Sharp R-330H Service Manual

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Page 1

R-330H

SHARP CORPORATION

SERVICE MANUAL

S8305R330HPJ/

MICROWAVE OVEN

MODEL

R-330H

In interests of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used.

TABLE OF CONTENTS

Page

CAUTION, MICROWAVE RADIATION............................................................................................................. 1

WARNING..........................................................................................................................................................1

PRODUCT SPECIFICATIONS ......................................................................................................................... 2

GENERAL INFORMATION................................................................................................................................2

APPEARANCE VIEW ....................................................................................................................................... 3

OPERATION SEQUENCE................................................................................................................................ 4

FUNCTION OF IMPORTANT COMPONENTS ................................................................................................ 5

SERVICING AND TROUBLESHOOTING GUIDE ............................................................................................ 6

TEST PROCEDURE......................................................................................................................................... 8

TOUCH CONTROL PANEL.............................................................................................................................14

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE........................................................... 19

MICROWAVE MEASUREMENT .................................................................................................................... 25

WIRING DIAGRAM......................................................................................................................................... 26

PICTORIAL DIAGRAM ................................................................................................................................... 27

CONTROL UNIT CIRCUIT ..............................................................................................................................28

PRINTED WIRING BOARD .............................................................................................................................29

PARTS LIST ................................................................................................................................................... 30

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R-330H

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R-330H

SERVICE MANUAL

MICROWAVE OVEN

R-330H

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-330H

ITEM DESCRIPTION

Power Requirements 230 - 240 Volts

50 Hertz

Single phase, 3 wire earthed Power Consumption 1.6kW Power Output 1100 watts nominal of RF microwave energy (IEC Test Procedure)

Operating frequency 2450 MHz Case Dimensions Width 520 mm

Height 310 mm including foot

Depth 459 mm Turntable diameter 320 mm Control Complement Touch Control System

Clock ( 1:00 - 12:59)

Timer (0 - 99 minutes 99 seconds)

Microwave Power for Variable Cooking

Repetition Rate;

100P................................................Full power throughout the cooking time

70P.....................................................................approx. 70% of Full Power

50P......................................................................approx. 50% of Full Power

30P......................................................................approx. 30% of Full Power

10P......................................................................approx. 10% of Full Power

INSTANT ACTION pads

EASY DEFROST pad

EXPRESS DEFROST pad

NUMBER pads

POWER LEVEL pad

TIMER/CLOCK pad

STOP/CLEAR pad

INSTANT COOK/START pad Set Weight Approx. 16 kg

PRODUCT SPECIFICATIONS

GENERAL INFORMATION

WARNING

THIS APPLIANCE MUST BE EARTHED

IMPORTANT

THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:

GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE

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R-330H

APPEARANCE VIEW

1. Door open button

2. Door safety latches

3. Removable turntable support

4. Removable turntable tray

5. Oven lamp

6. See through door

7. Ventilation openings

8. Touch control panel

9. Liquid crystal display

10.Coupling

11.Waveguide cover

12.Power supply cord

13.Door hinges

14.Door seals and sealing surfaces

TOUCH CONTROL PANEL

NOTE: Some one-touch cooking features such as "INSTANT COOK" are disabled after three minutes when the oven is not in use. These features are automatically enabled when the door is opened and closed or the STOP/ CLEAR pad is pressed.

11 25

EXPRESS DEFROST PAD Press to select the Express Defrost menu.

POWER LEVEL PAD Press to select microwave power setting. If not pressed, HIGH is automatically selected. Press to alter the cookingresult for automaticoperations.

STOP/CLEAR PAD Press to clear during programming. Press once to stopoperation of oven duringcooking; press twice tocancel cooking programme.

INSTANT ACTION PADS Press to cook or reheat 8 popular menus.

EASY DEFROST PAD Press to selectthe Easy Defrost menu.

NUMBER PADS Press to enter cooking time, clock time, weight of food.

TIMER/CLOCK PAD Press to set clock, timer, childlock or demonstration mode.

INSTANT COOK/START PAD Press to start oven after setting programmes. Press once to cook for 1 minute at HIGH or increase by 1 minute multiples each time this pad is pressed during cooking.

Indicators

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R-330H

OPERATION SEQUENCE

OFF CONDITION

Closing the door activates all door interlock switches (1st. latch switch and 2nd. interlock relay control switch).

IMPORTANT When the oven door is closed, the monitor switch contacts (COM-NC) must be open. When the microwave oven is plugged in a wall outlet, rated voltage is supplied to the noise filter and the control unit.

Figure O-1 on page 25

1. The display shows flashing "88:88".

2. To set any programmes or set the clock, you must first touch the STOP/CLEAR pad.

3. : appears in the display.

NOTE: When the oven door is opened, the oven lamp

comes on at this time.

MICROWAVE COOKING CONDITION

HIGH COOKING

Enter a desired cooking time with the touching NUMBER pad and start the oven with touching START pad.

Function sequence

Figure O-2 on page 25

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

1. 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 channelled through the waveguide (transport channel) into the oven cavity, where the food is placed to be cooked.

4. When the cooking time is up, a signal tone is heard and the relays RY1+RY2 go back to their home position. The circuits to the oven lamp, power transformer, fan motor and turntable motor are cut off.

5. When the door is opened during a cook cycle, the switches come to the following condition

CONDITION DURING DOOR OPEN

SWITCH CONTACT COOKING

(NO COOKING) 1st. latch switch COM-NO Closed Open 2nd. interlock relay

control switch

COM-NO Closed Open

Monitor switch COM-NC Open Closed

The circuits to the power transformer, fan motor and turntable motor are cut off when the 1st. latch switch and 2nd. interlock relay control switch are made open. The oven lamp remains on even if the oven door is opened after the cooking cycle has been interrupted,

because the relay RY1 stays closed. Shown in the display is the remaining time.

6. MONITOR SWITCH CIRCUIT The monitor switch is mechanically controlled by oven door, and monitors the operation of the 1st. latch switch and 2nd. interlock relay.

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

cycle of a cooking program, the 1st. latch switch and 2nd. interlock relay control switch must open their contacts first. After that the contacts (COM-NC) of the monitor switch can be closed.

6-2. When the oven door is closed, the contacts (COM-

NC) of the monitor switch must be opened. After that the contacts of the 1st. latch switch and 2nd. interlock relay control switch are closed.

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

1st. latch switch and 2nd. interlock relay remain closed. The fuse F10A will blow, because the monitor switch is closed and a short circuit is caused.

MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW COOKING

When the microwave oven is preset for variable cooking power, rated voltage is supplied to the power transformer intermittently within a 32-second time base through the relay contact which is coupled with the current-limiting relay. The following levels of microwave power are given.

SETTING;

NOTE: The ON/ OFF time ratio does not exactly correspond

to the percentage of microwave power, because approx. 3 seconds are needed for heating up the magnetron filament.

POWER OUTPUT REDUCTION

After 100% power cooking mode is carried out for more than 40 minutes, the power out-put is automatically reduced to 70%.

100P

32 sec. ON

70P

Approx. 70%

100%

24 sec. ON 8 sec. OFF

14 sec. OFF

20 sec. OFF

26 sec. OFF

50P Approx. 50%

18 sec. ON

30P

Approx. 30%

12 sec. ON

10P Approx. 10%

6 sec. ON

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R-330H

FUNCTION OF IMPORTANT COMPONENTS

OVEN TEMPERATURE FUSE

The temperature fuse, located on the top of the oven cavity, is designed to prevent damage to the oven by fire. If the food load is overcooked, by either error in cook time or defect in the control unit, the temperature fuse will open. Under normal operation, the temperature fuse remains closed. However, when abnormally high temperatures are reached within the oven cavity, the temperature fuse will open at 150˚C, causing the oven to shut down.

MAGNETRON TEMPERATURE FUSE

The temperature fuse 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 temperature fuse remains closed. However, when abnormally high temperatures are reached within the magnetron, the temperature fuse will open at 150˚C causing the oven to shut down.

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 vents surrounding the magnetron and cools the magnetron. This air is channelled through the oven cavity to remove steam and vapours given off from the heating foods. It is then exhausted through the exhausting air vents at the oven cavity.

NOISE FILTER

The noise filter prevents the radio frequency interference that might flow back in the power circuit.

DOOR OPEN MECHANISM

he door is opened by pushing the open button on the control panel, refer to the Figure D-1. When the open button is pushed, the open button pushes up the switch lever, and then the switch lever pushes up the latch head. The latch heads are moved upward and released from latch hook. Now the door will open.

Figure D-1. Door Open Mechanism

1ST. LATCH SWITCH AND 2ND. INTERLOCK RELAY CONTROL SWITCH

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

2. When the oven door is opened, the contacts (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 (COMNC) must be closed.

3. If the oven door is opened and the contacts (COM-NO) of the 1st. latch switch and 2nd. interlock relay fail to open, the fuse F10A blows simultaneously with closing the contacts (COM-NC) of the monitor switch.

CAUTION: BEFORE REPLACING A BLOWN FUSE F10A

TEST THE 1ST. LATCH SWITCH, 2ND. INTERLOCK RELAY, MONITOR SWITCH AND MONITOR RESISTOR FOR PROPER OPERATION.

HIGH VOLTAGE FUSE

The high voltage fuse blows when the high voltage rectifier or magnetron is shorted.

FUSE F10A

1. The fuse F10A blows when the contacts (COM-NO) of the 1st. latch switch and 2nd. interlock relay remain closed with the oven door open and when the monitor switch closes.

2. If the wire harness or electrical components are shortcircuited, this fuse F10A blows to prevent an electric shock or fire hazard.

Latch Heads

Door

Switch Lever

Latch Hook

Monitor Switch

2nd. Interlock Relay Control Switch

1st Latch Switch

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R-330H

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 fuse, High voltage harness.

REMEMBER TO CHECK 3D

1) Disconnect the supply.

2) Door opened, and wedged open.

3) Discharge the high voltage capacitor. WARNING: AGAINST THE CHARGE OF THE

HIGH-VOLTAGE CAPACITOR

The high-voltage capacitor remains charged about 60 seconds after the oven has been switched off. Wait for 60 seconds and then short-circuit the connection of the 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.

REMEMBER TO CHECK

1) Reconnect all leads removed from components during testing.

2) Replace the outer case (cabinet).

3) Reconnect the supply.

4) Run the oven. Check all functions.

Microwave ovens should not be run empty. To test for the presence of microwave energy within a cavity, place a cup of cold water on the oven turntable, close the door and set the microwave timer for two (2) minutes. Set the power level to HIGH and push the START button. When the two minutes has elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out

3D checks and reexamine the connections to the component being tested.

When 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.

When all service work is completed, and the oven is fully assembled, the microwave power output should be checked and microwave leakage test should be carried out.

TROUBLESHOOTING GUIDE

IMPORTANT: If the oven becomes inoperative because

of a blown fuse F10A in the 1st. latch switch - 2nd. interlock relay - monitor switch circuit, check the 1st. latch switch, 2nd. interlock relay and monitor switch before replacing the fuse F10A.

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R-330H

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

HIGH VOLTAGE CAPACITOR

1ST. LATCH SWITCH

2ND. INTERLOCK RELAY CONTROL

SWITCH

MONITOR SWITCH

TEMPERATURE FUSE (OVEN, MG)

FAN MOTOR

TURNTABLE MOTOR

FUSE F10A

TOUCH CONTROL PANEL

KEY UNIT

RELAY (RY-1, RY-2)

FOIL PATERN ON P.W.B.

POWER SUPPLY CORD

SHORTED WIRE HARNESS

OPENED WIRE HARNESS

OVEN LAMP

WALL OUTLET

MISADJUSTMENT SWITCH

HOME FUSE OR BREAKER

BLOCKED COOLING FAN

BLOCKED VENTILATION

NOISE FILTER

HIGH VOLTAGE FUSE

Home fuse blows when power supply cord is plugged into wall outlet.

FUSE F10A blows when power supply cord is plugged into wall outlet.

Display does not show anything when power supply cord is plugged into wall outlet.

Display does not operate properly when STOP/CLEAR pad is touched.

Oven lamp does not light at door opened. (Display appears.)

Oven 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 100%)

Oven does not seems to be operating properly when 70%, 50%, 30% or 10% is set. (Oven operates properly at 100% and then the STOP/ CLEAR pad is touched the oven stops.)

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

TEST PROCEDURE

CK = Check / RE = Replace

ABCDEEEFG GHKLMN

RECK CK RE CK CKCK CK CK

CONDITION

PROBLEM

POSSIBLE CAUSE

AND

DEFECTIVE PARTS

ON CONDITION

OFF CONDITION

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R-330H

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 IEC test procedure, i.e. it can be measured by using water load how much it can be absorbed by the water load. To measure the microwave output power in the microwave oven, the relation of calorie and watt is used. When P(W) heating works for t(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+ 0.55 x mc (T2-T0)/4.187P (W) = 4.187 x V x ∆T / t + 0.55 x mc (T2-T0)/t Our condition for water load is as follows:

Room temperature (T0) ... around 20°CPower supply Voltage.............. Rated voltage

Water load..................................1000 g Initial temperature (T1) ...................... 10±1°C

Heating time.............................. 38 sec. Mass of container (mc) ......................... 330 g

T2............................ Final Temperature P = 110 x ∆T + 0.55 x mc (T2-T0)/38

Measuring condition:

1. Container The water container must be a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190 mm.

2. Temperature of the oven and vessel The oven and the empty vessel are at ambient temperature prior to the start of the test.

3. Temperature of the water The initial temperature of the water is (10±1)˚C.

4. Select the initial and final water temperature so that the maximum difference between the final water temperature and the ambient temperature is 5˚C.

5. Select stirring devices and measuring instruments in order to minimize addition or removal of heat.

6. The graduation of the thermometer must be scaled by 0.1˚C at minimum and an accurate thermometer.

7. The water load must be (1000±5) g.

8. “t” is measured while the microwave generator is operating at full power. Magnetron filament heatup time is not included.

NOTE: The operation time of the microwave oven is “t + 3” sec. 3 sec. is magnetron filament heat-

up time.

Measuring method:

1. 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 ˚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.

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

A MAGNETRON TEST

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R-330H

Room temperature .................. To = 21˚C Initial temperature................. T1 = 11°C

Temperature after (38 + 3) = 41 sec. ................................................................ T2 = 21°C

Temperature difference Cold-Warm .............................................................. ∆T1 = 10°C

Measured output power

The equation is “P = 110 x ∆T” ........................................... P = 110 x 10°C = 1100 Watts

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

JUDGEMENT: The measured output power should be at least ± 15 % of the rated output power.

CAUTION: 1°C CORRESPONDS TO 110 WATTS REPEAT MEASUREMENT IF THE POWER IS

INSUFFICIENT.

1000g

T1˚C

T2˚C

Heat up for 41 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. 1.9 Ω

b. Secondary winding ...............approx. 104 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.

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.

HIGH VOLTAGE RECTIFIER

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R-330H

G MOTOR WINDING TEST

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

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. 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 Test

Temperature of "ON" condition Temperature of "OFF" condition Indication of ohmmeter

Parts Name (closed circuit) (˚C) (open circuit) (˚C) (When room temperature

is approx. 20˚C)

Temperature fuse 150˚C This is not resetable type. Above 150˚C Closed circuit.

If incorrect readings are obtained, replace the temperature fuse. An open circuit temperature fuse (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 temperature fuse (OVEN) indicates that the foods in the oven may catch fire, this may

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

F TEMPERATURE FUSE 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.

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R-330H

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

Table: Resistance of Motor

Motors Resistance Fan motor Approximately 250 Ω Turntable motor Approximately 14.5 kΩ

If incorrect readings are obtained, replace the motor. CARRY OUT

4R CHECKS

CARRY OUT 3D CHECKS.

1. If the fuse F10A 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 F10A is blown when the door is opened, check the 1st. latch switch, 2nd. interlock relay and monitor switch. If the fuse F10A is blown by incorrect door switching replace the defective switch(s) and the fuse F10A.

CARRY OUT 4R CHECKS. CAUTION: ONLY REPLACE FUSE F10A WITH THE CORRECT VALUE REPLACEMENT

H BLOWN FUSE F10A

I 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

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

CARRY OUT 3D CHECKS. If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.

Check them and replace the defective parts and high voltage fuse. CARRY OUT 4R CHECKS. CAUTION: ONLY REPLACE THE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE RE-

PLACEMENT

J HIGH VOLTAGE FUSE TEST

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.

RED

WHT

FUSE F10A

LINE CROSS CAPACITOR

0.068µ/AC250V

NOISE SUPPRESSION COIL

LINE BYPASS CAPACITOR

0.0022µ/AC250V

LINE BYPASS CAPACITOR

0.0022µ/AC250V

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R-330H

M RELAY TEST

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

L KEY UNIT TEST

1, CARRY OUT 3D CHECKS.

2. Isolate the key unit with the control panel frame to be tested.

3. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check the circuit between the pins of the key unit that correspond to the STOP/CLEAR pad. When the pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the ohmmeter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and must be replaced. About the other pads, the above method may be used.

4. CARRY OUT 4R CHECKS.

1. Key Unit. Note: Check key unit ribbon connection before replacement. The following symptoms indicate a defective key unit. Replace the control unit assembly. 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.

Remove the outer case and check voltage between the normal open terminal of the relay RY1 and the normal open 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.

INSTANT COOK

START

G6 G7 G8G3

G10

G11

G12

G4 G5

G2G1

4 7

5 8

91 3 6

EASY

DEFROST EXPRESS

DEFROST

TIMER

CLOCK

STOP

CLEAR

POWER

LEVEL

JACKET

POTATO

DINNER

PLATE

FROZEN

VEGETABLES

FRESH

VEGETABLES

PIE

PIZZA

RICE-PASTA

BEVERAGE

Pin NO. G12

Pin NO. G1

Key unit ribbon cable

Key unit (Membrane Switch) front view

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R-330H

o 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.

the normal open terminal of the relay RY1 and the normal open 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 replace control unit assembly. 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 control unit assembly.

CARRY OUT 4R CHECKS.

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

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

(PWB) IS OPEN

RY1 and RY2 Relay Test These relays are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.

DC. voltage indicated............... Defective relay.

DC. voltage not indicated......... Check diode which is connected to the relay coil. If diode is good,

control unit is defective.

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

RY1 APPROX. -11.8V D.C. Oven lamp / Turntable motor / Cooling fan motor RY2 APPROX. -10.5V D.C. Power transformer

CARRY OUT 4R CHECKS.

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R-330H

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 P22, P23, P24, P25, P26, P31, P32 and P33. When a key pad is touched, a signal is completed through the key unit and passed back to the LSI through P50, P51, P52 and P53 to perform the function that was requested.

Control Unit

Control unit consists of LSI, reset circuit, indicator circuit, power source circuit, relay circuit, buzzer circuit, synchronizing signal circuit and back light circuit.

1) Reset Circuit

This circuit generates a signal which resets the LSI to the initial state when power is supplied.

2) Indicator Circuit

This circuit consists of 14 segments and 3 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

VSS -5V 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) 2nd. Interlock Relay Control 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- LD3).

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R-330H

1 P50 IN Signal coming from touch key.

When either G9 line on key matrix is touched, a corresponding signal out of P22 - P26 and P31 - P33 will be input into P50. When no key is touched, the signal is held at “H” level.

2 P51 IN Signal similar to P50.

When either G10 line on key matrix is touched, a corresponding signal will be input into P51.

3 P52 IN Signal similar to P50.

When either G11 line on key matrix is touched, a corresponding signal will be input into P52.

4 P53 IN Signal similar to P50.

When either G12 line on key matrix is touched, a corresponding signal will be input into

P53. 5ICINConnected to VSS. 6XT1 IN Connected to VSS. 7XT2 _ Terminal not used. 8 VDD IN Power source voltage input terminal.

The power souce voltage to drive the LSI. Connected to GND. 9 VSS IN Power source voltage input terminal.

The power souce voltage to drive the LSI.

10 X1 IN Internal clock oscillation frequency input setting.

The internal clock frequency is set by inserting the resistor-capacitor oscillation circuit with

respect to X2 terminal.

11 X2 OUT Internal clock oscillation frequency control output.

Output to control oscillation input of X1.

12 RESET IN Auto clear terminal.

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

13-15 P00-P02 OUT Terminal not used.

16 P03 OUT Back light circuit (Light emitting diodes) driving signal. 17 CAPH _ Terminal not used. 18 CAPL _ Terminal not used.

19-21

VLC0-VLC2

IN Power source voltage input terminal.

Standard voltage for LCD.

22 COM0 OUT Common data signal.

Connected to LCD signal COM1.

23 COM1 OUT Common data signal.

Connected to LCD signal COM2.

24 COM2 OUT Common data signal.

Connected to LCD signal COM3.

25 COM3 OUT Terminal not used.

26-39

SEG0-SEG13

OUT Segment data signal.

Connected to LCD.

The relation between signals are as follows: LSI signal (Pin No.) LCD (segment) LSI signal (Pin No.) LCD (segment) SEG 0 (26)

...................................

SEG 1 SEG 7 (33)

................................

SEG 8

SEG 1 (27)

...................................

SEG 2 SEG 8 (34)

................................

SEG 9

SEG 2 (28)

...................................

SEG 3 SEG 9 (35)

..............................

SEG 10

SEG 3 (29)

...................................

SEG 4 SEG 10 (36)

..............................

SEG 11

SEG 4 (30)

...................................

SEG 5 SEG 11 (37)

..............................

SEG 12

SEG 5 (31)

...................................

SEG 6 SEG 12 (38)

..............................

SEG 13

SEG 6 (32)

...................................

SEG 7 SEG 13 (39)

..............................

SEG 14

40 SEG14 OUT Terminal not used. 41 P70 OUT Oven lamp, fan motor and turntable motor driving signal

To turn on and off shut off relay (RY1). The

square waveform voltage is delivered to the

RY1 driving circuit and RY2 control circuit.

42 P71 OUT Terminal not used.

LSI

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

Pin No. Signal I/O Description

20 msec.

During cooking

H : GND

L : -5V

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R-330H

43 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 cooking modes (variable cooking) the signal turns to “H” level and “L” level in repetition according to the power level.

44 AVDD IN A/D converter power source voltage.

The power source voltage to drive the A/D converter in the LSI. Connected to GND.

45-48 AIN5-AIN2 IN Terminal to change cooking input 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. 49 AIN1 IN This is the terminal to detect the voltage of the signal coming from the touch key. 50 AIN0 IN Signal similar to AIN1. 51 AVSS IN A/D converter power source voltage.

The power source voltage to drive the A/D converter in the LSI. 52 P11 IN To input signal which communicates the door open/close information to LSI.

Door close “H” level signal (0V). Door open “L” level signal (-5V). 53 P10 OUT Terminal not used. 54 P33 OUT Key strobe signal.