Sharp R-120DB User manual

R-120DB
R-120DK
R-120DR
R-120DW
MICROWAVE OVEN
R-120DB
R-120DK
R-120DR
R-120DW
Intheinterestofuser-safetytheovenshouldberestoredtoitsoriginal
condition and only parts identical to those specified should be used.
WARNING TO SERVICE PERSONNEL: Microwave ovens con-
tain circuitry capable of producing very high voltage and
current, contact with following parts may result in a severe,
possibly fatal, electrical shock. (High Voltage Capacitor, High
Voltage Power Transformer, Magnetron, High Voltage Recti-
fier Assembly, High Voltage Harness etc..)
TABLE OF CONTENTS Page
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ...................INSIDE FRONT COVER
BEFORE SERVICING ......................................................................................................INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL................................................................................................................1
MICROWAVE MEASUREMENT PROCEDURE ...................................................................................................2
FOREWORD AND WARNING...............................................................................................................................3
PRODUCT SPECIFICATIONS ..............................................................................................................................4
GENERAL INFORMATION...................................................................................................................................4
OPERATION..........................................................................................................................................................6
TROUBLESHOOTING GUIDE ..............................................................................................................................8
TEST PROCEDURE ............................................................................................................................................10
TOUCH CONTROL PANEL .................................................................................................................................16
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ................................................................20
PICTORIAL DIAGRAM ........................................................................................................................................26
CONTROL PANEL CIRCUIT ...............................................................................................................................27
PRINTED WIRING BOARD .................................................................................................................................28
PARTS LIST ........................................................................................................................................................29
PACKING AND ACCESSORIES .........................................................................................................................33
S3007R120DPW/
MODELS
SERVICEMANUAL
SHARP CORPORATION This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
HALF PINT
ON DEF LBS QTY CHECK
START/MINUTE LUS
STOP/CLEAR

R-120DB
R-120DK
R-120DR
R-120DW
PRECAUTIONS TO BE OBSERVED BEFOREAND
DURING SERVICING TOAVOID POSSIBLE
EXPOSURE TO EXCESSIVE MICROWAVE
ENERGY
(a) Do not operate or allow the oven to be operated with the door open.
(b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other
microwave source, and make repairs as necessary: (1) interlock operation, (2) proper door closing, (3)
seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and
latches, (5) evidence of dropping or abuse.
(c) Before turning on microwave power for any service test or inspection within the microwave generating
compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment,
integrity, and connections.
(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave
generation and transmission systems shall be repaired, replaced, or adjusted by procedures described
in this manual before the oven is released to the owner.
(e) A microwave leakage check to verify compliance with the Federal Performance Standard should be
performed on each oven prior to release to the owner.
BEFORE SERVICING
Before servicing an operative unit, perform a microwave emission check as per the Microwave
Measurement Procedure outlined in this service manual.
If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS
CORPORATION immediately @1-800-237-4277.
If the unit operates with the door open, service person should 1) tell the user not to operate the oven
and 2) contact SHARP ELECTRONICS CORPORATION and Food and Drug Administration's
Center for Devices and Radiological Health immediately.
ServicepersonnelshouldinformSHARPELECTRONICSCORPORATIONofanycertifiedunitfound
with emissions in excess of 4mW/cm2. The owner of the unit should be instructed not to use the unit
until the oven has been brought into compliance.

1
R-120DB
R-120DK
R-120DR
R-120DW
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of pro-
ducing very high voltage and current, contact with
following parts
may result in a severe, possibly
fatal, electrical shock.
(Example)
HighVoltageCapacitor,HighVoltagePowerTrans-
former,Magnetron,HighVoltageRectifierAssem-
bly, High Voltage Harness etc..
Read the Service Manual carefully and follow all
instructions.
Before Servicing
1. Disconnect thepower supplycord ¬,and thenremove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
WARNING:RISK OF ELECTRIC SHOCK.
DISCHARGE THE HIGH-VOLTAGE
CAPACITOR BEFORE SERVICING.
The high-voltage capacitor remains charged about 60
secondsaftertheovenhasbeenswitchedoff.Waitfor60
secondsandthenshort-circuittheconnectionofthehigh-
voltagecapacitor (thatis theconnectinglead ofthehigh-
voltage rectifier) against the chassis with the use of an
insulated screwdriver.
Whenever troubleshooting is performed the power supply
mustbedisconnected.Itmay,insomecases,benecessary
to connect the power supply after the outer case has been
removed, in this event,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power
transformer.
5. Ensure that the leads remain isolated from other
components and oven chassis by using insulation tape.
6. After that procedure, reconnect the power supply cord.
When the testing is completed,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power
transformer.
5. Reinstall the outer case (cabinet).
6. Reconnectthe powersupply cordafter theouter caseis
installed.
7. Run the oven and check all functions.
After repairing
1. Reconnect all leads removed from components during
testing.
2. Reinstall the outer case (cabinet).
3. Reconnectthe powersupply cordafter theouter caseis
installed.
4. Run the oven and check all functions.
Microwave ovens should not be run empty. To test for the
presence of microwave energy within a cavity, place a cup
of cold water on the oven turntable, close the door and set
the power to HIGH and set the microwave timer for two (2)
minutes.When thetwo minuteshas elapsed(timer atzero)
carefully check that the water is now hot. If the water
remainscoldcarryout BeforeServicingprocedureandre-
examine the connections to the component being tested.
When all service work is completed and the oven is fully
assembled,themicrowavepoweroutputshouldbechecked
and a microwave leakage test should be carried out.
Don't Touch !
Danger High Voltage

2
R-120DB
R-120DK
R-120DR
R-120DW MICROWAVE MEASUREMENT PROCEDURE
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven
shouldnotexceed1mW/cm2atanypoint5cmormorefromtheexternalsurfaceoftheoven,measuredpriortoacquisition
byapurchaser,andthereafter(throughtheusefullifeoftheoven),5mW/cm2atanypoint 5cmor morefrom theexternal
surface of the oven.
2) Safety interlock switches Primary interlock relay and door sensing switch shall prevent microwave radiation emission in
excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission
in excess of 5 mW/cm2at any point 5cm or more from the external surface of the oven.
B. Preparation for testing:
Before beginning the actual measurement of leakage, proceed as follows:
1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for
microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.
2) Place the oven tray in the oven cavity.
3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5˚C (68˚F) in the center of the oven cavity.
The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.)
and made of an electrically nonconductive material such as glass or plastic.
Theplacing of this standard load in the ovenisimportant not only to protect the oven, but alsoto insure that any leakage
is measured accurately.
4) Set the cooking control on Full Power Cooking Mode
5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed,
replace it with 275 ml of cool water.
C. Leakage test:
Closed-door leakage test (microwave measurement)
1) Grasptheprobeofthesurveyinstrumentandholditperpendiculartothegapbetweenthedoorandthebodyoftheoven.
2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on
the meter.
3) Checkforleakageatthedoorscreen,sheetmetalseamsandotheraccessiblepositionswherethecontinuityofthemetal
has been breached (eg., around the switches, indicator, and vents).
Whiletestingforleakagearoundthedoorpullthedoorawayfromthefrontoftheovenasfarasispermittedbytheclosed
latch assembly.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2,
and that the secondary interlock switch does turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.

3
R-120DB
R-120DK
R-120DR
R-120DW
SHARP ELECTRONICS CORPORATION
SHARP PLAZA, MAHWAH,
NEW JERSEY 07430-2135
SERVICE MANUAL
MICROWAVE OVEN
R-120DB/ R-120DK/ R-120DR/ R-120DW
FOREWORD
This Manual has been prepared to provide Sharp Electronics Corp.
Service Personnel with Operation and Service Information for the
SHARP MICROWAVE OVEN, R-120DB, R-120DK, R-120DR, R-
120DW.
It is recommended that service personnel carefully study the entire
text of this manual so that they will be qualified to render satisfactory
customer service.
Check the interlock switches and the door seal carefully. Special
attention should be given to avoid electrical shock and microwave
radiation hazard.
WARNING
Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is no other visible damage with the oven.
Servicing and repair work must be carried out only by trained service
personnel. DANGER
Certaininitialpartsareintentionallynotgroundedandpresent
a risk of electrical shock only during servicing. Service
personnel - Do not contact the following parts while the
appliance is energized;
High Voltage Capacitor, Power Transformer, Magnetron,
High Voltage Rectifier Assembly, High Voltage Harness;
If provided, Vent Hood, Fan assembly, Cooling Fan Motor.
Allthepartsmarked“*”onpartslistareusedatvoltagesmorethan
250V.
Removal of the outer wrap gives access to voltage above 250V.
Allthepartsmarked“∆”onpartslistmaycauseunduemicrowave
exposure, by themselves, or when they are damaged, loosened
or removed.
PRODUCT DESCRIPTION
GENERAL INFORMATION
OPERATION
TROUBLESHOOTING GUIDE AND
TEST PROCEDURE
TOUCH CONTROL PANEL
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
WIRING DIAGRAM
PARTS LIST

4
R-120DB
R-120DK
R-120DR
R-120DW
GENERAL INFORMATION
GROUNDING INSTRUCTIONS
This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed
and grounded in accordance with the National Electrical Code and local codes and ordinances.
In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the
electric current.
WARNING: Improper use of the grounding plug can result in a risk of electric shock.
Electrical Requirements
The electrical requirements are a 115 -120 volt 60 Hz, AC only,
15or20amp.fusedelectricalsupply.Itisrecommendedthataseparatecircuitservingonlythisappliancebeprovided.When
installing this appliance, observe all applicable codes and ordinances.
A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord.
Where a two-pronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to
contact a qualified electrician and have it replaced with a properly grounded three-pronged wall receptacle or have a
grounding adapter properly grounded and polarized. If the extension cord must be used, it should be a 3-wire, 15 amp. or
higherrated cord. Do not drapeover a countertop or tablewhere it can be pulledonby children or tripped overaccidentally.
ITEM DESCRIPTION
Power Requirements 120 Volts
60 Hertz
Single phase, 3 wire grounded
Power Consumption 1030W / Approx. 9 Amperes
Power Output 600 W nominal of RF microwave energy (IEC Test procedure)
Operating frequency 2450 MHz
Case Dimensions Width 14-3/8"
Height 14-1/8"
Depth 14"
Cooking Cavity Dimensions Width 11-3/4"
(0.7 Cubic feet) Height 16"
Depth 11-7/8"
Control Complement Touch Control System
Clock (1:00 - 12:59)
Timer (0 - 99 minutes 45 seconds)
POPCORN pad
EXPRESS DEFROST pad
COMPU COOK pad
DOUBLE QUANTITY pad
STOP/ CLEAR pad (STOP/CLEAR button)
CLOCK/ TIMER pad
10 MINUTES pad
1 MINUTE pad
15 SECONDS pad
START/ MINUTE PLUS button
Oven Cavity Light Yes
Safety Standard UL Listed.
FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
PRODUCT DESCRIPTION
SPECIFICATIONS

5
R-120DB
R-120DK
R-120DR
R-120DW
CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR RE-
MOVE THE ROUND GROUNDING PRONG FROM THIS
PLUG.
OVEN DIAGRAM
1. Oven door with see-through
window
2. Safety door latches.
The oven will not operate unless
the door is securely closed.
3. Door hinges
4. Door seals and sealing surfaces
5. Door handle
Pull to the open.
6. Turntable motor shaft
7. Removable turntable support
8. Removable turntable
Placetoturntableontheturntable
support securely. The turntable
will rotate clockwise or
counterclockwise.Onlyremovefor
cleaning.
9. Ventilation openings. (Rear)
10.Oven light
Itwilllightwhenovenisoperating.
11.Wave guide cover. DO NOT
REMOVE.
12.Control panel display
13.Start/Minute Plus button
14.Stop/Clear button TOUCH CONTROL PANEL
3-Pronged
Plug
Grounded
Receptacle Box
Grounding Pin
3-Pronged Receptacle
NOTE:
1. Open the door to program the oven.
2. The STOP/CLEARand theSTART/MINUTEPLUSpadscanbe
used even if the door closed.
3. MINUTE PLUS feature is disabled after one minute when the
ovenisnotinuse.Thisfeatureisautomaticallyenabledwhen
the door is opened and closed or the STOP/ CLEAR pad is
pressed.
,,,
,,,
,,,
,,
,,
,,
,,
,,,
HALF PINT
SHARP
C
aroucel
START/MINUTE LUS
STOP/CLEAR
1
67
8
910 12
4
5
3
2
13 14
11
,,
,,
,,
,,
,,
,,
COMPUCOOK GUIDE
POPCORN
MINUTES
10 1 15
MINUTE SECONDS
EXPRESS
DEFROST
STOP
CLEAR
CLOCK
TIMER
COMPU
COOK
DOUBLE
QUANTITY
1. Pizza 1-2 slices
2. Coffee/Tea 1-2 cups
3. Rolls/Muffins 1-2 medium size
4. Casseroles 1-2 cups
5. Frozen Entree 3-6 or 8-10 ounces
6. Baked Potates 1-2 medium size
ON DEF LBS QTY CHECK
Control panel display
Wards will light in the display to indicate feature and cooking
instructions.

6
R-120DB
R-120DK
R-120DR
R-120DW
Figure O-1. Oven Schematic-Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
Thefollowingisadescriptionofcomponentfunctionsduring
oven operation.
OFF CONDITION
Closing the door activates the door sensing switch and
secondary interlock switch. (In this condition, the monitor
switch contacts are opened.)
When the oven is plugged in, 120 volts A.C. is supplied to
the control unit. (Figure O-1).
1. The display will show flashing "88:88".
Toset any programor set the clock,you must first touch
the STOP/CLEAR pad. The display will clear, and " : "
will appear.
COOKING CONDITION
Open the door. Program desired cooking time by touching
theNUMBER pads. Andprogram the powerlevel by touch-
ing the POWER LEVEL pad and then a Number pad.
When close the door and the START pad is touched, the
following operations occur:
1. The contacts of the relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Figure O-2)
RELAY CONNECTED COMPONENTS
RY-1 oven lamp/turntable motor/fan motor
RY-2 power transformer
2. 120 volts A.C. is supplied to the primary winding of the
power transformer and is converted to about 3.5 volts
A.C. output on the filament winding, and approximately
2000 volts A.C. on the high voltage winding.
3. The filament winding voltage heats the magnetron
filamentandtheH.V.windingvoltageissenttoavoltage
doubler circuit.
4. The microwave energy produced by the magnetron is
channelled through the waveguide into the cavity feed-
box, and then into the cavity where the food is placed to
be cooked.
5. Upon completion of the cooking time, the power
transformer, oven lamp, etc. are turned off, and the
generation of microwave energy is stopped. The oven
will revert to the OFF condition.
6. When the door is opened during a cook cycle, the
monitorswitch,doorsensingswitch,secondaryinterlock
switch and primary interlock relay are activated with the
followingresults.Thecircuitstotheovenlamp,turntable
motor, the cooling fan motor, and the high voltage
components are de-energized, and the digital read-out
displays the time still remaining in the cook cycle when
the door was opened.
7. Themonitorswitchiselectricallymonitoringtheoperation
of the secondary interlock switch and primary interlock
relay(RY2)andismechanicallyassociatedwiththedoor
so that it will function in the following sequence.
(1) When the door opens from the closed position, the
secondary interlock switch, door sensing switch and
primaryinterlockrelay(RY2)opentheircontacts.Then
the monitor switch contacts close.
(2) When the door is closed from the open position, the
monitor switch contacts open first. Then the contacts
of the secondary interlock switch and door sensing
switch close.
Ifthesecondaryinterlockswitchand primaryinterlockrelay
(RY2)failwiththecontactsclosedwhenthedoorisopened,
the closing of the monitor switch contacts will form a short
circuitthroughtheC/Tfuse,secondary interlockswitchand
primaryinterlock relay (RY2), causing the C/T fuse to blow.
POWER
TRANSFORMER
RECTIFIER MAGNETRON
CAPACITOR
0.72µF
C/T FUSE
120V AC
60 Hz
OVEN
LAMP TURN-
TABLE
MOTOR FAN
MOTOR
MONITOR
SWITCH
SECONDARY
INTERLOCK
SWITCH
TTM
OL FM
GRN
A3
COM.
N.O.
DOOR
SENSING
SWITCH
B2 B1
(RY-1) (RY-2)
CONTROL UNIT
PRIMARY
INTERLOCK
RELAY
MAGNETRON
THERMAL CUT-OUT
A1

7
R-120DB
R-120DK
R-120DR
R-120DW
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR OPENED.
2. COOKINGTIMEPROGRAMMED.
3. DOOR CLOSED.
4. START/MINUTE PLUS BUTTON
PUSHED.
Figure O-2. Oven Schematic-Cooking Condition
DESCRIPTION AND FUNCTION OF COMPONENTS
DOOR OPEN MECHANISM
The door is opened by pulling the door, refer to the Figure
D-1.
Figure D-1. Door Open Mechanism
DOOR SENSING AND SECONDARY INTERLOCK
SWITCHES
The secondary interlock switch is mounted in the lower
positionofthelatchhook andthedoorsensingswitchinthe
primaryinterlocksystemismountedintheupperpositionof
thelatchhook.Theyare activatedbythelatchheadsonthe
door. When the door is opened, the switches interrupt the
power to all high voltage components. A cook cycle cannot
take place until the door is firmly closed thereby activating
both interlock switches. The primary interlock system con-
sists of the door sensing switch and primary interlock relay
located on the control circuit board.
MONITOR SWITCH
Themonitorswitchisactivated(thecontactsopened)bythe
latch head on the door while the door is closed. The switch
is intended to render the oven inoperative, by means of
blowing the C/T fuse, when the contacts of the primary
interlock relay (RY2) and secondary interlock switch fail to
open when the door is opened.
Functions:
1. When the door is opened, the monitor switch contacts
close (to the ON condition) due to their being normally
closed.Atthistimetheprimaryinterlockrelay(RY2)and
secondary interlock switch are in the OFF condition
(contacts open) due to its being normally open contact
switches.
2. Asthedoorgoestoaclosedposition,themonitorswitch
contacts are first opened and then the door sensing
switch and secondary interlock switch contacts close.
3. If the door is opened, and the primary interlock relay
(RY2) and the secondary interlock switch contact fail to
open, the C/T fuse blows simultaneously with closing of
the monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN C/T FUSE,
TEST THE DOOR SENSING SWITCH, PRI-
MARY INTERLOCK RELAY (RY2), SECOND-
ARY INTERLOCK SWITCH AND MONITOR
SWITCH FOR PROPER OPERATION. (RE-
FER TO CHAPTER "TEST PROCEDURE").
NOTE: C/T FUSE AND MONITOR SWITCH ARE
REPLACED AS AN ASSEMBLY
TURNTABLE MOTOR
The turntable motor rotates the turntable located on the
bottom of the oven cavity, so that the food on the turntable
iscooked evenly. Theturntable may turn ineither direction.
COOLING FAN MOTOR
The cooling fan motor drives a blade which draws external
cool air. This cool air is directed through the air vanes
surrounding the magnetron and cools the magnetron. This
Latch heads
Latch hook
Door
Door sensing
switch
Monitor
switch
Secondary
interlock
switch
POWER
TRANSFORMER
RECTIFIER MAGNETRON
CAPACITOR
0.72µF
C/T FUSE
120V AC
60 Hz
OVEN
LAMP TURN-
TABLE
MOTOR FAN
MOTOR
MONITOR
SWITCH
SECONDARY
INTERLOCK
SWITCH
TTM
OL FM
GRN
A3
COM.
N.O.
DOOR
SENSING
SWITCH
B2 B1
(RY-1) (RY-2)
CONTROL UNIT
PRIMARY
INTERLOCK
RELAY
MAGNETRON
THERMAL CUT-OUT
A1

8
R-120DB
R-120DK
R-120DR
R-120DW
air is channelled through the oven cavity to remove steam
and vapours given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven
cavity.
MAGNETRON THERMAL CUT-OUT
The thermal cut-out located on the air duct is designed to
prevent damage to the magnetron if an over heated condi-
tion develops in the tube due to cooling fan failure, ob-
structed air guide, dirty or blocked air intake, etc.
Undernormaloperation,thethermalcut-outremainsclosed.
However,whenabnormallyhightemperaturesare reached
withinthemagnetron,thethermalcut-outwillopenat203˚F
(95˚C),causing the oven to shut down. The thermal cut-out
will reset automatically below approximately 167˚F(75˚C).
TROUBLESHOOTING GUIDE
Nevertouch anypartin thecircuitwith yourhandor anuninsulatedtool whilethepower supplyisconnected.
Whentroubleshootingthemicrowave oven,itishelpful tofollowtheSequence ofOperationinperforming thechecks.Many
ofthepossiblecausesoftroublewillrequirethataspecifictestbeperformed.Thesetestsaregivenaprocedureletterwhich
will be found in the "Test Procedure "section.
IMPORTANT: If the oven becomes inoperative because of a blown C/T fuse, check the monitor switch, primary
interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the C/T fuse.
If the C/T fuse is replaced, the monitor switch must also be replaced. Use part FFS-BA027WRKZ as an
assembly.
IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may, in some cases,
be necessary to connect the power supply cord after the outer case has been removed, in this event,
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power transformer.
5. Ensurethattheleadsremain isolatedfromothercomponentsandovenchassisbyusing insulationtape.
6. After that procedure, reconnect the power supply cord.
When the testing is completed,
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Reconnect all leads removed from components during testing.
5. Reinstall the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.
C/T FUSE
1. TheC/Tfuse blowswhenthe contacts(COM-NO) ofthe
primary interlock relay (RY2) and secondary interlock
switchremainclosedwiththeoven dooropenand when
the monitor switch closes.
2. If the wire harness or electrical components are short-
circuited,thisC/Tfuseblows topreventanelectricshock
or fire hazard.
3. The C/T fuse, located on the top of the oven cavity, is
designed to prevent damage to the oven by fire. If the
food load is overcooked, by either error in cook time or
defect in the timer, the C/T fuse will open.
Under normal operation, the C/T fuse remains closed.
However,whenabnormallyhightemperaturesare reached
within the oven cavity, the C/T fuse will open at 248˚F
(120˚C),causingtheoventoshutdownorwhentheelectric
currents beyond 13A flow, the C/T fuse will open.

9
R-120DB
R-120DK
R-120DR
R-120DW
CK = Check / RE = Replace
RE CK AB C D EFFGHRE RE CK I/K CK CKCK J L M
SHORT IN POWER CORD SHORT OR OPEN WIRING MAGNETRON POWER TRANSFORMER H.V. RECTIFIER ASSEMBLY HIGH VOLTAGE CAPACITOR MAGNETRON THERMAL CUT-OUT PRIMARY INTERLOCK SYSTEM SECONDARY INTERLOCK SWITCH MONITOR SWITCH C/T FUSE OVEN LAMP OR SOCKET COOLING FAN MOTOR TURNTABLE MOTOR CONTROL UNIT OR RELAY WRONG OPERATION LOW VOLTAGE DIRTY OVEN CAVITY KEY UNIT COMPU COOK FOIL PATTERN ON PWB.
Home fuse blows when power cord
is plugged into wall receptacle.
C/T fuse blows when power cord is
plugged into wall receptacle.
All letters and indicators do not ap-
pear in display when power cord is
first plugged into wall outlet.
Display does not operate properly
whenSTOP/CLEARkeyistouched.
(Buzzer should sound and time of
day should appear in display.)
C/T fuse blows when the door is
opened.
Fan motor does not operate. (All
otherelectriccomponentsfunction.)
Oven lamp does not light at all. (All
otherelectriccomponentsfunction.)
Turntablemotordoesnot operate.(All
other electric components function.)
Oven does not go into cook cycle
when START pad is touched
Ovenseemstobeoperatingbutlittle
or no heat is produced in oven load.
(Food incompletely cooked or not
cooked at all at end of cook cycle.)
Oven goes into a cook cycle but
extremely uneven heating is pro-
duced in oven load (food).
Oven lamp, turntable motor and fan
motor do not operate.
OvengoesintoEXPRESSDEFROST
but food is not defrosted well.
TEST PROCEDURE
PROBLEM
CONDITION
OFF
CONDITION
COOKING
CONDITION
POSSIBLE CAUSE
AND
DEFECTIVE PARTS

10
R-120DB
R-120DK
R-120DR
R-120DW
BPOWER TRANSFORMER TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the primary input terminals and measure the resistance of the transformer with an
ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x 1 scale, the resistance of
the primary coil should be less than 1 ohm and the resistance of the high voltage coil should be
approximately 164 ohms; the resistance of the filament coil should be less than 1 ohm.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
AMAGNETRON ASSEMBLY TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check
across the magnetron filament leads should indicate less than 1 ohm.
5. Totestforashortedmagnetron,connecttheohmmeterleadsbetweenthemagnetronfilamentleads
and chassis ground. This test should indicate an infinite resistance. If there is little or no resistance
the magnetron is grounded and must be replaced.
6. Reconnect all leads removed from components during testing.
7. Reinstall the outer case (cabinet).
8. Reconnect the power supply cord after the outer case is installed.
9. Run the oven and check all functions.
MICROWAVE OUTPUT POWER
The following test procedure should be carried out with the microwave oven in a fully assembled
condition (outer case fitted).
HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD
BE OBSERVED.
Power output of the magnetron can be measured by performing a water temperature rise test. This test
shouldonlybeusedifabovetestsdonotindicateafaultymagnetronandthereisnodefectinthefollowing
componentsorwiring:siliconrectifier,highvoltagecapacitorandpowertransformer.Thistestwillrequire
a 16 ounce (453cc) measuring cup and an accurate mercury thermometer or thermocouple type
temperature tester. For accurate results, the following procedure must be followed carefully:
1. Fillthemeasuringcupwith16oz.(453cc)oftapwaterandmeasurethetemperatureofthewaterwith
a thermometer or thermocouple temperature tester. Stir the thermometer or thermocouple through
the water until the temperature stabilizes. Record the temperature of the water.
2. Place the cup of water in the oven. Operate oven with selecting more than 60 seconds cook time.
Allow the water to heat for 60 seconds, measuring with a stop watch, second hand of a watch or the
digital read-out countdown.
3. Remove the cup from the oven and again measure the temperature, making sure to stir the
thermometer or thermocouple through the water until the maximum temperature is recorded.
4. Subtractthe coldwater temperaturefrom the hotwater temperature.The normalresult should be18
to 29.2˚F(10 to 16.2˚C) rise in temperature. If the water temperatures are accurately measured and
tested for the required time period the test results will indicate if the magnetron tube has low power
output (low rise in water temperature) which would extend cooking time or high power output (high
risein water temperature) which would reduce cooking time. Because cooking time can be adjusted
to compensate for power output, the magnetron tube assembly should be replaced only if the water
temperaturerisetestindicatesapoweroutputwellbeyondthenormallimits.Thetestisonlyaccurate
if the power supply line voltage is 120 volts and the oven cavity is clean.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST

11
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R-120DK
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R-120DW
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
(HIGHVOLTAGESARE PRESENTAT THEHIGHVOLTAGE TERMINAL,SO DONOT ATTEMPTTO
MEASURE THE FILAMENT AND HIGH VOLTAGE.)
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads
and check for short or open between the terminals using an ohmmeter.
Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate
continuity for a short time and should indicate an open circuit once the capacitor is charged. If the
above is not the case, check the capacitor with an ohmmeter to see if it is shorted between either of
the terminals and case. If it is shorted, replace the capacitor.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
DHIGH VOLTAGE CAPACITOR TEST
EMAGNETRON THERMAL CUT-OUT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. A continuity check across the thermal cut-out terminals should indicate a closed circuit. If the
temperature of the magnetron reaches approximately 203˚F(95˚C), the thermal cut-out opens. The
thermal cut-out will reset automatically below approximately 167˚F(75˚C). An open thermal cut-out
indicatesoverheatingofthemagnetron.Checkforrestrictedairflowtothemagnetron,especiallythe
cooling fan air guide.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
CAUTION: IFTHETHERMALCUT-OUTINDICATESANOPENCIRCUITATROOMTEMPERATURE,
REPLACE THERMAL CUT-OUT.
C HIGH VOLTAGE RECTIFIER TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance
across the terminals and observe, reverse the leads to the rectifier terminals and observe meter
reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions,
the rectifier is probably defective and should be replaced.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
NOTE:Besure to use an ohmmeterthatwill supply a forwardbiasvoltage of more than 6.3volts.
F SECONDARY INTERLOCK SWITCH TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Isolatetheswitchandconnecttheohmmetertothecommon(COM.)andnormallyopen(NO)terminal

12
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1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Before performing this test, make sure that the secondary interlock switch and the primary interlock
relayareoperatingproperly,accordingtotheaboveSwitchTestProcedure.Disconnectthewirelead
fromthe monitor switch (COM) terminal. Checkthe monitor switch operation by using theohmmeter
asfollows.Whenthedoorisopen,themetershouldindicateaclosedcircuit.Whenthemonitorswitch
actuatoris pushed by a screw driver through thelowerlatch hole on the front plate of the ovencavity
withthedooropened(inthisconditiontheplungerofthemonitorswitchispushedin),themetershould
indicate an open circuit. If improper operation is indicated, the switch may be defective. After testing
the monitor switch, reconnect the wire lead to the monitor switch (COM) terminal and check the
continuity of the monitor circuit.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after
the outer case is installed.
8. Run the oven and check all functions.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the secondary interlock switch.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
PRIMARY INTERLOCK SYSTEM TEST
DOOR SENSING SWITCH
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Isolatetheswitchandconnecttheohmmetertothecommon(COM.)andnormallyopen(NO)terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the door sensing switch.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
PRIMARY INTERLOCK RELAY (RY2)
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect two (2) wire leads from the male tab terminals of the Primary Interlock Relay. Check the
stateoftherelaycontactsusingaohmmeter.Therelaycontactsshouldbeopen.Iftherelaycontacts
are closed, replace the circuit board entirely or the relay itself.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
GMONITOR SWITCH TEST
Screw
driver
Ohmmeter
Monitor
switch

13
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H BLOWN C/T FUSE TEST
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. If the C/T fuse is blown when the door is opened, check the primary interlock relay, secondary
interlockswitchandmonitorswitchaccordingtothe"TESTPROCEDURE"forthoseswitchesbefore
replacing the blown C/T fuse.
CAUTION: BEFORE REPLACING A BLOWN C/T FUSE, TEST THE PRIMARY INTERLOCK RELAY,
SECONDARYINTERLOCKSWITCH,DOORSENSINGSWITCHANDMONITORSWITCH
FOR PROPER OPERATION.
If the C/T fuse is blown by improper switch operation, the C/T fuse and monitor switch must be
replaced with "C/T fuse and monitor switch assembly" part number FFS-BA027WRKZ, even if the
monitor switch operates normally. The C/T fuse and monitor switch assembly is comprised of a 13
ampere fuse and switch.
AcontinuitycheckacrosstheC/Tfuseterminalsshouldindicateaclosedcircuitunlessthetemperature
of the C/T fuse reaches approximately 248˚F(120˚C).
AnopenC/T fuseindicates theovenoverheated, Replacethe ovenC/T fuseandcheck theinside ofthe
oven cavity, the proper setting of cooking time and the proper operation of control unit. Also check for
proper air flow through the ovens venting system. Especially check the cooling fan for proper operation
and the air guide for restriction.
CAUTION: IFTHEC/TFUSEINDICATESANOPENCIRCUITATROOMTEMPERATURE,REPLACE
THE C/T FUSE.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter
and ohmmeter.
In this service manual, troubleshooting by unit replacement is described according to the symptoms
indicated.
Before testing,
1) Disconnect the power supply cord and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power transformer.
5) Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
1. Tact switch.
The following symptoms indicate a defective tact switch.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
2. Control Unit.
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the tact switch test (Procedure J) to determine if control unit is faulty.
2-1 In connection with pads.
a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.
2-2 In connection with indicators
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
I TOUCH CONTROL PANEL ASSEMBLY TEST

14
R-120DB
R-120DK
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R-120DW
KRELAY TEST
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
2-3 Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.
When testing is completed,
1) Disconnect the power supply cord and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Reconnect all leads removed from components during testing.
5) Re-install the outer case (cabinet).
6) Reconnect the power supply cord after the outer case is installed.
7) Run the oven and check all functions.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
JTACT SWITCH TEST
1. Disconnect the power supply cord and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. By using an ohmmeter, check the tact switch operation.
5.Whenthetactswitchisnotdepressed,anohmmetershouldindicateanopencircuit.Whenthetactswitch
isdepressed,anohmmetershouldindicateashortcircuit.Ifimproperoperationisindicated,thetactswitch
is probably defective and should be checked.
1. Disconnect the power supply cord and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power transformer.
5.Ensurethat theseleadsremain isolatedfrom othercomponentsand ovenchassisby usinginsulation
tape.
6. After that procedure, re-connect the power supply cord.
7. 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 120 volts, if not check oven circuit.
RY1 and RY2 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated.................... Defective relay.
DC. voltage not indicated.............. Checkdiodewhichisconnectedtotherelaycoil.Ifdiodeisgood,
control unit is defective.
RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS
RY1 Approx. 12.0V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 Approx. 12.0V D.C. Power transformer
8. Disconnect the power supply cord and then remove outer case.
9. Open the door and block it open.
10. Discharge high voltage capacitor.
11. Reconnect all leads removed from components during testing.

15
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(1) Place one cup of water in the center of the turntable tray in the oven cavity.
(2) Open the door, and touch COMPU COOK pad three times.
(3) Close the door, and then touch the "START" pad.
(4) The oven is in COMPU COOK condition.
(5) The oven will operate as follows. (in case of 1 piece of Rolls/muffins cooking)
1ST STAGE
LEVEL TIME
100% 15sec.
(6) If improper cooking time is indicated, the control unit is probably defective and should be checked.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
12. Re-install the outer case (cabinet).
13. Reconnect the power supply cord after the outer case is installed.
14. Run the oven and check all functions.
LCOMPU COOK TEST
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on
the PWB, this foil pattern acts as a fuse.
1. Foil pattern check and repairs.
1) Disconnect the power supply cord and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Follow the troubleshooting guide given below for repair.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
2 Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".
5) Makeavisualinspectionofthe varistor.
Checkforburneddamageandexamine
the transformer with a tester for the
presence of layer short-circuit (check
the primary coil resistance which is
approximately 563Ω±10%). If any
abnormalconditionisdetected,replace
the control unit.
6) Reconnect all leads removed from components during testing.
7) Re-install the outer case (cabinet).
8) Reconnect the power supply cord after the outer case is installed.
9) Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if indicator does not light up after above check and
repairs are finished.
1) Disconnect the power supply cord and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power transformer.
5) Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
6) After that procedure, re-connect the power supply cord.
M FOIL PATTERN ON THE PRINTED WIRING BOARD TEST
Q10
1
T1
7
RY2
(J1) (C10) B
a
b
dc
VRS1
D21

16
R-120DB
R-120DK
R-120DR
R-120DW
Thetouchcontrolsectionconsistsofthefollowingcircuitsas
shown in the touch control panel circuit.
The principal functions of these circuits and their related
signals are explained below.
Tact Switch
Signals generated in the LSI are sent to the tact switches
through P10, P11, P12 and P13.
Whenatactswitchistouched,asignaliscompletedthrough
the tact switch and passed back to the LSI through AN4,
AN5 and AN6 to perform the function that was requested.
Control Unit
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit and syn-
chronizing signal circuit.
1) ACL
ThiscircuitgeneratesasignalwhichresetstheLSItothe
initial state when power is supplied.
2) Indicator Circuit
This circuit consists of 4-digits, 12-segments and 3-
common electrodes using a Liquid Crystal Display.
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
3) Power Source Circuit
This circuit generates voltage necessary in the control
unitfromtheAClinevoltage.Inaddition,thesynchronizing
signal is available in order to compose a basic standard
time in the clock circuit.
Symbol Voltage Application
VC -5V LSI(IC1)
4) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audiblesounds(tactswitchtouchsoundandcompletion
sound).
6) 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.
7) Door Sensing Switch
A switch to "tell" the LSI if the door is open or closed.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
7) Follow the troubleshooting guide given below for repair.
STEPS OCCURRENCE CAUSE OR CORRECTION
The rated AC voltage is not present between
1 Pin No. 3 of the 2-pin connector (A) and the Check supply voltage and oven power cord.
common terminal of the relay RY2.
2The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.
side of low voltage transformer. Check and replace the control unit.
8) Disconnect the power supply cord and then remove outer case.
9) Open the door and block it open.
10) Discharge high voltage capacitor.
11) Reconnect all leads removed from components during testing.
12) Re-install the outer case (cabinet).
13) Reconnect the power supply cord after the outer case is installed.
14) Run the oven and check all functions.

17
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R-120DW
1 VSS IN Power source voltage: -5V.
VSS voltage of power source circuit input.
2 XIN IN Internal clock oscillation frequency setting input.
Theinternalclockfrequencyissetbyinsertingthecapacitor-resistoroscillationcircuit
with respect to XOUT terminal.
3 XOUT OUT Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
4 TEST IN Connected to VC.
5 VDD IN Power source voltage input terminal.
Connected to GND.
6-7 P21-P22 IN/OUT Terminal not used.
8 RESET IN Auto clear terminal.
Signalis input to reset the LSI to the initial state when power is supplied. Temporarily
set"L"levelthemomentpower issupplied,at thistimethe LSIisreset. Thereafterset
at "H" level.
9 P20 IN/OUT Terminal not used.
10-12 AIN0-AIN2 IN Terminal to change functions according to the Model.
By using the A/D converter contained in the LSI, DC voltage in accordance with the
Model in operation is applied to set up its function.
13 INT0 IN Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
14 AIN4 IN Signal coming from touch tact switch.
WhentactswitchSW8,SW9 andSW10onswitchmatrixistouched,acorresponding
signal out of P10-P13 will be input into AIN4.
15 AIN5 IN Signal coming from touch tact switch.
When either one of tact switches SW4, SW5, SW6 and SW7 on switch matrix is
touched, a corresponding signY\ out of P10-P13 will be input into AIN5.
16 AIN6 IN Signal coming from touch tact switch.
When either one of tact switch SW1, SW2 and SW3 on switch matrix is touched, a
corresponding signal out of P10-P13 will be input into AIN6 when no key is touched,
the signal is held at "H" level.
17 AIN7 IN To input signal which communicates the door open/close information to LSI.
Door close "H" level signal (0V). Door open "L" level (-5V).
18 VAREF IN Connected to GND.
19 AVDD IN Connected to GND.
20 P10 OUT Switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to AIN4-AIN6 terminal
while one of tact switches SW1, SW5 and SW8 on switch matrix is touched.
21 P11 OUT Switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to AIN4-AIN6 terminal
while one of tact switches SW2, SW6 and SW9 on switch matrix is touched.
22 P12 OUT Switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to AIN4-AIN6 terminal
while one of tact switches SW3, SW7 and SW10 on switch matrix is touched.
23 P13 OUT Switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to AIN4-AIN6 terminal
while tact switch SW4 on switch matrix is touched.
24 P14 IN/OUT Terminal not used.
25 P15 OUT Terminal not used.
DESCRIPTION OF LSI
LSI(IXA038DR)
The I/O signal of the LSI(IXA038DR) are detailed in the following table.
Pin No. Signal I/O Description
16.7 msec.
H : GND
L : -5V

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26-27 P16-17 OUT Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2).
Thesignalsholds "L"level duringmicro-
wave cooking and "H" level while not
cooking.
28-34 P50-P56 IN/OUT Terminal not used.
35 P57 OUT Oven lamp, fan motor and turntable motor driving signal.
Toturn onand offshut offrelay (RY1).
Thesquarewaveform voltageis deliv-
eredtotheRY1drivingcircuitandRY2
control circuit.
36-39 SEG15-SEG12 IN/OUT Terminal not used.
40-51 SEG0-SEG11 OUT Segment data signal.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.) LCD (Pin No.) LSI signal (Pin No.) LCD (Pin No.)
SEG 0 (51).............................. S1 SEG 6 (45)............................... S7
SEG 1 (50).............................. S2 SEG 7 (44)............................... S8
SEG 2 (49).............................. S3 SEG 8 (43)............................... S9
SEG 3 (48).............................. S4 SEG 9 (42)............................. S10
SEG 4 (47).............................. S5 SEG 10 (41)........................... S11
SEG 5 (46).............................. S6 SEG 11 (40)........................... S12
52 COM3 OUT Terminal not used.
53 COM2 OUT Common data signal:COM1.
Connected to LCD (Pin No. C3)
54 COM1 OUT Common data signal:COM2.
Connected to LCD (Pin No. C2)
55 COM0 OUT Common data signal:COM1.
Connected to LCD (Pin No. C1)
56 V3 IN Connected to GND.
57-58 V1,V2 IN Power source voltage input terminal.
Standard voltage for LCD.
59-60 C1-C0 IN/OUT Terminal not used.
61 P30 OUT Signal to sound buzzer (2.0 kHz).
A: tact switch touch sound.
B: Completion sound.
62-64 P31-P33 IN/OUT Terminal not used.
Pin No. Signal I/O Description
P-HI
H : GND
L : -5V
H : GND
L : -5V
P-70
ON
ON
OFF
OFF OFF
24 sec.
8 sec.
16.7 msec.
During cooking
H : GND
L : -5V
A
B
0.1 sec.
2 sec.
H : GND
L : -5V
H : GND
L : -5V