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R380L(W)
SERVICE MANUAL
S1701R380LPJW
MICROWAVE OVEN
HEALTHYMENUS
LOWFAT
VEGETABLES
EXPRESS
DEFROST
DEFROST
MEAL
SENSORCOOK
EASY
LESS HELP
EXPRESSMENUS
EXPRESS
QUICK&
VEGETARIAN
MEAL
EXPRESS
COOK
MEAL
RICE/
DESSERTS
PASTA
SENSOR
EASY
REHEAT
MORE
MODELS
R-380L(S)
R-380L(W)
In the interest of user-safety the oven should be restored to its
original condition and only parts identical to those specified
should be used.
CONTENTS
CHAPTER 1. BEFORE SERVICING
CHAPTER 2. WARNING TO SERVICE PERSONNEL
CHAPTER 3. PRODUCT SPECIFICATIONS
CHAPTER 4. APPEARANCE VIEW
CHAPTER 5. OPERATION SEQUENCE
CHAPTER 6. FUNCTION OF IMPORTANT COMPONENTS
CHAPTER 7. TROUBLESHOOTING GUIDE
CHAPTER 8. TEST PROCEDURES
CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY
CHAPTER 10. PRECAUTIONS FOR USING LEADFREE SOLDER
CHAPTER 11. COMPONENT REPLACEMENT AND
ADJUSTMENT PROCEDURE
CHAPTER 12. MICROWAVE MEASUREMENT
CHAPTER 13. CIRCUIT DIAGRAMS
Parts List
This document has been published to be used for
after sales service only.
The contents are subject to change without notice.
CONTENTS
CHAPTER 1. BEFORE SERVICING
CHAPTER 2. WARNING TO SERVICE PERSONNEL
CHAPTER 3. PRODUCT SPECIFICATIONS
CHAPTER 4. APPEARANCE VIEW
CHAPTER 5. OPERATION SEQUENCE
[1] OFF CONDITION........................................ 5-1
[2] MICROWAVE COOKING CONDITION....... 5-1
[3] POWER OUTPUT REDUCTION ................ 5-1
[4] SENSOR COOKING CONDITION.............. 5-1
CHAPTER 6. FUNCTION OF IMPORTANT COMPONENTS
[1] DOOR OPEN MECHANISM ....................... 6-1
[2] 1ST. LATCH SWITCH AND 2ND. IN-
TERLOCK RELAY CONTROL SWITCH..... 6-1
[3] MONITOR SWITCH ................................... 6-1
[4] FUSE F10A................................................. 6-1
[5] HIGH VOLTAGE FUSE .............................. 6-1
[6] OVEN TEMPERATURE FUSE ................... 6-1
[7] TURNTABLE MOTOR................................. 6-1
[8] FAN MOTOR............................................... 6-1
[9] NOISE FILTER............................................ 6-1
CHAPTER 7. TROUBLESHOOTING GUIDE
CHAPTER 8. TEST PROCEDURES
[1] A: MAGNETRON (MG) TEST..................... 8-1
[2] B: POWER TRANSFORMER TEST ........... 8-2
[3] C: HIGH VOLTAGE RECTIFIER TEST....... 8-2
[4] D: HIGH VOLTAGE CAPACITOR TEST..... 8-2
[5] E: SWITCH TEST ....................................... 8-3
[6] F: TEMPERATURE FUSE TEST ................ 8-3
[7] G: MOTOR WINDING TEST....................... 8-3
[8] H: FUSE F10A ............................................ 8-3
[9] I: NOISE FILTER TEST .............................. 8-3
[10] J: HIGH VOLTAGE FUSE TEST ................. 8-4
[11] K: TOUCH CONTROL PANEL ASSEM-
BLY TEST ................................................... 8-4
[12] L: KEY UNIT (MEMBRANE SWITCH)
TEST........................................................... 8-4
[13] M: RELAY TEST ......................................... 8-5
[14] N: PROCEDURES TO BE TAKEN
WHEN THE FOIL PATTERN ON THE
PRINTED WIRING BOARD (PWB) IS
OPEN.......................................................... 8-5
[15] O: AH SENSOR TEST................................ 8-5
[3] SERVICING FOR TOUCH CONTROL
PANEL ........................................................ 9-2
CHAPTER 10. PRECAUTIONS FOR USING LEADFREE SOLDER
CHAPTER 11. COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
[1] BEFORE OPERATING ..............................11-1
[2] OUTER CASE REMOVAL .........................11-1
[3] POWER TRANSFORMER REMOVAL ......11-2
[4] HIGH VOLTAGE RECTIFIER ASSEM-
BLY, HIGH VOLTAGE FUSE AND HIGH
VOLTAGE CAPACITOR REMOVAL...........11-2
[5] MAGNETRON REMOVAL .........................11-2
[6] POSITIVE LOCK CONNECTOR (NO-
CASE TYPE) REMOVAL ...........................11-2
[7] CONTROL PANEL ASSEMBLY RE-
MOVAL.......................................................11-3
[8] GRAPHIC SHEET AND MEMBRANE
SWITCH REPLACEMENT .....................
[9] TURNTABLE MOTOR REMOVAL .............11-3
[10] COOLING FAN MOTOR REMOVAL..........11-3
[11] POWER SUPPLY CORD REPLACE-
MENT.........................................................11-4
[12] 1ST. LATCH SWITCH, 2ND. INTER-
LOCK RELAY CONTROL SWITCH AND
MONITOR SWITCH ADJUSTMENT..........11-4
[13] 1ST. LATCH SWITCH, 2ND. INTER-
LOCK RELAY CONTROL SWITCH AND
MONITOR SWITCH ADJUSTMENT..........11-5
[14] DOOR REPLACEMENT ............................11-5
CHAPTER 12. MICROWAVE MEASUREMENT
CHAPTER 13. CIRCUIT DIAGRAMS
[1] Oven Schematic........................................ 13-1
[2] Pictorial Diagram....................................... 13-2
[3] Power Unit Circuit ..................................... 13-3
[4] CPU Unit Circuit........................................ 13-4
[5] LCD Circuit................................................ 13-5
[6] Printed Wiring Board (Figure S-3)............. 13-6
Parts List
....11-3
CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY
[1] OUTLINE OF TOUCH CONTROL PAN-
EL ............................................................... 9-1
[2] ABSOLUTE HUMIDITY SENSOR CIR-
CUIT............................................................ 9-1
R380L(W)
1 – 1
R380L(W)
Service Manual
CHAPTER 1. BEFORE SERVICING
GENERAL IMPORTANT INFORMATION
This Manual has been prepared to provide Sharp Corp. Service engineers with Operation and Service Information.
It is recommended that service engineers carefully study the entire text of this manual, so they will be qualified to render satisfactory customer service.
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 microwave exposure, by themselves, or when they are damaged,
loosened or removed.
WARNING: THIS APPLIANCE MUST BE EARTHED
IMPORTANT
THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW --------------EARTH
BLUE -----------------------------------NEUTRAL
BROWN ---------------------------------------LIVE
R380L(W)
2 – 1
R380L(W)
Service Manual
CHAPTER 2. 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 and High voltage fuse.
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge the 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 connection of the highvoltage capacitor (that is, of the connecting lead of the
high-voltage rectifier) against the chassis with the use of
an insulated screwdriver.
Sharp recommend that wherever possible fault-finding is carried out
with the supply disconnected. It may, in some cases, be necessary to
connect the supply after the outer 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 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) 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 (timer at zero) carefully check that
the water is now hot. If the water remains cold carry out 3D
checks and
reexamine 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
should be carried out.
R380L(W)
3 – 1
R380L(W)
Service Manual
CHAPTER 3. PRODUCT SPECIFICATIONS
ITEM DESCRIPTION
Power Requirements
230 - 240 Volts
50 Hertz
Single phase, 3 wire earthed
Power Consumption 1.67 k W
Power Output
1200 watts nominal of RF microwave energy (IEC Test Procedure)
Operating frequency 2450 MHz
Case Dimensions
Width 520 mm
Height 310 mmincluding foot
Depth 440 mm
Turntable Diameter 320 mm
Control Complement
Touch Control System
Clock (1:00 - 12:59)
Timer (0 - 99 minutes 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
100P ..................................................................... Full power throughout the cooking time
70P ....................................................................... approx. 70% of FULL Power
50P ....................................................................... approx. 50% of FULL Power
30P ...................................................................... approx. 30% of FULL Power
10P ....................................................................... approx. 10% of FULL Power
SENSOR COOK pads
SENSOR REHEAT pad
HEALTHY MENUS pads
EXPRESS MENUS pads
EASY DEFROST pad
QUICK AND EASY pad
NUMBER pads
POWER LEVEL pad
TIMER/CLOCK pad
STOP/CLEAR pad
INSTANT COOK/START pad
LESS/MORE pads
HELP pad
Set Weight (Approx.) 17 kg
R380L(W)
4 – 1
R380L(W)
Service Manual
CHAPTER 4. APPEARANCE VIEW
OVEN
1. Door open button
2. Door safety latches
3. Removable turntable support
4. Removable turntable tray
5. Oven lamp
6. See through door
7. Ventilation openings
8. Touch control panel
9. Liquid crystal display
10. Coupling
11. Wave guide cover
12. Power supply cord
13. Door hinges
14. Door seal and sealing surfaces
TOUCH CONTROL PANEL
1. HEALTHY MENUS PADS
Press to select “Healthy Menus” menu.
2. NUMBER PADS
Press to enter cooking times, clock time, weight or quantity of food.
3. TIMER/CLOCK PAD
Press to set Timer and Clock.
4. POWER LEVEL PAD
Press to select microwave power setting. If not pressed, 100% is automatically
selected.
5. INSTANT COOK/START PAD
Press once to cook for 1 minute on 100% or increase by 1 minute multiples each
time this pad is pressed during manual cooking. Press to start oven after setting
programmes.
6. STOP/CLEAR PAD
Press to clear during programming. Press once to stop operation of oven during
cooking; press twice to cancel cooking programme.
7. EXPRESS MENUS PADS
Press to select “Express Menus” menus.
8. SENSOR COOK PADS
Press to select Sensor Cook menus.
9. SENSOR REHEAT PAD
Press to select a reheat menu.
10.QUICK AND EASY PAD
Press to select Quick and Easy menus.
11.EASY DEFROST PAD
Press to defrost frozen food by entering quantity.
12.MORE, LESS PADS
Press to increase/decrease the time in one minute increments during cooking or
to alter the cooking result for the automatic operations.
13.HELP PAD
Press to select auto start, child lock, demonstration modes or info on pads.
Press to get cooking information.
NOTE: Some one-touch cooking features such as “INSTANT COOK” are disabled after one minute when the oven is not in use. These fea-
tures are automatically enabled when the door is opened and closed or the STOP/CLEAR pad is pressed.
12
4
7
3
8
9
14
2
6
13
10
11
2
5
EXPRESS MENUS
DEFROST
EXPRESS
COOK
EXPRESS
MEAL
EXPRESS
MORE
LESS HELP
SENSOR COOK
QUICK&
EASY
EASY
DEFROST
SENSOR
REHEAT
RICE/
PAS TA
DESSERTS
VEGETABLES
HEALTHY MENUS
LOW FAT
MEAL
VEGETARIAN
MEAL
1
3
5
7
8
12
9
2
4
6
10
11
13
R380L(W)
5 – 1
R380L(W)
Service Manual
CHAPTER 5. OPERATION SEQUENCE
[1] OFF CONDITION
Closing the door activates all door interlock switches (1st. latch switch
and 2nd. interlock relay control switch).
MPORTANT
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 noise filter and the control unit.
Figure O-1 on page 13-1
1. The display shows “MICRO-, WAVE, OVEN” repeatedly.
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.
[2] MICROWAVE COOKING CONDITION
1. 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 13-1
1. Rated voltage is supplied to the primary winding of the power trans-
former. 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 magnetron fila-
ment and the high voltage (2000 volts) 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 gen-
erates a wave length of 12.24 cm. This energy is channelled
through the waveguide (transport channel) into the oven cavity,
where the food is placed to be cooked.
4. When the cooking time is up, a signal tone is heard and the relays
(RY1+RY2) go back to their home position. The circuits to the oven
lamp, power transformer, fan motor and turntable motor are cut off.
5. When the door is opened during a cook cycle, the switches come to
the following condition
The circuits to the power transformer, fan motor and turntable motor
are cut off when the 1st. latch switch and 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, and
monitors the operation of the 1st. latch switch and 2nd. interlock
relay.
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.
2) When the oven door is closed, the contacts (COM-NC) of the
monitor switch must be opened. After that the contacts of the
1st. latch switch and 2nd. interlock relay control switch are
closed.
3) When the oven door is opened and the contacts of the 1st. latch
switch and 2nd. interlock relay remain closed. The fuse F10A
will blow, because the monitor switch is closed and a short circuit is caused.
2. 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 32second time base through the relay contact which is coupled with the
current-limiting relay. The following levels of microwave power are
given.
SETTING;
NOTE: The ON/OFF time ratio does not exactly correspond to the
percentage of microwave power, because approx. 3 seconds
are needed for heating up the magnetron filament.
[3] POWER OUTPUT REDUCTION
After 100% power cooking mode is carried out for more than 40 minutes, the power out-put is automatically reduced to 70%.
[4] SENSOR COOKING CONDITION
Using the SENSOR function, the food is cooked without figuring time,
power level or quantity. When the oven senses enough steam from the
food, it relays the information to its microprocessor which will calculate
the remaining cooking time and power level needed for best results.
When the food is cooked, water vapor is developed. The sensor
“senses” the vapor and its resistance increases gradually. When the
resistance reaches the value set according to the menu, supplementary cooking is started. The time of supplementary cooking is determined by experiment with each food category and inputted into the
LSI.
An example of how sensor works: (POTATOES)
1. Potatoes at room temperature. Vapor is emitted very slowly.
CONNECTED COMPONENTS RELAY
Oven lamp, Fan motor, Turntable motor RY1
Power transformer RY2
CONDITION
SWITCH CONTACT
DURING
COOKING
DOOR OPEN
(NO COOKING)
1st. latch switch COM-NO Closed Open
2nd. interlock relay
control switch
COM-NO Closed Open
Monitor switch COM-NC Open Closed
100P
32 sec. ON
70P
Approx. 70%
100%
24 sec. ON 8 sec. OFF
14 sec. OFF
20 sec. OFF
26 sec. OFF
50P Approx. 50%
18 sec. ON
30P
Approx. 30%
12 sec. ON
10P Approx. 10%
6 sec. ON
R380L(W)
5 – 2
2. Heat potatoes. Moisture and humidity is emitted rapidly. You can
smell the aroma as it cooks.;
3. Sensor detects moisture and humidity and calculates cooking time
and variable power.
1. Cooking Sequence.
1. 1.Operate the oven in sensor cooking mode by referring to the
operation manual.
NOTE: The oven should not be operated on SENSOR immediately
after plugging in the unit. Wait two minutes before cooking on
SENSOR.
2. The coil of shut-off relay (RY-1) is energized, the turntable motor,
oven lamp and cooling fan motor are turned on, but the power
transformer is not turned on.
3. After about 16 seconds, the cook relay (RY-2) is energized. The
power transformer is turned on, microwave energy is produced and
first stage is started. The 16 seconds is the cooling time required to
remove any vapor from the oven cavity and sensor.
NOTE: During this first stage, do not open the door or touch STOP/
CLEAR pad.
4. When the sensor detects the vapor emitted from the food, the display switches over to the remaining cooking time and the timer
counts down to zero. At this time, the door may be opened to stir,
turn, or season food.
5. When the timer reaches zero, an audible signal sounds. The shutoff relay and cook relay are de-energized and the power transformer, oven lamp, etc. are turned off.
6. Opening the door or touching the STOP/CLEAR pad, the time of
day will reappear on the display and the oven will revert to an OFF
condition.
M
IC R OWA V E
MIC R OW A V E
AH S ENS OR
R380L(W)
6 – 1
R380L(W)
Service Manual
CHAPTER 6. FUNCTION OF IMPORTANT COMPONENTS
[1] 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
the latch head. The latch heads are moved upward and released from
latch hook. Now the door will open.
Figure D-1. Door Open Mechanism
[2] 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.
[3] 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 too pen, the fuse F10A
blows simultaneously with closing the contacts (COM-NC) of the
monitor switch.
CAUTION: BEFORE REPLACING A BLOWN FUSE F10ATEST THE
1ST. LATCH SWITCH, 2ND.INTERLOCK RELAY, MONITOR SWITCHAND MONITOR RESISTOR FOR PROPEROPERATION.
[4] FUSE F10A
1. The fuse F10A blows when the contacts (COM-NO) oft he 1st. latch
switch and 2nd. interlock relay remain closed with the oven door
open and when the monitors witch closes.
2. If the wire harness or electrical components are short-circuited, this
fuse F10A blows to prevent an electric shock or fire hazard.
[5] HIGH VOLTAGE FUSE
The high voltage fuse blows when the high voltage rectifier or the magnetron is shorted.
[6] OVEN TEMPERATURE FUSE
The temperature fuse, located on the top of the oven cavity, is
designed to prevent damage to the oven by fire.If the food load is overcooked, by either error in cook time or defect in the control unit, the
temperature fuse will open.Under normal operation, the temperature
fuse remains closed. However, when abnormally high temperatures
are reached within the oven cavity, the temperature fuse will open at
150°C, causing the oven to shut down.
[7] TURNTABLE MOTOR
The turntable motor drives the turntable roller assembly to rotate the
turntable.
[8] FAN MOTOR
The fan motor drives a blade which draws external cool air.This cool
air is directed through the air vents surrounding the magnetron and
cools the magnetron. This air is channelled through the oven cavity to
remove steam and vapours given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven cavity.
[9] NOISE FILTER
The noise filter prevents the radio frequency interference that might
flow back in the power circuit.
Latch Hook
Monitor Switch
2nd. Interlock
Relay Control
Switch
1st Latch Switch
Latch
Heads
Door
R380L(W)
7 – 1
R380L(W)
Service Manual
CHAPTER 7. 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 of a blown fuse F10A in the
1st. latch switch - 2nd. interlock relay - monitor switch circuit, check the
1st. latch switch, 2nd.interlock relay and monitor switch before replacing the fuse F10A.
MAGNETRON
POWER TRANSFORMER
H.V. RECTIFIER ASSEMBLY
HIGH VOLTAGE CAPACITOR
1ST. LATCH SWITCH
2ND. INTERLOCK RELAY CONTROL
SWITCH
MONITOR SWITCH
TEMPERATURE FUSE (OVEN)
FAN MOTOR
TURNTABLE MOTOR
FUSE F10A
TOUCH CONTROL PANEL
KEY UNIT
RELAY (RY-1, RY-2)
FOIL PATERN ON P.W.B.
POWER SUPPLY CORD
SHORTED WIRE HARNESS
OPENED WIRE HARNESS
OVEN LAMP
WALL OUTLET
MISADJUSTMENT SWITCH
HOME FUSE OR BREAKER
BLOCKED COOLING FAN
BLOCKED VENTILATION
NOISE FILTER
HIGH VOLTAGE FUSE
AH SENSOR
TEST PROCEDURE
CK = Check / RE = Replace
ABC
D
EEEFGGHKLMN
RE CK CK RE CK CK CK CK CK
IJO
CONDITION
PROBLEM
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
ON
SENSO
RCOOKING
CONDITION
CONDITION
OFF
CONDITION
Home fuse blows when power
supply cord is plugged into wall
outlet.
FUSE F10A blows when power
supply cord is plugged into wall
outlet.
Display does not show anything
when power supply cord is plugged into wall outlet.
Display does not operate properly when STOP/CLEAR pad is
touched.
Oven lamp does not light at door
opened. (Display appears.)
Oven lamp does not light (Display appears.)
Fan motor does not operate.
(Display appears.)
Turntable motor assembly does
not operate. (Display appears.)
Oven does not start when the
START pad is touched. (Display appears)
Oven or any electrical parts does
not stop when cooking time is 0
or STOP/CLEAR pad is touched.
Oven goes into cook cycle but
shuts down before end of cooking cycle.
Oven stops at 16 sec. after starting.
AH sensor does not end during
Sensor cooking condition. (Oven
doesnot shut off after a cup of water is boiling by sensor cooking.)
Oven seems to be operating but
littleornoheatisproducedin
oven load. (Microwave power level is set at 100%)
Oven does not seems to be operating properly when 70%, 50%,
30% or 10% is set. (Oven operates properly a t 100% and then
the STOP/CLEAR pad is touched
theovenstops.)
R380L(W)
8 – 1
R380L(W)
Service Manual
CHAPTER 8. TEST PROCEDURES
[1] A: MAGNETRON (MG) TEST
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION.
CARRY OUT 3D
CHECKS.
Isolate the magnetron from the high voltage circuit by removing all leads connected to the 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 a short circuit 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 (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 IEC test procedure, i.e. it can be measured by using water load how much it can be absorbed by the water
load. To measure the microwave output power in the microwave oven, the relation of calorie and watt is used. When P(W) heating works for t (sec-
ond), 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.
Measuring condition:
1) Container
The water container must be a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of
approximately 190 mm.
2) Temperature of the oven and vessel
The oven and the empty vessel are at ambient temperature prior to the start of the test.
3) Temperature of the water
The initial temperature of the water is (10±1)°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) Select stirring devices and measuring instruments in order to minimize addition or removal of heat.
6) The graduation of the thermometer must be scaled by 0.1°C at minimum and an accurate thermometer.
7) The water load must be (1000±5) g.
8) “t” 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 + 3" sec. 3 sec. is magnetron filament heat-up time.
Measuring method:
1) 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 100% for the temperature of the water rises by a value T of 10°C.
5) Stir the water to equalize temperature throughout the vessel.
6) Measure the final water temperature. (Example: The final temperature T2 = 21°C)
7) Calculate the microwave power output P
in watts from above formula.
JUDGEMENT: The measured output power should be at least ± 15% of the rated output power.
CAUTION: 1°C CORRESPONDS TO 120 WATTS. REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.
The formula is as follows;
P x t / 4.187 = V x T+ 0.55 x mc (T2-T0)/4.187 P (W) = 4.187 x V x T / t + 0.55 x mc (T2-T0)/t
Our condition for water load is as follows:
Room temperature (T0) ......................... around 20°C Power supply ........................... VoltageRated voltage
Water load .........................................................1000 g Initial temperature (T1) .................................... 10±1°C
Heating time ..................................................... 35 sec. Mass of container (mc) ...................................... 330 g
T2 .................................................... Final Temperature T = T2 - T1 P = 120 x T + 0.55 x mc (T2-T0)/35
Room temperature ................................................................... To = 21°C
Initial temperature ..................................................................... T1 = 11°C
Temperature after (35+ 3) = 38 sec. ..................................... T2 = 21°C
Temperature difference Cold-Warm ( T = T2 - T1) .......... T = 10°C
Measured output power
The equation is "P = 120 x T" .................... P = 120 x 10°C = 1200 Watts
R380L(W)
8 – 2
[2] B: POWER TRANSFORMER TEST
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:
If the reading obtained are not stated as above, then the power transformer is probably faulty and should be replaced.
CARRY OUT 4R
CHECKS.
[3] C: 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 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 kΩ in the other direction.
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 DIRECTION.
[4] D: HIGH VOLTAGE CAPACITOR TEST
CARRY OUT 3D CHECKS.
1. Isolate the high voltage capacitor from the circuit.
2. Continuity check must be carried out with measuring instrument which is set to the highest resistance range.
3. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ after it has been charged.
4. A short-circuited capacitor shows continuity all the time.
5. An open capacitor constantly shows a resistance about 10 MΩ because of its internal 10MΩ resistance.
6. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
7. 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.
WARNING: High voltages and large currents are present at the secondary winding and filament 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.
RTRN-A756WRZZ RTRN-A709WRZZ
Primary winding approx. 1.34Ω approx. 1.25Ω
Secondary winding approx. 104.6Ω approx. 101.9Ω
Filament winding less than 1Ω
1000g
1000g
1000g
T1 C
T2 C
Heat up for 38 sec.
B
C
HIGH VOLTAGE RECTIFIER
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