Sharp R-340A User manual

R-340A
SHARP CORPORATION
SERVICE MANUAL
S7717R340APHR
MICROWAVE OVEN
MODEL R-340A
In interests of user-safety the oven should be restored to its
original condition and only parts identical to those specified
should be used.
TABLE OF CONTENTS Page
CAUTION, MICROWAVE RADIATION ............................................................................................................ 1
WARNING..........................................................................................................................................................1
PRODUCT SPECIFICATIONS......................................................................................................................... 2
GENERAL INFORMATION ............................................................................................................................... 2
APPEARANCE VIEW....................................................................................................................................... 3
OPERATION SEQUENCE ............................................................................................................................... 4
FUNCTION OF IMPORTANT COMPONENTS ................................................................................................ 5
SERVICING ...................................................................................................................................................... 6
TEST PROCEDURE ........................................................................................................................................ 8
TOUCH CONTROL PANEL ............................................................................................................................ 14
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE........................................................... 18
MICROWAVE MEASUREMENT .................................................................................................................... 24
WIRING DIAGRAM ........................................................................................................................................ 25
PICTORIAL DIAGRAM................................................................................................................................... 26
POWER UNIT CIRCUIT.................................................................................................................................. 27
CPU UNIT CIRCUIT........................................................................................................................................ 28
PRINTED WIRING BOARD ............................................................................................................................ 29
PARTS LIST.................................................................................................................................................... 30
INSTANT ACTION
Toadjust quantity - touch pad again
BEVERAGE REHEAT PIE
REHEAT PORRIDGE
REHEAT PIZZA
FRESH VEGETABLES
FROZEN VEGETABLES
JACKET POTATO
RICE
DEFROST
POWER LEVEL TIMER/CLOCK
1.
SREAK/ CHOPS
2.
ROASTMEAT
3.
POULTRY
4.
CHICKENPIECES
INSTANT COOK /START
STOP/CLEAR
1 2 3

4 5 6

7 8
O9

COOK KG DEF HELP

R-340A

R-340A
1
SERVICE MANUAL
MICROWAVE OVEN
R-340A
GENERAL IMPORTANT INFORMATION
ThisManualhasbeenpreparedtoprovideSharpCorp.Service
engineers with Operation and Service Information.
It is recommended that service engineers carefully study the
entire text of this manual, so they will be qualified to render
satisfactory customer service.
CAUTION
MICROWAVE RADIATION
DO NOT BECOME EXPOSED TO RADIATION FROM
THE MICROWAVE GENERATOR OR OTHER PARTS
CONDUCTING MICROWAVE ENERGY.
Service engineers should not be exposed to the microwave
energy which may radiate from the magnetron or other
microwave generating devices if it is improperly used or
connected. All input and output microwave connections,
waveguides, flanges and gaskets must be secured. Never
operate the device without a microwave energy absorbing
load attached. Never look into an open waveguide or
antenna while the device is energized.
WARNING
Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is not any other visible damage with the oven.
Servicing and repair work must be carried out only by trained
service engineers.
All the parts marked "*" on parts list are used at voltages more
than 250V.
Removal of the outer wrap gives access to potentials above
250V.
All the parts marked "∆" on parts list may cause undue micro-
wave exposure, by themselves, or when they are damaged,
loosened or removed.
SHARP CORPORATION
OSAKA, JAPAN
PRODUCT SPECIFICATIONS
APPEARANCE VIEW
OPERATING SEQUENCE
FUNCTION OF IMPORTANT
COMPONENTS
SERVICING AND
TROUBLESHOOTING CHART
TEST PROCEDURE
TOUCH CONTROL PANEL
ASSEMBLY
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
MICROWAVE MEASUREMENT
WIRING DIAGRAM
PARTS LIST

R-340A
2
ITEM DESCRIPTION
Power Requirements 220 Volts
50 Hertz
Single phase, 3 wire earthed
Power Consumption 1.5kW
Power Output 1000 watts nominal of RF microwave energy (IEC 705)
Operating fequency 2450 MHz
Case Dimensions Width 520 mm
Height 302 mm including foot
Depth 403 mm
Cooking Cavity Dimensions Width 348 mm
Height 212 mm
Depth 379 mm
Turntable diameter 335mm
Control Complement Touch Control System
Clock ( 1:00 - 12:59)
Timer (0 - 99 minutes 99 seconds)
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
INSTANT ACTION pads
DEFROST pad
NUMBER pads
POWER LEVEL pad
TIMER / CLOCK pad
STOP/CLEAR pad
INSTANT COOK/START pad
Set Weight Approx. 17 kg
PRODUCT SPECIFICATIONS
GENERAL INFORMATION
WARNING
THIS APPLIANCE MUST BE EARTHED
IMPOTANT
THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW : EARTH
BLUE : NEUTRAL
BROWN : LIVE

R-340A
3
APPEARANCEVIEW
1. Ventilation openings
2. Oven lamp
3. Door hinges
4. Door safety latches
5. See through door
6. Door seals and sealing
surfaces
7. Coupling
8. Door open button
9. Touch control panel
10.Digital readout
11.Wave guide cover
12.Power supply cord
13.Rating label
14.Turntable tray
15.Turntable support
TOUCH CONTROL PANEL
8
11 13
7
2
6
3
5
49
12
10
1
14
15
INSTANT ACTION
To adjust quantity - touch pad again
BEVERAGE REHEAT PIE
REHEAT PORRIDGE
REHEAT PIZZA
FRESH VEGETABLES
FROZEN VEGETABLES
JACKET POTATO
RICE
DEFROST
POWER LEVEL TIMER/CLOCK
1. 
SREAK / CHOPS
2. 
ROAST MEAT
3. 
POULTRY
4. 
CHICKEN PIECES
INSTANT COOK /START
STOP/CLEAR
123

456

78
O9

NUMBER PADS
Press to enter cooking times, clock
time or weight of food.


POWER LEVEL PAD
Press to select microwave power
setting. If not pressed, 100% is au-
tomatically selected.
Press to alter the cooking result for
automatic operations.

STOP/CLEAR PAD
Press to clear during programming.
Press once to stop operation of oven
during cooking; press twice to can-
cel cooking programme.
DEFROST PAD
Press to select the Defrost menu.


TIMER / CLOCK PAD
Press to set Clock, timer, child
lock or demonstration mode.

I NSTANT COOK/START PAD
Press to start oven after setting
programmes. Press once to cook
for 1 minute on HIGH or increase
in 1 minute increments each time
this pad is pressed during cook-
ing. 

Indicator
I NSTANT ACTION PADS
Press to cook or reheat 8 popular 
manus.

COOK KG DEF HELP

R-340A
4
OPERATION SEQUENCE
OFF CONDITION
Closingthe door activatesall door interlockswitches (1st.
latch switch and 2nd. interlock relay control switch).
IMPORTANT
Whentheovendoorisclosed,themonitorswitchcontacts
(COM-NC) must be open.
Whenthemicrowaveovenispluggedinawalloutlet,rated
voltage is supplied to the control unit.
Figure O-1 on page 25
1. The display will show flashing "88:88".
2. To set any programmes or set the clock, you must first
touch the STOP/CLEAR pad.
3. " : " appears in the display.
NOTE: When the oven door is opened, the oven lamp
comes on at this time.
MICROWAVE COOKING CONDITION
HIGH COOKING
Enter a desired cooking time with the touching NUMBER
pad and start the oven with touching START pad.
Function sequence
Figure O-2 on page 25
CONNECTED COMPONENTS RELAY
Oven lamp, Fan motor, Turntable motor RY1
Power transformer RY2
1. Ratedvoltage.issuppliedtotheprimarywindingofthe
power transformer. The voltage is converted to about
3.3 volts A.C. output on the filament winding and high
voltage of approximately 2000 volts A.C. on the
secondary winding.
2. The filament winding voltage (3.3 volts) heats the
magnetronfilamentandthehighvoltage(2000volts)is
sent to the voltage doubling circuit, where it is doubled
to negative voltage of approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the
magnetron generates a wave length of 12.24 cm. This
energyischannelledthroughthewaveguide(transport
channel)into the oven cavity,where the food isplaced
to be cooked.
4. Whenthecookingtimeisup,asignaltoneisheardand
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.
5. When the door is opened during a cook cycle, the
switches come to the following condition
CONDITION
DURING DOOR OPEN
SWITCH CONTACT COOKING (NO COOK-
ING)
1st. latch switch COM-NO Closed Open
2nd. interlock relay
control switch COM-NO Closed Open
Monitor switch COM-NC Open Closed
The circuits to the power transformer, fan motor and
turntable motor are cut off when the 1st. latch switch
and2nd. interlock relay control switchare madeopen.
The oven lamp remains on even if the oven door is
opened after the cooking cycle has been interrupted,
because the relay RY1 stays closed. Shown in the
display is the remaining time.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by
ovendoor,andmonitorstheoperationofthe1stlatch
switch and 2nd. interlock relay.
6-1 When the oven door is opened during or after the
cycle of a cooking program, the 1st. latch switch and
2nd. interlock relay control switch must open their
contacts first.
After that the contacts (COM-NC) of the monitor
switch can be closed.
6-2. When the oven door is closed, the contacts (COM-
NC) of the monitor switch must be opened. After that
thecontactsofthe1st.latchswitchand2nd.interlock
relay control switch are closed.
6-3. Whentheovendoorisopenedandthecontactsofthe
1st. latch switch and 2nd. interlock relay remain
closed.ThefuseM10Awillblow,becausethemonitor
switch is closed and a short circuit is caused.
MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW
COOKING
When the microwave oven is preset for variable cooking
power, rated voltage is supplied to the power transformer
intermittently within a 32-second time base through the
relay contact which is coupled with the current-limiting
relay. The following levels of microwave power are given.
SETTING;
HIGH 
32 sec. ON
MEDIUM HIGH Approx. 70%
24 sec. ON 8 sec. OFF
14 sec. OFF
20 sec. OFF
26 sec. OFF
MEDIUM Approx. 50%
18 sec. ON
MEDIUM LOW Approx. 30%
12 sec. ON
LOW Approx. 10%
6 sec. ON
NOTE: TheON/OFFtimeratiodoesnotexactlycorrespond
to the percentage of microwave power, because
approx. 2 seconds are needed for heating up the
magnetron filament.

R-340A
5
FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM
The door is opened by pushing the open button on the
control panel, refer to the Figure D-1.
When the open button is pushed, the open button pushes
up the switch lever, and then the switch lever pushes up
thethelatchhead.Thelatchheadsaremovedupwardand
released from latch hook. Now the door will open.
Latch Hook

2nd. Interlock
Relay Control
Switch
Monitor 
Switch
Switch
Lever
Latch
Heads
Door
1st. Latch 
Switch
Figure D-1. Door Open Mechanism
1ST. LATCH SWITCH AND 2ND. INTERLOCK
RELAY CONTROL SWITCH
1. When the oven door is closed, the contacts COM-NO)
must be closed.
2. When the oven door is opened, the contacts .(COM-
NO) must be opened.
MONITOR SWITCH
1. Whentheovendoorisclosed,thecontacts(COM-NC)
must be opened.
2. When the oven door is opened, the contacts (COM-
NC) must be closed.
3. Iftheovendoorisopenedandthecontacts(COM-NO)
of the 1st. latch switch and 2nd. interlock relay fail to
open,thefuseM10Ablows simultaneouslywithclosing
the contacts (COM-NC) of the monitor switch.
CAUTION: BEFORE REPLACING A BLOWN FUSE
M10ATESTTHE1ST.LATCHSWITCH, 2ND.
INTERLOCK RELAY, 2ND. INTERLOCK
RELAY CONTROL SWITCH, MONITOR
SWITCH AND MONITOR RESISTOR FOR
PROPER OPERATION.
MONITOR RESISTOR R 0.8Ω20W
The monitor resistor prevents the fuse M10A bursting
when the fuse M10A blows due to the operation of the
monitor switch.
FUSE M10A
1. ThefuseM10Ablowswhenthecontacts(COM-NO)of
the 1st. latch switch and 2nd. interlock relay remain
closed with the oven door open and when the monitor
switch closes.
2. If the wire harness or electrical components are short-
circuited, this fuse M10A blows to prevent an electric
shock or fire hazard.
HIGH VOLTAGE FUSE 0.75A
Thehighvoltagefuseblowswhenthehighvoltagerectifier
or the magnetron is shorted.
OVEN THERMAL CUT-OUT
Thethermal cut-out, located on thetop ofthe oven cavity,
is designed to prevent damage to the oven by fire. If the
foods load is overcooked, by either error in cook time or
defect in the control unit, the thermal cut-out will open.
Undernormaloperation,theoventhermalcut-outremains
closed.However,whenabnormallyhightemperaturesare
reached within the oven cavity, the oven thermal cut-out
will open at 125˚C, causing the oven to shut down. The
defective thermal cut-out must be replaced with new one.
MAGNETRON THERMAL CUT-OUT
The thermal cut-out located near the magnetron is de-
signed to prevent damage to the magnetron if an over
heated condition develops in the tube due to cooling fan
failure,obstructedairguide,dirtyorblockedairintake,etc.
Under normal operation, the thermal cut-out remains
closed.However,whenabnormallyhightemperaturesare
reached within the magnetron, the thermal cut-out will
open at 95˚C causing the oven to shut down, when the
magnetronhascooledto75˚C,thethermalcut-out closes
and cook cycle will resume.
TURNTABLE MOTOR
Theturntablemotordrivestheturntablerollerassemblyto
rotate the turntable.
FAN MOTOR
Thefanmotordrivesabladewhichdrawsexternalcoolair.
Thiscool air is directed throughthe air vanessurrounding
the magnetron and cools the magnetron. This air is
channeled through the oven cavity to remove steam and
vapors given off from the heating foods. It is then ex-
hausted through the exhausting air vents at the oven
cavity
NOISE FILTER
The noise filter prevents the radio frequency interference
that might flow back in the power circuit.

R-340A
6
SERVICING
WARNING TO SERVICE PERSONNEL
Microwaveovenscontaincircuitrycapableofproducingveryhighvoltageandcurrent,contactwithfollowingparts
of the high voltage circuit will result in electrocution. High voltage capacitor, Power transformer, Magnetron, High
voltage rectifier assembly, High voltage harness.
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
WARNING: AGAINST THE CHARGE OF THE
HIGH-VOLTAGE CAPACITOR
Thehigh-voltagecapacitorremainschargedabout
60 seconds after the oven has been switched off.
Wait for 60 seconds and then short-circuit the
connectionofthehigh-voltagecapacitor(thatis,of
the connecting lead of the high-voltage rectifier)
against the chassis with the use of an insulated
screwdriver.
Sharprecommendthatwhereverpossiblefault-finding
is carried out with the supply disconnected. It may in,
some cases, be necessary to connect the supply after
the outer case has been removed, in this event carry
out 3D checks and then disconnect the leads to the
primary of the power transformer. Ensure that these
leads remain isolated from other components and the
ovenchassis.(Useinsulationtapeifnecessary.)When
the testing is completed carry out 3D checks and
reconnect the leads to the primary of the power trans-
former.
REMEMBER TO CHECK 4R
1) Reconnect all leads removed from components
during testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
Microwave ovens should not be run empty. To test for
the presence of microwave energy within a cavity,
place a cup of cold water on the oven turntable, close
the door and set the microwave timer for two (2)
minutes. Set the power level to HIGH and push the
START button. When the two minutes has elapsed
(timeratzero)carefullycheckthatthewaterisnowhot.
If the water remains cold carry out 3D checks and re-
examine the connections to the component being
tested.
When all service work is completed, and the oven is fully assembled, the microwave power output should be
checked and microwave leakage test carried out
When troubleshooting the microwave oven, it is helpful to
follow the Sequence of Operation in performing the
checks.Manyofthepossiblecausesoftroublewillrequire
that a specific test be performed. These tests are given a
procedure letter which will be found in the "Test
Procedure"section.
IMPORTANT: If the oven becomes inoperative because
of a blown fuse M10A in the 1st. latch
switch-2nd.interlockrelay-monitorswitch
- monitor resistor circuit, check the 1st.
latch switch, 2nd. interlock relay control
switch,2nd.interlockrelay,monitorswitch
and monitor resistor before replacing the
fuse M10A.
TROUBLESHOOTING GUIDE

R-340A
7
MAGNETRON POWER TRANSFORMER H.V. RECTIFIER ASSEMBLY HIGH VOLTAGE CAPACITOR
1ST. LATCH SWITCH
2ND. INTERLOCK RELAY CONTROL SWITCH
MONITOR SWITCH MONITOR RESISTOR THERMAL CUT-OUT 95˚C
THERMAL CUT-OUT 125˚C
FAN MOTOR TURNTABLE MOTOR FUSE M10A TOUCH CONTROL PANEL
KEY UNIT RELAY (RY-1, RY-2) FOIL PATTERN ON P.W.B. POWER SUPPLY CORD SHORTED WIRE HARNESS OPENED WIRE HARNESS
OVEN LAMP OR SOCKET WALL OUTLET MISADJUSTMENT SWITCH HOME FUSE OR BREAKER BLOCKED COOLING FAN
BLOCKED VENTILATION NOISE FILTER HIGH VOLTAGE FUSE
Homefuseblowswhenpower
supply cord is plugged into
wall outlet.
FUSE M10A blows when
power supply cord is plugged
into wall outlet.
Display does not show any-
thingwhenpowersupplycord
is plugged into wall outlet.
Display doesnotoperateprop-
erly when STOP/CLEAR pad
is touched.
Oven lamp does not light at
door opened. (Display ap-
pears.)
Oven does not start when the
START pad is touched. (Dis-
play appears)
Ovenlampdoesnotlight(Dis-
play appears.)
Fan motor does not operate.
(Display appears.)
Turntable motor assembly
does not operate. (Display
appears.)
Oven or any electrical parts
does not stop when cooking
timeis0orSTOP/CLEARpad
is touched.
Oven seems to be operating
butlittleornoheatisproduced
in oven load. (Microwave
power level is set at HIGH)
Oven does not seems to be
operatingproperlywhenoven
is set for variable cooking
power. (Oven operates prop-
erly at HIGH and when the
STOP/CLEARpadis touched
the oven stops.)
Oven goes into cook cycle but
shutsdownbeforeendofcook-
ing cycle.
OFF
CONDITION
PROBLEM
CONDITION
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
TEST PROCEDURE
ON
CONDITION
CK = Check / RE = Replace
ABC D EEEGFFHHI LMNO RE CK CK RE CK CKCK CK CK JK

R-340A
8
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
AMAGNETRON TEST
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL
WHILE THE OVEN IS IN OPERATION.
CARRY OUT 3D CHECK.
Isolatethe magnetron from high voltagecircuit by removingall leads connected to filamentterminal.
Totestforanopencircuitfilamentuseanohmmetertomakeacontinuitytestbetweenthemagnetron
filament terminals, the meter should show a reading of less than 1 ohm.
Totestforshortfilamenttoanodecondition,connectohmmeterbetweenoneofthefilamentterminals
and the case of the magnetron (ground). This test should be indicated an infinite resistance. If a low
or zero resistance reading is obtained then the magnetron should be replaced.
MICROWAVE OUTPUT POWER (1 Litre water load)
The following test procedure should be carried out with the microwave oven in a fully assembled
condition (outer case fitted). Microwave output power from the magnetron can be measured by way
of IEC 705, i.e. it can be measured by using water load how much it can be absorbed by the water
load.Tomeasurethemicrowaveoutputpowerinthemicrowaveoven,therelationofcalorieandwatt
is used. When P(W) heating works for t(second), approximately P x t/4.187 calorie is generated. On
theotherhand,ifthetemperatureofthewaterwithV(ml)rises∆T(°C)duringthismicrowaveheating
period, the calorie of the water is V x ∆T.
The formula is as follows;
P x t / 4.187 = V x ∆T P (W) = 4.187 x V x ∆T / t
Our condition for water load is as follows:
Room temperature ......... around 20°C Power supply Voltage........... Rated voltage
Water load........1000 g Initial temperature........ 10±2°C Heating time.......42 sec.
P = 100 x ∆T
Measuring condition:
1. Container
The water container must be a cylindrical borosilicate glass vessel having a maximum material
thickness of 3 mm and an outside diameter of approximately 190 mm.
2. Temperature of the oven and vessel
The oven and the empty vessel are at ambient temperature prior to the start the test.
3. Temperature of the water
The initial temperature of the water is (10±2)°C.
4. Select the initial and final water temperature so that the maximum difference between the final
water temperature and the ambient temperature is 5˚C.
5. Selectstirringdevicesandmeasuringinstrumentsinordertominimizeadditionorremovalofheat.
6. The graduation of the thermometer must be scaled by 0.1°C at minimum and accurate
thermometer.
7. The water load must be (1000±5) g.
8. “t”ismeasuredwhilethemicrowavegeneratorisoperatingatfullpower.Magnetronfilamentheat-
up time is not included.
NOTE: The operationtime ofthemicrowave oven is“t +2”sec. 2sec.ismagnetron filamentheat-uptime.
Measuring method:
1. Measure the initial temperature of the water before the water is added to the vessel.
(Example: The initial temperature T1 = 11°C)
2. Add the 1 litre water to the vessel.
3. Place the load on the centre of the shelf.
4. Operate the microwave oven at HIGH for the temperature of the water rises by a value ∆T of
(10 ±2)˚C.
5. Stir the water to equalize temperature throughout the vessel.
6. Measure the final water temperature. (Example: The final temperature T2 = 21°C)
7. Calculate the microwave power output P in watts from above formula.

R-340A
9
Initial temperature............................................................................................. T1 = 11°C
Temperature after (42 + 2) = 44 sec................................................................. T2 = 21°C
Temperature difference Cold-Warm ............................................................... ∆T1 = 10°C
Measured output power
The equation is “P = 100 x ∆T”............................................ P = 100 x 10°C = 1000 Watts
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
JUDGMENT: The measured output power should be at least ±15 % of the rated output power.
CAUTION: 1°C CORRESPONDS TO 100 WATTS REPEAT MEASUREMENT IF THE POWER IS
INSUFFICIENT.
1000g
1000g
1000g
T1˚C T2˚C
Heat up for44 sec.
B POWER TRANSFORMER TEST
WARNING: Highvoltagesandlargecurrentsarepresentatthesecondarywindingandfilament
winding of the power transformer. It is very dangerous to work near this part when
the oven is on. NEVER make any voltage measurements of the high-voltage
circuits, including the magnetron filament.
CARRY OUT 3D CHECKS.
Disconnect the leads to the primary winding of the power transformer. Disconnect the filament and
secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a low
range, it is possible to check the continuity of all three windings. The following readings should be
obtained:
a. Primary winding ................... approx. 1.2 Ω
b. Secondary winding............... approx. 86 Ω
c. Filament winding .................. less than 1Ω
If the reading obtained are not stated as above, then the power transformer is probably faulty and
should be replaced.
CARRY OUT 4R CHECKS.
C HIGH VOLTAGE RECTIFIER ASSEMBLY TEST
CARRY OUT 3D CHECKS.
IsolatethehighvoltagerectifierassemblyfromtheHVcircuit.Thehighvoltagerectifier canbetested
using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C of the
high voltage rectifier and note the reading obtained. Reverse the meter leads and note this second
reading.Thenormalresistanceisinfiniteinonedirectionandmorethan100kΩintheotherdirection.
CARRY OUT 4R CHECKS.
NOTE: FORMEASUREMENTOFTHERESISTANCEOFTHERECTIFIER,THE BATTERIES OF THE
MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6 VOLTS, BECAUSE
OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
BC
HIGH VOLTAGE RECTIFIER

R-340A
10
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
CARRY OUT 3D CHECKS.
A. Isolate the high voltage capacitor from the circuit.
B. Continuity check must be carried out with measuring instrument which is set to the highest resistance
range.
C. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩafter
it has been charged.
D. A short-circuited capacitor shows continuity all the time.
E. Anopencapacitorconstantlyshowsaresistanceabout10MΩbecauseofitsinternal10MΩresistance.
F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
G. The resistance across all the terminals and the chassis must be infinite when the capacitor is normal.
If incorrect reading are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS.
DHIGH VOLTAGE CAPACITOR TEST
ESWITCH TEST
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the
following table.
Table: Terminal Connection of Switch
Plunger Operation COM to NO COM to NC COM; Common terminal
Released Open circuit Short circuit NO; Normally open terminal
Depressed Short circuit Open circuit NC; Normally close terminal
If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.
CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the thermal cut-out. Then using an ohmmeter, make a
continuity test across the two terminals as described in the table below.
CARRY OUT 4R CHECKS. Table: Thermal cut-out Test
Temperature of "ON" condition Temperature of "OFF" condition Indication ofohmmeter
Parts Name (closed circuit) (˚C) (open circuit) (˚C) (When room temperature
is approx. 20˚C)
Thermal cut-out 125˚C This is not resetable type. Above 125˚C Closed circuit.
Thermal cut-out 95˚C Below 75˚C Above 95˚C Closed circuit.
If incorrect readings are obtained, replace the thermal cut-out.
Anopencircuitthermalcut-out95˚C(MG)indicates that the magnetron has overheated, this maybe
duetoresistrictedventilation,coolingfanfailureorafaultconditionwithinthemagnetronorHVcircuit.
An open circuit thermal cut-out 125˚C (OVEN) indicates that the foods in the oven may catch fire,
this may be due to over heating produced by improper setting of the cooking time or failure of the
control panel.
F THERMAL CUT-OUT TEST
G MONITOR RESISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the monitor resist. Using an ohmmeter and set on a low range. Check
between the terminals of the monitor resistor.
The resistance of monitor resistor is approx. 0.8 ohms.
If incorrect readings are obtained, replace the monitor resistor. CARRY OUT 4R CHECKS.

R-340A
11
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor.
Usinganohmmeter,checktheresistancebetweenthetwoterminalsasdescribedinthetablebelow.
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 390 Ω
Turntable motor Approximately 16.08 kΩ
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
H MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
1. If the fuse M10A is blown, there could be shorts or ground in electrical parts or wire harness.
Check them and replace the defective parts or repair the wire harness.
2. IfthefuseM10Aisblownwhenthedoorisopened,checkthe1st.latchswitch,2nd.interlockrelay,
2nd. interlock relay control switch, monitor switch and monitor resistor.
Ifthe fuse M10A is blownby incorrectdoor switching replace the defectiveswitch(s) and the fuse
M10A.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE FUSE M8A WITH THE CORRECT VALUE REPLACEMENT.
I BLOWN FUSE F M10A
J NOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the noise
filter. Using an ohmmeter, check between the termi-
nals as described in the following table.
MEASURING POINT INDICATION OF
OHMMETER
Between N and L Open circuit
Between terminal N and WHITE Short circuit
Between terminal L and RED Short circuit
If incorrect readings are obtained, replace the noise filter unit.
CARRY OUT 4R CHECKS.
N
LCx L
L
Cy
WHT
RED
L (min) Cx ±20% Cy ±20%
600µH 0.068µF 0.0022µF
K HIGH VOLTAGE FUSE TEST
CARRY OUT 3D CHECKS.
If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.
Check them and replace the defective parts and the high voltage fuse.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE REPLACE-
MENT.

R-340A
12
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
L TOUCH CONTROL PANEL ASSEMBLY TEST
ThetouchcontrolpanelconsistsofcircuitsincludingsemiconductorssuchasLSI,ICs,etc.Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a
voltmeterandohmmeter.Inthisservicemanual,thetouchcontrolpanelassemblyisdivided intotwo
units, Control Unit and Key Unit, and also the Control Unit is divided into two units, CPU Unit and
Power Unit, and troubleshooting by unit replacement is described according to the symptoms
indicated.
1. Key Unit. Note: Check key unit ribbon connection before replacement.
The following symptoms indicate a defective key unit. Replace the key unit.
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.
Thefollowingsymptomsindicateadefectivecontrolunit.Beforereplacingthecontrolunit,perform
the Key unit test (Procedure K) 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.
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 troubles 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.
M KEY UNIT TEST
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable
ismakinggoodcontact,verifythatthedoorsensingswitch(stopswitch)operatesproperly;thatisthe
contacts are closed when the door is closed and open when the door is open.
Ifthedoorsensingswitch(stopswitch)isgood,disconnecttheflatribboncablethatconnectsthekey
unittothecontrolunitandmakesurethedoorsensingswitchisclosed(eitherclosethedoororshort
thedoorsensingswitchconnector). Use the key unit matrixindicatedonthecontrolpanelschematic
and place a jumper wire between the pins that correspond to the STOP/CLEAR pad making
momentarycontact.Ifthecontrolunitrespondsbyclearingwithabeepthekeyunitisfaultyandmust
be replaced. If the control unit does not respond, it is faulty and must be replaced.
If a specific pad does not respond, the above method may be used (after clearing the control unit) to
determine if the control unit or key pad is at fault.
CARRY OUT 3D CHECKS.
12
3
4
5
6
78
90
STOP
CLEAR
DEFROST
RICE
INSTANT
COOK
START
POWER
LEVEL TIMER
CLOCK
REHEAT
PIZZA
REHEAT
PIE
JACKET
POTATO
REHEAT
PORRIDGE
BEVERAGE
FRESH
VEGETABLES
FROZEN
VEGETABLES
G12
G11
G10
G 9
G 8 G 7 G 6 G 5 G 4 G 3 G 2 G 1

R-340A
13
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary
onthePWB,thisfoilpatternactsasafuse.Ifthefoilpatternisopen,followthetroubleshootingguide
given below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 The rated AC voltage is not present between Check supply voltage and oven power cord.
Pin No. 3 of the 2-pin connector (A) and the
common terminal of the relay RY2.
2 The rated AC voltage is present to primary Low voltage transformer or secondary circuit defective.
side of low voltage transformer. Check and repair.
3 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
4 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 and
examine the transformer with a tester
for the presence of layer short-circuit
(check the primary coil resistance). If
any abnormal condition is detected,
replace the defective parts.
CARRY OUT 4R CHECKS.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
O PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
Remove the outer case and check voltage between Pin No 3 of the 2-pin connector (A) and the
commonterminaloftherelayRY2onthepowerunitwithanA.C.voltmeter.Themetershouldindicate
220 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 or
convection 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. 13.1V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 APPROX. 11.7V D.C. Power transformer
CARRY OUT 4R CHECKS.
N RELAY TEST
RY2
a
b
cd
HVT
AC
(COM)
VH
XH
3
3
CN - A
(J1)

R-340A
14
The touch control section consists of the following units.
(1) Key Unit
(2) Control Unit (The Control Unit consists of Power Unit
and CPU Unit).
The principal functions of these units and the signals
communicated among them are explained below.
Key Unit
Thekeyunitiscomposedofamatrix,signalsgeneratedin
theLSIaresenttothekeyunitthroughP20-P26andAN3.
Whenakeypadistouched,asignal is completed through
thekeyunitand passedbacktotheLSIthroughP44-P47
to perform the function that was requested.
Control Unit
Control unit consists of LSI, ACL circuit, indicator circuit,
powersource circuit, relay circuit,buzzer circuit, synchro-
nizing signal circuit and back light circuit.
1) ACL
This circuit generates a signal which resets the LSI to
the initial state when power is supplied.
2) Indicator Circuit
This circuit consists of 25 segments and 4 common
electrodes using a Liquid Crystal Display.
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
3) Power Source Circuit
Thiscircuitgeneratesvoltagesnecessaryinthecontrol
unit from the AC line voltage.
In addition, the synchronizing signal is available in
order to compose a basic standard time in the clock
circuit.
Symbol Voltage Application
VC -5.1V LSI(IC1)
4) Relay Circuit
A circuit to drive the magnetron, fan motor, turntable
motor and light the oven lamp.
5) Buzzer Circuit
The buzzer is responds to signals from the LSI to emit
audible sounds (key touch sound and completion
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.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1 - LD5).
Pin No. Signal I/O Description
DESCRIPTION OF LSI
LSI(IZA813DR):
The I/O signal of the LSI(IZA813DR) is detailed in the following table.
1-2 VL2-VL1 IN Power source voltage input terminal.
Standard voltage for LCD.
3-6 AN7-AN4 IN Terminal to change cooking input according to the Model.
ByusingtheA/DconvertercontainedintheLSI,DCvoltageinaccordancewiththe
Model in operation is applied to set up its cooking constant.
7 AN3 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G1 line keys on key matrix is touched.
8 AN2 IN Toinputsignalwhichcommunicatesthedooropen/closeinformationtoLSI.
Door closed "H" level signal (0V). Door opened "L" level signal (-5V)
9-10 P61-P60 OUT Terminal not used.
11 P57 OUT Terminal not used.
12 P56 OUT Oven lamp, fan motor and turntable motor driving signal.
Toturnonandoffshutoffrelay(RY1).The
square waveform voltage is delivered to
the RY1 driving circuit and RY2 control
circuit.
20.0 msec.
During cooking
H : GND
L : -5V

R-340A
15
Pin No. Signal I/O Description
13 P55 OUT Terminal not used.
14 P54 OUT Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
15 P53 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)the sig-
nal turns to "H" level and "L" level in
repetitionaccordingtothepowerlevel. (ON and OFF times for other power level.)
16-18 P52-P50 OUT Terminal not used.
19 P47 IN Signal coming from touch key.
When either G12 line on key matrix is touched, a corresponding signal out of AN3
and P20 - P26 will be input into P47. When no key is touched, the signal is held at
"H" level.
20 P46 IN Signal similar to P47.
WheneitherG11lineonkeymatrixistouched,acorrespondingsignalwillbeinput
into P46.
21 P45 IN Signal similar to P47.
WheneitherG10lineonkeymatrixistouched,acorrespondingsignalwillbeinput
into P45.
22 P44 IN Signal similar to P47.
When either G9 line on key matrix is touched, a corresponding signal will be input
into P44.
23 P43 OUT Terminal not used.
24 INT0 IN Signal synchronized with commercial power source frequency.
Thisisthebasictimingfortimeprocessing
of LSI.
25 P41 OUT Terminal not used.
26 P40 IN Connected to VC.
27 RESET IN Auto clear terminal.
SignalisinputtoresettheLSItotheinitialstatewhenpowerisapplied.Temporarily
setto"L"levelthemomentpowerisapplied,atthistimetheLSIisreset.Thereafter
set at "H" level.
28-29 P71-P70 OUT Terminal not used.
30 XIN OUT Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XIN terminal.
31 XOUT OUT Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
32 VSS IN Power source voltage: -5.0V.
VC voltage of power source circuit input.
33 P27 OUT Terminal not used.
34 P26 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G8 line keys on key matrix is touched.
35 P25 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G7 line keys on key matrix is touched.
A
B
0.12 sec.
2.4 sec.
H : GND
L : -5V
H : GND
L : -5V
P-HI
H : GND
L : -5V
H : GND
L : -5V
P-70
ON
ON
OFF
OFF OFF
24 sec.
8 sec.
20.0 msec.
H : GND
L : -5V

R-340A
16
Pin No. Signal I/O Description
36 P24 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G6 line keys on key matrix is touched.
37 P23 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G5 line keys on key matrix is touched.
38 P22 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G4 line keys on key matrix is touched.
39 P21 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G3 line keys on key matrix is touched.
40 P20 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G2 line keys on key matrix is touched.
41-44 P17-P14 OUT Terminal not used.
45-47 P13-P11 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.)
P13 (45)......................... S16 (25) SEG 13 (59)....................S20 (12)
P12 (46)......................... S15 (24) SEG 11 (61)....................S21 (11)
P11 (47)......................... S14 (23) SEG 10 (62)....................S22 (10)
SEG 24 (48)................... S13 (22) SEG 9 (63).......................S23 ( 9)
SEG 23 (49)................... S12 (21) SEG 8 (64).......................S24 ( 8)
SEG 22 (50)................... S11 (20) SEG 7 (65).......................S25 ( 7)
SEG 21 (51)................... S10 (19) SEG 6 (66).......................S26 ( 6)
SEG 19 (53)..................... S9 (18) SEG 5 (67)........................S 4 ( 5)
SEG 18 (54)..................... S8 (17) SEG 3 (69)........................S 3 ( 4)
SEG 17 (55)..................... S7 (16) SEG 2 (70)........................S 2 ( 3)
SEG 16 (56)..................... S6 (15) SEG 1 (71)........................S 1 ( 2)
SEG 15 (57)..................... S5 (14) SEG 0 (72)........................S 0 ( 1)
SEG 14 (58)................... S19 (13)
48-51 SEG24-SEG21 OUT Segment data signal.
Signal similar to P13.
52 SEG20 OUT Terminal not used.
53-59 SEG19-SEG13 OUT Segment data signal.
Signal similar to P13.
60 SEG12 OUT Terminal not used.
61-67 SEG11-SEG5 OUT Segment data signal.
Signal similar to P13.
68 SEG4 OUT Terminal not used.
69-72 SEG3-SEG0 OUT Segment data signal.
Signal similar to P13.
73/74 VCC/VREF IN Connected to GND.
75 AVSS IN Connected to VC.
76 COM3 OUT Common data signal: COM3.
Connected to LCD signal C3 (Pin No. 29)
77 COM2 OUT Common data signal: COM2.
Connected to LCD signal C2 (Pin No. 28)
78 COM1 OUT Common data signal: COM1.
Connected to LCD signal C1 (Pin No. 27)
79 COM0 OUT Common data signal: COM0.
Connected to LCD signal C0 (Pin No. 26)
80 VL3 IN Power source voltage input terminal.
Standard voltage for LCD.

R-340A
17
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the
circuits. When handling these parts, the following
precautions should be strictly followed. CMOS LSI
haveextremely high impedance at itsinput andoutput
terminals. For this reason, it is easily influenced by the
surroundinghighvoltagepowersource,staticelectricity
charge in clothes, etc, and sometimes it is not fully
protected by the built-in protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap them
in aluminium foil. Also wrap all PW boards containing
them in aluminium foil.
2) Whensoldering,groundthetechnicianasshowninthe
figureandusegroundedsolderingironandworktable.
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. To perform
the servicing, power to the touch control panel is
availableeitherfromthepowerlineoftheovenitselfor
from an external power source.
(1) Servicingthetouchcontrolpanelwithpowersupply
of the oven:
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING
SERVICING 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.
SERVICING
approx. 1M ohm
For those models, check and repair all the controls
(sensor-related ones included) of the touch control
panel while keeping it connected to the oven.
B. On some models, the power supply cord between the
touchcontrolpanelandtheovenproperislongenough
thattheymaybeseparatedfromeach other. Forthose
models,therefore,itispossibletocheckandrepairthe
controls of the touch control panel while keeping it
apartfromtheovenproper;inthiscaseyoumustshort
both ends of the door sensing switch (on PWB) of the
touch control panel with a jumper, which brings about
anoperational state that isequivalent to the ovendoor
being closed. As for the sensor-related controls of the
touchcontrolpanel,checkingthemispossibleifdummy
resistor(s) with resistance equal to that of the controls
are used.
(2) Servicingthetouchcontrolpanelwithpowersupply
from an external power source:
Disconnectthetouchcontrolpanelcompletelyfromthe
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 the touch
controlpanel,thenitispossibletocheckandrepairthe
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
Tools required to service the touch control panel
assembly.
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) Before turning on the power source of the control unit,
removethe aluminium foilapplied for preventingstatic
electricity.
2) Connecttheconnectorofthekeyunittothecontrolunit
being sure that the lead wires are not twisted.
3) Afteraluminiumfoilisremoved,becarefulthatabnormal
voltagedueto static electricity etc. isnotappliedto the
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.
ECB
Transistor
2SA933S
KRC243M

R-340A
18
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
1. CARRY OUT 3D CHECKS.
2. Makesurethatadefinite” click”canbeheardwhenthe
microwave oven door is unlatched. (Hold the door in a
closedpositionwithonehand,thenpushthedooropen
buttonwiththeother,thiscausesthelatchleadstorise,
it is 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 gasket or seal or damaged.
4. The door is bent or warped.
5. There are defective parts in the door interlock system.
6. Therearedefective partsinthemicrowavegenerating
and transmission assembly.
7. There is visible damage to the oven.
Do not operate the oven:
1. Without the RF gasket (Magnetron).
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any
of the following removal procedures:
WARNING FOR WIRING
To prevent an electric shock, take the following
manners.
1. Before wiring,
1) Disconnect the power supply.
2) Open the door and wedge the door open.
3) Dischargethehighvoltagecapacitorandwaitfor
60 seconds.
2. Don't let the wire leads touch to the following parts;
1) High voltage parts:
Magnetron, High voltage transformer, High
voltage capacitor and High voltage rectifier
assembly.
2) Hot parts:
Ovenlamp,Magnetron,Highvoltagetransformer
and Oven cavity.
3) Sharp edge:
Bottom plate, Oven cavity, Weveguide flange,
Chassis support and other metallic plate.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch, Switch lever,
Open button.
3. Donotcatchthewireleadsintheoutercasecabinet.
4. Insert the positive lock connector certainly until its
pin is locked. And make sure that the wire leads
should not come off even if the wire leads is pulled.
5. To prevent an error function, connect the wire leads
correctly, referring to the Pictorial Diagram.
2. Secure transformer with four screws to bottom plate
right.
3. Re-connect wire leads (primary and high voltage) to
powertransformerandfilamentleadsoftransformerto
magnetron and high voltage capacitor. Refer to
"PICTORIAL DIAGRAM".
4. Re-install outer case and check that oven is operating
properly.
OUTER CASE REMOVAL
To remove the components, procedure as follows.
1. Disconnect oven from power supply.
2. Remove four(4) screws from rear and one (1) screw
along the right side edge of case.
3. Slidetheentirecasebackoutabout1inch(3cm)tofree
1. CARRY OUT 3D CHECKS.
2. Disconnect wire leads from power transformer,
magnetron and capacitor terminals.
3. Removefour(4)screws holding transformer to bottom
plate right.
4. Remove transformer from bottom plate right.
Re-install
1. Rest transformer on the bottom plate right with its
primary terminals toward the oven face plate.
POWER TRANSFORMER REMOVAL
it from retaining clips on the cavity face plate.
4. Lift entire case from the unit.
CAUTION: DISCONNECT OVEN FROM POWER SUP-
PLY BEFORE REMOVING OUTER CASE.