Sharp R-204 User manual

R-204(W)
TABLE OF CONTENTS Page
CAUTION, MICROWAVE RADIATION.................................................................................................... 1
WARNING.................................................................................................................................................1
SERVICING ............................................................................................................................................. 2
PRODUCT SPECIFICATIONS .................................................................................................................5
GENERAL INFORMATION.......................................................................................................................5
APPEARANCE VIEW .............................................................................................................................. 6
OPERATION SEQUENCE........................................................................................................................7
FUNCTION OF IMPORTANT COMPONENTS ....................................................................................... 8
TROUBLESHOOTING GUIDE .................................................................................................................9
TEST PROCEDURE.............................................................................................................................. 10
CONTROL PANEL ASSEMBLY ............................................................................................................15
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE.................................................. 18
MICROWAVE MEASUREMENT ........................................................................................................... 24
TEST DATA AT A GLANCE .................................................................................................................. 25
WIRING DIAGRAM................................................................................................................................ 25
PICTORIAL DIAGRAM .......................................................................................................................... 26
CONTROL PANEL CIRCUIT ..................................................................................................................27
PRINTED WIRING BOARD ....................................................................................................................28
PARTS LIST .......................................................................................................................................... 29
S8102R204PHW/
MICROWAVE OVEN
MODEL R-204(W)
Ininterests ofuser-safety theovenshouldberestoredto its original
conditionandonlypartsidenticaltothosespecifiedshouldbeused.
SERVICE MANUAL
SHARP CORPORATION
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R-204(W)
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 påfel 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
Käyttäjäei saa joutua alttiiksi mikroaaltoenergialle, jota voi säteillämagnetronista tai
muusta mikroaaltoja kehittävästälaitteesta, jos sitäkäytetään tai jos se kytketään väärin.
Kaikkien mikroaaltoliitäntöjen sekäsyöttö-ettäulostulopuolella, 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 måikke 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 måfestes 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 måvære forsvarligt udført.
Anvend aldrig ovnen uden en mikrobølgesabsorberende anordning. Se aldrig ind i en
åben bølgeleder eller antenne, mens ovnen er i brug.

R-204(W)
1
WARNING
Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is not any other visible damage with the oven.
Servicing and repair work must be carried out only by trained
service engineers.
Removal of the outer wrap gives access to potential above 250V.
All the parts marked "∆" on the parts list may cause undue
microwave exposure, by themselves, or when they are dam-
aged, loosened or removed.
SHARP CORPORATION
OSAKA, JAPAN
SERVICE MANUAL
MICROWAVE OVEN
R-204(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.
WARNING
Note: Thepartsmarked"*"areusedatvoltagemore
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.
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
R-204(W)
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
WARNING: AGAINST THE CHARGE OF THE HIGH-
VOLTAGE CAPACITOR
The high-voltage capacitor remains charged about 60 sec-
onds after the oven has been switched off. Wait for 60
seconds and then short-circuit the connection of the high-
voltagecapacitor(that is, oftheconnecting lead ofthehigh-
voltage rectifier) against the chassis with the use of an
insulated screwdriver.
Sharp recommend that wherever possible fault-finding is
carried out with the supply disconnected. It may in, some
cases, be necessary to connect the supply after the outer
casehasbeenremoved,inthiseventcarryout3Dchecksand
then disconnect the leads to the primary of the power trans-
former. Ensure that these leads remain isolated from other
components and the oven chassis. (Use insulation tape if
necessary.) When the testing is completed carry out 3D
checks and reconnect the leads to the primary of the power
transformer.
SERVICING
WARNING TO SERVICE PERSONNEL
GB Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts will
result in electrocution.
High voltage capacitor, Power transformer, Magnetron, High voltage rectifier assembly, High voltage harness.
REMEMBER TO CHECK 4R
1) Reconnectallleadsremovedfromcomponentsduring
testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
Microwave ovens should not be run empty. To test for the
presence of microwave energy within a cavity, place a cup of
cold water on the oven turntable, close the door and set the
powertoHIGHandsetthemicrowavetimerfortwo(2)minutes.
When the two minutes has elapsed (timer at zero) carefully
check that the water is now hot. If the water remains cold carry
out 3D checks and re-examine the connections to the compo-
nent being tested.
When all service work is completed, and the oven is fully
assembled,themicrowavepoweroutputshouldbecheckedand
a microwave leakage test 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.Somsishetnodigomdestroomtoevoer
weer tot stand te brengen nadat de buitenmantel verwijderd
is. Herhaal dan de bovengenoemde 3 stappen en haal de
electrische draden uit de primaire zijde van de
vermogenstransformator. Zorg ervoor dat deze draden
geïsoleerd blijven van andere elementen en van het chassis
van de oven. (Gebruik zo nodig isolatieband.) Wanneer de
test is uitgevoerd, herhaalt u de bovenstaande 3 stappen en
verbindt u de electrische draden weer aan de primaire zijde
van de vermogenstransformator.
VERGEET DE VOLGENDE 4 STAPPEN NIET
1) Sluit de draden weer aan diezijn losgehaald voor de test.
2) Plaatsdebuitenmantelweeromhettoestelheen(kabinet).
3) Stop de stekker weer in het stopcontact.
4) Zet de oven aan. Controleer alle functies.
Magnetronovens mogen niet leeg aangezet worden. Om te
controleren of er microgolf-energie binnen de oven wordt
geproduceerd, plaatst u een mok met koud water op de
draaitafel van de oven, sluit de deur, zet de oven op HIGH en
steltdeklokvandemagnetroninoptwee(2)minuten.Wanneer
de twee minuten voorbij zijn (klok staat op nul), controleert u
voorzichtig of het water heet is. Indien het water nog steeds
koud is, herhaalt u de allereerste drie stappen en controleer
nogmaals de aansluitingen naar de geteste onderdelen.
Wanneer alle reparaties zijn uitgevoerd en de oven weer in
elkaar is gezet, moet de het magnetronvermogen worden
gecontroleerd en moet worden gecontroleerd of er geen
microgolflekkage is.

R-204(W)
3
E Los hornos de microondas contienen circuitos eléctricos capaces de producir voltajes de alta tensión y descargas
eléctricas.Para evitar el riesgo deelectrocución, absténgasede tocar los siguientes componentes:condensador dealta
tensión, transformador de alta tensión, magnetrón, dispositivo del rectificador de alta tensión y arnés de alta tensión.
RECUERDE LA COMPROBACION 3D
1) Desconecte la alimentación.
2) Deje la puerta abierta y calzada.
3) Descargue el condensador de alto voltaje.
ADVERTENCIA SOBRE LA CARGA DEL
CONDENSADOR DEALTO VOLTAJE
El condensador de alto voltaje permanece cargado unos
60 segundos después de haber apagado el horno. Espere
60segundos y luego ponga en cortocircuito laconexión del
condensador de alto voltaje (esto es, del conductor de
conexión del rectificador de alto voltaje) al chasis con un
destornillador de mango aislado.
Se recomienda encarecidamente que siempre que sea
posiblela localizaciónde fallosse realicecon laalimentación
desconectada. Puede ser que en algunos casos sea
necesarioconectarla alimentación despuésdehaber retirado
lacarcasa exterior.En estecaso, 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
unacavidad, coloque una taza deagua fríaen el plato giratorio
del horno, cierre la puerta y ponga la potencia en HIGH (alta)
y coloque el temporizador en dos (2) minutos. Cuando
transcurranlos dos minutos(temporizador a cero) compruebe
cuidadosamente que el agua se ha calentado. Si el agua
permaneciese fría, efectúe las comprobaciones 3D y vuelva a
examinar las conexiones de los componentes que han sido
probados.
Cuandohaya terminadola 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)tillchassietmedhjälpavenisolerad
skruvmejsel.
Sharp rekommenderar att felsökning sker med strömmen
fränkopplad. Ibland kan det var nödvändigt att koppla på
strömmen efter det att höljet avlägsnats, utför da 3 Steg
kontrollen och koppla sedan från ledarna till transformatorns
primärsida. Se till att ledarna är isolerade från andra
komponenter och chassiet. (Använd isoleringsband om det
behövs). När Du testat färdigt utför Du 3 Steg kontrollen och
ansluter ledningarna till transformatorns primärsida igen.
KOM IHÅG ATT KONTROLLERA 4 STEG
1) Anslut alla ledningar som använts vid testning
2) Sätt tillbaka ytterhöljet.
3) Anslut strömkällan på nytt.
4) Sätt på ugnen. Kontrollera alla funktioner.
Mikrovågsugnar får inte användas tomma. Kontrollera
mikrovågsstrålningen i olika delar av ugnen genom att placera
en kopp med kallt vatten på ugnens tallrik, stäng dörren, ställ
inHIGHochställin2minuterpåtimern.Närtvåminuterhargått
(timemvisar0)kontrollerardu 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.

4
R-204(W)
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
60secondidopolospegnimento delforno. Occorrequindi
spettare 60 secondi prima di cortocircuitare, utilizzando
un cacciavite con impugnatura isolata, il collegamento
del condensatore ad alta tensione (cioè del conduttore
di collegamento del raddrizzatore ad alta tensione) sul
telaio del forno.
Sharp raccomanda, nei limiti del possibile, che la ricerca
dei guasti avvenga in assenza di alimentazione elettrica.
In alcuni casi tuttavia, può essere necessario alimentare
l'apparecchio dopo aver rimosso la scatola esterna. In
questo caso eseguire i tre controlli sopra citati e quindi
scollegare i connettori dal primario del trasformatore.
Assicurarsiche tali connettori non vengano acontattocon
altri componenti, ne con il telaio del forno (fare uso, se
necessario, di nastro isolante). Al termine dell'intervento,
eseguirenuovamente itre controllie ricollegarei conduttori
al primario del trasformatore.
QUATTRO VERIFICHE IMPORTANTI DA NON
DIMENTICARE
1) Ricollegaretutti i conduttori staccati dai varicomponenti
durante l'intervento.
2) Rimontare la scatola esterna.
3) Ripristinare l'alimentazione elettrica.
4) Rimettereinfunzioneil forno.Controllare tuttele funzioni.
Iforni a microonde non devono mai funzionare avuoto.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
erimontato ilforno, è necessariocontrollare lapotenza delle
microonde emesse ed eseguire un test per verificare che
non vi sia alcuna dispersione.

R-204(W)
5
PRODUCT DESCRIPTION
SPECIFICATION
ITEM DESCRIPTION
Power Requirements 230 Volts
50 Hertz
Single phase, 3 wire earthed
Power Consumption 1.18 kW
Power Output 800 W nominal of RF microwave energy (measured by method of IEC 60705)
Operating fequency 2450 MHz
Case Dimensions Width 460 mm
Height 275 mm including foot
Depth 353 mm
Cooking Cavity Dimensions Width 322 mm
Height 187 mm
Depth 336 mm
Turntable diameter 272 mm
Control Complement Timer (0 - 30 minutes)
Microwave Power for Variable Cooking
Repetition Rate;
800W .....................................Full power throughout the cooking time
560W ....................................................... approx. 70% of Full Power
400W ....................................................... approx. 50% of Full Power
240W ....................................................... approx. 30% of Full Power
80W ......................................................... approx. 10% of Full Power
Set Weight Approx. 12 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

6
R-204(W)
APPEARANCE VIEW
OVEN
1. Control panel
2. Door opening button
3. Waveguide cover
4. Seal packing
5. Oven cavity
6. Door
7. Door safety latch
CONTROL PANEL
12
13
11
1
8
9
3
2
10
476 5
8. Door hinges
9. Door seals and sealing surfaces
10.Safety door latches
11.Ventilation openings
12.Outer case
13.Power cord
Timer (0 - 30 Min.)
Light display.
Microwave power control.
Door opening button.
Menu guide.
These are the cooking guides for 1 serve.
Use 800W power level
Turntable
Roller stay
Seal packing
1. Place the roller stay on the floor of the oven cavity,
engaging shaft into turntable motor shaft.
2. Then place the turntable on the roller stay.

R-204(W)
7
OPERATION SEQUENCE
OFF CONDITION
Closingthedooractivatesalldoorinterlockswitches(1st.
interlock switch and 2nd. interlock relay control switch).
IMPORTANT
When the timer knob is at "0" the oven in the OFF
condition.
Whentheovendoorisclosed,themonitorswitchcontacts
(COM-NC) must be open.
When the microwave oven is plugged in a wall outlet
(230V 50Hz), the noise filter and the control panel are
energized.
Figure O-1 on page 25
MICROWAVE COOKING CONDITION
HIGH COOKING
When the door is closed, the contacts (COM-NO) of the
1st. interlock switch (SW1) and the monitor switch (SW2)
are closed. When the microwave power is set to 800W
positionbypressingthemicrowavepowerlevelbuttonand
cooking time is selected by turning the timer knob, the
following components are energized: H.V. transformer,
Magnetron, Oven lamp, Turntable motor and Fan motor.
Function sequence
Figure O-2 on page 25
CONNECTED COMPONENTS RELAY
Oven lamp, Fan motor, Turntable motor RY1
High voltage transformer RY2
1. The line voltage is supplied to the primary winding of
thehighvoltagetransformer. 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
magnetronfilamentandthehighvoltage(2000volts)is
sentto the voltage doublingcircuit, where it isdoubled
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
energyischannelledthroughthewaveguide(transport
channel)intotheovencavity,wherethefoodisplaced
to be cooked.
4. Whenthecookingtimeisup,asignaltoneisheardand
the relays RY1+RY2 open. The circuits to the oven
lamp, high voltage transformer, fan motor and turnta-
ble motor are cut off.
5. When the door is opened during a cook cycle, the
switches come to the following condition.
CONDITION
DURING DOOR OPEN
SWITCH CONTACT COOKING (NOCOOKING)
1st. interlock switch COM-NO Closed Open
Monitor switch COM-NC Open Closed
2nd. interlock relay
control switch COM-NO Closed Open
The circuits to the high voltage transformer, fan motor
turntablemotor,andtheovenlamparecutoffwhenthe
1st. interlock switch (SW1) and 2nd. interlock relay
control switch (SW3) are made open.
6. MONITOR SWITCH CIRCUIT
The monitor switch (SW2) is mechanically controlled
by oven door, and monitors the operation of the 1st.
interlock switch (SW1).
6-1 When the oven door is opened during or after the
cycle of a cooking program, the 1st. interlock switch
(SW1) and 2nd. interlock relay control switch (SW3)
must open their contacts first. After that the contacts
(COM-NC)ofthemonitorswitch(SW2)canbeclosed.
6-2. When the oven door is closed, the contacts (COM-
NC)ofthemonitorswitch(SW2)mustbeopenedfirst.
Afterthatthecontacts(COM-NO) ofthe1st. interlock
switch (SW1) and 2nd. interlock relay control switch
(SW3) are closed.
6-3. When the oven door is opened and the contacts
(COM-NO) of the 1st. interlock switch (SW1) remain
closed, the fuse F will blow, because the contacts
(COM-NC) of the monitor switch are closed and a
short circuit is caused.
560W, 400W, 240W, 80W 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-seconds time base
through the relay contact which is coupled with the cur-
rent-limitingrelay RY2. The followinglevels of microwave
power are given.
SETTING;
NOTE: The ON/OFF time ratio does not exactly corre-
spond to the percentage of microwave power,
because approx. 3 seconds are needed for heat-
ing up the magnetron filament.
POWER OUTPUT REDUCTION
After 100% power cooking mode is carried out for more
than20minutes,thepoweroutputisautomaticallyreduced
to 70%. Even if the cooking time is shorter than for 20
minutes, the power output is reduced to 70% after total
cooking time over 20 minutes when the oven is started in
100% power cooking mode again within 1 minute and 35
seconds.
32 sec. ON
Approx. 70%
100%
800W
560W
400W
240W
80W
24 sec. ON 8 sec. OFF
14 sec. OFF
10 sec. OFF
26 sec. OFF
Approx. 50%
18 sec. ON
Approx. 30%
12 sec. ON
Approx. 10%
6 sec. ON

8
R-204(W)
FUNCTION OF IMPORTANT COMPONENTS
If the food load is overcooked, by either error in cook time
ordefectinthecontrolunit,thetemperaturefusewillopen.
Under normal operation, the temperature fuse remains
closed.However,whenabnormallyhightemperaturesare
reached within the oven cavity, the temperature fuse will
open at 248˚F(120˚C), causing the oven to shut down.
TURNTABLE MOTOR (TTM)
Theturntablemotordrivestheturntablerollerassemblyto
rotate the turntable.
FAN MOTOR (FM)
Thefanmotordrivesabladewhichdrawsexternalcoolair.
This cool air is directed through the air vents 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 at the rear of the oven
cavity.
NOISE FILTER
The noise filter assembly prevents radio frequency inter-
ference that might flow back in the power circuit.
DOOR OPEN MECHANISM
The door is opened by pushing the open button on the
control panel, refer to the Figure D-1.
Whenthe open buttonis pushed, theopen button pushes
up the switch lever, and then the switch lever pushes up
the latch head. The latch heads are moved upward and
released from latch hook. Now the door will open.
Figure D-1. Door Open Mechanism
IST. INTERLOCK SWITCH (SW1) AND 2ND. IN-
TERLOCK RELAY CONTROL SWITCH (SW3)
1. Whentheovendoorisclosed,thecontacts(COM-NO)
must be closed.
MONITOR SWITCH (SW2)
1. Whentheovendoorisclosed,thecontacts(COM-NC)
must be opened.
2. When the oven door is opened, the contacts (COM-
NC) must be closed.
3. Ifthe oven door is opened and hecontacts (COM-NO)
of the ist. interlock switch (SW1) fail to open, the fuse
F8Ablowsimmediatelyafterclosingthecontacts(COM-
NC) of the monitor switch (SW2).
CAUTION: BEFORE REPLACING A BLOWN FUSE F1
TESTIST.INTERLOCKSWITCH(SW1)AND
MONITOR SWITCH (SW2) FOR PROPER
OPERATION. (REFERTOCHAPTER“TEST
PROCEDURE”).
FUSE (F1)
1. ThefuseF1blowswhenthecontacts(COM-NO)ofthe
1st.interlockswitch(SW1)remainclosedwiththeoven
door open and when the contacts (COM-NC) of the
monitor switch (SW2) are closes.
2. If the wire harness or electrical components are short-
circuited, the fuse F8A blows to prevent an electric
shock or fire hazard.
HIGH VOLTAGE FUSE (F2)
Thehighvoltagefuseblowswhenthehighvoltagerectifier
or the magnetron is shorted.
TEMPERATURE FUSE (TF)
The temperature fuse, located on the top of the oven
cavity, is designed to prevent damage to the oven by fire.
Latch Heads
Latch Hook
Door
SW3:
2nd. Interlock Relay
Control Switch
SW2:
Monitor Switch
Switch Lever SW1:
1st. Interlock
Switch

R-204(W)
9
When troubleshooting the microwave oven, it is helpful to
followtheSequenceofOperationinperformingthechecks.
Many of the possible causes of trouble will require that a
specifictestbe performed. These tests are given a proce-
dure letter which will be found in the “Test Procedure”
section.
IMPORTANT: If the oven becomes inoperative because
ofablownfuseF1.Checktheist.interlock
switch (SW1), monitor switch(SW2) and
2nd. interlock relay (RY2) before replac-
ing the F1 fuse.
TROUBLESHOOTING GUIDE
CONDITION PROBLEM
ABCD EEE FG H IIJKLLM
Home fuse blows when power cord
is plugged into wall outlet.
Fuse F8A blows when power cord
is plugged into wall outlet. (Timer
off)
Oven does not operate at all.
Timer is not set but when door
closed, oven starts operation.
Oven does not start when timer
knob is turned, door closed.
Oven lamp does not light, when in
operation.
Fan motor does not operate.
Turntable motor assembly does
not operate.
Oven or electrical parts does not
stop when timer knob is at "0".
Oven seems to be operating but
little or no heat is produced in oven
load. (Microwave power level is set
at 800W.)
Oven does not operate properly during
the variable cooking condition except
800w cooking condition.
Oven goes into cook cycle but
shuts down before end of cooking
cycle.
Oven stops as soon as the oven is
started.
Fan motor, oven lamp and
turntable motor do not operate at
the same time.
OFF
CONDITION
COOKING
CONDITION
TEST PROCEDURE
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
MAGNETRON HIGH VOLTAGE TRANSFORMER H.V. RECTIFIER HIGH VOLTAGE CAPACITOR 1ST. INTERLOCK SWITCH (SW1) 2ND. INTERLOCK RELAY CONTROL SWITCH (SW3) MONITOR SWITCH (SW2) TEMPERATURE FUSE 120˚C FUSE F1 NOISE FILTER FAN MOTOR TURNTABLE MOTOR POWER SUPPLY CORD OVEN LAMP SHORTED WIRE HARNESS OPENED WIRE HARNESS MIS-ADJUSTMENT SWITCHES NO POWER AT WALL OUTLET HIGH VOLTAGE FUSE CONTROL UNIT RELAY RY1 RELAY RY2 FOIL PATTERN ON P.W.B.

10
R-204(W)
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
AMAGNETRON TEST
CARRY OUT 3D CHECKS.
Isolate the magnetron from the high voltage circuit by removing all leads connected to the filament
terminal.
Totestforanopencircuitfilamentuseanohmmetertomakeacontinuitytestbetweenthemagnetron
filament terminals, the meter should show a reading of less than 1 ohm.
To test for a short circuit filament to anode condition, connect ohmmeter between one of the filament
terminalsand the case of themagnetron(ground).Thistestshouldbe indicated an infinite resistance.
If a low or zero resistance reading is obtained then the magnetron should be replaced.
MICROWAVE OUTPUT POWER (IEC60705)
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 IEC
testprocedure,i.e. it can bemeasuredby using water load howmuch it can be absorbedbythe water
load. 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.
The formula is as follows;
P x t / 4.187 = V x ∆T+ 0.55 x mc (T2-T0)/4.187 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.............................. 52 sec. Mass of container (mc) ......................... 330 g
T2............................ Final Temperature P = 80 x ∆T + 0.55 x mc (T2-T0)/52
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. Selecttheinitialandfinalwatertemperaturesothatthemaximumdifferencebetweenthefinalwater
temperature and the ambient temperature is 5˚C.
5. Selectstirringdevicesandmeasuringinstrumentsinordertominimize additionorremoval ofheat.
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”ismeasuredwhilethemicrowavegenerator 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 ˚C.
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.

R-204(W)
11
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
Room temperature ....................... To = 21˚C Initial temperature .................... T1 = 11°C
Temperature after (52 + 3) = 55 sec. ..................................................................... T2 = 21°C
Temperature difference Cold-Warm ................................................................... ∆T1 = 10°C
Measured output power
The equation is “P = 80 x ∆T”...................................................... P = 80 x 10°C = 800 Watts
JUDGEMENT: The measured output power should be at least ±15 % of the rated output power.
CAUTION: 1°C CORRESPONDS TO 80 WATTS. REPEAT MEASUREMENT IF THE POWER IS
INSUFFICIENT.
Heat up for 55 sec.
BHIGH VOLTAGE TRANSFORMER TEST
WARNING: High voltage and large currents are present at the secondary winding and
filamentwindingofthehighvoltagetransformer.Itisverydangeroustowork
nearthis part when the oven is on.NEVERmake any voltage measurements
of the high-voltage circuits, including the magnetron filament.
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 .......................... 2.4 ohms approximately
b. Secondary winding .................... 185 ohms approximately
c. Filament winding..................................... less than 1 ohm
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.
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 of the high
voltagerectifier andnotethereading obtained.Reversethemeter leads andnotethissecond reading.
The normal resistance is infinite in one direction and more than 100 kΩin the other direction.
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF
THEMEASURINGINSTRUMENTMUSTHAVEAVOLTAGEATLEAST6VOLTS,BECAUSE
OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
CARRY OUT 3D CHECKS.
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.
DHIGH VOLTAGE CAPACITOR TEST
1000g
1000g
1000g
T1˚CT2˚C

12
R-204(W)
FTEMPERATURE FUSE TEST
CARRY OUT 3D CHECKS.
A continuity check across the temperature fuse terminals should indicate a closed circuit unless the
temperature of the temperature fuse reaches approximately 248˚F(120˚C).
An open temperature fuse indicates overheating of the oven, exchange the temperature fuse and
checkinside of oven cavity and forimpropersettingofcookingtimeor operation of control unit.Check
forrestrictedairflowthroughtheventholesoftheovencavity,especiallythecoolingfanandairguide.
CARRY OUT 4R CHECKS.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
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, 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 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.
GBLOWN FUSE F1
CARRY OUT 3D CHECKS.
1. Ifthe fuseF1 isblown,there couldbeashorts or groundsinelectricalparts orwireharness.Check
them and replace the defective parts or repair the wire harness.
2. IfthefuseF1isblownwhenthedoorisopened,checkthe1st.interlockswitch(SW1),monitorswitch
(SW2) and 2nd. interlock relay (RY2).
IfthefuseF1isblownbyincorrectdoorswitchingreplacethedefectiveswitch(es)andthe fuseF8A.
CARRY OUT 4R CHECKS.
CAUTION: Only replace fuse with the correct value replacement.
HNOISE 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.

R-204(W)
13
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
MEASURING POINTS INDICATION OF OHMMETER
Between N and L Approx. 680 kΩ
Between terminal N and WHITE Short circuit
Between terminal L and RED Short circuit
If incorrect readings are obtained, replace the noise filter unit.
CARRY OUT 4R CHECKS.
IMOTOR 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 400 Ω
Turntable motor Approximately 12 kΩ
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
FUSE
M8A
F1:
NL
LINE CROSS CAPACITOR
0.068µ/AC250V
NOISE SUPPRESSION COIL
LINE BYPASS
CAPACITOR
0.0022µ/AC250V
LINE BYPASS
CAPACITOR
0.0022µ/AC250V
NOISE FILTER
WHT RED
CARRY OUT 3D CHECKS.
If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.
Check them and replace the defective parts and the high voltage fuse.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE REPLACE-
MENT.
JHIGH VOLTAGE FUSE TEST
KCONTROL PANEL ASSEMBLY TEST
Thecontrolpanelconsistsof circuitsincludingsemiconductorssuch asLSI,ICs, etc.Therefore,unlike
conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and
ohmmeter.
In this service manual, troubleshooting by replacement is described according to the symptoms
indicated.
1. Control Panel
The following symptoms indicate a defective control unit.
1-1 In connection with LEDs
a) At a certain LED, all or some LEDs do not light up.
b) At a certain LED, brightness is low.
c) Only one LED does not light up.
d) All or some LEDs continue to light up.
e) A certain group of LEDs do not light up.
f) The LEDs flicker.
1-2 Tact switch
a) When touching a tact switch, a tact switch produces no signal.
1-3 Other possible troubles caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Cooking is not possible.
c) Cooking time can not be set.
d) Power level can not be set.

14
R-204(W)
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
LRELAY TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin No. 3 of the 2 pin connector (A) and the
common terminal of the relay RY2 on the control unit with an A.C. voltmeter.
The meter should indicate 230 volts, if not check oven circuit.
Relay Test
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. 12.0V D.C. Oven lamp / Turntable motor / Fan motor
RY2 Approx. 11.0V D.C. High voltage transformer
CARRY OUT 4R CHECKS.
MPROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD(PWB) IS OPEN
Toprotecttheelectronic circuits,thismodelisprovidedwithafinefoilpatternaddedtothe inputcircuit
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 between Check supply voltage and oven power cord.
Pin No, 3 of the 2-pin connector CN-A and
the common terminal of the relay RY2.
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
burning damage and examine the
transformer with tester for the pres-
ence of layer short circuit (check pri-
mary coil resistance).
If any abnormal condition is detected,
replace the defective parts.
CARRY OUT 4R CHECKS.
VRS1
T1
P
1
RY1
a
b
c
d
CNA
3
J1

R-204(W)
15
Control Unit
ControlunitconsistsofLSI,powersourcecircuit,synchro-
nizing signal circuit, ACL circuit, buzzer circuit, encoder
circuit, indicator circuit and potentiometer circuit.
1) LSI
ThisLSIcontrolstheencodersignal,tactswitchstrobe
signal, relay driving signal for oven function, buzzer
signal and LED signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
Symbol Voltage Application
VC -5.0V LSI(I-1)
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
A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.
CONTROL PANEL ASSEMBLY
OUTLINE OF CONTROL PANEL
5) Buzzer Circuit
ThebuzzerisresponsivetosignalsfromtheLSItoemit
audible sounds (tact switch touch sound and comple-
tion sound).
6) 2nd. Interlock Relay Control Switch
A switch to "tell" the LSI if the door is open or closed.
7) Relay Circuit
Todrivethemagnetron,fanmotor,turntablemotorand
light the oven lamp.
8) Encoder
Theencodergeneratesthepulsesignal,andthepulse
signal is sent to the LSI.
9) Indicator Circuit
IndicatorelementsaretheLight-emittingdiodes(LD1-
LD24).
This circuit consists of 4-digits and 6 segments.
10) Potentiometer Circuit
Thecircuitmakessettingofthepowerlevelbyvariable
resistance.
DESCRIPTION OF LSI
LSI
The I/O signal of the LSI are detailed in the following table.
Pin No. Signal I/O Description
1 VDD IN Power source voltage: 0V.
Connected to 0V.
2 VSS IN Power source voltage: -5V.
Connected to -5V.
3 XIN IN Internal clock oscillation frequency input setting.
Theinternalclockfrequencyisgeneratedbyconnectingthecapacitorandresistor
to XIN.
4 XOUT OUT Terminal not used.
5 CNVSS IN Connected to VSS through resistor R5.
6 RESET IN Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied.
7 P21 IN Signal to synchronize LSI with commercial power source frequency.
This is basic timing for all real time
processing of LSI.
20 msec
H : GND
L : -5V

16
R-204(W)
Pin No. Signal I/O Description
8 P20 OUT Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2).
The signal holds "L" level during
microwave cooking and "H" level while
not cooking. In other cooking modes
(70%, 50%, 30%, 10%) the signal turns
to "H" level and "L" level in repetition
according to the power level.
9 D5 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD19 - LD24).
10 D4 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD13 - LD18).
11 D3 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD7 - LD12).
12 D2 OUT Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD6, LD12, LD18 and
LD24).
13 D1 OUT Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD5, LD11, LD17 and
LD23).
14 D0 OUT Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD4, LD10, LD16 and
LD22).
15 INT IN Signal coming from encoder.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into INT.
16 CNTR OUT Signal to sound buzzer.
Completion sound.
17 P11 IN Signal coming from encoder.
Signal similar to INT. Pulse signals are input into P11.
18 P10 OUT Oven lamp, turntable motor and fan motor driving signal (Square Waveform
: 50Hz).
To turn on and off shut-off relay (RY1). The
square waveform voltage is delivered to the
relay (RY1) driving circuit and relay(RY2)
control circuit.
19 P03 OUT Digit selection signal.
Signal is input to the anodes of the light-emitting diodes (LD1 - LD6).
20 P02 OUT Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD3, LD9, LD15 and
LD21).
21 P01 OUT Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD2, LD8, LD14 and
LD20).
22 P00 OUT Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD1, LD7, LD13 and
LD19).
23 AIN3 IN Signal coming from potentiometer.
ByinputtingDCvoltagecorrespondingtothepowerlevelsetbythepotentiometer,
this input is converted into the power level by the A/D converter built into the LSI.
24 AIN2 IN Input signal which communicates the door open/close information to LSI.
Door closed; "H" level signal.
Door opened; "L" level signal.
ON/OFF time ratio in Mi-
cro cooking
(a. 32second time base)
MICRO ON OFF
COOK
100% 32sec. 0sec.
70% 24sec. 8sec.
50% 18sec. 14sec.
30% 12sec. 20sec.
10% 6sec. 26sec.
H: GND
L: -5V
2.0 sec
20 msec
During cooking
H
L

R-204(W)
17
SERVICING
As for the sensor-related controls of the touch
control panel, checking them is possible if the
dummy resistor(s) with resistance equal to that
of the controls are used.
(2) Servicing the touch control panel with power
supply from an external power source:
Disconnectthetouchcontrolpanelcompletelyfrom
the oven proper, and short both ends of the door
sensingswitch(onPWB)ofthetouchcontrolpanel,
which brings about an operational state that is
equivalent to the oven door being closed. Connect
an external power source to the power input termi-
nal of the touch control panel, then it is possible to
check and repair the controls of the touch control
panel;itisalsopossibletocheckthesensor-related
controls of the touch control panel by using the
dummy resistor(s).
3. Servicing Tools
Tools required to service the touch control panel as-
sembly.
1) Soldering iron: 30W
(It is recommended to use a soldering iron with a
grounding terminal.)
2) Oscilloscope: Single beam, frequency range: DC -
10MHz type or more advanced model.
3) Others: Hand tools
4. Other Precautions
1) Before turning on the power source of the control
unit,remove the aluminium foil applied for prevent-
ing static electricity.
2) Connecttheconnector of the key unittothe control
unit being sure that the lead wires are not twisted.
3) After aluminium foil is removed, be careful that
abnormal voltage due to static electricity etc. is not
applied to the input or output terminals.
4) Attach connectors, electrolytic capacitors, etc. to
PWB, making sure that all connections are tight.
5) Be sure to use specified components where high
precision is required.
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the
circuits. When handling these parts, the following pre-
cautions should be strictly followed. CMOS LSI have
extremely high impedance at its input and output
terminals.For this reason, itis easily influencedby the
surroundinghighvoltagepowersource, staticelectric-
ity charge in clothes, etc., and sometimes it is not fully
protected by the built-in protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap
them in aluminium foil. Also wrap PW boards con-
taining them in aluminium foil.
2) Whensoldering,groundthetechnicianasshownin
the figure and use grounded soldering iron and
work table.
2. Servicing of Touch Control Panel
We describe the procedures to permit servicing of the
touch control panel of the microwave oven and the
precautions you must take when doing so.
To perform the servicing, power to the touch control
panelisavailableeitherfromthepowerlineoftheoven
itself or from an external power source.
(1)Servicing the touch control panel with power
supply of the oven :
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING
SERVICING AND PRESENTS A HAZARD .
Therefore, when checking the performance of the
touch control panel, put the outer cabinet on the
oven to avoid touching the high voltage trans-
former, or unplug the primary terminal (connector)
ofthehighvoltagetransformertoturnit off; the end
ofsuchconnectormustbeinsulatedwithaninsulat-
ing tape. After servicing, be sure to replace the
leads to their original locations.
A. On some models, the power supply cord be-
tweenthetouchcontrolpanelandtheovenitself
is so short that the two can't be separated.
For those models, check and repair all the
controls (sensor-related ones included) of the
touch control panel while keeping it connected
to the oven.
B. On some models, the power supply cord be-
tween the touch control panel and the oven
proper is so long enough that they may be
separated from each other. For those models,
therefore, it is possible to check and repair the
controlsofthetouchcontrolpanelwhilekeeping
it apart from the oven proper; in this case you
mustshortboth ends of the door sensing switch
(on PWB) of the touch control panel with a
jumper,whichbringsaboutanoperationalstate
thatisequivalent to the oven door being closed.
approx. 1M ohm

18
R-204(W)
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below
before operating the oven.
1. Disconnect oven from power supply.
2. Make sure that a definite”click”can be heard when
themicrowaveovendoorisunlatched.(Holdthedoor
inaclosedpositionwithonehand,thenpushthedoor
openbuttonwiththeother,thiscausesthelatchleads
to rise, it is then possible to hear a “click’as the door
switches operate.)
3. Visually check the door and cavity face plate for
damage (dents, cracks, signs of arcing etc.).
Carry out any remedial work that is necessary before
operating the oven.
Donotoperatetheovenifanyofthefollowingconditions
exist;
1. Door does not close firmly.
2. Door hinge, support or latch hook is damaged.
3. The door gasket or seal is damaged.
4. The door is bent or warped.
5. Therearedefectivepartsinthedoorinterlocksystem.
6. There are defective parts in the microwave generat-
ing and transmission assembly.
7. There is visible damage to the oven.
Do not operate the oven:
1. Without the RF gasket (Magnetron).
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any
of the following removal procedures:
WARNING FOR WIRING
To prevent an electric shock, take the following
manners.
1. Before wiring,
1) Disconnect the power supply.
2) Open the door and wedge the door open.
3) Discharge the high voltage capacitor and wait for
60 seconds.
2. Don't let the wire leads touch to the following parts;
1) High voltage parts:
Magnetron, High voltage transformer, High volt-
age capacitor, High voltage rectifier assembly
and High voltage fuse.
2) Hot parts:
Ovenlamp, Magnetron,Highvoltagetransformer
and Oven cavity.
3) Sharp edge:
Oven cavity, Waveguide flange, other metallic
plate.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch and Turntable
motor.
3. Donotcatchthewireleadsintheoutercasecabinet.
4. Insertthepositivelockconnectorcertainlyuntilitspin
is locked. And make sure that the wire leads should
not come off even if the wire leads is pulled.
5. To prevent an error function, connect the wire leads
correctly, referring to the Pictorial Diagram.
3) Discharge high voltage capacitor.
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
To To remove the outer case, procedure as follows.
1. Disconnect the power supply cord.
2. Open the oven door and block it open.
3. Remove the two (2) screws along the right side of the
outer case.
4. Remove the remaining five (5) screws from the rear of
the outer case.
5. Slidetheentireoutercasebackoutabout1inch(3cm)
to free it from retaining clips on the cavity face plate.
6. Lift entire outer case from the unit.
7. Discharge the H. V. capacitor before curring out any
OUTER CASE REMOVAL
further work.
8. Do notoperatetheoven with the outer case removed.
NOTE: Step1,2and7fromthebasisofthe3Dchecks.
CAUTION:1. DISCONNECT OVEN FROM POWER
SUPPLY BEFORE REMOVING OUTER
CASE.
2. DISCHARGE THE HIGH VOLTAGE CA-
PACITOR BEFORE TOUCHING ANY
OVEN COMPONENTS OR WIRING.