY2 and RY3 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated............. 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. 24.0V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 Approx. 18.0V D.C. Heating element
RY3 Approx. 18.0V D.C. High voltage transformer
TEST PROCEDURES

17
R-733 -
PROCEDURE
LETTER COMPONENT TEST
PPROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the
PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide 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)
4 Pattern 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 burn-
ingdamageandexaminethetransformer
withtesterforthepresenceoflayer short-
circuit (check primary coil resistance). If
any abnormal condition is detected, re-
place the defective parts.
CARRY OUT 4R CHECKS.
RY2
OL / FM
/ TTM
AC
51
D20
VRS1
a
b
d
c
CN - A
D21 RY1
(J1)
T1
TEST PROCEDURES

18
R-733 -
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units as
shown in the touch control panel circuit.
The principal functions of these units and the signals com-
municated among them are explained below.
Tact Switch
Signals R60, R61, R62 and R63 generated in the LSI are
sent to the tact switches.
When a tact switch is touched, a signal is completed through
the tact switch and passed back to the LSI through R53 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 and indicator circuit.
1) LSI
This LSI controls the tact switch strobe signal, relay
driving signal for oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unite.
Symbol Voltage Application
VC +5V 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.
4) ACL Circuit
A circuit to generate a signals which resets the LSI to the
initial state when power is supplied.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion sound).
6) Door Sensing Switch
A switch to "tell" the LSI if the door is open or closed.
7) Relay Circuit
To drive the magnetron, fan motor, turntable motor, grill
heating element and 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
The encoder converts the signal generated by LSI into the
pulse signal, and the pulse signal is returned to the LSI.
10) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LED1-LED4)
TOUCH CONTROL PANEL ASSEMBLY