Sharp R-3A88 User manual

R-3A88
SHARP CORPORATION
SERVICE MANUAL
In interests of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.
MODEL R-3A88
S3614R3A88PX/
MICROWAVE OVEN
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
CONTROL PANEL CIRCUIT ...............................................................................................................................27
PRINTED WIRING BOARD .................................................................................................................................28
PARTS LIST ....................................................................................................................................................... 29

R-3A88

R-3A88
1
SERVICE MANUAL
PRODUCT SPECIFICATIONS
SHARP CORPORATION
OSAKA, JAPAN
TEST PROCEDURE
SERVICING AND
TROUBLESHOOTING CHART
FUNCTION OF IMPORTANT
COMPONENTS
OPERATING SEQUENCE
APPEARANCE VIEW
MICROWAVE MEASUREMENT
WIRING DIAGRAM
PARTS LIST
TOUCH CONTROL PANEL
ASSEMBLY
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
MICROWAVE OVEN
R-3A88
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.
Serviceengineersshouldnotbeexposedtothemicrowave
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
microwave exposure, by themselves, or when they are dam-
aged, loosened or removed.

R-3A88
2
PRODUCT SPECIFICATIONS
ITEM DESCRIPTION
Power Requirements 220 Volts
50 Hertz
Single phase, 3 wire earthed
Power Consumption 1.35 kW
Power Output 850 watts nominal of RF microwave energy (IEC 705)
Operating fequency 2450 MHz
Case Dimensions Width 520 mm
Height 305 mm
Depth 389mm
Cooking Cavity Dimensions Width 348 mm
Height 197 mm
Depth 368 mm
Turntable diameter 325mm
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
HELP pad, REHEAT pad
RICE COOK pad
STEAM MENU pad
MORE, LESS pads
INTERNATIONAL MENU pads
SLOW COOK pad
EASY DEFROST pad
NUMBER pads,
POWER LEVEL pad
AUTO START/ pad
STOP/CLEAR pad
INSTANT COOK/START pad
Set Weight Approx. 15 kg
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-3A88
3
APPEARANCEVIEW
TOUCH CONTROL PANEL
aHELP PAD
Touch to select child lock, language or demonstration modes.
Touch to get cooking information.
bREHEAT PAD
Touch to reheat 3 popular menus.
cRICE COOK PAD
Touch to cook rice, congee or porridge.
dSTEAM MENU PAD
Touch to cook steam menus.
e. INTERNATIONAL MENUE OADS
Touch to cook 3 international menus.
fSLOW COOK PAD
Touch to cook slowly and longer time.
gEASY DEFROST PAD
Touch to defrost meat by entering weight.
hMORE ( ), LESS ( ) PADS
Touch to adjust the doneness of food in one minute increments
during cooking or to increase/decrease the time whilst
programming the REHEAT, RICE COOK, STEAM MENU,
INTERNATIONAL MENU or EASY DEFROST modes.
iNUMBER PADS
Touch to enter cooking times, clock time, weight or quantity of
food.
jAUTO START/CLOCK PAD
Touch to set clock or Auto Start time.
kPOWER LEVEL PAD
Touch to select microwave power setting.
If not touched, HIGH is automatically selected.
lSTOP/CLEAR PAD
Touch to clear during programming.
Touch once to stop operation of oven during cooking; touch
twice to cancel cooking programme.
mINSTANT COOK/START PAD
Touchoncetocookfor1minuteatHIGHorincreaseby1minute
multiples each time this pad is touched during cooking.
Touch to start oven after setting programmes.
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.Earth wire
8
9
10
4 2
713
5
3
6
11 4
1
12
14
INTERACTIVE
DISPLAY
HELP
REHEAT RICE COOK STEAM MENU
INTERNATIONAL MENU
1 Dishes
3 Bread
2
Beverage
1 Rice
3 Porridge
2 Congee
1 Fish
3
Dumpling
2 Meat
Mini pizza
SLOW COOK
POWER LEVEL
INSTANTCOOK/START
AUTO START/
STOP / CLEAR
EASYDEFROST
Sukiyaki Tom Yum Kung
1234
5 
6789

O 

a
d
g
i
c
b
e
j
l
k
m
f
h
COOK KG DEF HELP
Indicator

R-3A88
4
OPERATION SEQUENCE
OFF CONDITION
Closing the door activates all door interlock switches (1st.
latch switch and 2nd. interlock relay control switch).
IMPORTANT
When the oven door is closed, the monitor switch contacts
(COM-NC) must be open.
When the microwave oven is plugged in a wall outlet, rated
voltage is supplied to the point A3+A5 in the control unit.
Figure O-1 on page 25
1. The display shows SHARP , MICRO- , WAVE
and OVEN .
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. Rated voltage. is supplied to the primary winding of the
powertransformer.Thevoltageisconvertedtoabout3.3
volts A.C. output on the filament winding and high
voltageofapproximately2000voltsA.C.onthesecondary
winding.
2. The filament winding voltage (3.3 volts) heats the
magnetron filament and the high voltage (2000 volts) is
senttothevoltagedoublingcircuit,whereitisdoubledto
negative voltage of approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the
magnetron generates a wave length of 12.24 cm. This
energy is channelled through the waveguide (transport
channel)intotheovencavity,wherethefoodisplacedto
be cooked.
4. When the cooking time is up, a signal tone is heard and
therelaysRY1+RY2gobacktotheirhomeposition.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 (NOCOOKING)
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
turntablemotorarecutoffwhenthe1st.latchswitchand
2nd. interlock relay control switch are made open. The
oven lamp remains on even if the oven door is opened
after the cooking cycle has been interrupted, because
the relay RY1 stays closed. Shown in the display is the
remaining time.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by oven
door,andmonitors theoperationofthe 1stlatchswitch
and 2nd. interlock relay.
6-1 Whentheoven door isopenedduringorafter the cycle
of a cooking program, the 1st. latch switch and 2nd.
interlock relay control switch must open their contacts
first.
Afterthat thecontacts(COM-NC) ofthemonitor switch
can be closed.
6-2. Whentheoven dooris closed,the contacts(COM-NC)
of the monitor switch must be opened. After that the
contactsofthe1st.latchswitchand2nd.interlockrelay
control switch are closed.
6-3. When the oven door is opened and the contacts of the
1st.latchswitchand2nd.interlockrelayremainclosed.
The fuse M8A will blow, because the monitor switch is
closed and a short circuit is caused.
MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW
COOKING
When the microwave oven is preset for variable cooking
power, rated voltage is supplied to the power transformer
intermittently within a 32-second time base through the
relaycontactwhichiscoupledwiththecurrent-limitingrelay.
The following levels of microwave power are given.
SETTING;
32 sec. ON
24 sec. ON
18 sec. ON
12 sec. ON
6 sec. ON
8 sec. OFF
14 sec. OFF
20 sec. OFF
26 sec. OFF
HIGH
MEDIUM HIGH
MEDIUM
MEDIUM LOW
LOW
Approx. 70%
Approx. 50%
Approx. 30%
Approx. 10%
NOTE: TheON/OFFtimeratiodoesnotexactlycorrespond
to the percentage of microwave power, because
approx. 2 seconds are needed for heating up the
magnetron filament.

R-3A88
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.
Whentheopenbuttonispushed,theopenbuttonpushesup
the switch lever, and then the switch lever pushes up the
latch head. The latch heads are moved upward and re-
leased from latch hook. Now the door will open.
LATCH
HEADS
LATCH HOOK
2ND. INTERLOCK
RELAY CONTROL
SWITCH
MONITOR 
SWITCH
SWITCH
LEVER
1ST. LATCH
SWITCH
Figure D-1. Door Open Mechanism
1ST. LATCH SWITCH AND 2ND. INTERLOCK RE-
LAY CONTROL SWITCH
1. When the oven door is closed, the contacts (COM-NO)
must be closed.
2. Whentheovendoorisopened,thecontacts.(COM-NO)
must be opened.
MONITOR SWITCH
1. When the oven door is closed, the contacts (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 the contacts (COM-NO)
of the 1st. latch switch and 2nd. interlock relay fail to
open, the fuse M8A blows simultaneously with closing
the contacts (COM-NC) of the monitor switch.
CAUTION: BEFORE REPLACING A BLOWN FUSE M8A
TEST THE 1ST. LATCH SWITCH, 2ND. IN-
TERLOCK RELAY, 2ND. INTERLOCK RELAY
CONTROLSWITCH,MONITORSWITCHAND
MONITORRESISTORFORPROPEROPERA-
TION.
MONITOR RESISTOR R 0.8Ω20W
The monitor resistor prevents the fuse M8A bursting when
the fuse M8A blows due to the operation of the monitor
switch.
FUSE M8A
1. ThefuseM8Ablowswhenthecontacts(COM-NO)ofthe
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 M8A blows to prevent an electric
shock or fire hazard.
THERMAL CUT-OUT TC 145˚C (MG)
This thermal cut-out protects the magnetron against over-
heating. If the temperature goes up higher than 145˚C
because the fan motor is interrupted, the ventilation open-
ings are blocked, the thermal cut-out will open and the line
voltage to the power transformer will be cut off and the
operation of the magnetron will be stopped.
The defective thermal cut-out must be replaced with new
one.
THERMAL CUT-OUT TC 145˚C (OVEN)
The thermal cut-out located on the top of the oven cavity is
designed to prevent damage to the oven if the foods in the
oven catch fire due to over heating produced by improper
setting of cook time or failure of control unit. Under normal
operation, the oven thermal cut-out remains closed. How-
ever, when abnormally high temperatures are reached
within the oven cavity, the oven thermal cut-out will open at
145˚C, causing the oven to shut down. The defective
thermal cut-out must be replace with new one.
THERMAL CUT-OUT 95˚C (FAN MOTOR)
Thethermalcut-out protectthefanmotor against overheat-
ing.Ifitstemperaturegoesuphigherthan95˚Cbecausethe
fanmotorislockedortheventilation operating are blocked,
the contacts of the thermal cut-out will open and switch off
the oven. When the oven cools itself down to 75˚C, the
contacts of the thermal cut-out will close again.
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-
nelled through the oven cavity to remove steam and va-
pours given off from the heating foods. It is then exhausted
through the exhausting air vents at the oven cavity

R-3A88
6
SERVICING
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of producing very high voltage and current, contact with any part 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
The high-voltage capacitor remains charged about
60 seconds after the oven has been switched off.
Wait for 60 seconds and then short-circuit the con-
nection of the high-voltage capacitor (that is, of the
connectingleadof thehigh-voltagerectifier)against
thechassiswith theuseofan insulated screwdriver.
Sharp recommend that wherever possible fault-finding
is carried out with the supply disconnected. It may in,
some cases, be necessary to connect the supply after
theouter casehasbeen removed,inthis eventcarryout
3D checks and then disconnect the leads to the primary
of the power transformer. Ensure that these leads re-
main isolated from other components and the oven
chassis. (Use insulation tape if necessary.) When the
testing is completed carry out 3D checks and reconnect
the leads to the primary of the power transformer.
REMEMBER TO CHECK 4R
1) Reconnectallleadsremovedfromcomponentsduring
testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
Microwave ovens should not be run empty. To test for
thepresenceofmicrowave energy withinacavity,place
acupofcoldwateronthe oven turntable, close the door
andset the microwavetimerfor two(2)minutes.Setthe
powerleveltoHIGHand push the START button. When
the two minutes has elapsed (timer at zero) carefully
checkthatthewaterisnowhot.Ifthewaterremainscold
carry out3D checks and re-examine the connections to
the component being tested.
Whenallserviceworkiscompleted,andtheoven isfullyassembled,themicrowavepoweroutputshouldbechecked
and microwave leakage test carried out
TROUBLESHOOTING GUIDE
When troubleshooting the microwave oven, it is helpful to
follow the Sequence of Operation in performing the
checks. Many of the possible causes of trouble will require
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
ofablownfuseM8Ainthe1st.latchswitch
- 2nd. interlock relay - monitor switch -
monitorresistorcircuit,checkthe1st.latch
switch, 2nd. interlock relay, 2nd. interlock
relay control switch, monitor switch and
monitor resistor before replacing the fuse
M8A.

R-3A88
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 145˚C FAN MOTOR TURNTABLE MOTOR FUSE M8A 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
Home fuse blows when power
supply cord is plugged into wall
outlet.
FUSE M8A blows when power
supply cord is plugged into wall
outlet.
Display does not show anything
whenpowersupplycordisplugged
into wall outlet.
Display does not operate prop-
erly when STOP/CLEAR pad is
touched.
Oven lamp does not light at door
opened. (Display appears.)
Oven does not start when the
START pad is touched. (Display
appears)
Ovenlampdoes notlight(Display
appears.)
Fanmotordoesnotoperate.(Dis-
play appears.)
Turntable motor assembly does
not operate. (Display appears.)
Oven or any electrical parts does
notstopwhencookingtimeis0or
STOP/CLEAR pad is touched.
Oven seems to be operating but
little or no heat is produced in
ovenload.(Microwavepowerlevel
is set at HIGH)
Oven does not seems to be oper-
ating properly when MEDIUM
HIGH, MEDIUM, MEDIUM LOW
or LOW is set. (Oven operates
properly at HIGH and when the
STOP/CLEARpad istouched the
oven stops.)
Oven goes into cook cycle but
shutsdownbeforeend of cooking
cycle.
OvenstopsassoonastheSTART
pad is touched.
OFF
CONDITION
PROBLEM
CONDITION
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
TEST PROCEDURE
ON
CONDITION
CK = Check / RE = Replace
ABC D E E EGFFHHI KLMNRECKCKRE CK CKCKCK CK

R-3A88
8
TEST PROCEDURES
PROCEDURE
LETTER
CARRY OUT 3D CHECK.
Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal.
To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron
filament terminals, the meter should show a reading of less than 1 ohm.
To test for short filament to anode condition, connect ohmmeter between one of the filament terminals
and the case of the magnetron (ground). This test should be indicated an infinite resistance. If a low or
zero resistance reading is obtained then the magnetron should be replaced.
MICROWAVE OUTPUT POWER (IEC 705)
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.
Tomeasurethemicrowaveoutputpower inthemicrowaveoven, therelationof calorieandwattis used.
When P(W) heating works for t(second), approximately P x t/4.187 calorie is generated. On the other
hand, if the temperature of the water with V(ml) rises∆T (°C) during this microwave heating period, the
calorie of the water is V x ∆T.
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL
WHILE THE OVEN IS IN OPERATION.
AMAGNETRON TEST
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 PowersupplyVoltage.........Ratedvoltage
Water load.........1000 g Initial temperature...........10±2°C Heating time.........49 sec.
P = 85 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. Selecttheinitialandfinalwatertemperaturesothatthemaximumdifference between the final water
temperature and the ambient temperature is 5˚C.
5. Select stirring devices and measuring instruments in order to minimize addition or removal of heat.
6. Thegraduation ofthethermometermustbescaledby 0.1°Cat minimumandaccurate thermometer.
7. The water load must be (1000±5) g.
8. “t” is measured while the microwave generator is operating at full power. Magnetron filament heat-
up time is not included.
NOTE:The operation time of the microwave oven is “t + 2” sec. 2 sec. is magnetron filament heat-up time.
Measuring method:
1. Measure the initial temperature of the water before the water is added to the vessel.
(Example: The initial temperature T1 = 11°C)
2. Add the 1 litre water to the vessel.
3. Place the load on the centre of the shelf.
4. Operate the microwave oven at HIGH for the temperature of the water rises by a value ∆T of
(10 ±2)˚C.
5. Stir the water to equalize temperature throughout the vessel.
COMPONENT TEST

R-3A88
9
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
6. Measure the final water temperature. (Example: The final temperature T2 = 21°C)
7. Calculate the microwave power output P in watts from above formula.
Initial temperature .................................................................................................. T1 = 11°C
Temperature after (49 + 2) = 51 sec. ..................................................................... T2 = 21°C
Temperature difference Cold-Warm.................................................................... ∆T1 = 10°C
Measured output power
The equation is “P = 85 x ∆T” ...................................................... P = 85 x 10°C = 850 Watts
JUDGMENT: The measured output power should be at least ±15 % of the rated output power.
CAUTION: 1°C CORRESPONDS TO 85 WATTS REPEAT MEASUREMENT IF THE POWER IS
INSUFFICIENT.
1000g
1000g
1000g
T1˚C T2˚C
Heat up for51 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
secondarywindingconnectionsfromtherestoftheHVcircuitry.Usinganohmmeter,setonalowrange,
it is possible to check the continuity of all three windings. The following readings should be obtained:
a. Primary winding ....................approx. 1.4 Ω
b. Secondary winding ...............approx. 98 Ω
c. Filament winding...................less than 1Ω
Ifthereadingobtainedarenotstatedasabove,thenthepowertransformerisprobablyfaultyandshould
be replaced.
CARRY OUT 4R CHECKS.
C HIGH VOLTAGE RECTIFIER ASSEMBLY TEST
HIGH VOLTAGE RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested
using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C of the high
voltage rectifier and note the reading obtained. Reverse the meter leads and note this second reading.
The normal resistance is infinite in one direction and more than 100 kΩin the other direction.

R-3A88
10
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER COMPONENT TEST
BC
HIGH VOLTAGE RECTIFIER
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, 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.
D HIGH VOLTAGE CAPACITOR 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. Anormalcapacitorshowscontinuityforashorttime(kick)andthenaresistanceofabout10MΩafterithas
been charged.
D. A short-circuited capacitor shows continuity all the time.
E. An open capacitor constantly shows a resistance about 10 MΩbecause of its internal 10MΩresistance.
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.
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
Released O.C. S.C.
Depressed S.C. O.C.
COM; Common terminal,
NO; Normally open terminal
NC; Normally close terminal
S.C.; Short,
O.C.; Open circuit
If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.
CARRY OUT 4R CHECKS.
FTHERMAL CUT-OUT TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the thermal cut-out. Then using an ohmmeter, make a
continuity test across the two terminals as described in the 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 145˚C This is not resetable type Above 145˚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.
An open circuit thermal cut-out 145˚C (MG) indicates that the magnetron has overheated, this may be
due to resistricted ventilation, cooling fan failure or a fault condition within the magnetron or HV circuit.
An open circuit thermal cut-out 145˚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.
An open circuit thermal cut-out 95˚C (FAN) indicates that the fan motor winding has overheated, this
may be due to blocked ventilation or locked cooling fan.

R-3A88
11
PROCEDURE
LETTER COMPONENT TEST
TEST PROCEDURES (CONT'D)
CARRY OUT 3D CHECKS.
Disconnecttheleadsfromthemonitorresist.Usinganohmmeterandsetonalowrange.Checkbetween
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.
G MONITOR RESISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor.
Using an ohmmeter, check the resistance between the two terminals as described in the table below.
HMOTOR WINDING TEST
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 370 Ω
Turntable motor Approximately 16.08 kΩ
If incorrect readings are obtained, replace the motor. CARRY OUT 4R CHECKS
IBLOWN FUSE F M8A
CARRY OUT 3D CHECKS.
1. If the fuse M8A 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. If the fuse M8A is blown when the door is opened, check the 1st. latch switch, 2nd. interlock relay,
2nd. interlock relay control switch, monitor switch and monitor resistor.
IfthefuseM8Aisblownbyincorrectdoorswitchingreplacethedefectiveswitch(s)andthefuseM8A.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE FUSE M8A WITH THE CORRECT VALUE REPLACEMENT.
J TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter
and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key
Unit, and troubleshooting by 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 Panel
The following symptoms indicate a defective control unit. Before replacing the control unit,
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.

R-3A88
12
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER COMPONENT TEST
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.
K KEY UNIT TEST
Ifthe displayfailsto clearwhenthe STOP/CLEARpadis depressed,firstverify theflatribbon ismarking
goodcontact, verifythatthe doorsensingswitch (stopswitch)operates properly;thatis thecontactsare
closedwhenthedoorisclosedand open when the door is open. If thedoorsensingswitch(stopswitch)
is good, disconnecct the flat ribbon cable that connects the key unit to the control unit and make sure
thedoor sensingswitchisclosed(either closethedoororshortthedoorsensingswitchconnecter).Use
the Key unit matrix indicated on the control panel schematic and place a jumper wire between the pins
that correspond to the STOP/CLEAR pad marking momentary contact. If the control unit responds by
clearing with a beep the key unit is faulty and must be replaced. If the control unit does not respond, it
isfaulty andmustbe replaced. Ifaspecific paddoesnot respond,theabove methodmaybe used(after
clearing the control unit) to determine if the control unit or key pad is at fault.
G12
G11
G10
G 9
G 8 G 7 G 6 G 5 G 4 G 3 G 2 G 1
KEY UNIT
54321
09876
EASY DEFROST Sukiyaki
INSTANT
COOK
START
REHEAT
HELP
Mini pizza
SLOW COOK RICE COOK
STEAM MENU
POWER LEVEL
STOP / CLEAR
AUTO START
Tom Yum Kung
L RELAY TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check the voltage between Pin Nos. 3 and 5 of the 3 pin connector (A) on the
control unit with an A.C. voltmeter.
The meter should indicate 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.
DC. voltage indicated .............. Defective relay.
DC.voltage not indicated........Check diodewhichis connectedtothe relay coil.If diode isgood,control
unit is defective.

R-3A88
13
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER COMPONENT TEST
RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS
RY1 APPROX. 25.0V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 APPROX. 25.0V D.C. Power transformer
CARRY OUT 4R CHECKS.
NPROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on
thePWB,thisfoilpatternactsasafuse.Ifthefoil pattern is open, follow the troubleshooting guide given
below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS OCCURANCE CAUSE OR CORRECTION
1 The rated AC voltage is not present at Check supply voltage and oven power cord.
POWER terminal of CPU connector (CN-A).
2 The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.
side of low voltage transformer. Check and repair.
3 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
4 Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".
(CARRY OUT 3D CHECKS BEFORE REPAIR)
NOTE: *At the time of making these repairs,
make a visual inspection of the varistor.
check for burned damage and examine
thetransformerwithatesterforthepres-
enceoflayershort-circuit(checkprimary
coil resistance). If any abnormal condi-
tion is detected, replace the defective
parts.
CARRY OUT 4R CHECKS.
36
VRS1
(J1)
(J2)
5
CN-A 1
a
b
cd
LOT NO.

R-3A88
14
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units
as shown in the touch control panel circuit.
(1) Key Unit
(2) Control Unit
The principal functions of these units and the signals com-
municated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals generated in
the LSI are sent to the key unit through R10, R11, R12, R13,
R20, R21 and R22.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through R00, R01,
R02 and R03 to perform the function that was requested.
Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, ACL circuit, buzzer circuit and indicator
circuit.
1) LSI
This LSI controls the key strobe signal, relay driving signal
for oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltages necessary in the control
unit.
Symbol Voltage Application
VC -5V LSI(IC1)
VP -34V Fluorescent display tube : Grid
and anode voltage
VF1 2.2Vac Filament of fluorescent display
tube
VF2 (VF1 to VF2 voltage)
3) Synchronizing Signal Circuit
Thepowersourcesynchronizingsignalisavailableinorder
to compose a basic standard time in the clock circuit. It
accompanies a very small error because it works on com-
mercial frequency.
4) ACL Circuit
A circuit to generate a signals which resets the LSI to the
initial state when power is supplied.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion sound).
6) Door Sensing Switch
A switch to “tell” the LSI if the door is open or closed.
7) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
8) Indicator Circuit
Indicator element is a Fluorescent Display.
Basically,aFluorescentDisplayistriodehavingacathode,
agridand an anode.Usually,the cathode ofa Fluorescent
Display is directly heated and the filament serves as
cathode.
The Fluorescent Display has 7-digits, 15-segments are
used for displaying figures.

R-3A88
15
DESCRIPTION OF LSI
LSI(IZA683DR)
The I/O signal of the LSI(IZA683DR) are detailed in the following table.
Pin No. Signal I/O Description
1 Vdisp IN Anode (segment) of Fluorescent Display light-up voltage: -34V
Vp voltage of power source circuit input.
2 R00 IN Signal coming from touch key.
Wheneitherone ofG12linekeysonkeymatrixistouched,acorrespondingsignaloutofR10
- R13, R20, R21 and R22 will be input into R00. When no key is touched, the signal is held
at "L" level.
3 R01 IN Signal coming from touch key.
Wheneitherone ofG11linekeysonkeymatrixistouched,acorrespondingsignaloutofR10
- R13, R20, R21 and R22 will be input into R01. When no key is touched, the signal is held
at "L" level.
4 R02 IN Signal coming from touch key.
Wheneitherone ofG10linekeysonkeymatrixistouched,acorrespondingsignaloutofR10
- R13, R20, R21 and R22 will be input into R02. When no key is touched, the signal is held
at "L" level.
5 R03 IN Signal coming from touch key.
When either one of G9 line keys on key matrix is touched, a corresponding signal out of R10
- R13, R20, R21 and R22 will be input into R03. When no key is touched, the signal is held
at "L" level.
6 TEST IN Connected to VC.
7 RESET IN Auto clear terminal.
Signalis inputto resettheLSI tothe initialstate whenpower isapplied.Temporarily setto “L”
level the moment power is applied, at this time the LSI is reset. Thereafter set at “H” level.
8 OSC1 IN Internal clock oscillation frequency input setting.
Theinternalclockfrequencyissetbyinsertingtheceramicfilteroscillationcircuitwithrespect
to OSC1 terminal.
9 OSC2 OUT Internal clock oscillation frequency control output.
Output to control oscillation input of OSC2.
10/11 GND/AVSS IN/IN Connected to VC.
12 AN0 IN Input signal which communicates the door open/close information to LSI.
Door closed; "H" level signal.
Door opend; "L" level signal.
13-14 AN1-AN2 IN Terminal to change cooking constant.
15 R33 OUT Oven lamp, turntable motor and cooling fan motor driving signal. (Square Waveform
: 50Hz)
Toturnonandoffshut-offrelay.Thesquare(50Hz)isdeliveredtotherelaydrivingcircuitand
cook relay control circuit.
16 P40 OUT Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay. In 100% power operation, the signals holds “L” level during
microwavecookingand “H”levelwhilenotcooking. Inothercookingmodes(10%,30%,50%,
70%power)thesignalturnsto “H”leveland“L”levelin repetitionaccordingtothepowerlevel.
17-19 R41-R43 OUT Segment data signal.
Refer to the touch control panel circuit for the relationship between signals and indicators.
Normally, one pulse is output in every synchronized signal period, and input to the anode of
the fluorescent display.
20/21 AVCC/VCC IN/IN Connected to GND.
22 INT IN Signal to synchronized with commercial source frequency(50Hz).
This is basic timing for time processing of LSI.
23-24 D1-D2 OUT Segment data signal.
Refer to the touch control panel circuit for the relationship between signals and indicators.
Normally, one pulse is output in every synchronized signal period, and input to the anode of
the fluorescent display.

R-3A88
16
Pin No. Signal I/O Description
25 BUZZ OUT Signal to sound buzzer.
A: key touch sound (0.12 sec.).
B: Completion sound (2.4 sec.).
26-27 D4-D5 OUT Segment data signal.
Refer to the touch control panel circuit for the relationship between signals and indicators.
Normally, one pulse is output in every synchronized signal period, and input to the anode of
the fluorescent display.
28 D6 OUT Segment data signal.
Signal similar to P41.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R00-R03 terminal while one of
G8 line keys on key matrix is touched.
29-30 D7-D8 OUT Digit selection signal.
Refertothetouchcontrolpanelcircuitabouttherelationbetweensignalsanddigits.Normally,
onepulseisoutputineverysynchronizedsignalperiod,andinputtothegridofthefluorescent
display.
31-34 R80-R83 OUT Digit selection signal.
Refertothetouchcontrolpanelcircuitabouttherelationbetweensignalsanddigits.Normally,
onepulseisoutputineverysynchronizedsignalperiod,andinputtothegridofthefluorescent
display.
35 R10 OUT Digit selection signal.
Refertothetouchcontrolpanelcircuitabouttherelationbetweensignalsanddigits.Normally,
onepulseisoutputineverysynchronizedsignalperiod,andinputtothegridofthefluorescent
display.
36 R11 OUT Segment data signal.
Signal similar to P41.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R00-R03 terminal while one of
G7 line keys on key matrix is touched.
37 R12 OUT Segment data signal.
Signal similar to P41.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R00-R03 terminal while one of
G6 line keys on key matrix is touched.
38 R13 OUT Segment data signal.
Signal similar to P41.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R00-R03 terminal while one of
G5 line keys on key matrix is touched.
39 R20 OUT Segment data signal.
Signal similar to P41.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R00-R03 terminal while one of
G4 line keys on key matrix is touched.
40 R21 OUT Segment data signal.
Signal similar to P41.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R00-R03 terminal while one of
G3 line keys on key matrix is touched.
41 R22 OUT Segment data signal.
Signal similar to P41.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to R00-R03 terminal while one of
G2 line keys on key matrix is touched.
42 R23 OUT Segment data signal.
Signal similar to P41.

R-3A88
17
SERVICING
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the circuits.
Whenhandlingtheseparts,thefollowingprecautionsshould
bestrictlyfollowed.CMOSLSI haveextremelyhighimped-
ance 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 some-
timesitisnotfullyprotectedbythebuilt-inprotectioncircuit.
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) 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
Wedescribetheprocedurestopermitservicingofthetouch
control panel of the microwave oven and the precautions
you must take when doing so. To perform the servicing,
power supply to the touch control panel 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 MICRO-
WAVE 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
touchingthehighvoltagetransformer,orunplugtheprimary
terminal (connector) of the high voltage transformer to turn
it off; and 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. Onsomemodels, the power supply cordbetweenthe touch
controlpanelandtheovenitselfissoshortthatthetwocan’t
be separated. For those models, check and repair all the
controls(sensor-relatedonesincluded)ofthetouchcontrol
panel while keeping it connected to the oven.
B. Onsomemodels, the power supply cordbetweenthe touch
control panel and the oven proper is long enough that they
may be separated from each other. For those models,
therefore, it is possible to check and repair the controls of
thetouchcontrol panelwhilekeeping it apartfromthe oven
proper; in this case you must short both ends of the door
sensing switch (on PWB) of the touch control panel with a
jumper, which brings about an operational state that is
equivalenttotheovendoorbeingclosed.Asforthesensor-
related controls of the touch control panel, checking them
is possible if dummy resistor(s) with resistance is equal to
that 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
doorbeingclosed.Connectanexternalpowersourcetothe
power input terminal of the touch control panel, then it is
possibletocheckandrepairthecontrolsofthetouchcontrol
panelitisalsopossibletocheckthesensor-relatedcontrols
of the touch control panel by using the dummy resistor(s).
4. Servicing Tools
Toolsrequiredtoservicethetouchcontrolpanelassembly.
1) Soldering iron: 30W
(Itisrecommendedtouseasolderingironwithagrounding
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,
remove the aluminium foil applied for preventing static
electricity.
2) After aluminium foil is removed, be careful that abnormal
voltageduetostaticelectricityetc.isnotappliedtotheinput
or output terminals.
3) Attach connectors, electrolytic capacitors, etc. to PWB,
making sure that all connections are tight.
4) Be sure to use specified components where high precision
is required.
Transistor
2SA933S
DTA143ES
KRA101M
KRC243M
ECB

18
R-3A88
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
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. 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.
1. Disconnect oven from power supply.
2. Make sure that a definite” click” can be heard when the
microwave oven door is unlatched. (Hold the door in a
closed position with one hand, then push the door open
button with the other, this causes the latch leads to rise,
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;
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any of
the following removal procedures:
OUTER CASE REMOVAL
To remove the outer case proceed as follows.
1. Disconnect oven from power supply.
2. Open the oven door and wedge it open.
3. Removethesix (6) screws from rear and along theright
side edge of case.
4. Slide the entire case back about 3cm to free it from
retaining clips on the cavity face plate.
5. Lift the entire case from the unit.
6. Discharge the H.V. capacitor before carrying out any
further work.
7. Do not operate the oven with the outer case removed.
N.B.; Step 1, 2 and 7 form the basis of the 3D checks.
CAUTION: DISCHARGE HIGH VOLTAGE CAPACITOR
BEFORETOUCHINGANYOVENCOMPONENT
OR WIRING.
MAGNETRON REMOVAL
4. Re-installoutercaseandcheckthattheovenisoperating
properly.
CAUTION: WHENREPLACINGMAGNETRON,BESURE
THER.F.GASKETISINPLACEANDMOUNT-
ING SCREWS ARE TIGHTENED SECURELY
Removal
1. CARRY OUT 3D CHECKS.
2. Disconnect wire leads from magnetron.
3. Remove the two (2) screws holding chassis support to
oven cavity front plate and magnetron.
4. Remove the chassis support from oven.
5. Carefully remove the two (2) screws holding magnetron
to waveguide flange.
6. Lift up magnetron with care so that magnetron antenna
is not hit by any metal object around antenna.
7. Now, the magnetron is free.
Re-install
1. Re-install the magnetron to waveguide flange with the
two (2) screws diagonally as shown in Figure C-1.
2. Re-install the chassis support to oven cavity front plate
and magnetron with the two (2) screws.
3. Reconnect the wire leads to the magnetron. Refer to
"PICTORIAL DIAGRAM". Figure C-1. Magnetron replacement
WAVEGUIDE
FLANGE
SCREWS
MAGNETRON
POWER TRANSFORMER REMOVAL
1. CARRY OUT 3D CHECKS.
2. Disconnect wire leads from power transformer, magnetron and capacitor terminals.
3. Remove four (4) screws holding transformer to bottom