Sharp R-244(W)M User manual

R-244M - 1
SHARP CORPORATION
SERVICE MANUAL
S40189R244M//
R
MICROWAVE OVEN
MODELS
R-244(W)M
R-244(G)M
R-244(B)M
R-244(SL)M
SERVICING ............................................................................................................................................. 2
CAUTION/WARNING............................................................................................................................... 3
PRODUCT SPECIFICATIONS ................................................................................................................ 3
APPEARANCE VIEW................................................................................................................................ .4
OPERATION SEQUENCE........................................................................................................................ 5
OUTPUT POWER TEST PROCEDURE................................................................................................... 6
TEST PROCEDURES................................................................................................................................ 7
TOUCH CONTROL ASSEMBLY .............................................................................................................. 9
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ................................................... 13
MICROWAVE MEASUREMENT PROCEDURE...................................................................................... 16
SCHEMATIC DIAGRAMS.........................................................................................................................17
PICTORIAL DIAGRAM .......................................................................................................................... 18
CONTROL PANEL CIRCUIT ................................................................................................................. 19
SWITCH UNIT CIRCUIT DIAGRAM ....................................................................................................... 20
PRINTED WIRING BOARD OF CONTROL PANEL DIAGRAM ............................................................. 21
PRINTED WIRING BOARD OF SWITCH UNIT DIAGRAM.................................................................... 22
PARTS LIST........................................................................................................................................... 23
EXPLODED DIAGRAM OF OVEN.......................................................................................................... 26
CONTROL PANEL/DOOR PARTS ......................................................................................................... 27
PACKING AND ACCESSORIES ........................................................................................................... 28
TABLE OF CONTENTS Page
In interests of user-safety the oven should be restored to its
original condition and only parts identical to those specified
should be used.

2
R-244M -
Microwaveovenscontaincircuitrycapableofproducingveryhighvoltageandcurrent.Contactwithfollowingparts
will result in electrocution:-
High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier, High voltage wires.
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 seconds after the oven has been switched off. Wait for 60
secondsandthenshort-circuittheconnectionofthehigh-voltagecapacitor(thatis,oftheconnectingleadfrom the
high-voltage rectifier) against the chassis using a screwdriver with an insulated handle.
Sharp recommend that wherever possible, fault-finding is carried out with the supply disconnected. In some cases,
it may be necessary to connect the supply with the cover removed to carry out fault investigation in the control
circuitry. In such cases, the high voltage circuit should be disabled as described below to reduce the hazards:-
• Carry out 3D checks (see above).
• Disconnect the supply leads from the high voltage transformer, making a note of the polarity. Insulate the
connectors, ensuring they are positioned away from the transformer and fastened there.
• Connect any relevant test equipment e.g. voltmeter.
• Reconnect the oven to the supply, then close the door.
• Note the results of the test, taking care to keep clear of the operational oven.
• Carry out 3D checks (see above).
• Reconnect the leads to the transformer. Take care to observe correct polarity.
• Carry out 4R checks (see below).
Microwave ovens should not be used without a load. 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 microwave timer for one (1) minute, set the
powerleveltoHIGH(100%)andpushthestartkey.Whentheone(1)minutehaselapsed(timeratzero)carefullycheck
that the water is now hot.
AFTER REPAIR REMEMBER TO CHECK 4R
1) Reconnect all leads removed from components during testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
When all service work is completed, and the oven is fully assembled, the microwave power output should be checked
and microwave leakage test carried out.
IMPORTANT: Iftheovenbecomesinoperativebecauseofablown F8AFuse,checkthemonitoredlatchswitchand
monitor switch before replacing the fuse .
WARNING: WIRING / RE-WIRING
Before carrying out any work; carry out 3D checks.
1) Disconnect the supply.
2) Open the door and wedge open.
3) Discharge the high voltage capacitor.
RE-WIRING
1) Wires must not touch:
a) High voltage parts.
b) Parts that become hot.
c) Sharp edges.
d) Movable parts.
2) Positive lock connectors are fitted correctly
3) Wires are connected correctly as per pictorial diagram.
4) No wire leads are trapped by the outer wrap.
WARNING TO SERVICE PERSONNEL
SERVICING

R-244M - 3
CAUTION / WARNING
WARNING
Servicing and repair work must be carried out only by
trained service engineers.
The parts marked '*' on the parts list and schematic
diagram have voltages in excess of 250V.
Removal of the outer wrap gives access to potential
above 250V.
Allthepartsmarked"∆"onthepartslistmaycauseundue
microwave exposure, by themselves, or when they are
damaged, loosened or removed.
CAUTION
MICROWAVE RADIATION
Donotbecomeexposedtoradiationfromthemagnetron
or other parts conducting microwave energy. All input
andoutputmicrowaveconnections,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 an-
tenna while the device is energized.
WARNING
THIS APPLIANCE MUST BE EARTHED. THE WIRES IN THIS MAINS LEAD ARE COLOURED IN
ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE
If the mains lead is replaced, only part number QACCBA030WRE4 should be used
SPECIFICATION
Power Requirements 230-240 Volts 50 Hertz Single phase, 3 wire grounded
Power Consumption 1.2kW
Power Output 800W watts nominal of RF microwave energy (measured by way of IEC60705)
Operating frequency of 2450 MHz
Case Dimensions Width 449mm / Height 282mm including foot / Depth 385mm
Cooking Cavity Dimensions Width 287mm / Height 220mm / Depth 311mm
Turntable diameter 272mm
Control Complement Touch Control System
Clock(1:00-12:59 or 0:00-23:59)
Microwave Power for Variable Cooking
Repetition Rate;
HIGH .................. Full power throughout the cooking time
MEDIUM HIGH ...................... approx. 70% of Full Power
MEDIUM ................................ approx. 50% of Full Power
MEDIUM LOW....................... approx. 30% of Full Power
LOW ...................................... approx. 10% of Full Power
EXPRESS COOK button
EXPRESS DEFROST button
POWER LEVEL/WEIGHT button
STOP/CLEAR button
START/AUTO MINUTE button
Net Weight Approx. 13.3 kg
PRODUCT DESCRIPTION
As part of our policy of continuous improvement, we reserve the right to
alter design and specifications without notice

4
R-244M -
APPEARANCE VIEW
1. Door
2. Door hinges
3. Waveguide cover
4. Oven lamp
5. Control panel
6. Rubber seal
7. Door latch openings
8. Oven cavity
9. Door seals and sealing surfaces
10. Safety door latches
11. Ventilation openings
12. Outer case
13. Power supply cord
3 4
1
10
7
6
2
98
11
5
12
13
Turntable
Roller stay
Seal packing
1. Place the roller stay on the floor of the oven cavity,
engaging shaft.
2. Then place the turntable on the roller stay.
1. DIGITAL DISPLAY
2. EXPRESS COOK pad
3. EXPRESS DEFROST pad
4. TIMER Pads
5. POWER /WEIGHT STOP/CLEAR
START/AUTO MINUTE Pads
1.
2.
3.
4.
5.
OVEN

R-244M - 5
OPERATING SEQUENCE
1. Whentheovendoorisopened,theovenlampcomeson
at this time.
MICROWAVE COOKING CONDITION
2. When the cooking time is up, a single tone is heard and
the relays RY1 + RY2 go back to their home position.
The circuits to the oven lamp, power transformer, fan
motor and turntable motor are cut off.
CONNECTED COMPONENTS RELAY
Oven lamp, Fan motor, Turntable motor RY1
Power transformer RY2
CONDITION
DURING DOOR OPEN
SWITCH CONTACT COOKING (NO COOKING)
Monitor switch COM-NC Open Closed
Monitored latch switch COM-NO Closed Open
Stop switch COM-NO Closed Open
3. When the door is opened during a cook cycle, the
switches come to the following condition.
The circuits to the power transformer, fan motor and
turntablemotorarecutoffwhenthe monitored latch switch
and stop switch are made open.
Theovenlampremains on even if the ovendoor is opened
after the cooking cycle has been interrupted, because the
relayRY1staysclosed.Showninthedisplayistheremaining
time.
HIGH, MEDIUM HIGH, MEDIUM, MEDIUM
LOW, LOW COOKING
When the microwave oven is preset for variable cooking
power,thelinevoltageissuppliedtothe powertransformer
intermittently within a 32-second time base through the
relaycontactwhichiscoupledwiththecurrent-limitingrelay
(RY2). The following levels of microwave power are given.
SETTING
MEDIUM HIGH
MEDIUM LOW
Approx. 10% = 80 Watts
32 sec. ON
6 sec. ON
12 sec. ON
18 sec. ON
24 sec. ON
26 sec. OFF
20 sec. OFF
14 sec. OFF
8 sec. OFF
LOW
MEDIUM
HIGH
Approx. 70% = 560Watts
Approx. 50% = 400 Watts
Approx. 30% = 240 Watts
NOTE: TheON/OFFtimeratiodoesnotexactlycorrespond
to the percentage of microwave power, because
approx. 3 seconds are needed for heating up the
magnetron filament.
Approx. 100% = 800 Watts
OFF CONDITION DOOR OPEN MECHANISM
The door can be opened by pulling the door.
Figure D-1. Door Open Mechanism
MONITORED LATCH SWITCH AND STOP
SWITCH
1. Whentheovendoor isclosed,thecontacts(COM-NO)
must be closed.
MONITOR SWITCH
1. Whenthe oven doorisclosed,thecontacts(COM-NC)
must be opened.
2. When the oven door is opened, the contacts (COM-
NC) must be closed.
3. If the oven door is opened and he contacts (COM-NO)
of the monitored latch switch fail to open, the fuse F1
blows immediately after closing the contacts (COM-
NC) of the monitor switch.
CAUTION: BEFORE REPLACING A BLOWN FUSE F1
TEST MONITORED LATCH SWITCH (SW1)
AND MONITOR SWITCH FOR PROPER
OPERATION. (REFERTOCHAPTER“TEST
PROCEDURE”).
FUSE
1. ThefuseF1blowswhenthecontacts(COM-NO)ofthe
monitored latch switch remain closed with the oven
door open and when the contacts (COM-NC) of the
monitor switch are closed.
2. If the wire harness or electrical components are short-
circuited,thefuseF1blowstopreventanelectricshock
or fire hazard.
HVT THERMOSTAT 150˚C
Thethermostatprotectsthehighvoltagetransformeragainst
overheating.Ifthetemperaturegoesuphigherthan150˚C
because the fan motor is interrupted or the ventilation
openings are blocked, the thermostat will cycle, line volt-
age to the high voltage transformer will also cycle. (If
operated, check the magnetron for damage.)
Latch hook
SW3: Stop switch
Door
SW2: Monitor switch
SW1: Monitored latch switch
Latch heads

6
R-244M -
MICROWAVE OUTPUT POWER (IEC-60705)
The power output of this oven is rated using the method specified by IEC-60705. Full details of how to carry out this
procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre
(part number SERV-LITMW01).
Using this procedure, the heating time to raise 1000g of water by 10°C is approximately 50 seconds.
The IEC-60705 procedure must be carried out using laboratory-type procedures and equipment. These requirements
make the procedure unsuitable for routing performance checks. An indication of the power being produced by the oven
can however be obtained using the procedure given below.
Alternative simplified method:
1. Place 2 litres of cold water (between 12°C and 20°C) in a suitable container.
2. Stir the water and measure the temperature in °C. Note temperature as T1.
3. Place the container in the microwave and heat the water for 2 minutes on full power.
4. When the 2 minutes is completed, remove the container and stir the water. Note the water temperature as T2.
5. Calculate the output power using the following formula:
R.F. Power Output = (T2 - T1) x 70.
Note: The result from this test should be within 10% of the power rating stated on the rating label.
MICROWAVE LEAKAGE TEST
This oven should be tested for microwave leakage on completion of any repair or adjustment, following the procedure
described in the Sharp Technical Training notes (part number SERV-LITMW01). The maximum leakage permitted in
BS EN 60335-2-25 is 50W/m2 (equivalent to 5mW/cm2), however it is not normal to detect any significant leakage,
therefore, any leakage which is detected should be investigated.
It is essential that only leakage detectors with current calibration traceable to the National Physical Laboratories are used.
Suitable leakage detectors : CELTEC A100
APOLLO X1
OUTPUT POWER TEST PROCEDURE
THERMAL CUT-OUT 125˚C (OVEN)
The thermal cut-out located on the top of the oven cavity is
designed to prevent damage to the oven, if the food in the
oven catch fire due to over heating produced by improper
setting of cook time or failure of control unit. Under normal
operation, the thermal cut-out remains closed. However,
when abnormally high temperatures are reached within the
oven cavity, the thermal cut-out will open at 125˚C, causing
theoventoshutdown.Thedefectivethermalcut-outmustbe
replaced with a new one.
TURNTABLE MOTOR
The turntable motor drives the turntable roller assembly to
rotate the turntable.
FAN MOTOR
The fan motor drives a blade which draws external cool air.
This cool air is directed through the air vanes surrounding
the magnetron and cools the magnetron. This air is chan-
nelledthroughtheovencavitytoremovesteamandvapours
givenofffrom heating food. It isthenexhaustedthroughthe
exhaust vents at the rear of the oven cavity.
NOISE FILTER
Thenoise filter assemblyprevents radiofrequencyinterfer-
ence that might flow back into the power circuit.
OPERATING SEQUENCE

R-244M - 7
PROCEDURE
ATOUCH CONTROL PANEL ASSEMBLY TEST
COMPONENT TEST
BTACT SWITCH TEST
1. Disconnect the oven from the power supply.
2. Discharge the high voltage capacitor.
3. Remove the control unit from the control panel.
4. By using an ohmmeter, check the tact switch operation.
5. When the tact switch is not depressed, an ohmmeter should indicate an open circuit. When the tact
switch is depressed, an ohmmeter should indicate a short circuit. If improper operation is indicated,
the tact switch is probably defective and should be checked.
CRELAY TEST
Do not touch the electrical parts and the printed wiring board to prevent an electric
CAUTION shock. Because the control unit is " TRANSLESS CIRCUIT " and all electrical parts
are used at A.C. line voltage.
ThetouchcontrolpanelconsistsofcircuitsincludingsemiconductorssuchasLSI,ICs,etc.Therefore,
unlikeconventionalmicrowaveovens,propermaintenancecannotbeperformedwithonlyavoltmeter
and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and
Switch Unit, and troubleshooting by unit replacement is described according to the symptoms
indicated.
1. Switch Unit. Note : Check switch unit lead wire harness connection before replacement.
The following symptoms indicate a defective switch unit. Replace the switch unit.
a) When touching the keys, a certain key produces no signal at all.
b) When touching a key, two figures or more are displayed.
c) When touching the keys, sometimes a key produces no signal.
2. Control Unit
The following symptoms indicate a defective control unit. Before replacing the control unit
perform the Switch unit test (Procedure M) to determine if control unit is faulty.
2-1 In connection with keys.
a) When touching the keys, a certain group of keys do not produce a signal.
b) When touching the keys, no keys produce a signal.
2-2 In connection with indicators
a) At a certain digit, all or some dots do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding dots 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.
TEST PROCEDURES
LETTER
Remove the outer case and check voltage between Pin No 5 of the 3 pin connector (A) and common
terminal of the relay (RY2) on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, 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. 18.0V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 Approx. 7.0V D.C. High voltage transformer

8
R-244M -
PROCEDURE
LETTER COMPONENT TEST
EPROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
TEST PROCEDURES
To protect the electronic circuits, this model is provided with a fine foil pattern added to the input circuit 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.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 The rated voltage is not applied between Pin Check supply voltage and oven power cord.
No. 5 of the 3 pin connector (A) and the
common terminal of the relay RY2.
2 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
3 Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".
NOTE: *At the time of making these repairs,
makeavisualinspectionofthevaristor.
Check for burned damage. If any ab-
normal condition is detected, replace
the defective parts.
(J1)
b
c d
a
51
R70
RY2
R1
D71
VRS1
ZD70
RY1
DSWITCH UNIT TEST
Ifthe displayfails toclear whentheSTOP/CLEAR
key is depressed, first verify the lead wire harness
is making good contact, verify that the stop switch
operates properly; that is the contacts are closed
whenthedoorisclosedandopenwhenthedooris
open. If the stop switch is good, disconnect the
lead wire harness that connects the switch unit to
the display unit and make sure the stop switch is
closed (either close the door or short the stop
switch connector). Use the Switch unit matrix indi-
cated on the switch unit circuit and place a jumper
wire between the pins that correspond to the
STOP/CLEAR key making momentary contact. If
the display unit responds by clearing with a beep
theswitchunitisfaultyandmustbereplaced.Ifthe
displayunitdoesnotrespond,itisafaultyandmust
bereplaced.Ifaspecifickeydoesnotrespond,the
above method may be used (after clearing the
display unit) to determine if the display unit or
switch unit is at fault.
1
2
3
4
SW4
5
6
SW5
SW6
SW7
10
sec.
10
min.
1
min.
COOK
DEFROST
STOP
CLEAR
SW8
SW1
CN - C
CN - C
6Pin HARNESS
SW2
SW3
POWER
WEIGHT
START
AUTO MINUTE

R-244M - 9
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
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
audible sounds (tact switch touch sound and completion
sound).
6) Synchronizing Signal Circuit
The power source synchronizing signal is available in
ordertocomposeabasicstandardtimeintheclockcircuit.
It accompanies a very small error because it works on
commercial frequency.
7) Door Sensing Switch (Stop Switch)
A switch to "tell" the LSI if the door is open or closed.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LED1-LED3)
The touch control section consists of the following units.
(1) Switch Unit
(2) Control Unit
The principal functions of these units and the signals
communicated among them are explained below.
Switch Unit
Theswitchunitiscomposedofamatrix,signalsgenerated
intheLSIaresenttotheswitchunitthroughR60,R61,R62
and R63.
When a switch button is touched, a signal is completed
throughtheswitchunitandpassedbacktotheLSIthrough
R81 and R83 to perform the function that was requested.
Control Unit
Control unit consists of LSI, ACL circuit, indicator circuit,
powersource circuit, relaycircuit, buzzercircuit, synchroniz-
ing signal circuit and back light circuit.
1) ACL
Thiscircuit generatesasignal which resetsthe LSI tothe
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.
3) Power Source Circuit
Thiscircuitgeneratesvoltagenecessaryinthecontrolunit
from the AC line voltage.
Symbol Voltage Application
VC +5V LSI(IC1)

10
R-244M -
HIGH
H : +5V
L : 0V
H : +5V
L : 0V
MEDIUM
HIGH
ON
ON
OFF
OFF OFF
24 sec.
8 sec.
A
B
0.1 sec.
2 sec.
H : +5V
L: 0V
H : +5V
L: 0V
20.0 msec
During cooking
H : +5V
L : 0V
20.0 msec
H : +5V
L : 0V
1-12 SEG0 - OUT Segment data signal.
SEG11 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 (1) ................................ S6 SEG 6 (7)........................... S12
SEG 1 (2) ................................ S7 SEG 7 (8)............................. S5
SEG 2 (3) ................................ S8 SEG 8 (9)............................. S4
SEG 3 (4) ................................ S9 SEG 9 (10)........................... S3
SEG 4 (5) .............................. S10 SEG 10 (11)......................... S2
SEG 5 (6) .............................. S11 SEG 11 (12)......................... S1
13 R60 OUT Tact switch strobe signal.
Signalappliedto tactswitchsection.A pulsesignalisinput toR81or R83 terminal
while the tact switch SW1 or SW8 is touched.
14 R61 OUT Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81or R83 terminal
while the tact switch SW2 or SW5 is touched.
15 R62 OUT Tact switch strobe signal.
Signalappliedto tactswitchsection.A pulsesignalisinput toR81or R83 terminal
while the tact switch SW3 or SW6 is touched.
16 R63 OUT Tact switch strobe signal.
Signalappliedto tactswitchsection.A pulsesignalisinput toR81or R83 terminal
while the tact switch SW4 or SW7 is touched.
17 AIN0 IN Toinputsignalwhichcommunicatesthedooropen/closeinformationtoLSI.
Door close "L" level signal (0V). Door open "H" level (+5V)
18-20 AIN1-AIN3 IN Terminal to change functions according to the Model.
ByusingtheA/DconvertercontainedintheLSI,DCvoltageinaccordancewiththe
Model in operation is applied to set up its function.
21 VSS IN Power source voltage: 0V.
VSS voltage of power source circuit input.
22 R70 OUT Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay
(RY2). The signals holds "L" level
during microwave cooking and "H"
levelwhilenotcooking.Inothercook-
ingmodes(variablecooking)thesig-
nal turns to "H" level and "L" level in
repetitionaccordingtothepowerlevel.
23 R71 OUT Signal to sound buzzer (2.0 kHz).
A: Tact switch touch sound.
B: Completion sound.
24 R72 OUT Oven lamp, fan motor and turntable motor driving signal.
Toturnonandoffshutoffrelay(RY1).The
square waveform voltage is delivered to
the RY1 driving circuit.
25 R73 IN Terminal not used.
26 INT2 IN Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
DESCRIPTION OF LSI
LSI(IXA085DR)
The I/O signal of the LSI(IXA085DR) are detailed in the following table.
Pin No. Signal I/O Description

R-244M - 11
Pin No. Signal I/O Description
27 R81 IN Signal coming from tact switch.
When either of tact switches SW5-SW8 is touched, a corresponding signal out of
R60,R61,R62 andR63 willbe inputinto R81.Whennotact switch istouched,the
signal is held at "H" level.
28 INT1 IN Terminal not used.
29 R83 IN Signal coming from tact switch.
When either of tact switches SW1-SW4 is touched, a corresponding signal out of
R60,R61,R62 andR63 willbe inputinto R83.Whennotact switch istouched,the
signal is held at "H" level.
30-32 R90-R92 OUT Terminal not used.
33 XIN IN Internal clock oscillation frequency setting input.
Theinternalclockfrequencyissetbyinsertingthecapacitorandresistorcircuitwith
respect to XOUT terminal.
34 XOUT OUT Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
35 RESET IN Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is supplied.
Temporarilyset"L"levelthemomentpowerissupplied,atthistimetheLSIisreset.
Thereafter set at "H" level.
36 HOLD IN/OUT Connected to VDD.
37 VLC IN Signal synchronized with commercial power source frequency.
Signal similar to VSS.
38 COM1 OUT Common data signal.
Connected to LCD(C1).
39 COM2 OUT Common data signal.
Connected to LCD(C2).
40 COM3 OUT Common data signal.
Connected to LCD (C3).
41 COM4 OUT Terminal not used.
42 VDD IN Power source voltage input terminal.
Connected to VC.
DESCRIPTION OF LSI
LSI(IXA085DR)
The I/O signal of the LSI(IXA085DR) are detailed in the following table

12
R-244M -
TOUCH CONTROL PANEL ASSEMBLY
SERVICING
1. Precautions for Handling Electronic Components
ThisunitusesCMOSLSIintheintegralpartofthecircuits.
When handling these parts, the following precautions
should be strictly followed. CMOS LSI have extremely
high impedance at its input and output terminals. For this
reason, it is easily influenced by the surrounding high
voltage power source, static electricity charge in clothes,
etc., and sometimes it is not fully protected by the built-in
protection circuit.
In order to protect CMOS LSI.
1) Whenstoring and transporting, thoroughlywrap them
in aluminium foil. Also wrap PW boards containing
them in aluminium foil.
2) When soldering, ground the technician as shown in
the figure and use grounded soldering iron and work
table.
approx. 1M ohm
2. Shapes of Electronic Components
3. 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.
Toperformtheservicing,powertothetouchcontrolpanel
is available either from the power line of the oven 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
MICROWAVEOVENISSTILLLIVEDURINGSERV-
ICING 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 transformer, or
unplug the primary terminal (connector) of the high
voltage transformer to turn it off; the end of such
connector must be insulated with an insulating tape.
After servicing, be sure to replace the leads to their
original locations.
A. On some models, the power supply cord between
the touch control panel and the oven itself is so
short that the two can't be separated.
Forthosemodels,checkandrepairallthecontrols
(sensor-relatedonesincluded)ofthetouchcontrol
ECB
Transistor
2SA1267Y
KRA101M
KRC101M
KRC105M
panel while keeping it connected to the oven.
B. On some models, the power supply cord between
the touch control panel and the oven proper is so
longenoughthattheymaybeseparatedfromeach
other.Forthose models, therefore, itis possible to
check and repair the controls of the touch control
panel while keeping it apart from the oven proper;
in this case you must short both ends of the door
sensingswitch(onPWB)ofthetouchcontrolpanel
with a jumper, which brings about an operational
state that is equivalent to the oven door being
closed. As for the sensor-related controls of the
touch control panel, checking them is possible if
thedummyresistor(s)withresistanceequaltothat
of the controls are used.
(2) Servicing the touch control panel with power
supply from an external power source:
Disconnect the touch control panel completely from
the oven proper, and short both ends of the door
sensing switch (on PWB) of the touch control panel,
which brings about an operational state that is
equivalent to the oven door being closed. Connect an
external power source to the power input terminal of
thetouchcontrolpanel,thenitispossibletocheckand
repair the controls of the touch control panel; it is also
possible to check the sensor-related controls of the
touch control panel by using the dummy resistor(s).
4. Servicing Tools
Toolsrequiredtoservicethetouchcontrolpanelassembly.
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
5. Other Precautions
1) Beforeturningonthepowersourceofthecontrolunit,
removethealuminiumfoilappliedforpreventingstatic
electricity.
2) Connecttheconnectorofthekeyunittothecontrolunit
being sure that the lead wires are not twisted.
3) Afteraluminiumfoilisremoved,becarefulthatabnormal
voltageduetostaticelectricityetc.isnotappliedtothe
input or output terminals.
4) Attachconnectors,electrolyticcapacitors,etc.toPWB,
making sure that all connections are tight.
5) Be sure to use specified components where high
precision is required.

R-244M - 13
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
1. CARRY OUT 3D CHECKS.
2. Make sure that a definite "click" can be heard when the
microwave oven door is unlatched. (Hold the door in a
closedposition with onehand, thenpushthe door open
buttonwiththeother,thiscausesthelatchheadstorise,
it should then possible to hear a "click" as the door
switches operate.)
3. Visuallycheckthedoorandcavityfaceplatefordamage
(dents, cracks, signs of arcing etc.).
Carry out any remedial work that is necessary before
operating the oven.
Do not operate the oven if any of the following conditions
exist;
1. Door does not close firmly.
2. Door hinge, support or latch hook is damaged.
3. The door seal is damaged.
4. The door is bent or warped.
5. There are defective parts in the door interlock system.
6. There are defective parts in the microwave generating
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.
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
Removal
1. CARRY OUT 3D CHECKS.
2. Remove the single (1) screw holding the green/yellow
wire to the cavity.
3. Disconnect the leads of the power supply cord from the
noise filter, referring to the Figure C-3 (a).
4. Release the power supply cord from the rear cabinet.
5. Now, the power supply cord is free.
Re-install
1. Insert the moulding cord stopper of power supply cord
into the square hole of the rear cabinet, referring to the
Figure C-3 (b). Installation of Power supply cord.
2. Install the earth wire lead of power supply cord to the
cavitywithone (1) screw andnut andtighten the screw.
3. Connectthebrownand blue wire leads ofpower supply
cordto the noisefiltercorrectly, referring tothe Pictorial
Diagram.
Figure C-3 (b) Replacement of Power Supply Cord
Figure C-3 (a) Replacement of Power Supply Cord
POWER SUPPLY CORD REPLACEMENT
OVEN CAVITY
BACK PLATE
SQUARE HOLE
MOULDING
CORD
STOPPER
POWER SUPPLY
CORD
GROMMET
MOULDING
OVEN CAVITY
BACK PLATE
BROWN WIRE
POWER
SUPPLY CORD
CHASSIS SUPPORT
BLUE WIRE
NOISE FILTER
N
L
F1
RED WHT
EARTH WIRE

14
R-244M -
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
REMOVAL
1. CARRY OUT 3D CHECKS.
2. Disconnectthewireleadsfromtheswitchesandcontrol
panel.
3. Removethecontrolpanelassemblyfromtheovencavity
front flange. Referring to chapter "CONTROL PANEL
ASSEMBLY REMOVAL".
4. Remove the two (2) screw holding the latch hook to the
oven flange.
5. Remove the latch hook assembly from the oven flange.
6. To remove the switch.
6-1. With pushing outward on the tab that is holding the
switch, turn the switch so that the post is an axis.
6-2. Pullouttheswitchfromthelatchhook.Donotbreakthe
post or tab of the latch hook.
6-3. Now the switch is free.
Re-install
1. Re-install each switch in its place. The monitored latch
switch is in the lower position and the monitor switch is
in the middle position. The stop switch is in the upper
position.
2. Re-connectwireleadstoeachswitch.Referto “Pictorial
Diagram”page 17.
3. Secure latch hook (with two (2) mounting screws) to
oven flange.
4. Re-installthe control panel assemblyto theoven cavity
front flange.
5. Re-connect wire leads to the control unit. Refer to
“Pictorial Diagram”page 17.
6. Makesurethatmonitorswitchisoperatingproperlyand
check continuity of the monitor circuit. Refer to chapter
MONITORED LATCH SWITCH, MONITOR SWITCH AND STOP SWITCH ADJUSTMENT
1. CARRY OUT 3D CHECKS.
Ifthemonitoredlatchswitch,stopswitchandmonitorswitch
donot operateproperly dueto a misadjustment,thefollow-
ing adjustment should be made.
2. Loosen the two (2) screws holding the latch hook to the
flange of the oven front face.
3. Withthedoorclosed,adjustlatchhookbymovingitback
and forth and up and down. In and out play of the door
allowedbytheupperandlowerpositionofthelatchhook
should be less than 0.5mm. The horizontal position of
the latch hook should be adjusted so that the monitor
switch is activated with the door closed. The vertical
positionof the latchhook shouldbe adjustedsothat the
stopswitchandthemonitoredlatchswitchareactivated
with the door closed.
4. Secure the screws firmly.
5. Check the operation of all switches. If each switch has
not activated with the door closed, loosen screw and
adjust the latch hook position.
After adjustment, make sure of the following.
1. In and out play of the door remains less than 0.5mm
when in the latched position. First check upper position
of latch hook, pushing and pulling upper portion of door
toward the oven face. Then check lower portion of the
latch hook, pushing and pulling lower portion of door
toward the oven face. Both results (play in the door)
should be less than 0.5mm.
2. Themonitoredlatchswitchandstopswitchinterruptthe
circuit before the door can be opened.
3. Themonitorswitch contacts (COM-NC) close when the
door is opened.
4. Re-install outer case and check for microwave leakage
around the door with an approved microwave survey
meter. (Refer to Microwave Measurement Procedure.)
Figure C-3. Latch Switch Adjustments
Latch hook
Tab
SW3: Stop switch
SW2: Monitor switch
SW1: Monitored latch switch
Tab
Tab
Latch hook
SW3: Stop switch
Door
SW2: Monitor switch
SW1: Monitored latch switch
Latch heads
“Test Procedure”, and Adjustment Procedure below.
Figure C-2. Latch Switch Removal

R-244M - 15
REMOVAL
1. Disconnect the power supply cord.
2. Open the door slightly.
3. Remove the choke cover taking care not to break clips
byinsertingan ironplate(thicknessofabout0.5mm)or
flat type screw driver to the gap between the choke
cover and door panel as shown Figure C-4 to free the
engaged parts.
4. Release choke cover from door panel.
5. Now choke cover is free.
Figure C-4. Door Disassembly
6. Releasetwo (2)pins ofdoor panel fromtwo(2) holesof
upper and lower oven hinges by lifting up.
7. 1. Remove door assy by removing screws (4).
8. Releasedoorpanelfromtabsofdoorframeandremove
door frame by sliding the door panel downward.
9. Now, door panel with inner sealer film is free.
10.Tear inner sealer film from door panel.
11.Now, door panel is free.
12.Slide latch head upward and remove it from door frame
with releasing latch spring from door frame and latch
head.
13.Now, latch head and latch spring are free.
14.Remove Glass Stopper Screw (noting position of
stopper) and slide stopper down while lifting up.
15.Slide glass towards Glass Stopper position and
then down towards the lower edge of the door
frame.
16.Liftupperedgeofglass,whichwillnowbefreefrom
upper clips and remove from lower clips.
17.Refitting is a reversal of the above when refitting,
ensure the glass and the glass stopper is in the
original position.
RE-INSTALL
1. Re-installtheouterdoorglasstothedoorframewiththe
glass stopper.
2. Hold the glass stopper with the one (1) screw.
3. Re-installlatchspringtothehead.Re-installlatchspring
to the door frame. Re-install latch head to the door
frame.
4. Re-installdoorpaneltodoorframebyfittingtabsofdoor
frame to holes of door panel.
5. Put sealer film on door panel. Refer to “Inner Sealer
Film”and figure C-6, on how to handle the new film.
6. Catchtwo(2)pinsofdoorpanelontwo(2)holeofupper
and lower oven hinges.
7. Re-install choke cover to door panel by pushing.
Note: After any service to the door;
(A) Makesurethatmonitoredlatchswitch,stopswitch
and monitor switch are operating properly. (Refer
to chapter “Test Procedures”.).
(B) An approved microwave survey meter should be
usedtoassurecompliancewithpropermicrowave
radiation emission limitation standards.
After any service, make sure of the following :
1. Door latch heads smoothly catch latch hook through
latch holes and that latch head goes through center of
latch hole.
2. Deviation of door alignment from horizontal line of
cavity face plate is to be less than 1.0mm.
3. Door is positioned with its face pressed toward cavity
face plate.
4. Check for microwave leakage around door with an
approvedmicrowavesurveymeter. (RefertoMicrowave
Measurement Procedure.)
Note: The door on a microwave oven is designed to
actasanelectronicsealpreventingtheleakage
of microwave energy from oven cavity during
cook cycle. This function does not require that
doorbe air-tight,moisture(condensation)-tight
orlight-tight.Therefore,occasionalappearance
of moisture, light or sensing of gentle warm air
movement around oven door is not abnormal
anddonotofthemselves,indicate aleakageof
microwave energy from oven cavity.
Figure C-5. Door Replacement
INNER SEALER FILM
NOTE: When carrying out any repair to the door,
do not bend or warp the slit choke (tabs on
the door panel assembly) to prevent
microwave leakage.
Installation
1. Tear away the backing film.
3. Put the pasted side of the inner sealer film on the door
panel.
10
54
12
8
7
9
11
32
1
Choke Cover
Door Frame
Putty Knife
6
Pin
Pin Lower
Oven
Hinge
Lower Oven
Hinge
Upper
Oven
Hinge Upper Oven
Hinge
Door Panel
Choke Cover
Slit Choke
Door film
Finger tab
Backing film
Figure C-6. Inner Sealer Film
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

16
R-244M -
MICROWAVE MEASUREMENT
Afteranyrepair,themicrowaveovenmustbecheckedformicrowaveleakagetoensurecontinuedsafeoperation.BSEN60335-
2-25 specifies that the maximum permitted leakage with a load of 275 ml is 50 W/m2 (equivalent to 5 mW/cm2) at a distance of
5 cm from the oven.
PREPARATION
The following items are required to carry out this test:-
1. A low form of 600 ml beaker made from an electrically non-conductive material, such as glass or plastic, with an inside
diameter of approximately 8.5 cm. This must contain 275 ±15 ml of water, at an initial temperature of 20 ±2˚C.
2. A leakage detector which hasbeen calibrated within the preceding 12months to a standard whoseaccuracy can be traced
to National Physical Laboratory Standards.
Recommended instruments are:
Apollo “XI”
Celtec “A100”
Before commencing the test, check that the leakage detector is functioning and adjusted according to the manufacturer’s
instructions, and any spacers are fitted to ensure that measurement is taken 5cm from the surface of the oven.
PROCEDURE
1. Placethebeakercontainingthewaterloadintheovencavityatthecentreoftheturntable.Theplacingofthisstandardload
in the oven is important, not only to protect the oven, but also to ensure that any leakage it is not disguised by too large a
load absorbing energy.
2. Close the oven door, andwith the powerlevelset to FULL,turn the ovenON withthe timer setfora few minutesoperation.
Should the water begin to boil before the test has been completed, it should be replaced.
3. As shown in the diagram below, move the probe slowly (not faster than 2.5 cm/sec.);-
a) around the edge of the door following the gap
b) across the face of the door
c) across any vents in the oven’s sides, rear or top
Dotted line indicates the path by the leakage detector.
Whilst the maximum leakage permitted in BS60335 2-25 is 50 /W/m 2(equivalent to 5 W/cm2),it is not normal to detect any
significant leakage, and therefore any detected leakage should be investigated.

R-244M - 17
Figure 0-1 Schematic-OFF Condition, Door Closed
SCHEMATIC DIAGRAMS
T: HIGH VOLTAGE
TRANSFORMER
WITH 150˚C THERMOSTAT
IN PRIMARY WINDING
MG: MAGNETRON
H.V. RECTIFIER
C:
H.V. CAPACITOR
0.88µF/ AC2100V
TURNTABLE MOTOR FAN MOTOR
OVEN LIGHT
D72
D3 D1
D71D70
SW3: STOP
SWITCH
CONTROL UNIT
TC: OVEN THERMAL
CUT-OUT 125˚C
SW1: MONITORED
LATCH SWITCH SW2: MONITOR SWITCH
B2
B1
A5
A1
A3
OL
FM
TTM
N.O.
N.O.
N.C.
RY-1
COM. N.O.
COM.
RY-2
EARTH
BLU BRN
LIVENEUTRAL G-Y
F1: FUSE
( F8A)
NL
0.22µ/AC250V
680K/ 0.5W
10M/ 0.5W
NOISE SUPPRESSION COIL
0.0033µ/ 250V 0.0033µ/ 250V
NOISE FILTER
230V-240v ˜50Hz
T: HIGH VOLTAGE
TRANSFORMER
WITH 150˚C THERMOSTAT
IN PRIMARY WINDING
MG: MAGNETRON
H.V. RECTIFIER
C:
H.V. CAPACITOR
0.88µF/ AC2100V
TURNTABLE MOTOR FAN MOTOR
OVEN LIGHT
D72
D3 D1
D71D70
SW3: STOP
SWITCH
CONTROL UNIT
TC: OVEN THERMAL
CUT-OUT 125˚C
SW1: MONITORED
LATCH SWITCH SW2: MONITOR SWITCH
B2
B1
A5
A1
A3
OL
FM
TTM
N.O.
N.O.
N.C.
RY-1
COM. N.O.
COM.
RY-2
EARTH
BLU BRN
LIVENEUTRAL G-Y
F1: FUSE
(F8A)
NL
0.22µ/AC250V
680K/ 0.5W
10M/ 0.5W
NOISE SUPPRESSION COIL
0.0033µ/ 250V 0.0033µ/ 250V
NOISE FILTER
230V-240v ˜50Hz
Figure 0-2 Schematic-ON Condition, Door Closed.
*NOTE: PARTS WITH POTENTIALS ABOVE 250V

18
R-244M -
Figure S-1. Pictorial Diagram
PICTORIAL DIAGRAM
NOTE: Most of the terminals are Positive Lock (No-Case type)
.
HIGH VOLTAGE COMPONENTS
SW1: MONITORED
LATCH SWITCH
SW2: MONITOR
SWITCH
TTM: TURNTABLE
MOTOR
COM.
COM.
ORG
NL
RED
WHT
ORG
N.C.
SW3: STOP SWITCH
WHT WHT
WHT
ORG ORG
ORG
WHT
ORG RED
G/Y
CONTROL UNIT
WHT WHT
ORG
BLU
BRN
RED
RED
TC: THERMAL CUT-OUT
(OVEN)
OL: OVEN
LAMP
SP30
IC1
CN-A
RY1
CN-B
RY2
1
12
5
RED
ORG
WHT
CN-A CN-B
2RED
ORG
1
3 4 5
WHT
RED
WHT WHT
RED
ORG
WHT
2 1
N.O.
COM.
N.O.
FM: FAN MOTOR
NOISE FILTER
WHT
H.V.WIRE B
MG: MAGNETRON
C: H.V. CAPACITOR
H.V. RECTIFIER
T: HIGH VOLTAGE TRANSFORMER
POWER SUPPLY CORD
LIVE
NEUTRAL
WHT

R-244M - 19
Figure S-2. Control Panel Circuit
CONTROL PANEL CIRCUIT DIAGRAM
+
–
+
–
+
–
+
–
+
–
+
–
A 1 A 5 A 3
COM
NO
B 1 B 2
R70 VSS
AIN3
AIN2
AIN1
AIN0
R63
R62
R61
R60 S1
S2
S3
S4
S5
S12
S11
S10
S9
S8
S7
S6
C3
C2
C1
SEG11
SEG10
SEG9
SEG8
SEG7
SEG6
SEG5
SEG4
SEG3
SEG2
SEG1
SEG0
22 21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
R71 23
R72 24
R73 25
INT2 26
R81 27
INT1 28
R83 29
R90 30
R91 31
R92 32
XIN 33
XOUT 34
RESET 35
HOLD 36
VLC 37
COM1 38
COM2 39
COM3 40
COM4 41
VDD 42
ab
c
dD1 R1
R1-5 1k x 5 2w
R40 1.5k 1/2w
Q20 KRA 101M
Q70 KRC105M
Q21 KRC 105M
RY1
D71
D80
JW1
D74
RY2
D3 1N4005E
D70-71 1N4005E
ZD70-71 HZ7C2
Q30 KRC 101M
R2 R3 R4 R10 27k R11 27k
LIQUID CRYSTAL DISPLAY
CN - C
CN - B
CN - A
AC(N)
OVEN LAMP FAN MOTOR TURNTABLE MOTOR
HIGH VOLTAGE TRANSFORMER
DOOR SWITCH
NOTE :
AC(L)
FM
CN-C
5
CN-C
4
CN-C
3
CN-C
2
CN-C
1CN-C
6
IC1 IXA085DR
R5
: IF NOT SPECIFIED 1/4W ±5% : IF NOT SPECIFIED 1SS270A : IF NOT SPECIFIED 0.01µF/16V
1N4005E
1N4005E
LED1 LED2 LED3
10G471K
VRS1
D2
ZD21 ZD20
SP30
D10
D20
D72
C80
R73 15k
R70 360 1w
R71 360 1w
ZD71 ZD70
D70
D73
R30 3.3k
R20
8.2k
R72
8.2k
R31 15k
R81
4.7k
R80
15k
R42 15k
10k
R12
R41 1k
R64 100k
RW 100k
R50 10kF
(JSW2)
(J2)(J3)
(J4)(J5)
(J6)(J7)
LED1-3
SLP-7117E
C1 220µ/16v
C20 220µ/35v
C41 47µ/16v
Q40 2SA1267Y
C21 10µ/35v
C42 0.1µ/50v C10
0.1µ
/50v
C43
C44
C50
33pF(CH)
C22 0.1µ/50v
C40 0.1µ/50v
C70 47µ/35v
C71 100µ/35v
ZD1 HZ12C1
ZD40 HZ4C3
HZ12C1 HZ12C1
FM

20
R-244M -
SWITCH UNIT CIRCUIT DIAGRAM
1
2
3
4
SW4
5
6
SW5
SW6
SW7
10
sec.
10
min.
1
min.
COOK
DEFROST
STOP
CLEAR
SW8
SW1
CN - C
CN - C
6Pin HARNESS
SW2
SW3
POWER
WEIGHT
START
AUTO MINUTE
Figure S-3. Switch Unit Circuit