Sharp R-380A Service Manual

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R-380A

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R-380A

SER VICE MANUAL

MICROWAVE OVEN

R-380A

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.

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

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R-380A

ITEM DESCRIPTION

Power Requirements 230 - 240 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

HELP pad

SENSOR INSTANT REHEAT pads

SENSOR COOK pad

SLOW COOK pad

EASY DEFROST pad

MEMORY pad

MORE, LESS pads

NUMBER pads

POWER LEVEL pad

CLOCK pad

TIMER 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

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R-380A

APPEARANCE VIEW

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

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TOUCH CONTROL PANEL



Info Display

HELP

DINNER

PLATE

CASSEROLE

SOUP

PIZZA

VEGETABLES

MEAT

SLOW COOK

POWER

LEVEL

STOP

CLEAR

INSTANT COOK

START

CLOCK TIMER

MEMORY

EASY

DEFROST

RICE/PASTA

DESSERTS

RICE PIE

Sensor Instant Reheat

Sensor Cook

LESS MORE

12345 6789O

COOK SENSOR KG DEF HELP

POWER LEVEL PAD Press to select microwave power setting. If not pressed, HIGH is automatically selected.



 STOP/CLEAR PAD

Press to clear during programming. Press once to stop operation of oven during cooking; press twice to cancel cooking programme.

TIMER / CLOCK PAD Press to set Timer.   INSTANT COOK/START PAD Press once to cook for 1 minute on HIGH or increase by 1 minute multiples each time this pad is pressed during cooking. Press to start the oven after setting programmes.

Indicator

HELP PAD Press to select auto start, information guide on/off, child lock, demonstration modes or info on pads. Press to get cooking information.

SENSOR INSTANT REHEAT PADS Press once to reheat 1 or 6 popular menus.

SLOW COOK PADS Press to cook slowly and for a longer time.

SENSOR COOK PADS Press to select Sensor Cook menus.

EASY DEFROST PAD Press to defrost frozen food by entering quantity.

MORE( ), LESS ( ) PADS Press to increase/ decrease the time in one minute increments during cooking or to after the cooking result for the Sensor Instant Reheat, Sensor Cook or Easy Defrost modes

NUMBER PADS Press to enter cooking times, clock time, weight or quantity of food.

MEMORY PAD Press to enter a frequently used cooking program. Press to recall the memorized program.

CLOCK PAD Press to set Clock.

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R-380A

OPERATION SEQUENCE

OFF CONDITION

Closing the door activates all door interlock switches (1st. latch switch, 2nd. latch switch and stop 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 28

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 28

CONNECTED COMPONENTS RELAY Oven lamp, Fan motor, Turntable motor RY1 Power transformer RY2

1. Rated voltage is supplied to the primary winding of the 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 magnetron filament 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 generates a wave length of 12.24 cm. This energy is channeled 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

CONDITION DURING DOOR OPEN

SWITCH CONTACT COOKING

(NO COOKING) 1st. latch switch COM-NO Closed Open 2nd. latch switch COM-NO Closed Open Monitor switch COM-NC Open Closed Stop switch COM-NO Closed Open

The circuits to the power transformer, fan motor and turntable motor are cut off when the 1st. latch switch, 2nd. latch switch, and stop 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 and 2nd. latch switches.

6-1 When the oven door is opened during or after the

cycle of a cooking program, the 1st. latch switch, 2nd. latch switch and stop 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 the contacts of the 1st. latch switch, 2nd. latch switch and stop switch are closed.

6-3. When the oven door is opened and the contacts of

the1st. latch switch, 2nd. latch switch remain closed. 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, 230-240 volts A.C. power 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;

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: The ON/OFF time ratio does not exactly correspond

to the percentage of microwave power, because approx. 2 seconds are needed for heating up the magnetron filament.

SENSOR COOKING CONDITION

Using the SENSOR COOK or SENSOR INSTANT REHEAT function, the foods are cooked or reheated 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.

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R-380A

An example of how sensor works:

1. Potatoes at room temperature. Vapor is emitted very slowly.

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.

Cooking Sequence.

1. Touch each SENSOR COOK or SENSOR INSTANT REHEAT function pad to operating the sensor cooking.

NOTE: The oven should not be operated on SENSOR

COOK or SENSOR INSTANT REHEAT immediately after plugging in the unit. Wait five minutes before cooking on SENSOR COOK or

SENSOR INSTANT REHEAT.

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 food, turn it or season, etc.

5. When the timer reaches zero, an audible signal sounds. The shut-off 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.

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 the latch head. The latch heads are moved upward and released from latch hook. Now the door will open.

Latch Hook 

2nd. Latch Switch

Monitor  Switch

Stop  Switch

Switch Lever

Latch Heads

Door

1st. Latch  Switch

Figure D-1. Door Open Mechanism

1ST. LATCH SWITCH, 2ND. LATCH SWITCH AND STOP SWITCH

1. When the oven door is closed, the contacts (COM-NO) must be closed.

2. When the oven door is opened, the contacts .(COMNO) 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. latch switch 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. LATCH SWITCH MONITOR SWITCH AND MONITOR RESISTOR FOR PROPER OPERATION.

MONITOR RESISTOR R 0.8Ω 20W

The monitor resistor prevents the fuse M8A bursting when the fuse M8A blows due to the operation of the monitor switch.

ASYMMETRIC RECTIFIER

The asymmetric rectifier is a solid state device that prevents current flow in both directions. And it prevents the temperature rise of the power transformer by blowing the fuse M8A when the high voltage rectifier is shorted.

D2 D1

ASYMMETRIC RECTIFIER

HIGH VOLTAGE  RECTIFIER

The rated peak reverse voltage of D1 of the asymmetric rectifier is 6 KV The rated peak reverse voltage of D2 of the asymmetric rectifier is 1.7 KV. D1 and D2 of the asymmetric rectifier or high voltage rectifier are shorted when the each peak reverse voltage goes beyond the each rated peak reverse voltage. (The process of blowing the fuse M8A.)

FUNCTION OF IMPORTANT COMPONENTS

MICROWAVE

AH SENSOR

MICROWAVE

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R-380A

1. The high voltage rectifier is shorted by any causes when microwave cooking.

2. The peak reverse voltage of D2 of the rectifier goes beyond the rated peak reverse voltage 1.7 KV in the voltage doubler circuit.

3. D2 of the rectifier is shorted.

4. The large electric currents flow through the high voltage winding of the power transformer.

5. The large electric currents beyond 8A flow through the primary winding of the power transformer.

6. The fuse M8A blows by the large electric currents.

7. The power supply to all the electrical parts are cut off.

FUSE M8A

1. The fuse M8A blows when the contacts (COM-NO) of the 1st. latch switch and 2nd. latch switch remain closed with the oven door open and when the monitor switch closes.

2. The fuse M8A also blows when asymmetric rectifier, H.V. rectifier, H.V. wire harness, H.V.capacitor, magnetron or secondary winding of power transformer is shorted.

3. If the wire harness or electrical components are shortcircuited, this fuse M8A blows to prevent an electric shock or fire hazard.

OVEN THERMAL CUT-OUT

The thermal cut-out, located on the top of the 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. Under normal operation, the oven thermal cut-out remains closed. However, when abnormally high temperatures are 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 designed to prevent damage to the magnetron if an over heated condition develops in the tube due to cooling fan failure, obstructed air guide, dirty or blocked air intake, etc. Under normal operation, the thermal cut-out remains closed. However, when abnormally high temperatures are reached within the magnetron, the thermal cut-out will open at 95˚C causing the oven to shut down, when the magnetron has cooled to 75˚C, the thermal cut-out closes and cook cycle will resume.

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 channeled through the oven cavity to remove steam and vapors given off from the heating foods. It is then exhausted 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.

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R-380A

SERVICING

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts 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 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.

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 connection of the high-voltage 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.

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. 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 M8A in the 1st. latch switch

- 2nd. latch switch - monitor switch - monitor resistor circuit, check the 1st. latch switch, 2nd. latch switch, monitor switch and monitor resistor before replacing the fuse M8A.

TROUBLESHOOTING GUIDE

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R-380A

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 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 does not start when the START pad is touched. (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 or any electrical parts does not stop when cooking time is 0 or STOP/CLEAR pad is touched.

Oven seems to be operating but little or no heat is produced in oven load. (Microwave power level is set at HIGH)

Oven does not seems to be operating properly when MEDIUM HIGH, MEDIUM, MEDIUM LOW or LOW is set. (Oven operates properly at HIGH and then the STOP/ CLEAR pad is touched the oven stops.)

Oven goes into cook cycle but shuts down before end of cooking cycle.

Oven stops as soon as when the START pad is touched.

AH sensor does not end during Sensor Cooking condition. (Oven does not shut off after a cup of water is boiling by sensor cooking.

Oven stops at 16 sec. after starting.

TEST PROCEDURE

CK = Check / RE = Replace

POSSIBLE CAUSE

AND

DEFECTIVE PARTS

CONDITION

PROBLEM

ON CONDITION

OFF CONDITION

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

HIGH VOLTAGE CAPACITOR

1ST. LATCH SWITCH

2ND. LATCH SWITCH

STOP SWITCH

MONITOR SWITCH

MONITOR RESISTOR

THERMAL CUT-OUT 95˚C /125˚C

FAN MOTOR

TURNTABLE MOTOR

FUSE M8A

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 OR SOCKET

WALL OUTLET

MISADJUSTMENT SWITCH

HOME FUSE OR BREAKER

BLOCKED COOLING FAN

BLOCKED VENTILATION

NOISE FILTER

AH SENSOR

SENSOR COOKING CONDITION

ABCDEEEEGFH HIK LMN

RE CK CK RE CK CKCK CK CK

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R-380A

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

A MAGNETRON 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. 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 (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. 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(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.

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. 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 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 heatup 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.

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.

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R-380A

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

T1˚C

T2˚C

Heat up for44 sec.

B POWER TRANSFORMER TEST

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.

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. 1.3 Ω

b. Secondary winding............... approx. 96 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

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 kΩ in the other direction.

CARRY OUT 4R CHECKS.

ASYMMETRIC RECTIFIER TEST CARRY OUT

3D CHECKS.

Isolate the high voltage rectifier assembly from the HV circuit. The asymmetric can be tested using an ohmmeter set to its highest range across the terminals A+B of the asymmetric rectifier and note

D2 D1

ASYMMETRIC RECTIFIER

HIGH VOLTAGE RECTIFIER

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TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

the reading obtained. Reverse the meter leads and note this second reading. If an open circuit is indicated in both direction then the asymmetric rectifier is good. If an asymmetric rectifier is shorted in either direction, then the asymmetric rectifier is probably faulty and must be replaced with high voltage rectifier. When the asymmetric rectifier is defective, check whether magnetron, high voltage rectifier, high voltage wire or filament winding of the power transformer is shorted.

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. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ after

it has been charged.

D. A short-circuited capacitor shows continuity all the time. E. An open capacitor constantly shows a resistance about 10 MΩ because of its internal 10MΩ resistance. 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.

E SWITCH 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 temperature fuse or 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: Temperature fuse and 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 temperature fuse or thermal cut-out. An open circuit thermal cut-out 95˚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 125˚C (OVEN) indicates that the foods in the oven may catch fire,

F TEMPERATURE FUSE AND THERMAL CUT-OUT TEST

Page 14

R-380A

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

this may be due to over heating produced by improper setting of the cooking time or failure of the control panel.

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.

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.

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 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 2nd. latch switch, monitor switch and monitor resistor. If the fuse M8A is blown by incorrect door switching replace the defective switch(s) and the fuse M8A.

3. If the fuse M8A is blown, there could be a short in the asymmetric rectifier or there could be a ground in wire harness. A short in the asymmetric rectifier may have occured due to short or ground in H.V. rectifier, magnetron, power transformer or H.V. wire. Check them and replace the defective parts or repair the wire harness.

CARRY OUT 4R CHECKS. CAUTION: ONLY REPLACE FUSE M8A WITH THE CORRECT VALUE REPLACEMENT

I BLOWN FUSE F M8A

J NOISE FILTER TEST

CARRY OUT 3D CHECKS. Disconnect the leads from the terminals of the noise filter. Using an ohmmeter, check between the terminals 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

WHT

RED

L (min) Cx ± 20% Cy ± 20% 600µH 0.068µF 0.0022µF

Page 15

R-380A

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

If incorrect readings are obtained, replace the noise filter unit. CARRY OUT 4R CHECKS.

L KEY UNIT TEST

If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable is making good contact, verify that the door sensing switch (stop switch) operates properly; that is the contacts are closed when the door is closed and open when the door is open. If the door sensing switch (stop switch) is good, disconnect the flat ribbon that connects the key unit to the control unit and make sure the door sensing switch is closed (either close the door or short the door sensing switch connector). 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 making 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 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.

K 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 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. The following symptoms indicate a defective control unit. Before replacing the control unit, perform the Key unit test (Procedure L) 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.

G 8

RICE

CLOCK

SOUP

TIMER

PIZZA

MEAT

HELP

POWER

LEVEL

STOP

CLEAR

DINNER

PLATE

SLOW COOK

MEMORY

RICE /

PASTA

LESS

PIE

VEGETABLES

CASSEROLE

DESSERTS

EASY

DEFROST

G 7

5 0

1 6

G 6 G 5 G 4 G 3 G 2 G 1

G12 G11 G10

G 9

START

INSTANT

COOK

Page 16

R-380A

CARRY OUT 3D CHECKS. Remove the outer case and check voltage between Pin No 3 of the 2-pin connector (A) and the common terminal of the relay RY2 on the power unit with an A.C. voltmeter. The meter should indicate 230 - 240 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 .........Check diode which is connected to the relay coil. If diode is good,

control unit is defective.

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

RY1 APPROX. 24.5V D.C. Oven lamp / Turntable motor / Cooling fan motor RY2 APPROX. 24.0V D.C. Power transformer

CARRY OUT 4R CHECKS.

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

M RELAY TEST

To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide 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,

make a visual inspection of the varistor. 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.

N PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD

(PWB) IS OPEN

RY2

HVT

(COM)

CN - A

(J1)

Checking the initial sensor cooking condition

(1) The oven should be plugged in at least two minutes before sensor cooking. (2) Room temperature should not exceed 35˚C. (3) The unit should not be installed in any area where heat and steam are generated. The unit should

not be installed, for example, next to a conventional surface unit. Refer to the "INSTALLATION Instructions" .

(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity. To

O AH SENSOR TEST

Page 17

R-380A

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

permit adequate ventilation, be sure to install so as n ot to block these vents. There should be some space for air circulation.

(5) Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any

moisture with a dry cloth or paper towel.

(6) The Sensor works with food at normal storage temperature. For example, chicken pieces would

be at refrigerator temperature and canned soup at room temperature.

(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The

sensor will detect the vapour given of by the spray and turn off before food is properly cooked.

(8) If the sensor has not detected the vapour of the food, ERROR will appear and the oven will shut

off.

Water load cooking test

Make sure the oven has been plugged in at least five minutes before checking sensor cook operation. The cabinet should be installed and screws tightened. (1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup. (2) Place the container on the center of tray in the oven cavity. (3) Close the door. (4) Touch SOUP pad of SENSOR INSTANT REHEAT once. Now, the oven is in the sensor cooking

condition and "SOUP", "SENSOR" and "REHEAT" will appear in the display.

(5) The oven will operate for the first 16 seconds, without generating microwave energy. NOTE: ERROR will appear if the door is opened or STOP/CLEAR pad is touched during first stage

of sensor cooking.

(6) After approximately 16 seconds, microwave energy is produced, and the display should start to

count down the remaining cooking time, and oven should turn off after water is boiling (bubbling).

If the oven does not turn off, replace the AH sensor or check the control unit, refer to explanation below.

TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT

To determine if the sensor is defective, the simplest method is to replace it with a new replacement sensor. (1) Disconnect oven from power supply and remove outer case. (2) Discharge the high voltage capacitor. (3) Remove the AH sensor. (4) Install the new AH sensor. (5) Re-install the outer case. (6) Reconnect the oven to the power supply and check the sensor cook operation proceed as follows:

6-1. Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup. 6-2. Place the container on the center of tray in the oven cavity. 6-3. Close the door. 6-4. Touch SOUP pad once. 6-5. The control panel is in automatic Sensor operation. 6-6. The display will start to count down the remaining cooking time, and the oven will turn off

automatically after the water is boiling (babbling).

If new sensor dose not operate properly, the problem is with the control unit.

CHECKING CONTROL UNIT

(1) Disconnect oven from power supply and remove outer case. (2) Discharge the high voltage capacitor. (3) Disconnect the wire leads from the cook relay. (4) Disconnect the sensor connector that is mounted to lower portion of control panel. (5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel. (6) Reconnect the oven to the power supply and check the sensor cook operation, proceed as follows:

6-1. Touch SOUP pad once. 6-2. The control panel is in the sensor cooking operation. 6-3. After approximately 20 seconds, push plunger of select switch. This condition is same as

judgement by AH sensor.

6-4. After approximately 3 seconds, the display shows " X X . X X " which is the remaining cooking

time, and the display count down.

Page 18

R-380A

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

If the above is not the case, the control unit is probably defective. If the above is proper, the AH sensor is probably defective.

R1,R2 : 22Ω ± 1% 1/2W R3 : 4.3kΩ ± 5% 1/4W R4 : 1MΩ ± 5% 1/4W

Plunger

NC NO

COM

R3 R4

1 2 3

F-1 F-2

F-3

To connector (F) on Control Unit.

CONNECTOR

Sensor Dummy Resistor Circuit

TOUCH CONTROL PANEL ASSEMBLY

OUTLINE OF TOUCH CONTROL PANEL 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

The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through P20 - P27. When a key pad is touched, a signal is completed through the key unit and passed back to the LSI through P74 - P77 to perform the function that was requested.

Control Unit

Control unit consists of LSI, ACL circuit, indicator circuit, power source circuit, relay circuit, buzzer circuit, synchronizing signal circuit, absolute humidity sensor 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.

3) Power Source Circuit

This circuit generates voltages necessary in the control 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 -5.3V 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 responsive 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).

9) Absolute Humidity Sensor Circuit

This circuit detects moisture of the cooking food to allow its automatic cooking.

Page 19

R-380A

DESCRIPTION OF LSI

LSI(IZA778DR):

The I/O signal of the LSI(IZA778DR) is detailed in the following table.

Pin No. Signal I/O Description

0.12 sec.

2.4 sec.

H : GND

L : -5V H : GND

L : -5V

1 C1 IN Terminal not used. 2 VL1 IN Power source voltage input terminal.

Standard voltage for LCD.

3-6 AN7-AN4 IN Terminal to change cooking constant according to the Model.

By using the A/D converter contained in the LSI, DC voltage in accordance with the

Model in operation is applied to set up its cooking constant. 7 AN3 OUT Terminal not used. 8 AIN2 IN To input signal which communicates the door open/close information to LSI.

Door closed; "H" level signal (0V).

Door opened; "L" level signal (-5V). 9 AN1 IN AH sensor input.

This input is an analog input terminal from the AH sensor circuit, and connected

the A/D converter built into the LSI. 10 AN0 IN Used for initial balancing of the bridge circuit (absolute humidity sensor). This input

is an analog input terminal from the AH sensor circuit, and connected to the A/D

converter built into the LSI. 11-13 P57-P55 OUT Terminal not used. 14 P54 OUT Signal to sound buzzer (2.0kHz).

A: key touch sound.

B: Completion sound.

15-18 P53-P50 OUT Terminal not used. 19-23 P47-P43 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor). 24 INT0 IN Signal synchronized with commercial power source frequency.

This is the basic timing for time process-

ing of LSI.

25-26 P41-P40 OUT Terminal not used. 27 P77 IN Signal coming from touch key.

When either G12 line on key matrix is touched, a corresponding signal out of P20

- P27 will be input into P77. When no key is touched, the signal is held at "H" level.

28 P76 IN Signal similar to R77.

When either G11 line on key matrix is touched, a corresponding signal will be input into R76. 29 P75 IN Signal similar to R77.

When either G10 line on key matrix is touched, a corresponding signal will be input into R75. 30 P74 IN Signal similar to R77.

When either G9 line on key matrix is touched, a corresponding signal will be input into R74. 31 P73 OUT Oven lamp, fan motor and turntable motor driving signal.

To turn on and off the shut-off relay (RY1).

The square waveform voltage is delivered

to the relay RY1 driving circuit and RY2

control circuit. 32 P72 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"

level while not cooking. In other cook-

ing modes (variable cooking) the sig-

nal turns to "H" level and "L" level in

repetition according to the power level. 33 P71 OUT Terminal not used. 34 P70 IN Connected to VC. 35 RESET IN Auto clear terminal.

Signal is input to reset the LSI to the initial state when power is supplied.

Temporarily set to "L" level the moment power is supplied, at this time the LSI is

reset. Thereafter set at "H" level.

20.0 msec.

H : GND

L : -5V

20.0 msec.

During cooking

H : GND

L : -5V

P-HI

H : GND

L : -5V H : GND

L : -5V

P-70

OFF

OFF OFF

24 sec.

8 sec.

Page 20

R-380A

36-37 P81-P80 OUT Terminal not used. 38 XIN IN Internal clock oscillation frequency input setting.

The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to XIN terminal.

39 XOUT OUT Internal clock oscillation frequency control output.

Output to control oscillation input of XOUT.

40 VSS IN Power source voltage: -5.1V.

VC voltage of power source circuit input.

41 P27 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal while one of G8 line keys on key matrix is touched.

42 P26 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal while one of G7 line keys on key matrix is touched.

43 P25 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal while one of G6 line keys on key matrix is touched.

44 P24 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal while one of G5 line keys on key matrix is touched.

45 P23 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal while one of G4 line keys on key matrix is touched.

46 P22 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal while one of G3 line keys on key matrix is touched.

47 P21 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal while one of G2 line keys on key matrix is touched.

48 P20 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P74 - P77 terminal

while one of G1 line keys on key matrix is touched. 49-50 P17-P16 OUT Terminal not used. 51-62 SEG39-SEG28 IN Terminal not used.

63-66 SEG27-SEG24 OUT Segment data signals.

Connected to LCD.

The relation between signals are as follows:

LSI Signal (Pin No.) LCD (Pin No.) LSI Signal (Pin No.) LCD (Pin No.)

SEG 27 (63)............................. S0 SEG 12 (78) ............................. S5

SEG 26 (64)............................. S1 SEG 11 (79) ............................. S6

SEG 25 (65)............................. S2 SEG 10 (80) ............................. S7

SEG 24 (66)............................. S3 SEG 9 (81) ............................... S8

SEG 22 (68)............................. S4 SEG 8 (82) ............................... S9

SEG 21 (69)........................... S26 SEG 6 (84) ............................. S10

SEG 20 (70)........................... S25 SEG 5 (85) ............................. S11

SEG 19 (71)........................... S24 SEG 4 (86) ............................. S12

SEG 18 (72)........................... S23 SEG 3 (87) ............................. S13

SEG 17 (73)........................... S22 SEG 2 (88) ............................. S14

SEG 16 (74)........................... S21 SEG 1 (89) ............................. S15

SEG 14 (76)........................... S20 SEG 0 (90) ............................. S16

SEG 13 (77)........................... S19

67 SEG23 OUT Terminal not used. 68-74 SEG22-SEG16 OUT Segment data signal.

Signal similar to SEG27. 75 SEG15 OUT Terminal not used. 76-82 SEG14-SEG8 OUT Segment data signal.

Signal similar to SEG27. 83 SEG7 OUT Terminal not used. 84-90 SEG6-SEG0 OUT Segment data signal.

Signal similar to SEG27. 91 VCC IN Connected to GND. 92 VREF IN Connected to GND.

Pin No. Signal I/O Description

Page 21

R-380A

Pin No. Signal I/O Description

93 AVSS IN Connected to VC. 94 COM3 OUT Common data signal: COM3.

Connected to LCD (Pin No. C0)

95 COM2 OUT Common data signal: COM2.

Connected to LCD (Pin No. C1)

96 COM1 OUT Common data signal: COM1.

Connected to LCD (Pin No. C2)

97 COM0 OUT Common data signal: COM0.

Connected to LCD (Pin No. C3)

98-99 VL3-VL2 IN Power source voltage input terminal.

Standard voltage for LCD.

100 C2 IN Terminal not used.

(1)Structure of Absolute Humidity Sensor

The absolute humidity sensor includes two thermistors as shown in the illustration. One thermistor is housed in the closed vessel filled with dry air while another in the open vessel. Each sensor is provided with the protective cover made of metal mesh to be protected from the external airflow.

ventilation opening for sensing

(2)Operational Principle of Absolute Humidity Sensor

The figure below shows the basic structure of an absolute humidity sensor. A bridge circuit is formed by two thermistors and two resistors (R1 and R2). The output of the bridge circuit is to be amplified by the operational amplifier. Each thermistor is supplied with a current to keep it heated at about 150˚C (302˚F), the resultant heat is dissipated in the air and if the two thermistors are placed in different humidity conditions they show different degrees of heat conductivity leading to a potential difference between them causing an output voltage from the bridge circuit, the intensity of which is increased as the absolute humidity of the air increases. Since the output is very minute, it is amplified by the operational amplifier.

Operational amplifier

Output voltage

S : Thermistor open vessel

C : Thermistor closed vessel

Absolute humidity (g/m )

Output voltage

Absolute humidity vs, output voltage characterist



(3) Detector Circuit of Absolute Humidity Sensor Circuit

This detector circuit is used to detect the output voltage of the absolute humidity circuit to allow the LSI to control sensor cooking of the unit. When the unit is set in the sensor cooking mode, 16 seconds clearing cycle occurs than the detector circuit starts to function and

the LSI observes the initial voltage available at its AN7 terminal. With this voltage given, the switches SW1 to SW5 in the LSI are turned on in such a way as to change the resistance values in parallel with R107 ~ R111 of IC2. Changing the resistance values results in that there is the same potential at both F-3 terminal of the absolute humidity sensor and AN6 terminal of the LSI. The voltage of AN7 terminal will indicate about -2.5V. This initial balancing is set up about 16 seconds after the unit is put in the Sensor Cooking mode. As the sensor cooking proceeds, the food is heated to generate moisture by which the resistance balance of the bridge circuit is deviated to increase the voltage available at AN7 terminal of the LSI. Then the LSI observes that voltage at AN7 terminal and compares it with its initial value, and when the comparison rate reaches the preset value (fixed for each menu to be cooked), the LSI causes the unit to stop sensor cooking; thereafter, the unit goes in the next operation automatically. When the LSI starts to detect the initial voltage at AN7 terminal 16 seconds after the unit has been put in the Sensor Cooking mode, if it is not possible to balance, of the bridge circuit due to disconnection of the absolute humidity sensor, ERROR will appear on the display and the cooking is stopped.

1) Absolute humidity sensor circuit

ABSOLUTE HUMIDITY SENSOR CIRCUIT

Sensing part (Open vessel)

Sensing part (Closed vessel)

Thermistors

SW1 SW2

SW3 SW4 SW5

R47 R46 R45 R44 R43

LSI (IC1)

AN0

AN1

620k

300k 150k

75k

37.4k

22 23

47k

IC2

10k

0.01uF

0.015uF

0.01uF

VA : -15V

R90

C101

C102

C103

C104

F-2

1.8k 360k

F-1

F-3

3.57k

3.32k

VC : -5V

0.1

C. Thermistor in  closed vesssl S. Thermistor in open vessel

R107



R108

R112

R105

R101

R103

R102

R104

D101

R109 R110 R111

R106

Page 22

R-380A

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

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 the touch control panel while keeping it apart from the 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 equivalent to the oven door being closed. As for the sensor-related controls of the touch control panel, checking them is possible if dummy resistor(s) with resistance 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 door being closed. Connect an external power source to the power input terminal of the touch control panel, then it is possible to check and repair the controls of the touch control panel it is also possible to check the sensor-related controls of the touch control panel by using the dummy resistor(s).

4. Servicing Tools

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, remove the aluminium foil applied for preventing static electricity.

2) Connect the connector of the key unit to the control unit being sure that the lead wires are not twisted.

3) After aluminium foil is removed, be careful that abnormal voltage due to static electricity etc. is not applied to the input or output terminals.

4) Attach connectors, electrolytic capacitors, etc. to PWB, making sure that all connections are tight.

5) Be sure to use specified components where high precision is required.

Transistor

2SB1238

Transistor

KRC243M

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 have extremely high impedance at its input and output terminals. For this reason, it is easily influenced by the surrounding high voltage power source, static electricity charge in clothes, etc, and sometimes it is not fully protected by the built-in protection circuit. In order to protect CMOS LSI.

1) 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.

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 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 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.

Page 23

R-380A

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. 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. Visually check the door and cavity face plate for damage (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. 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.

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) Discharge the high voltage capacitor and wait for 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: Oven lamp, Magnetron, High voltage transformer

and Oven cavity.

3) Sharp edge: Bottom plate, Oven cavity, Waveguide flange, Chassis support and other metallic plate.

4) Movable parts (to prevent a fault) Fan blade, Fan motor, Switch, Switch lever, Open button.

3. Do not catch the wire leads in the outer case cabinet.

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 power transformer and filament leads of transformer to 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. Slide the entire case back out about 1 inch(3 cm) to free

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 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.

Page 24

R-380A

HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL

1. CARRY OUT 3D CHECKS.

2. Disconnect the brown and blue wires of power supply cord from the noise filter.

3. Disconnect the connector of the main wire harness from the noise filter.

4. Remove one (1) screw holding the noise filter angle to the oven cavity rear plate.

5. Remove one the noise filter angle with noise filter from the oven cavity rear plate.

6. Disconnect the high voltage of the high voltage rectifier assembly from the power transformer.

7. Remove one (1) screw holding capacitor holder to the oven cavity rear plate.

8. Disconnect rectifier terminal from capacitor. Rectifier and high voltage assembly is now free.

9. Remove one (1) screw holding high voltage rectifier assembly to capacitor holder.

10.Disconnect wire leads from capacitor and remove capacitor holder.

11.High voltage rectifier assembly and high voltage capacitor are free now.

CAUTION: WHEN REPLACING HIGH VOLTAGE

RECTIFIER AND HIGH VOLTAGE CAPACITOR, GROUND SIDE TERMINAL OF THE HIGH VOLTAGE RECTIFIER MUST BE SECURED FIRMLY WITH A GROUNDING SCREW.

MAGNETRON REMOVAL

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. Insert the two (2) tabs of the chassis support to the oven cavity front plate and back plate.

3. Re-install the chassis support to oven cavity front plate and magnetron with the two (2) screws.

4. Reconnect the wire leads to the magnetron. Refer to

"PICTORIAL DIAGRAM".

5. Re-install outer case and check that the oven is operating properly.

CAUTION: WHEN REPLACING MAGNETRON, BE

SURE THE R.F. GASKET IS IN PLACE AND MOUNTING SCREWS ARE TIGHTENED SECURELY.

SCREWS

WAVEGUIDE FLANGE

MAGNETRON

Figure C-1. Magnetron replacement

1. CARRY OUT 3D CHECKS.

2. Pushing the lever of positive lock® connector.

3. Pull out the positive lock® connector. CAUTION: WHEN YOU (SERVICE ENGINEERS) CON-

NECT THE POSITIVE LOCK® CONNECTORS TO THE TERMINALS, CONNECT THE POSITIVE LOCK® SO THAT THE LEVER FACE YOU (SERVICE ENGINEERS).

POSITIVE LOCK® CONNECTOR REMOVAL

Terminal

Push

Pull down

Lever

Positive lock

connector

Figure C-2. Positive lock® connector

1. Open covers of the terminal insulator by using small flat type screw driver.

2. Remove the receptacle from the terminal insulator.

3. Now, the terminal insulator is free.

Installation

1. Insert the receptacle into terminal insulator.

2. Close covers of the terminal insulator, as shown illustlated below.

TERMINAL INSULATOR REPLACEMENT

RECEPTACLE

COVERS

Terminal  insulator

Flat type screw driver

Page 25

R-380A

Handle the CPU unit carefully so that the ribbon cable does not come off. Because the ribbon cable is sticked on the LCD and the printed wiring board only by heated paste.

Connector

Power unit

CPU unit

Solder

These should be parallel

Figure C-3. Side view of CPU unit and Power unit

Printed wiring board 

of CPU unit

Liquid Crystal

Display (LCD)

Ribbon cable

Figure C-4. CPU unit

1. CARRY OUT 3D CHECKS.

2. Disconnect the wire leads from panel components.

3. Make one (1) tab of the oven cavity front plate straight holding the control panel assembly to the oven flange.

Slide the control panel assembly upward and remove it.

5. Now, individual components can be removed.

NOTE: 1. Before attaching a new key unit, wipe off

remaining adhesive on the control panel frame surfaces completely with a soft cloth soaked in alcohol.

2. When attaching the key unit to the control panel frame, adjust the upper edge and right edge of the key unit to the correct position of control panel frame.

3. Stick the key unit firmly to the control panel frame by rubbing with soft cloth not to scratch.

CPU UNIT AND POWER UNIT NOTE: When soldering the CPU unit and the power unit,

make sure both the CPU unit and power unit are parallel, as shown figure C-3.

CONTROL PANEL ASSEMBLY REMOVAL

1. CARRY OUT 3D CHECKS.

2. Bend the tab of the partition angle holding the lamp socket.

3. Lift up the oven lamp socket.

4. Pull the wire leads from the oven lamp socket by pushing the terminal hole of the oven lamp socket with the small flat type screw driver.

5. Now, the oven lamp socket is free.

OVEN LAMP AND LAMP SOCKET REMOVAL

Oven lamp socket

Terminal

Wire lead

Terminal hole

Flate type small screw driver

Figure C-5. Oven lamp socket

TURNTABLE MOTOR REMOVAL

1. Disconnect oven from power supply.

2. Remove turntable and turntable support from oven cavity.

3. Lay the oven on it's backside. Remove the turntable motor cover by snipping off the material in four corner.

4. Where the corners have been snipped off bend corner areas flat. No sharp edge must be evident after removal of the turntable motor cover.

5. Disconnect wire leads from turntable motor.

(See "Positive lock connector removal")

6. Remove two (2) screws holding turntable motor to oven cavity.

7. Now the turntable motor is free.

8. After replacement use the one (1) screw to fit the turntable motor cover.

NOTE: The one (1) screw to fit the turntable motor cover

should be XFPSD40P12K00, XFPSD40P10K00 or XFPSD40P08K00.

COOLING FAN MOTOR REMOVAL

1. CARRY OUT 3D CHECKS.

2. Disconnect the wire leads from the fan motor.

3. Remove two (2) screws holding the chassis support to magnetron and oven cavity front plate. And remove chassis support.

4. Release the snap of the main wire harness from the fan duct.

5. Remove two (2) screws holding the fan duct assembly to the oven cavity top and front plates.

6. Release the main wire harness from the hole of the fan duct.

7. Release the fan duct from the waveguide flange.

8. Release the fan duct assembly from the oven cavity.

9. Remove the fan blade from the fan motor shaft according the following procedure.

1) Hold the edge of the rotor of the fan motor by using a pair of grove joint pliers.

CAUTION: * Make sure that any pieces do not enter the gap

between the rotor and the stator of the fan motor because the rotor is easily shaven by pliers and metal pieces may be produced.

* Do not touch the pliers to the coil of the fan motor

because the coil may be cut or injured.

Page 26

R-380A

* Do not disfigure the bracket by touching with the

pliers.

2) Remove the fan blade from the shaft of the fan motor by pulling and rotating the fan blade with your hand.

3) Now, the fan blade will be free.

CAUTION: * Do not reuse the removed fan blade because the

hole (for shaft) may be larger than normal.

10.Remove the two (2) screws holding the fan motor to the fan duct.

11.Now, the fan motor is free.

INSTALLATION

1. Install the fan motor to the fan duct with the two (2) screws.

2. Install the fan blade to the fan motor shaft according the following procedure.

1) Hold the center of the bracket which supports the shaft of the fan motor on the flat table.

2) Apply the screw lock tight into the hole (for shaft) of the fan blade.

3) Install the fan blade to the shaft of fan motor by pushing the fan blade with a small, light weight, ball peen hammer or rubber mallet.

CAUTION: * Do not hit the fan blade strongly when installed

because the bracket may be disfigured.

* Make sure that the fan blade rotates smooth after

installation.

* Make sure that the axis of the shaft is not slanted.

3. Catch three holes of fan duct on three tabs of the waveguide flange.

4. Install the fan duct assembly to the oven cavity top and front plate with the two (2) screws.

5. Insert the snap of the main wire harness to the hole of the fan duct and insert the main wire harness into the hole of the fan duct.

6. Install one (1) tab of the chassis support to oven cavity front plate and install another tab of it to rear plate. And then screw chassis support to magnetron and oven cavity front plate with two (2) screws.

7. Connect the wire leads to the fan motor, referring to the pictorial diagram.

Coil

Gap

Rotor

Bracket

Stator

Groove joint pliers

Shaft

Axis

Stator

These are the position where should be pinched with pliers

Rotor

Shaft

Table

Center of bracket

Side ViewRear View

POWER SUPPLY CORD REPLACEMENT

Removal

1. CARRY OUT 3D CHECKS.

2. Disconnect the brown and blue wires of the power supply cord from the noise filter.

3. Remove the single (1) screw holding the earth wire of power supply cord.

4. Remove the power supply cord from the oven cavity back plate.

Re-install

1. Insert the power supply cord into the oven cavity back plate.

2. Connect the brown and blue wires of power supply cord into the terminals of noise filter, referring to pictorial diagram.

3. Re-install the earth wire to bottom plate with one (1) screw.

4. CARRY OUT 4R CHECKS.

Note : Step 4 above is important, and it must be done

after replacing power supply cord.

Noise  filter

Power supply  cord

Brown wire

Blue wire

Green/Yellow wire

Figure C-6. Power supply cord replacement

1ST. LATCH SWITCH, 2ND. LATCH SWITCH, STOP SWITCH AND MONITOR SWITCH REMOVAL

1. CARRY OUT 3D CHECKS.

2. Disconnect wire leads from the switches.

3. Remove two (2) screws holding latch hook to oven flange.

4. Remove latch hook assembly from oven flange.

5. Push outward on the two (2) retaining tabs holding switch in place.

6. Switch is now free. At this time switch lever will be free, do not lose it.

Re-install

1. Re-install each switch lever and latch switch in its

place. The 1st. latch /stop/monitor switches are in the lower position and the 2nd. latch switch is in the upper position.

2. Re-connect wire leads to each switch. Refer to pictorial diagram.

3. Secure latch hook (with two (2) mounting screws) to oven flange.

4. Make sure that the monitor switch is operating properly and check continuity of the monitor circuit. Refer to chapter "Test Procedure" and Adjustment procedure.

Page 27

R-380A

REMOVAL

1. Disconnect oven from power supply.

2. Push the open button and open the door slightly.

3. Insert an putty knife (thickness of about 0.5mm) into the gap between the door stopper and the choke cover to free engaging parts as shown in Figure C-8.

4. Try the principles of the lever and lift up the door stopper.

5. Now, the door stopper is free from the door assembly.

6. Release two (2) pins of door panel from two (2) holes of upper and lower oven hinges by lifting up.

7. Now, door panel with door frame is free from oven cavity.

8. Insert an putty knife (thickness of about 0.5mm) into the gap between the choke cover and door frame as shown in Figure C-8 to free engaging parts.

9. Try the principles of the lever and lift up the choke cover by inserting a putty knife as shown Figure C-8.

10.Release choke cover from door panel.

11.Now choke cover is free.

Choke Cover

Door Frame

Putty Knife

Door stopper

Figure C-8. Door Disassembly

12.Release door panel from nine (9) tabs of door frame by

sliding door panel downward.

13.Now, door panel with sealer film is free.

14.Tear sealer film from door panel.

15.Now, door panel is free.

16.Slide latch head upward and remove it from door frame with releasing latch spring from door frame and latch head.

17.Now, latch head and latch spring are free.

18.Remove door screen from door frame by releasing two (2) tabs.

19.Now, door screen is free.

RE-INSTALL

1. Re-install door screen to door frame by fitting two (2) tabs of door frame to two (2) holes of door screen.

2. Re-install the latch spring to the latch head. Re-install the latch spring to the door frame. Re-install latch head to door frame.

3. Re-install door panel to door frame by fitting nine (9) tabs of door frame to nine (9) holes of door panel.

4. Hold the door panel to the door frame by sliding the door panel upward.

5. Put sealer film on door panel. Refer to “Sealer Film” about how to handle new one.

6. Re-install choke cover to door panel by pushing.

7. Catch two (2) pins of door panel on two (2) hole of upper and lower oven hinges.

8. Re-install the door stopper to the door assembly.

Note: After any service to the door; (A) Make sure that door sensing switch and secondary

interlock switch are operating properly. (Refer to chapter “Test Procedures”.).

(B) An approved microwave survey meter should be

used to assure compliance with proper microwave radiation emission limitation standards.

1ST. LATCH SWITCH, 2ND. LATCH SWITCH, STOP SWITCH AND MONITOR SWITCH ADJUSTMENT

If the 1st. latch switch, 2nd. latch switch, stop switch and monitor switch do not operate properly due to a misadjustment, the following adjustment should be made.

1. Loosen the two (2) screws holding latch hook to the oven cavity front flange.

2. With door closed, adjust latch hook by moving it back and forth, and up and down. In and out play of the door allowed by the upper and lower position of the latch hook should be less than 0.5mm. The vertical position of the latch hook should be adjusted so that the 1st. latch switch, 2nd. latch switch and stop switch are activated with the door closed. The horizontal position of the latch hook should be adjusted so that the plunger of the monitor switch is pressed with the door closed.

3. Secure the screws with washers firmly.

4. Check all switches operation. If each switch has not activated with the door closed, loosen screw and adjust the latch hook position.

After adjustment, check the following.

1. In and out play of door remains less than 0.5mm when in the latched position. First check upper position of latch hook, pushing and pulling upper portion of door toward the oven face. Then check lower portion of the

latch hook, pushing and pulling lower portion of the door toward the oven face. Both results (play in the door) should be less than 0.5mm.

2. The 1st. latch switch, 2nd. latch switch and stop switch interrupt the circuit before the door can be opened.

3. Monitor switch contacts close when door is opened.

4. Re-install outer case and check for microwave leakage around door with an approved microwave survey meter. (Refer to Microwave Measurement Procedure.)

Latch Hook 

2nd. Latch Switch

Monitor  Switch

Stop  Switch

Switch Lever

Latch Heads

Door

1st. Latch  Switch

Figure C-7. Latch Switch Adjustments

DOOR REPLACEMENT

Page 28

R-380A

After any service, make sure of the following :

1. Door latch heads smoothly catch latch hook through latch holes and that latch head goes through center of latch hole.

2. Deviation of door alignment from horizontal line of cavity face plate is to be less than 1.0mm.

3. Door is positioned with its face pressed toward cavity face plate.

4. Check for microwave leakage around door with an approved microwave survey meter. (Refer to Microwave Measurement Procedure.)

Note: The door on a microwave oven is designed to act

as an electronic seal preventing the leakage of microwave energy from oven cavity during cook cycle. This function does not require that door be air-tight, moisture (condensation)-tight or lighttight. Therefore, occasional appearance of moisture, light or sensing of gentle warm air movement around oven door is not abnormal and do not of themselves, indicate a leakage of microwave energy from oven cavity.

Upper oven hinge

Lower  oven hinge

Lower oven hinge

Door stopper

Choke cover

Door panel

Figure C-9. Door Replacement

SEALER FILM

Installation

1. Put the adhesive tape on the backing film of the sealer film as shown in Fig. C-10.

2. Tear the backing film by pulling the adhesive tape.

3. Put the pasted side of the sealer film on the door panel

Sealer film

Backing film

Adhesive tape

Figure C-10. Sealer film

Page 29

R-380A

MICROWAVE MEASUREMENT

After adjustment of door latch switches, monitor switch and door are completed individually or collectively, the following leakage test must be performed with a survey instrument and it must be confirmed that the result meets the requirements of the performance standard for microwave oven.

REQUIREMENT

The safety switch must prevent microwave radiation emission in excess of 5mW/cm2 at any point 5cm or more from external surface of the oven.

PREPARATION FOR TESTING:

Before beginning the actual test for leakage, proceed as follows;

1. Make sure that the test instrument is operating normally as specified in its instruction booklet. Important: Survey instruments that comply with the requirement for instrumentations as prescribed by the performance standard for microwave ovens must be used for testing.

Recommended instruments are: NARDA 8100 NARDA 8200 HOLADAY HI 1500 SIMPSON 380M

2. Place the oven tray into the oven cavity.

3. Place the load of 275 ± 15ml of water initially at 20 ± 5˚C in the centre of the oven tray. The water container should be a low form of 600 ml beaker with inside diameter of approx. 8.5cm and made of an electrically non-conductive material such as glass or plastic. The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage is measured accurately.

4. Close the door and turn the oven ON with the timer set for several minutes. If the water begins to boil before the survey is completed, replace it with 275ml of cool water.

5. Move the probe slowly (not faster that 2.5cm/sec.) along the gap.

6. The microwave radiation emission should be measured at any point of 5cm or more from the external surface of the oven.

mW cm

Microwave leakage measurement at 5 cm distance

SHARP

Page 30

R-380A

SCHEMATIC

NOTE: CONDITION OF OVEN

1.DOOR CLOSED

2.CLOCK APPEARS ON DISPLAY

NOTE: " " indicates components with potentials above 250V.

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. COOKING TIME PROGRAMMED

3. START KEY TOUCHED

Figure O-2. Oven Schematic-Cooking Condition

Figure O-1. Oven Schematic-OFF Condition

AH SENSOR

POWER TRANSFORMER

MAGNETRON

H.V. RECTIFIER

ASYMMETRIC

RECTIFIER

CAPACITOR

1.07µ

AC2200V

TURNTABLE MOTOR

FAN MOTOR

OVEN LAMP

STOP

SWITCH

MONITOR SWITCH

CONTROL

UNIT

THERMAL 

CUT-OUT

95˚C (MG)

1ST.

LATCH

SWITCH

TTM

N.O.

RY-1

COM.

THERMAL

CUT-OUT

125˚C (OVEN)

RY-2

2ND.

LATCH

SWITCH

MONITOR

RESISTOR

0.8/20W

EARTH

BLU

BRN

230-240V/50Hz

G-Y

FUSE

M8A

LINE CROSS CAPACITOR

0.068µ/AC250V

NOISE SUPPRESSION COIL

LINE BYPASS

CAPACITOR

0.0022µ/AC250V

LINE BYPASS

CAPACITOR

0.0022µ/AC250V

POWER TRANSFORMER

MAGNETRON

H.V. RECTIFIER

ASYMMETRIC

RECTIFIER

CAPACITOR

1.07µ

AC2200V

TURNTABLE MOTOR

FAN MOTOR

OVEN LAMP

STOP

SWITCH

MONITOR SWITCH

CONTROL

UNIT

THERMAL 

CUT-OUT

95˚C (MG)

1ST.

LATCH

SWITCH

TTM

N.O.

RY-1

COM.

THERMAL

CUT-OUT

125˚C (OVEN)

RY-2

2ND.

LATCH

SWITCH

MONITOR

RESISTOR

0.8/20W

EARTH

BLU

BRN

230-240V/50Hz

G-Y

FUSE

M8A

LINE CROSS CAPACITOR

0.068µ/AC250V

NOISE SUPPRESSION COIL

LINE BYPASS

CAPACITOR

0.0022µ/AC250V

LINE BYPASS

CAPACITOR

0.0022µ/AC250V

AH SENSOR

Page 31

R-380A

Figure S-1. Pictorial Diagram

HIGH 

VOLTAGE

CAPACITOR

HIGH 

VOLTAGE

WIRE A

H.V.

RECTIFIER

HIGH VOLTAGE COMPONENTS

OVEN LAMP 

AND SOCKET

MAGNETRON

COM.

MONITOR

SWITCH

COM.

N.O.

N.C.

2ND

LACTH

SWITCH

1ST 

LATCH

SWITCH

TURNTABLE

MOTOR

HIGH VOLTAGE

TRANSFORMER

COM.

CN-B

GRN

GRY

CN-A

WHT

BLK

GRY

ORG

BLK

RED

BLK

BLK

GRY

WHT

GRY

BLKRED

THERMAL CUT-OUT

125˚C (OVEN)

FAN MOTOR

RED

BLK

WHT

GRY

WHT

BLU

BRN

POWER

SUPPLY

CORD

EARTH

NOISE FILTER

M8A

NEUTRAL

LIVE

GRN

BLK

ORG

WHT

GRY

(OVEN SIDE)

STOP

SWITCH

COM.

GRY

GRN

G

/

WHT

THERMAL 

CUT-OUT

95˚C (MG)

WHT

ASYMMETRIC

RECTIFIER

WHT

RED

MONITOR

RESISTOR

BLK

GRY

NOTE:

Neutral (WHT) wire must

be connected to the

terminal with black mark

on the oven light socket.

WHT

RED

BLACK MARK

RY1

N.O.

COM.

RY2

RELAY

CN-B

CN-A

BLK

AH SENSOR

RED

WHT

123

CN-F

CONTROL UNIT

IC1

CN-G

CN-F

1 2 3

Page 32

R-380A

Figure S-2. Power unit Circuit

+ –

A 3

C 1

C 2

C 3

C 4

C 5

C 6

C 7

C 8

C 9

B 1

B 2

SH-B

SH-A

MICRO

NOTE

: IF NOT SPECIFIED, 1/4w ± 5% : IF NOT SPECIFIED, 1SS270A

TURNTABLE MOTOR OVEN LAMP FAN MOTOR

WH-1

R4 27

R5 4.7k

R2 680 1/2w

R6 3.3k

SP1

VRS1

C1 0.1µ/50v

C3 0.1µ/50v

ZD1

HZ16-1

C4 10µ/35v

C5 10µ/35v

R3 510

1/2w

C2 1000µ/35v

R1 2.4k

(J1)



RY1

RY2

Q2 2SB1238

2SB1238

D1-D4 11ES1

Q3 KRC243M

LD1-LD5

LD1 LD2 LD3 LD4 LD5

A 1

N.O.

COM



Page 33

R-380A

–

C 9

F 1

G 8

RICE

CLOCK

SOUP

TIMER

PIZZA

MEAT

HELP

POWER

LEVEL

STOP

CLEAR

DINNER

PLATE

SLOW

COOK

MEMORY

RICE /

PASTA

LESS

PIE

VEGETABLES

CASSEROLE

DESSERTS

EASY

DEFROST

G 7

G 6 G 5 G 4 G 3 G 2

KEY UNIT

G 1

G12

C10 47µ/16v

C20

D22

D30

0.1µ/50v

C12

0.1µ/50v

0.015µ/25v

0.1µ/50v

C102

C101

C13

0.1µ/50v

Q11

KRA101S

Q40

KRA101S

Q22

KRA105S

IC2

BA4558

S16

S15

S14

S13

S12

S11

S10

S19

S20

S21

S22

S23

S24

S25

S26

P73

100

P72

P71

P70

RESET

P80

XIN

XOUT

VSS

P27

P26

P25

P24

P23

P22

P21

P20

P17

P16

P81

C1 SEG10

SEG11

SEG12

SEG13

SEG14

SEG15

SEG16

SEG17

SEG18

SEG19

SEG20

SEG21

SEG22

SEG23

SEG24

SEG25

SEG26

SEG27

SEG28

SEG29

SEG30

SEG31

SEG32

SEG33

SEG34

SEG35

SEG36

SEG37

SEG38

SEG39

VL1

AN7

AN6

AN5

AN4

AN3

AN2

AN1

AN0

P57

P56

P55

P54

P53

P52

P51

P50

P47

P46

P45

P44

P43

P41

P40

P77

P76

P75

P74

INT0

VL2

VL3

COM0

COM1

COM3

AVSS

VREF

VCC

SEG0

SEG1

SEG2

SEG3

SEG4

SEG5

SEG6

SEG7

SEG8

SEG9

COM2

Q20 KRA101S

C11 0.1µ/50v

C30

C63 330p/50v

C62 330p/50v

C61 330p/50v

C60 330p/50v

R75 100k

R74 100k

R73 100k

R72 100k

C103

LIQUID CRY STAL DISPLAY

C104

IC2

D101

AH SENSOR

NOTE

IC1 IZA778DR

GND

INT

BUZZER

RY1

RY2

(RY3)

DOOR

SWITCH

: IF NOT SPECIFIED 1/10w ± 5%

: IF NOT SPECIFIED 1SS355

: IF NOT SPECIFIED 0.01µF/25v

R10 1k

R11 4.7k

R15 4.7k

C14

R30 4.7k

R105

3.32kD R90

330 1w

R113

R112

3.57kD

R104 47k

R31 15k

R71 15k

CF1

CST4.00MGW

R70 15k

R69 15k

R68 15k

R101

1.8kF

MA152

R103 10k

R102 360kF

R111 37.4kF

C.D.E.

D.E.F.

A.B.

A. B.

R110 75kF

R109 150kF

R108 300kF

R107 620kF

R106 47k

R12 10k

R60 15k

R80

R50

4.7k

R61 15k

R62 15k

R63 15k

R64 15k

R65 15k

R66 15k

R67 15k

(J10) 4.7k

(J12) 4.7k

(J14) 4.7k

(J16) 4.7k

(J11)

(J13)

(J15)

(J17)

R14 10k

R13 10k

ZD10 UDZ4.3B

Q10

2SA1037AK

G11 G10

G 9

F-2 F-3

C 8

C 7

C 6

C 5

C 4

C 3

C 2

C 1



START

INSTANT

COOK

COOK SENSOR LBS KG DEF HELP



Figure S-3. CPU Unit Circuit

Page 34

R-380A

Figure S-4. Printed Wiring Board

LD1 LD2 LD3 LD4 LD5

WH-1

SH-A (GREEN)

SH-B

(R2/J4)

(Q1)

(1) (3)

(7) (4)

RY1

RY2

HVT

OMIF

(COM)

OL FM AC

CN - A

TTM

(C4)

DIP

CN - C

(R1)

(ZD1)

(CN - B)

DOOR SW

(C3)

SP1

(J3)

(J2)

(J1)

C1 D4 D2 D1 D3

(D9)

VRS1

(RY3)

LOT NO.

WH-1

Page 35

R-380A

* * * *

∆

* *

∆

PARTS LIST

Note: The parts marked "∆" may cause undue microwave exposure.

The parts marked "*" are used in voltage more than 250V.

REF. NO. PART NO. DESCRIPTION Q'TY CODE

ELECTRIC PARTS

1- 1 QSW-MA110WRE0 1st. latch switch, 2nd. latch switch and stop switch 3 AK 1- 2 QSW-MA111WRE0 Monitor switch 1 AK 1- 3 FPWBFA306WRK0 Noise filter 1 AT 1- 4 RTHM-A078WRE0 Thermal cut-out 125˚C 1 AL 1- 5 QACCAA045WRE0 Power supply cord 1 AT 1- 6 FH-DZA046WRK0 High voltage rectifier assembly 1 AW 1- 6 FH-DZA065WRK0 High voltage rectifier assembly (Interchangeable) 1 AX 1- 7 RC-QZA215WRE0 High voltage capacitor 1 AY 1- 7 RC-QZA182WRE0 High voltage capacitor (Interchangeable) 1 AY 1- 8 RV-MZA197WRE0 Magnetron 1 BN 1- 8 RV-MZA222WRE0 Magnetron (Interchangeable) 1 BN 1- 9 RMOTEA340WRE0 Fan motor 1 AX 1-10 QSOCLA022WRE0 Oven lamp socket 1 AG 1-11 RLMPTA069WRE0 Oven lamp 1 AK 1-12 RMOTDA169WRE0 Turntable motor 1 AW 1-13 RTHM-A079WRE0 Thermal cut-out 95 deg. 1 AL 1-14 RTRN-A522WRE0 Power transformer 1 BQ 1-14 RTRN-A521WRE0 Power transformer (Interchangeable) 1 BP 1-15 QFS-CA010WRE0 Fuse M8A 1 AE 1-16 RR-WZA022WRE0 Monitor resistor 0.8Ω 20w 1 AK 1-17 FDTCTA176WRK0 AH sensor assembly 1 AV

CABINET PARTS

2- 1 GCABUA608WRP0 Outer case cabnet 1 BB 2- 2 GDAI-A261WRW0 Bottom plate left 1 AP 2- 3 GDAI-A286WRW0 Bottom plate right 1 AN 2- 4 GLEGPA023WRE0 Foot 2 AB 2- 5 GLEGPA067WRF0 Foot 1 AE

CONTROL PANEL PARTS

3- 1 CPWBFA741WRK0 Power unit (New Zealand only) 1 BD 3- 1A QCNCMA394DRE0 2-pin connector(CN-A) 1 AD 3- 1B QCNCMA275DRE0 2-pin connector(CN-B) 1 AB 3- 1C QCNCMA422DRE0 9-pin connector(CN-C) 1 AF 3- 1D FW-VZA196DRE0 Lead wire harness (WH-1) 1 AD 3- 1E LHLD-A171WRF0 LED holder 1 AE C1 RC-KZA087DRE0 Capacitor 0.1µF 50V 1 AB C2 VCEAB31VW108M Capacitor 1000µF 35V 1 AF C3 RC-KZA087DRE0 Capacitor 0.1µF 50V 1 AB C4-5 VCEAB31VW106M Capacitor 10µF 35V 2 AA D1-4 VHD11ES1///-1 Diode (11ES1) 4 AB D5-8 VHD1SS270A/-1 Diode (1SS270ATA) 4 AA LD1-5 VHPSLZ381A9-3 Light emitting diode 5 AC Q1-2 VS2SB1238//-3 Transistor (2SB1238) 2 AA Q3 VSKRC243M//-3 Transistor (KRC243M) 1 AB R1 VRD-B12EF242J Resistor 2.4k ohm 1/4W 1 AA R2 VRD-B12HF681J Resistor 680 ohm 1/2W 1 AA R3 VRD-B12HF511J Resistor 510 ohm 1/2W 1 AB R4 VRD-B12EF270J Resistor 27 ohm 1/4W 1 AA R5 VRD-B12EF472J Resistor 4.7k ohm 1/4W 1 AA R6 VRD-B12EF332J Resistor 3.3k ohm 1/4W 1 AA RY1 RRLY-A080DRE0 Relay (OJ-SH-124LM) 1 AG RY2 RRLY-A076DRE0 Relay (OMIF-S-124LM) 1 AK SP1 RALM-A014DRE0 Buzzer (PKM22EPT-THAI) 1 AG T1 RTRNPA112DRE0 Transformer 1 AS VRS1 RH-VZA032DRE0 Varistor (10G471K) 1 AE ZD1 VHEHZ161///-1 Zener diode (HZ16-1) 1 AA 3- 2 DPWBFB635WRK0 CPU unit 1 BC 3- 3 FPNLCB290WRK0 Control panel frame with key unit 1 BB 3- 3-1 FUNTKA801WRE0 Key unit 1 AZ 3- 4 PSHEPA588WRE0 LED sheet 1 AE 3- 5 JBTN-B029WRF0 Open button 1 AG 3- 6 MSPRCA050WRE0 Open button spring 1 AB 3- 7 XEPSD30P08XS0 Screw ; 3mm x 8mm 4 AA

OVEN PARTS

4- 1 LANGQA456WRP0 Noise filter angle 1 AG 4- 2 PCUSGA312WRP0 Cushion 1 AB 4- 3 PHOK-A095WRF0 Latch hook 1 AN

Page 36

R-380A

Note: The parts marked "∆" may cause undue microwave exposure.

The parts marked "*" are used in voltage more than 250V.

REF. NO. PART NO. DESCRIPTION Q'TY CODE

HOW TO ORDER REPLACEMENT PARTS

To have your order filled prompty and correctly, please furnish the following information.

1. MODEL NUMBER 2. REF. NO.

3. PART NO. 4. DESCRIPTION

∆ ∆

∆

4- 4 LBNDKA099WRW0 Capacitor holder 1 AD 4- 5 NFANJA029WRE0 Fan blade 1 AL 4- 6 PDUC-A652WRP0 Fan duct 1 AU 4- 7 FOVN-A375WRT0 Oven cavity 1 BH 4- 8 LANGFA180WRW0 Chassis support 1 AM 4- 9 LANGQA452WRP0 Partition angle 1 AK 4-10 LANGQA454WRP0 MG thermo angle 1 AH 4-11 MLEVPA194WRF0 Switch lever 1 AG 4-12 NCPL-A045WRF0 Coupling 1 AH 4-13 PPACGA084WRF0 TTM packing 1 AF 4-14 PCOVPA275WRE0 Waveguide cover 1 AR 4-15 PCUSGA339WRP0 Cushion 2 AG 4-16 PCUSUA212WRP0 Cushion 1 AB 4-17 PCUSUA329WRP0 Cushion 1 AC 4-18 PCUSUA376WRP0 Cushion 1 AG 4-20 LSTPPA162WRF0 Door stopper 1 AE 4-21 LANGTA338WRP0 Sensor mounting angle 1 AP 4-22 PCUSUA192WRP0 Cushion 1 AD

DOOR PARTS

5 CDORFA761WRK0 Door assembly 1 BL 5- 1 FDORFA303WRT0 Door panel 1 BA 5- 2 PSHEPA382WRE0 Sealer film 1 AH 5- 3 GWAKPA471WRR0 Door frame 1 AZ 5- 4 HPNL-A662WRE0 Door screen 1 AK 5- 5 GCOVHA370WRF0 Choke cover 1 AM 5- 6 LSTPPA139WRF0 Latch head 1 AF 5- 7 MSPRTA084WRE0 Latch spring 1 AB 5- 8 PCUSUA481WRP0 Cushion 1 AB 5- 9 PCUSUA452WRP0 Cushion 1 AB 5-10 XCPSD40P08000 Screw : 4mm x 8mm 2 AA

MISCELLANEOUS

6- 1 FROLPA079WRK0 Turntable support 1 AQ 6- 2 NTNT-A084WRE0 Turntable tray 1 AR 6- 3 FW-VZB556WRE0 Main wire harness 1 AW 6- 4 QW-QZA220WRE0 High voltage wire A 1 AH 6- 5 FW-VZB122WRE0 Switch harness 1 AP 6- 6 LHLDWA011WRE0 Purse lock M 1 AB 6- 7 TCAUHA214WRR0 Caution label 1 AC 6- 8 TINS-A600WRR0 Instruction book 1 AK 6- 9 TSPCNC443WRR0 Rating label 1 AC 6-10 PZET-A012WRE0 Terminal insulator 1 AB 6-11 TLABMA540WRR0 Menu label 1 AC

SCREWS,NUTS AND WASHERS

7- 1 XFPSD40P08K00 Screw : 4mm x 8mm 10 AA 7- 2 XFPSD30P06000 Screw : 3mm x 6mm 3 AA 7- 3 XHTSD40P08RV0 Screw : 4mm x 8mm 6 AA 7- 4 XOTSE40P08000 Screw : 4mm x 8mm 1 AA 7- 5 XOTSD40P12RV0 Screw : 4mm x 12mm 14 AA 7- 6 XOTSD40P12000 Screw : 4mm x 12mm 8 AA

Page 37

R-380A

OVEN AND CABINET PARTS

7-5

7-4

2-1

4-18

7-2

4-16

7-3

1-5

7-6

6-2

7-3

1-1

4-1

1-15

1-1

4-8

1-7

4-4

7-5

7-6

7-1

7-5

6-5

4-3

7-6

6-1

7-1

1-9

1-5

4-6

1-8

1-4

4-7

4-12

4-14

1-12

7-1

4-13

4-2

4-15

1-14

7-3

1-16

4-15

2-3

4-5

1-3

1-2

1-6

7-1

7-6

7-5

7-6

2-5

2-4

7-5

2-4

7-3

2-2

4-11

6-11

4-9

4-10

1-13

7-1

7-3

1-11

1-10

6-7

7-6

7-1

7-5

4-17

4-21

4-22

7-2

1-17

Page 38

R-380A

CONTROL PANEL PARTS

MISCELLANEOUS

DOOR PARTS

4-20

5-2

5-10

5-5

5-1

5-3

5-6

5-7

Actual wire harness may be different from illustration.

6-4

6-3

(CAPACITOR)

5-4

5-8

6-10

5-10

5-9

3 - 2

3 - 4

3 - 3

6 - 9

3 - 6

3 - 5

3 - 7

3-1E

3 - 1

3-3-1

Page 39

R-380A

PACKING AND ACCESSORIES

DOOR PROTECTION SHEET SPADPA204WRE0

TOP PAD ASSEMBLY FPADBA311WRK0

PLASTIC BAG SSAKHA034WRE0

Not replaceable items.

PACKING CASE SPAKCC883WRE0

BOTTOM PAD ASSEMBLY FPADBA351WRK0

6- 2 TURNTABLE TRAY

PRINTING MATTER

6- 1 TURNTABLE SUPPORT

TRAY PACK SPADFA397WRE0

INTO THE OVEN CAVITY

Page 40

R-380A

'97SHARP CORP. (5S0.730E) Printed in Australia