SHARP R-305HK, R-305HW Service Manual

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SERVICE MANUAL

S2305R305HPW/

MICROWAVE OVEN

R-305HK R-305HW

MODELS

R-305HK R-305HW

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

WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..)

Page PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO

AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY...................INSIDE FRONT COVER

BEFORE SERVICING ......................................................................................................INSIDE FRONT COVER

WARNING TO SERVICE PERSONNEL................................................................................................................1

MICROWAVE MEASUREMENT PROCEDURE ...................................................................................................2

FOREWORD AND WARNING...............................................................................................................................3

PRODUCT SPECIFICATIONS ..............................................................................................................................4

GENERAL INFORMATION...................................................................................................................................4

OPERATION..........................................................................................................................................................6

TROUBLESHOOTING GUIDE ..............................................................................................................................9

TEST PROCEDURE............................................................................................................................................10

TOUCH CONTROL PANEL.................................................................................................................................17

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ................................................................ 22

PICTORIAL DIAGRAM ........................................................................................................................................28

CONTROL UNIT CIRCUIT ..................................................................................................................................29

PRINTED WIRING BOARD .................................................................................................................................30

PARTS LIST ........................................................................................................................................................31

PACKING AND ACCESSORIES .........................................................................................................................32

SHARP CORPORATION

This document has been published to be used for after sales service only. The contents are subject to change without notice.

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R-305HK R-305HW

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY

(a) Do not operate or allow the oven to be operated with the door open. (b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other

microwave source, and make repairs as necessary: (1) interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse.

compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections.

(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave

generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner.

(e) A microwave leakage check to verify compliance with the Federal Performance Standard should be

performed on each oven prior to release to the owner.

BEFORE SERVICING

Before servicing an operative unit, perform a microwave emission check as per the Microwave Measurement Procedure outlined in this service manual. If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS CORPORATION immediately @1-800-237-4277.

If the unit operates with the door open, service person should 1) tell the user not to operate the oven and 2) contact SHARP ELECTRONICS CORPORATION and Food and Drug Administration's Center for Devices and Radiological Health immediately.

Service personnel should inform SHARP ELECTRONICS CORPORATION of any certified unit found with emissions in excess of 4mW/cm2. The owner of the unit should be instructed not to use the unit until the oven has been brought into compliance.

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WARNING TO SERVICE PERSONNEL

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

(Example) High Voltage Capacitor, High Voltage Power Trans-

former, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..

Read the Service Manual carefully and follow all instructions.

may result in a severe, possibly

Don't Touch ! Danger High Voltage

R-305HK R-305HW

Before Servicing

1. Disconnect the power supply cord , and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

WARNING:RISK OF ELECTRIC SHOCK.

DISCHARGE THE HIGH-VOLTAGE CAPACITOR BEFORE SERVICING.

The high-voltage capacitor remains charged about 60 seconds after the oven has been switched off. Wait for 60 seconds and then short-circuit the connection of the highvoltage capacitor (that is the connecting lead of the highvoltage rectifier) against the chassis with the use of an insulated screwdriver.

Whenever troubleshooting is performed the power supply must be disconnected. It may, in some cases, be necessary to connect the power supply after the outer case has been removed, in this event,

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the leads to the primary of the power transformer.

5. Ensure that the leads remain isolated from other components and oven chassis by using insulation tape.

6. After that procedure, reconnect the power supply cord.

When the testing is completed,

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Reconnect the leads to the primary of the power transformer.

5. Reinstall the outer case (cabinet).

6. Reconnect the power supply cord after the outer case is installed.

7. Run the oven and check all functions.

After repairing

1. Reconnect all leads removed from components during testing.

2. Reinstall the outer case (cabinet).

3. Reconnect the power supply cord after the outer case is installed.

4. Run the oven and 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 power to HIGH and set the microwave timer for two (2) minutes. When the two minutes has elapsed (timer at zero) carefully check that the water is now hot. If the water remains cold carry out Before Servicing procedure and reexamine the connections to the component being tested.

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

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R-305HK R-305HW

MICROWAVE MEASUREMENT PROCEDURE

A. Requirements:

1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external surface of the oven.

2) Safety interlock switches: Primary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission in excess of 5 mW/cm any point 5cm or more from the external surface of the oven.

B. Preparation for testing: Before beginning the actual measurement of leakage, proceed as follows:

1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.

Important: Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.

2) Place the oven tray in the oven cavity.

3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5˚C (68˚F) in the center of the oven cavity. The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made of an electrically nonconductive 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) Set the cooking control on Full Power Cooking Mode.

5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed, replace it with 275 ml of cool water.

C. Leakage test:

Closed-door leakage test (microwave measurement)

1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.

2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on the meter.

3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal has been breached (eg., around the switches, indicator, and vents). While testing for leakage around the door pull the door away from the front of the oven as far as is permitted by the closed latch assembly.

4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2, and that the secondary interlock switch and the primary interlock relay do turn the oven OFF before any door movement.

NOTE: After servicing, record data on service invoice and microwave leakage report.

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SERVICE MANU AL

R-305HK R-305HW

MICROWAVE OVEN

R-305HK/ R-305HW

FOREWORD

This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVENS,R-305HK and R-305HW.

It is recommended that service personnel carefully study the entire text of this manual so that they will be qualified to render satisfactory customer service.

Check the interlock switches and the door seal carefully. Special attention should be given to avoid electrical shock and microwave radiation hazard.

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 no other visible damage with the oven.

Servicing and repair work must be carried out only by trained service personnel.

DANGER

Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing. Service personnel - Do not contact the following parts while the appliance is energized; High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness; If provided, Vent Hood, Fan assembly, Cooling Fan Motor.

PRODUCT DESCRIPTION

GENERAL INFORMATION

OPERATION

TROUBLESHOOTING GUIDE AND TEST PROCEDURE

TOUCH CONTROL PANEL

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WIRING DIAGRAM

PARTS LIST

All the parts marked “*” on parts list are used at voltages more than 250V.

Removal of the outer wrap gives access to voltage 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 ELECTRONICS CORPORATION

SHARP PLAZA, MAHWAH,

NEW JERSEY 07430-2135

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R-305HK R-305HW

SPECIFICATION

ITEM DESCRIPTION

Power Requirements 120 Volts / 13.5 Amperes

60 Hertz Single phase, 3 wire grounded

Power Output 1100 watts (IEC TEST PROCEDURE)

Operating frequency of 2450MHz

Case Dimensions Width 20-1/2"

Height 12-1/4" Depth 17-3/4"

Cooking Cavity Dimensions Width 14-1/2"

Height 8-1/8"

1.0 Cubic Feet Depth 15-1/4" Control Complement Touch Control System

Clock ( 1:00 - 12:59 ) Timer (0 - 99 min. 99 seconds)

Microwave Power for Variable Cooking Repetition Rate;

P-HI..................................................Full power throughout the cooking time

P-90 ....................................................................approx. 90% of Full Power

P-80 ....................................................................approx. 80% of Full Power

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

P-60 ....................................................................approx. 60% of Full Power

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

P-40 ....................................................................approx. 40% of Full Power

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

P-20 ....................................................................approx. 20% of Full Power

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

P-0 ....................................................No power throughout the cooking time

POPCORN pad, MINUTE PLUS pad REHEAT pad, COOK pad DEFROST pad, Number selection pads POWER LEVEL pad, TIMER/CLOCK pad STOP/CLEAR pad, START pad

Oven Cavity Light Yes Safety Standard UL Listed FCC Authorized

DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J

GENERAL INFORMATION

GROUNDING INSTRUCTIONS

This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed and grounded in accordance with the National Electrical Code and local codes and ordinances. In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the electric current.

WARNING: Improper use of the grounding plug can result in a risk of electric shock.

Electrical Requirements The electrical requirements are a 120 volt 60 Hz, AC only, 15 or 20 amp. fused electrical supply. It is recommended that a separate circuit serving only this appliance be provided. When installing this appliance, observe all applicable codes and ordinances. A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord. Where a two-pronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to

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R-305HK R-305HW

contact a qualified electrician and have it replaced with a properly grounded three-pronged wall receptacle or have a grounding adapter properly grounded and polarized. If the extension cord must be used, it should be a 3-wire, 15 amp. or higher rated cord. Do not drape over a countertop or table where it can be pulled on by children or tripped over accidentally.

CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR RE-

MOVE THE ROUND GROUNDING PRONG FROM THIS PLUG.

OVEN DIAGRAM

11 310

1 Door opening button

Push to open door.

2 Oven door with see-through window 3 Safety door latches

The oven will not operate unless the door is securely closed.

4 Door hinges 5 Door seals and sealing surfaces 6 Turntable motor shaft 7 Removable turntable support

Carefully place the turntable support in the center of the oven floor.

8 Removable turntable

Place the turntable on the turntable support securely. The turntable will rotate clockwise or counterclockwise. Only remove for cleaning.

9 Ventilation openings (Rear) 10 Oven light

It will light when oven is operating door is open.

11 Waveguide cover: DO NOT REMOVE. 12 Auto-Touch control panel 13 Time display: 99 minutes, 99 seconds 14 Power supply cord

Grounded Receptacle Box

3-Pronged Plug

Grounding Pin

3-Pronged Receptacle

TOUCH CONTROL PANEL

NOTE: Some one-touch cooking features such as "MINUTE PLUS" 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.

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R-305HK R-305HW

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

The following is a description of component functions during oven operation.

OFF CONDITION

Closing the door activates the door sensing switch and secondary interlock switch. (In this condition, the monitor switch contacts are opened.) When oven is plugged in, 120 volts A.C. is supplied to the control unit. (Figure O-1).

1. The display will show flashing "88:88". To set any program or set the clock, you must first touch the STOP/CLEAR pad. The display will clear, and " : " will appear.

COOKING CONDITION

Program desired cooking time by touching the NUMBER pads. Program the power level by touching the POWER LEVEL pad. When the START pad is touched, the following operations occur:

1. The contacts of relays are closed and components connected to the relays are turned on as follows. (For details, refer to Figure O-2)

relay and is mechanically associated with the door so that it will function in the following sequence.

(1)When the door opens from the closed position, the

primary interlock relay (RY2) and secondary interlock switch open their contacts. And contacts of the relay (RY1) remains closed. Then the monitor switch contacts close.

(2)When the door is closed from the open position, the

monitor switch contacts open first. Then the contacts of the secondary interlock switch and door sensing switch

close. And contacts of the relay (RY1) open. If the secondary interlock switch and primary interlock relay (RY2) fail with the contacts closed when the door is opened, the closing of the monitor switch contacts will form a short circuit through the C/T fuse, secondary interlock switch, relay (RY1) and primary interlock relay (RY2), causing the C/T fuse to blow.

POWER LEVEL P-0 TO P-90 COOKING

When Variable Cooking Power is programmed, the 120 volts A.C. is supplied to the power transformer intermittently through the contacts of relay (RY-2) which is operated by the control unit within a 32 second time base. Microwave power operation is as follows:

RELAY CONNECTED COMPONENTS RY-1 oven lamp/turntable motor/fan motor RY-2 power transformer

2. 120 volts A.C. is supplied to the primary winding of the power transformer and is converted to about 3.3 volts A.C. output on the filament winding, and approximately 2360 volts A.C. on the high voltage winding.

3. The filament winding voltage heats the magnetron filament and the H.V. winding voltage is sent to a voltage doubler circuit.

4. The microwave energy produced by the magnetron is channelled through the waveguide into the cavity feedbox, and then into the cavity where the food is placed to be cooked.

5. Upon completion of the cooking time, the power transformer, oven lamp, etc. are turned off, and the generation of microwave energy is stopped. The oven will revert to the OFF condition.

6. When the door is opened during a cook cycle, the monitor switch, door sensing switch, secondary interlock switch, relay (RY1) and primary interlock relay are activated with the following results. The circuits to the turntable motor, the cooling fan motor, and the high voltage components are de-energized, the oven lamp remains on, and the digital read-out displays the time still remaining in the cook cycle when the door was opened.

7. The monitor switch electrically monitors the operation of the secondary interlock switch and primary interlock

VARI-MODE ON TIME OFF TIME P-HI (100% power) 32 sec. 0 sec. P-90 (approx. 90% power) 30 sec. 2 sec. P-80 (approx. 80% power) 26 sec. 6 sec. P-70 (approx. 70% power) 24 sec. 8 sec. P-60 (approx. 60% power) 22 sec. 10 sec. P-50 (approx. 50% power) 18 sec. 14 sec. P-40 (approx. 40% power) 16 sec. 16 sec. P-30 (approx. 30% power) 12 sec. 20 sec. P-20 (approx. 20% power) 8 sec. 24 sec. P-10 (approx. 10% power) 6 sec. 26 sec.

P-0 (approx. 0% power) 0 sec. 32 sec.

Note: The ON/OFF time ratio does not correspond with

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

POWER OUTPUT REDUCTION

If the oven is set for more than 20 minutes at 80, 90 or 100% power level, after the first 20 minutes the power level will automatically adjust itself to 70% power to avoid overcooking.

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R-305HK R-305HW

NOTE: CONDITION OF OVEN

SCHEMATIC

1. DOOR CLOSED

2. CLOCK APPEARS ON DISPLAY

C/T FUSE TEMPERATURE

GRN

120V AC 60 Hz

N.O.

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

FUSE 150˚C (OVEN)

N.O.

PRIMARY INTERLOCK RELAY

DOOR SENSING SWITCH

OVEN LAMP RELAY

(RY1)

COM.

CONTROL UNIT

OVEN LAMP

SECONDARY INTERLOCK SWITCH

TTM

TURNTABLE MOTOR

FAN MOTOR

COM.

Figure O-1. Oven Schematic-Off Condition

(RY2)

POWER TRANSFORMER

CAPACITOR

0.94µF AC 2200V

MONITOR

SWITCH

RECTIFIER

MAGNETRON

NOTE: CONDITION OF OVEN

SCHEMATIC

1. DOOR CLOSED

2. COOKING TIME PROGRAMMED

3. VARIABLE COOKING CONTROL "P-HI" (100%)

4. "START" PAD TOUCHED

120V AC 60 Hz

C/T FUSE TEMPERATURE

GRN

OVEN LAMP RELAY

N.O.

FUSE 150˚C (OVEN)

(RY1)

COM.

CONTROL UNIT

OVEN LAMP

SECONDARY INTERLOCK SWITCH

TTM

TURNTABLE MOTOR

FAN MOTOR

N.O.

COM.

PRIMARY INTERLOCK RELAY

(RY2)

DOOR SENSING SWITCH

POWER TRANSFORMER

CAPACITOR

0.94µF AC 2200V

MONITOR

SWITCH

RECTIFIER

MAGNETRON

Figure O-2. Oven Schematic-Cooking Condition

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R-305HK R-305HW

DESCRIPTION AND FUNCTION OF COMPONENTS

DOOR OPEN MECHANISM

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

Door

Latch Heads

Switch Lever

Latch Hook

Door Sensing Switch

Monitor Switch

Secondary Interlock Switch

Figure D-1. Door Open Mechanism

DOOR SENSING AND SECONDARY INTERLOCK SWITCHES

The secondary interlock switch is mounted in the lower position of the latch hook and the door sensing switch in the primary interlock system is mounted in the upper position of the latch hook. They are activated by the latch heads on the door. When the door is opened, the switches interrupt the power to all high voltage components. A cook cycle cannot take place until the door is firmly closed thereby activating both interlock switches. The primary interlock system consists of the door sensing switch and primary interlock relay located on the control circuit board.

MONITOR SWITCH

The monitor switch is activated (the contacts opened) by the latch head on the door while the door is closed. The switch is intended to render the oven inoperative, by means of blowing the C/T fuse, when the contacts of the primary interlock relay (RY2) and secondary interlock switch fail to open when the door is opened.

Functions:

1. When the door is opened, the monitor switch contacts close (to the ON condition) due to their being normally closed. At this time the primary interlock relay (RY2) and secondary interlock switch are in the OFF condition (contacts open) due to its being normally open contact switches.

2. As the door goes to a closed position, the monitor switch contacts are first opened and then the door sensing switch and secondary interlock switch contacts close.

3. If the door is opened, and the primary interlock relay (RY2) and the secondary interlock switch contact fail to

open, the C/T fuse blows simultaneously with closing of the monitor switch contacts.

CAUTION: BEFORE REPLACING A BLOWN C/T FUSE,

TEST THE DOOR SENSING SWITCH, PRIMARY INTERLOCK RELAY (RY2), SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").

NOTE: C/T FUSE AND MONITOR SWITCH ARE

REPLACED AS AN ASSEMBLY.

TURNTABLE MOTOR

The turntable motor rotates the turntable located on the bottom of the oven cavity, so that the food on the turntable is cooked evenly. The turntable may turn in either direction.

COOLING FAN MOTOR

The cooling 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.

TEMPERATURE FUSE (OVEN)

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 302˚F(150˚C), causing the oven to shut down.

C/T FUSE

1. The C/T fuse blows when the contacts (COM-NO) of the primary interlock relay (RY2) and secondary interlock switch remain closed with the oven door open and when the monitor switch closes.

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

3. The C/T fuse, located near the magnetron, is designed to prevent damage to the magnetron. If an over heated condition develops in the magnetron due to cooling fan failure, obstructed air guide, dirty or blocked air intake, etc., the C/T fuse will open.

Under normal operation, the C/T fuse remains closed. However, when abnormally high temperatures are reached within the oven cavity, the C/T fuse will open at 302˚F (150˚C), causing the oven to shut down or when the electric currents beyond 20A flow, the C/T fuse will open.

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R-305HK R-305HW

TROUBLESHOOTING GUIDE

Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.

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 C/T fuse, check the monitor switch, primary

interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the C/T fuse. If C/T fuse is replaced, the monitor switch must also be replaced. Use part FFS-BA034WRKZ as an assembly.

IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases,

be necessary to connect the power supply cord after the outer case has been removed, in this event,

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the leads to the primary of the power transformer.

5. Ensure that the leads remain isolated from other components and oven chassis by using insulation tape.

6. After that procedure, reconnect the power supply cord.

When the testing is completed,

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Reconnect the leads to the primary of the power transformer.

5. Reinstall the outer case (cabinet).

6. Reconnect the power supply cord after the outer case is installed.

7. Run the oven and check all functions.

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R-305HK R-305HW

CK = Check / RE = Replace

CONDITION

OFF CONDITION

COOKING CONDITION

TEST PROCEDURE

AND

POSSIBLE CAUSE

DEFECTIVE PARTS

PROBLEM

Home fuse or circuit breaker blows when power cord is plugged into wall receptacle

C/T fuse blows when power cord is plugged into wall receptacle.

All letters and indicators do not appear in display when power cord is first plugged into wall outlet.

Display does not operate properly when STOP/CLEAR key is touched. (Buzzer should sound and ":" or time of day should appear in display.)

Oven lamp does not light when door is opened.

Oven lamp does not go out when door is closed.

Oven lamp lights but fan motor and turntable motor do not operate.

Oven does not go into cook cycle when START pad is touched

Oven seems to be operating but little or no heat is produced in oven load. (Food incompletely cooked or not cooked at all at end of cook cycle.)

Oven goes into a cook cycle but extremely uneven heating is produced in oven load (food).

Oven does not cook properly when programmed for Cooking Power P50 mode. (Operates properly on Cooking Power P-HI (HIGH) mode.)

Oven goes into DEFROST but food is not defrosted well.

RE RE

ABCDEFFGH

SHORT IN POWER CORD

SHORT OR OPENED WIRING

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

RERE

HIGH VOLTAGE CAPACITOR

TEMPERATURE FUSE (OVEN)

PRIMARY INTERLOCK SYSTEM

SECONDARY INTERLOCK SWITCH

MONITOR SWITCH

C/T FUSE

OVEN LAMP

CKICK CKCK

COOLING FAN MOTOR

TURNTABLE MOTOR

TOUCH CONTROL PANEL

WRONG OPERATION

LOW VOLTAGE

DIRTY OVEN CAVITY

JKLM

KEY UNIT (MEMBRANE SWITCH)

RELAY (RY1)

DEFROST

FOIL PATTERN ON PWB.

PROCEDURE

LETTER

A MAGNETRON ASSEMBLY TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across the magnetron filament leads should indicate less than 1 ohm.

5. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and chassis ground. This test should indicate an infinite resistance. If there is little or no resistance the magnetron is grounded and must be replaced.

TEST PROCEDURES

COMPONENT TEST

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TEST PROCEDURES

R-305HK R-305HW

PROCEDURE

LETTER

COMPONENT TEST

6. Reconnect all leads removed from components during testing.

7. Reinstall the outer case (cabinet).

8. Reconnect the power supply cord after the outer case is installed.

9. Run the oven and check all functions.

MICROWAVE OUTPUT POWER

The following test procedure should be carried out with the microwave oven in a fully assembled condition (outer case fitted).

HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD BE OBSERVED.

Power output of the magnetron can be measured by performing a water temperature rise test. This test should only be used if above tests do not indicate a faulty magnetron and there is no defect in the following components or wiring: silicon rectifier, high voltage capacitor and power transformer. This test will require a 16 ounce (453cc) measuring cup and an accurate mercury thermometer or thermocouple type temperature tester. For accurate results, the following procedure must be followed carefully:

1. Fill the measuring cup with 16 oz. (453cc) of tap water and measure the temperature of the water with a thermometer or thermocouple temperature tester. Stir the thermometer or thermocouple through the water until the temperature stabilizes. Record the temperature of the water.

2. Place the cup of water in the oven. Operate oven at POWER P-HI(HIGH) selecting more than 60 seconds cook time. Allow the water to heat for 60 seconds, measuring with a stop watch, second hand of a watch or the digital read-out countdown.

3. Remove the cup from the oven and again measure the temperature, making sure to stir the thermometer or thermocouple through the water until the maximum temperature is recorded.

4. Subtract the cold water temperature from the hot water temperature. The normal result should be 32.1 to

59.7˚F(17.9 to 33.2˚C) rise in temperature. If the water temperatures are accurately measured and tested for the required time period the test results will indicate if the magnetron tube has low power output (low rise in water temperature) which would extend cooking time or high power output (high rise in water temperature) which would reduce cooking time. Because cooking time can be adjusted to compensate for power output, the magnetron tube assembly should be replaced only if the water temperature rise test indicates a power output well beyond the normal limits. The test is only accurate if the power supply line voltage is 120 volts and the oven cavity is clean.

B POWER TRANSFORMER TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the primary input terminals and measure the resistance of the transformer with an ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x 1 scale, the resistance of the primary coil should be less than 1 ohm and the resistance of the high voltage coil should be approximately 102 ohms; the resistance of the filament coil should be less than 1 ohm.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

(HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.)

C HIGH VOLTAGE RECTIFIER TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance across the terminals and observe, reverse the leads to the rectifier terminals and observe meter reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions, the rectifier is probably

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PROCEDURE

LETTER

defective and should be replaced.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

NOTE: Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3 volts.

D HIGH VOLTAGE CAPACITOR TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads and check for short or open between the terminals using an ohmmeter. Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate continuity for a short time and should indicate an open circuit once the capacitor is charged. If the above is not the case, check the capacitor with an ohmmeter to see if it is shorted between either of the terminals and case. If it is shorted, replace the capacitor.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

COMPONENT TEST

E TEMPERATURE FUSE TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. A continuity check across the temperature fuse terminals should indicate a closed circuit unless the temperature of the temperature fuse reaches approximately 302˚F(150˚C). An open temperature fuse indicates overheating of the oven, exchange the temperature fuse and check inside of oven cavity and for improper setting of cooking time or operation of control unit. Check for restricted air flow through the vent holes of the oven cavity, especially the cooling fan and air guide.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

F SECONDARY INTERLOCK SWITCH TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal of the switch. The meter should indicate an open circuit with the door open and a closed circuit with the door closed. If improper operation is indicated, replace the secondary interlock switch.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

PRIMARY INTERLOCK SYSTEM TEST

DOOR SENSING SWITCH

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

5. Reconnect all leads removed from components during testing.

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TEST PROCEDURES

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LETTER

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions. NOTE: If the door sensing switch contacts fail in the open position and the door is closed, the cooling fan,

turntable and oven light will be activated by RY1.

PRIMARY INTERLOCK RELAY (RY2)

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect two (2) wire leads from the male tab terminals of the Primary Interlock Relay. Check the state of the relay contacts using a ohmmeter. The relay contacts should be open. If the relay contacts are closed, replace the circuit board entirely or the relay itself.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

G MONITOR SWITCH TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Before performing this test, make sure that the secondary interlock switch and the primary interlock relay are operating properly, according to the above Switch Test Procedure. Disconnect the wire lead from the monitor switch (COM) terminal. Check the monitor switch operation by using the ohmmeter as follows. When the door is open, the meter should indicate a closed circuit. When the monitor switch actuator is pushed by a screw driver through the lower latch hole on the front plate of the oven cavity with the door opened (in this condition the plunger of the monitor switch is pushed in), the meter should indicate an open circuit. If improper operation is indicated, the switch may be defective. After testing the monitor switch, reconnect the wire lead to the monitor switch (COM) terminal and check the continuity of the monitor circuit.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

COMPONENT TEST

Monitor Switch

GRY WHT

Screw Driver

BLK

Secondary Interlock Switch

Ohmmeter

H BLOWN C/T FUSE TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. If the C/T fuse is blown when the door is opened, check the primary interlock relay, secondary interlock switch and monitor switch according to the "TEST PROCEDURE" for those switches before replacing the blown C/T fuse.

CAUTION: BEFORE REPLACING A BLOWN C/T FUSE, TEST THE PRIMARY INTERLOCK RELAY,

SECONDARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION.

If the C/T fuse is blown by improper switch operation, the C/T fuse and monitor switch must be replaced with "C/T fuse and monitor switch assembly" part number FFS-BA034WRKZ, even if the monitor switch operates normally. The C/T fuse and monitor switch assembly is comprised of a 20 ampere fuse and switch.

A continuity check across the C/T fuse terminals should indicate a closed circuit unless the temperature of the C/T fuse reaches approximately 302˚F(150˚C). An open C/T fuse indicates overheating of the magnetron. Check for restricted air flow to the magnetron,

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I TOUCH CONTROL PANEL ASSEMBLY TEST

COMPONENT TEST

especially the cooling fa air guide.

CAUTION: IF THE C/T FUS E INDI CATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE

THE C/T FUSE.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

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.

Before testing,

1) Disconnect the power supply cord, and then remove outer case.

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Disconnect the leads to the primary of the power transformer.

5) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.

1. Key Unit. NOTE ;

1) Re-install the outer case (cabinet).

2) Reconnect the power supply cord after the outer case is installed. 3 ) Run the oven and check all functions. The following symptoms indicate a defective 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.

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 problems 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.

3. If the Key unit or control unit is defective.

1) Disconnect the power supply cord, and then remove outer case.

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Replace the control unit assembly.

5) Reconnect all leads removed from components during testing.

6) Re-install the outer case (cabinet).

7) Reconnect the power supply cord after the outer case is installed.

8) Run the oven and check all functions.

4. When testing is completed,

1) Disconnect the power supply cord, and then remove outer case.

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TEST PROCEDURES

G 2G 1

MINUTE

PLUS

DEFROST

POWER

LEVEL

REHEAT

COOK

POPCORN

TIMER

CLOCK

9 3 6

8 0

G 3 G 4 G 5 G 6 G 7 G 8

G 9

G10

G11

G12

1 4 7

START

STOP

CLEAR

R-305HK R-305HW

PROCEDURE

LETTER

J KEY UNIT TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check the circuit

5. Reconnect all leads removed from components during testing.

6. Re-install the outer case (cabinet).

7. Reconnect the power supply cord after the outer case is installed.

8. Run the oven and check all functions.

COMPONENT TEST

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Reconnect all leads removed from components during testing.

5) Re-install the outer case (cabinet).

6) Reconnect the power supply cord after the outer case is installed.

7) Run the oven and check all functions.

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.

Pin NO. G12

Pin NO. G1

Key unit (Membrane Switch) front view

K RELAY TEST

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the leads to the primary of the power transformer.

5. Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.

6. After that procedure, re-connect the power supply cord.

7. 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 control unit with an A.C. voltmeter. The meter should indicate 120 volts, if not check oven circuit.

RY1 and RY2 Relay Test

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

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

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

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

8. Disconnect the power supply cord, and then remove outer case.

9. Open the door and block it open.

10. Discharge high voltage capacitor.

RY1 Approx. -12.0V D.C. Oven lamp / Turntable motor / Cooling fan motor RY2 Approx. -11.0V D.C. Power transformer

Key unit ribbon cable

control unit is defective.

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TEST PROCEDURES

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COMPONENT TEST

11. Reconnect all leads removed from components during testing.

12. Re-install the outer case (cabinet).

13. Reconnect the power supply cord after the outer case is installed.

14. Run the oven and check all functions.

L DEFROST TEST

WARNING : The oven should be fully assembled before following procedure.

(1) Place one cup of water in the center of the turntable tray in the oven cavity. (2) Close the door, touch the “ DEFROST ” pad once. And then touch the number pad 2. (3) Touch the number pad 5 and then touch the start pad. (4) The oven is in Defrost cooking condition. (5) The oven will operate as follows.

MENU 1ST STAGE 2ND STAGE 3RD STAGE

Steaks/Chops LEVEL TIME LEVEL TIME LEVEL TIME

0.5lb 70% 17sec. 60% 27sec. 30% 40sec.

(6) If improper operation is indicated, the control unit is probably defective and should be checked.

M FOIL PATTERN ON THE PRINTED WIRING BOARD 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.

1. Foil pattern check and repairs.

1) Disconnect the power supply cord, and then remove outer case.

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Follow the troubleshooting guide given below for repair.

STEPS OCCURRENCE CAUSE OR CORRECTION

1 Only pattern at “a” is broken. *Insert jumper wire J1 and solder. 2 Pattern at “a” and “b” are broken. *Insert the coil RCILF2003YAZZ between “c” and “d”.

5) 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 which is approximately 563Ω ± 10%). If any abnormal condition is detected, replace the control unit assembly.

6) Reconnect all leads removed from components during

testing.

7) Re-install the outer case (cabinet).

8) Reconnect the power supply cord after the outer case is

installed.

9) Run the oven and check all functions.

2. Follow the troubleshooting guide given below, if indicator does not light up after above check and repairs are finished.

1) Disconnect the power supply cord, and then remove

outer case.

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Disconnect the leads to the primary of the power transformer.

5) Ensure that these leads remain isolated from other components and oven chassis by using insulation

tape.

6) After that procedure, re-connect the power supply cord.

7) Follow the troubleshooting guide given below for repair.

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TEST PROCEDURES

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PROCEDURE

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COMPONENT TEST

STEPS OCCURRENCE CAUSE OR CORRECTION

The rated AC voltage is not present between

1 the normal open terminal of the relay RY1 and Check supply voltage and oven power cord.

the normal open terminal of the relay RY2. The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.

side of low voltage transformer. Check and replace control unit assembly.

8) Disconnect the power supply cord, and then remove outer case.

9) Open the door and block it open.

10) Discharge high voltage capacitor.

11) Reconnect all leads removed from components during testing.

12) Re-install the outer case (cabinet).

13) Reconnect the power supply cord after the outer case is installed.

14) Run the oven and check all functions.

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.

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) Door Sensing Switch

A switch to “tell” the LSI if the door is open or closed.

2) Indicator Circuit

This circuit consists of 14 segments and 3 common electrodes using a Liquid Crystal Display.

8) Back Light Circuit

A circuit to drive the back light (Light emitting diodes LD1- LD3).

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DESCRIPTION OF LSI

LSI

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

Pin No. Signal I/O Description

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

5ICINConnected to VSS. 6XT1 IN Connected to VSS. 7XT2

8 VDD IN

9 VSS IN

10 X1 IN

11 X2 OUT

12 RESET IN

13-15 P00-P02 OUT Terminal not used.

16 P03 OUT Back light circuit (Light emitting diodes) driving signal. 17 CAPH 18 CAPL

19-21

VLC0-VLC2 IN Power source voltage input terminal.

22 COM0 OUT

23 COM1 OUT

24 COM2 OUT

25 COM3 OUT Terminal not used.

26-39

SEG0-SEG13

OUT Segment data signal.

Signal similar to P50.

When either G12 line on key matrix is touched, a corresponding signal will be input into P53.

Terminal not used.

Power source voltage input terminal.

The power souce voltage to drive the LSI. Connected to GND.

Power source voltage input terminal.

The power souce voltage to drive the LSI.

Internal clock oscillation frequency input setting.

The internal clock frequency is set by inserting the resistor-capacitor oscillation circuit with respect to X2 terminal.

Internal clock oscillation frequency control output.

Output to control oscillation input of X1.

Auto clear terminal.

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

Terminal not used.

Standard voltage for LCD.

Common data signal.

Connected to LCD signal COM1.

Common data signal.

Connected to LCD signal COM2.

Common data signal.

Connected to LCD signal COM3.

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 (27) SEG 2 (28) SEG 3 (29) SEG 4 (30) SEG 5 (31) SEG 6 (32)

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

SEG 1 SEG 7 (33) SEG 2 SEG 8 (34) SEG 3 SEG 9 (35) SEG 4 SEG 10 (36) SEG 5 SEG 11 (37) SEG 6 SEG 12 (38) SEG 7 SEG 13 (39)

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

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

SEG 8

SEG 9 SEG 10 SEG 11 SEG 12 SEG 13 SEG 14

40 SEG14 OUT Terminal not used.

Page 21

Pin No. Signal I/O Description

41 P70 OUT Oven lamp, fan motor and turntable motor driving signal

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

16.7 msec.

square waveform voltage is delivered to the RY1 driving circuit and RY2 control circuit.

During cooking

42 P71 OUT Terminal not used. 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.

Maximum output

70% of maximum output

OFF

OFF OFF

24 sec.

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.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G1 line keys on key matrix is touched. 55 P32 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G2 line keys on key matrix is touched. 56 P31 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G3 line keys on key matrix is touched. 57 INTP0 IN

Signal synchronized with commercial power source frequency.

This is the basic timing for time processing of LSI.

16.7 msec.

8 sec.

R-305HK R-305HW

H : GND

L : -5V

H : GND

L : -5V H : GND

L : -5V

H : GND

L : -5V

58 P26 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G4 line keys on key matrix is touched. 59 P25 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G5 line keys on key matrix is touched. 60 P24 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G6 line keys on key matrix is touched. 61 P23 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G7 line keys on key matrix is touched. 62 P22 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal

while one of G8 line keys on key matrix is touched.

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Pin No. Signal I/O Description

63 BZO90 OUT Signal to sound buzzer (2.0 kHz).

A: key touch sound. B: Completion sound.

64 P20 OUT Terminal not used.

TOUCH CONTROL PANEL SERVICING

0.1 sec.

2.0 sec.

H : GND

L : -5V H : GND

L : -5V

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.

approx. 1M ohm

2. 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 AND PRESENTS A HAZARD.

Therefore, before checking the performance of the touch control panel,

1) Disconnect the power supply cord, and then remove outer case.

2) Open the door and block it open.

3) Discharge high voltage capacitor.

4) Disconnect the leads to the primary of the power transformer.

5) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.

6) After that procedure, re-connect the power supply cord.

After checking the performance of the touch control panel,

1) Disconnect the power supply cord.

2) Open the door and block it open.

3) Re-connect the leads to the primary of the power transformer.

4) Re-install the outer case (cabinet).

5) Re-connect the power supply cord after the outer case is installed.

6) Run the oven and check all functions.

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. 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, 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 activates 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 activates 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).

3. 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

4. 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 connectors 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.

Page 23

PRECAUTIONS FOR USING LEAD-FREE SOLDER

1. Employing lead-free solder

The "Main PWB" of this model employs lead-free solder. This is indicated by the "LF" symbol printed on the PWB and in the service manual. The suffix letter indicates the alloy type of the solder. Example:

Sn-Ag-Cu

Indicates lead-free solder of tin, silver and copper.

2. Using lead-free wire solder

When repairing a PWB with the "LF" symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder may result in cold soldered joints and damage to printed patterns.) As the melting point of lead-free solder is approximately 40˚C higher than tin/lead alloy solder, it is recommend that a dedicated bit is used, and that the iron temperature is adjusted accordingly.

3. Soldering

As the melting point of lead-free solder (Sn-Ag-Cu) is higher and has poorer wettability, (flow), to prevent damage to the land of the PWB, extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time. Remove the bit as soon as a good flow is achieved. The high content of tin in lead free solder will cause premature corrosion of the bit. To reduce wear on the bit, reduce the temperature or turn off the iron when it is not required. Leaving different types of solder on the bit will cause contamination of the different alloys, which will alter their characteristics, making good soldering more difficult. It will be necessary to clean and replace bits more often when using lead-free solder. To reduce bit wear, care should be taken to clean the bit thoroughly after each use.

R-305HK R-305HW

Page 24

R-305HK R-305HW

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WARNING AGAINST HIGH VOLTAGE:

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in severe, possibly fatal, electric shock. (Example) High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..

WARNING:

1. Disconnect the power supply cord.

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;

Avoid possible exposure to microwave energy. Please follow the instructions below before operating the oven.

WARNING FOR WIRING

To prevent an electric shock, take the following precautions.

1. Before wiring,

1) Disconnect the power supply cord.

2) Open the door block it 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, Power transformer and Oven cavity.

1. Door does not close firmly.

2. Door hinge, support or latch hook is damaged.

3. The door gasket or seal is 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.

3) Sharp edge:

Bottom plate, Oven cavity, Waveguide flange and other metallic plate.

4) Movable parts (to prevent a fault)

Fan blade, Fan motor, Turntable motor, Switch, Switch lever, Open button.

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

4. Insert the positive lock connector until its pin is locked and make sure that the wire leads do not come off even if the wire leads are pulled.

5. To prevent an error function, connect the wire leads correctly, referring to the Pictorial Diagram.

Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any of the following removal procedures:

OUTER CASE REMOVAL

To remove the outer case, proceed as follows.

1. Disconnect the power supply cord.

2. Open the oven door and block it open.

3. Remove the two (2) screws from the lower portion of the rear cabinet using a T20H Torx type or GTXH20-100 screw driver.

4. Remove the remaining three (3) screws from rear and one (1) screw along the right side of outer case.

5. Slide the entire outer case back out about 1 inch (3 cm) to free it from retaining clips on the cavity face plate.

6. Lift entire outer case from the unit.

Page 25

CAUTION: 1. DISCONNECT OVEN FROM POWER SUP

PLY BEFORE REMOVING OUTER CASE.

2. DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING.

NOTE: When replacing the outer case, the 2 special

Torx screws must be reinstalled in the same locations.

POWER TRANSFORMER REMOVAL

Special screw

Screw Driver (Type: TORX T20 H or GTXH20-100)

R-305HK R-305HW

1. Disconnect the power supply cord and then remove outer case.

2. Open the oven door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect wire leads (primary) from power transformer and the filament leads and high voltage wire from the magnetron and capacitor terminals.

5. Remove four (4) screws (two (2) screws from the upper side and two (2) screws from bottom side) holding transformer to bottom plate.

6. Remove transformer from bottom plate.

HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL

1. Disconnect the power supply cord and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the high voltage wire of the power transformer from the high voltage capacitor.

5. Disconnect the high voltage wire of high voltage rectifier assembly from the magnetron.

6. Disconnect the filament lead (short one) of the power transformer from the high voltage capacitor.

7. Remove the one (1) screw holding capacitor holder to

Reinstallation

1. Rest transformer on the bottom plate with its primary terminals toward the oven face plate.

Secure transformer with four (4) screws

(two (2) screws from the upper side and two (2) screws from bottom side) to bottom plate.

3. Reconnect wire leads (primary) to power transformer and filament leads and high voltage wire of transformer to magnetron and high voltage capacitor. Refer to "PICTORIAL DIAGRAM" on page 28.

4. Reinstall outer case and check that oven is operating properly.

bottom plate.

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

9. Disconnect rectifier terminal from capacitor. High voltage rectifier assembly is now free.

10.Remove capacitor holder. Capacitor is now free.

CAUTION: WHEN REPLACING HIGH VOLTAGE RECTI-

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

MAGNETRON REMOVAL

Removal

1. Disconnect the power supply cord and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect all wire leads from magnetron.

5. Remove the one (1) screw holding the chassis support to the magnetron.

6. Release the chassis support from the hole of the oven cavity front flange.

7. Remove the two (2) screws holding air duct to magnetron and oven cavity top plate.

8. Remove the air duct from oven.

9. Carefully remove the four (4) screws holding magnetron to waveguide flange.

10.Remove magnetron with care so that magnetron antenna is not hit by any metal object around antenna.

11.Now, the magnetron is free.

Reinstallation

1. Reinstall the magnetron to waveguide flange with the four (4) screws.

2. Reinstall the air duct to the oven cavity top plate and the magnetron with two (2) screws.

3. Insert the end of the chassis support into the hole of the oven cavity front flange.

4. Hold the other end of the chassis support to the magnetron with the one (1) screw.

5. Reconnect the wire leads to the magnetron. Refer to "PICTORIAL DIAGRAM".

6. Reinstall 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.

Page 26

R-305HK R-305HW

POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Push the lever of positive lock® connector.

5. Pull down on the positive lock® connector.

CAUTION: WHEN CONNECTING THE POSITIVE LOCK

CONNECTORS TO THE TERMINALS, CONNECT THE POSITIVE LOCK® SO THAT THE LEVER FACES YOU

CONTROL PANEL ASSEMBLY REMOVAL

1. Disconnect the power supply cord and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the wire leads from control unit.

Terminal

Positive lock® connector

Push

Lever

Pull down

Figure C-1. Positive lock® connector

5. Remove the one (1) screw holding the control panel assembly to the oven flange.

6. Slide the control panel assembly upward and remove it.

7. Now, individual components can be removed.

CONTROL UNIT ASSEMBLY REPLACEMENT

Removal

1. Disconnect the power supply cord and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Remove the control panel assembly, referring to chapter of CONTROL PANEL ASSEMBLY REMOVAL.

5. Tear away the graphic sheet from the control panel frame and control unit assembly

6. Remove the two (2) screws holding the control unit assembly to the control panel frame.

7. Release the ontrol unit assembly from the six (6) tabs of the control panel frame.

8. Now, the ontrol unit assembly is free.

Installation

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

2. Make sure that the LED sheet and liquid crystal display are installed in position.

3. Reinstall the control unit assembly to the control panel frame with the two (2) screws.

4. Tear the backing paper from the graphic sheet.

5. Adjust the upper edge and left edge of the graphic sheet to the large depression on the surface of the control panel frame.

6. Attach the graphic sheet to the control panel frame by rubbing with a soft cloth not to scratch.

NOTE: Do not contact the contact surface of the ribbon cable (edge) and the rubber connector directly with your fingers. This is to avoid oxidized. If display digits are missing or scrambled, remove control unit and clean

contact surface with alcohol. After cleaning, do not attach the rubber connector until alcohol dries up. Do not use alcohol or solution to clean the rubber connector. Make sure that there is no trash or foreign substance on contact surface of the rubber connector.

Control panel frame

LED sheet

Liquid crystal display

Graphic sheet

Control panel frame (Rear side)

Contact surface

Ribbon cable of membrane switch

Rubber connector

Figure C-2. Graphic Sheet Attachment

Page 27

TURNTABLE MOTOR REMOVAL

R-305HK R-305HW

1. Disconnect the power supply cord.

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 corners.

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

COOLING FAN MOTOR REMOVAL

REMOVAL

1. Disconnect the power supply cord and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the wire leads from the fan motor.

5. Remove the two (2) screws holding the fan motor to the oven cavity back plate.

6. Remove the fan blade from the fan motor shaft according to the following procedure.

7. Hold the edge of the rotor of the fan motor by using a pair of groove joint pliers.

CAUTION: *Make sure that no metal pieces 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.

* Do not disfigure the bracket by touching with the

pliers.

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

9. Now, the fan blade will be free.

Coil

Groove joint pliers

5. Disconnect wire leads from turntable motor. (See "Positive lock connector removal")

6. Remove one (1) screw 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.

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

(for shaft) may be larger than normal.

10.Now, the fan motor is free.

INSTALLATION

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

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

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

4. 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.

5. Install the fan motor to the oven cavity back plate with the two (2) screws.

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.

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

Shaft

Stator

Gap

Bracket

Rotor

Rear View

Shaft

Axis

Stator

Rotor

Table

These are the positions that should be pinched with pliers.

Center of bracket

Side View

DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL

Disconnect the power supply cord and remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect wire leads from the switches.

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

6. Remove latch hook assembly from oven flange.

7. Push outward on the two (2) retaining tabs holding

switch in place.

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

Reinstallation

1. Reinstall each switch in its place. The secondary interlock/ monitor switches are in the lower position and the door sensing switch is in the upper position.

Page 28

R-305HK R-305HW

2. Reconnect wire leads to each switch. Refer to pictorial diagram.

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

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.

oven flange.

DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

If the door sensing switch, secondary interlock switch and monitor switch do not operate properly due to a misadjustment, the following adjustment should be made.

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

5. 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 door sensing switch and secondary interlock 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.

6. Secure the screws with washers firmly.

7. Check the operation of all switches. 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 door sensing switch and secondary interlock switch interrupt the circuit before the door can be open.

3. Monitor switch contacts close when door is opened.

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

Door

Latch Heads

Switch Lever

Latch Hook

Door Sensing Switch

Monitor Switch

Secondary Interlock Switch

Figure C-3. Latch Switch Adjustments

DOOR REPLACEMENT

REMOVAL

1. Disconnect the power supply cord.

2. Open the door slightly.

3. Insert a putty knife (thickness of about 0.5mm) into the gap between the choke cover and door frame as shown in Figure C-4 to free engaging parts.

4. Pry the choke cover by inserting a putty knife as shown Figure C-4.

5. Release choke cover from door panel.

6. Now choke cover is free.

NOTE: When carrying out any repair to the door, do not

bend or warp the slit choke (tabs on the door panel assembly) to prevent microwave leakage.

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

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

Choke Cover

Door Frame

Putty Knife

Figure C-4. Door Disassembly

9. Release door panel from ten (10) tabs of door frame.

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

11.Tear sealer film from door panel.

12.Now, door panel is free.

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

Page 29

R-305HK

Sealer film

Backing film

Adhesive tape

R-305HW

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

15.Remove door screen from door frame.

16.Now, door screen is free.

REINSTALLATION

1. Reinstall door screen to door frame .

2. Reinstall the latch spring to the latch head. Reinstall the latch spring to the door frame. Reinstall latch head to door frame.

3. Reinstall door panel to door frame by fitting ten (10) tabs of door frame to ten (10) holes of door panel.

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

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

6. Reinstall choke cover to door panel by pushing.

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.

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 airtight, moisture (condensation)-tight or light-tight. 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.

Slit choke of door panel

Hinge

Upper Oven Hinge

Lower Oven Hinge

Choke Cover

Upper Oven Hinge

Lower Oven

Figure C-5. Door Replacement

SEALER FILM

Installation

1. Put the adhesive tape on the backing film of the sealer film as shown in Fig. C-6.

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

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

Figure C-6. Sealer film

Page 30

R-305HK

HIGH VOLTAGE

CAPACITOR

H.V. RECTIFIER

POWER SUPPLY

CORD 120V 60Hz

HIGH VOLTAGE COMPONENTS

MAGNETRON

COM.

MONITOR

SWITCH

COM.

N.O.

N.C.

DOOR

SENSING

SWITCH

SECONDARY

INTERLOCK

SWITCH

TURNTABLE

MOTOR

POWER

TRANSFORMER

COM.

NOTE:

The neutral (WHT) wire must be

connected to the terminal with "N"

mark on the power supply cord.

GRY

WHT

GRY

RED

GRY

GRN

GRY

GRN

BLK

GRY

WHT

GRY

RED

BLK

PNK

GRY

C/T FUSE

FAN MOTOR

TEMPERATURE

FUSE (OVEN)

BLK

WHT

RED

RY1

PRIMARY

INTERLOCK

RELAY

CN-B

N.O.

COM.

RY2

N.O.

COM.

CONTROL UNIT

NOTE:

The grounding conductor of

the power supply cord has

been grounded by power

supply cord fixing screw.

The screw must allways be

kept tight.

GRY

OVEN LAMP

PNK

RED

PNK

R-305HW

Figure S-1. Pictorial Diagram

Page 31

R-305HK

SEG14

AIN1

AIN0

SEG0

P20

VLC2

VLC1

VLC0

CAPL

CAPH

P70

AIN 5

P03

COM0

IC-1

AIN 2

AIN 3

AIN 4

SEG13

SEG12

SEG11

SEG10

SEG9

SEG8

SEG7

P11

P10

P33

P32

P31

INTP0

P26

P25

AVSS

P24

P23

P22

BZO90

COM

RY1

OMIF-S-112LM

DU12D1-1P(M)-R

RY2

D20

D21

Q21

DTD143ES

C21

10uF/35V

D22

D40

Q22

SP1

1000uF/25V

0.1uF/25V

220uF/10V

ZD1

HZ4B3

C10

0.1uF/25V

15K

0.01uF/25V

Q10

R10

15K

C11

0.01uF/25V

Q20

DTA143EKA

C20

0.1uF

25V

R41

15K

R40

4.7K

OVEN LAMP

TURNTABLE MOTOR

FAN MOTOR

MICRO

DOOR

SWNSING

SWITCH

VRS1

10G471K

D1--D4 1N4002

SEG1 SEG3

SEG2 SEG4

SEG5 SEG6 SEG7 SEG8 SEG9 SEG10 SEG11 SEG12

COM3

COM2

COM1

DOOR

RST

-5V

INT

COM

C40

GND

560 1/2W

CN-B

AC(H)

AC(N)

AC120V

60HZ

(J1)

DTA123JS

G10

G11

G12

R30

3.3K

0. 01uF

25V

COM1 COM2 COM3

SEG1 SEG2 SEG3 SEG4 SEG5 SEG6

P71

P72

AVDD

P01

P00

RESET

VSS

VDD

XT2

XT1

P53

P52

P51

P50

P02

SEG13 SEG14

R60

R61

R7R8R9

R62

R63

0.1uF

25V

4.7K4.7K4.7K

COM

R60-R63

270K x4

POWER UNIT

R80

11KF

C80

22pF/50V

(J12)

(J11) ( J10)

(J13)

(J15) (J14)

(J17) (J16)

4.7K

Q30

4.7K

10K

4.7K

82, 1/4W

LD1LD2

LD3

WHA

2.2K

10K

POPCORN

REHEAT

C61

C62

C63

330pF/50V x 4

C60-C63

C60

PA151DR

LIQUID CRYSTAL DISPLAY

COOK DEF. START CHECK

LSI UNIT

MINUTE

PLUS

START

TIMER

CLOCK

STOP

CLEAR

POWER

LEVEL

COOK

DEFROST

DTA143EKA

2SA1037AK

KTA1267Y

R-305HW

Figure S-2. Control Unit Circuit

Page 32

R-305HK R-305HW

Figure S-3. Printed Wiring Board of Power Unit

Page 33

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-MA147WRZZ Secondary interlock switch / door sensing switch 2 AG 1-2 FFS-BA034WRKZ 1-3 FACCDA083WRE0 Power supply cord 1 AQ 1-3 FACCDA085WREZ Power supply cord (Interchangeable) 1 AQ 1-4 FH-DZA075WRK0 High voltage rectifier assembly 1 AR

1-4 FH-DZA109WRKZ High voltage rectifier assembly(Interchangeable) 1 AR

1-5 RC-QZA213WRE0 High voltage capacitor 1 AV

1-5 RC-QZA286WRZZ High voltage capacitor (Interchangeable) 1 AV

1-5 RC-QZA211WRE0 High voltage capacitor (Interchangeable) 1 AV

1-6 RMOTEA346WRE0 Fan motor 1 AV 1-6 RMOTEA356WRE0 Fan motor (Interchangeable) for production use 1 -1-7 QFS-TA014WRE0 Temperature fuse 150deg.C (oven) 1 AG 1-8 RLMPTA082WRZZ Oven lamp 1 AL 1-8 RLMPTA085WRZZ Oven lamp (Interchangeable) for production use 1 -1-9 RMOTDA211WRE0 Turntable motor 1 AS 1-9 RMOTDA186WRE0 Turntable motor (Interchangeable) 1 AW 1-10 RTRN-A705WRZZ Power transformer 1 BK

∆

1-11 RV-MZA288WRE0 Magnetron 1 BK

∆

1-11 RV-MZA321WRZZ Magnetron (Interchangeable) for production use 1 --

2-1 GCABUA883WRPZ Outer case cabinet (R-305HW) 1 BF 2-1 GCABUA889WRPZ Outer case cabinet (R-305HK) 1 BF 2-2 FDAI-A265WRYZ Bottom plate 1 AW 2-3 GLEGPA074WRE0 Foot 4 AC

3-1 CPWBFA858WRKZ Control unit assembly 1 BQ 3-2 HPNLCB804WRFZ Control panel frame (R-305HW) 1 AS 3-2 HPNLCB805WRFZ Control panel frame (R-305HK) 1 AS 3-3 PSHEPA912WRZZ Graphic sheet (R-305HW) 1 AW 3-3 PSHEPA920WRZZ Graphic sheet (R-305HK) 1 AW 3-4 XOTSD40P08000 Screw : 4mm x 8mm 2 AA 3-5 JBTN-B241WRFZ Open button (R-305HW) 1 AG 3-5 JBTN-B242WRFZ Open button (R-305HK) 1 AG 3-6 MSPRCA050WRE0 Button spring 1 AB

4-1 PHOK-A131WRFZ Latch hook 1 AL

∆

4-2 LBNDKA163WRPZ Capacitor holder 1 AK 4-3 NFANJA020WRE0 Fan blade 1 AG 4-4 ************* Oven cavity (Not a replacement part) 1--

∆

4-5 MLEVPA233WRF0 Switch lever 1 AG 4-6 PCLICA032WRE0 Hand clip 4 1 AD 4-7 PCOVPA394WREZ Waveguide cover 1 AK 4-8 PDUC-A831WRWZ Air duct 1 AN 4-9 PDUC-A832WRWZ Fan duct 1 AP 4-10 PPACGA176WREZ TTM packing 1 AC 4-11 PCUSGA399WRE0 Cushion 1 AF 4-12 PCUSUA515WRP0 Cushion 1 AD 4-13 PCUSUA235WRP0 Cushion 1 AE 4-14 PCUSGA614WRPZ Cushion 1 AE 4-15 PCUSGA615WRPZ Cushion 1 AE 4-16 MROD-A019WREZ Chassis support 1 AN 4-17 PCUSGA616WRPZ Cushion 1 AK

5-1 FDORFA364WRTZ Door panel 1 AS

∆

5-2 PSHEPA382WRE0 Sealer film 1 AH 5-3 GWAKPA897WRFZ Door frame (R-305HW) 1 AX

∆

5-3 GWAKPA898WRFZ Door frame (R-305HK) 1 AX

∆

5-4 HPNL-A801WRRZ Door screen (R-305HW) 1 AU 5-4 HPNL-A803WRRZ Door screen (R-305HK) 1 AU 5-5 LSTPPA188WRF0 Latch head 1 AG

∆

5-6 MSPRTA187WRE0 Spring 1 AC 5-7 GCOVHA450WRFZ Choke cover 1 AG

∆

C/T fuse(150deg.C/20A) and monitor switch (D3V-1G-2C25) assembly

1AS

CABINET PARTS

CONTROL PANEL PARTS

OVEN PARTS

DOOR PARTS

R-305HK R-305HW

Page 34

R-305HK R-305HW

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

MISCELLANEOUS

6-1 FROLPA101WRKZ Turntable support 1 AR 6-2 NTNT-A117WREZ Turntable 1 AS 6-3 FW-VZB968WREZ Main wire harness 1 AT 6-4 TCAUAA268WRRZ DHHS caution label 1 AF 6-5 TCAUAA280WRRZ Monitor caution 1 AF 6-6 TINSEA973WRRZ Instruction book 1 AP

SCREWS,NUTS AND WASHERS

7-1 XHPSD40P08K00 Screw : 4mm x 8mm 2 AA 7-2 LX-CZA070WRE0 Special screw 2 AC 7-3 LX-CZA073WRE0 Special screw 2 AC 7-4 LX-CZ0052WRE0 Special screw 2 AA 7-5 LX-EZA042WRE0 Special screw 2 AB 7-6 XHPSD30P06000 Screw : 3mm x 6mm 1 AA 7-7 XHPSD40P08000 Screw : 4mm x 8mm 5 AA 7-8 XHTSD40P08RV0 Screw : 4mm x 8mm 4 AA 7-9 XHTSD40P12RV0 Screw : 4mm x 12mm 1 AA 7-10 XOTSD40P08000 Screw : 4mm x 8mm 14 AA 7-11 XOTSE40P08000 Screw : 4mm x 8mm (R-305HW) 1 AA 7-11 XOTSF40P08000 Screw : 4mm x 8mm (R-305HK) 1 AA 7-12 XHTSD40P08000 Screw : 4mm x 8mm 1 AA

HOW TO ORDER REPLACEMENT PARTS

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

1. MODEL NUMBER 2. REF. NO. 3. PART NO. 4. DESCRIPTION

Order Parts from the authorized SHARP parts Distributor for your area. Defective parts requiring return should be returned as indicated in the Service Policy.

PACKING AND ACCESSORIES

DOOR PROTECTION SHEET SPADPA204WRE0

FOAM SHEET SPAKHA012WREZ

(only for R-305HK)

6-6 INSTRUCTION BOOK

6-2 TURNTABLE TRAY

TOP PAD ASSEMBLY FPADBA515WRKZ

PLASTIC SHEET (for R-305HK) SPADPA616WREZ

PLASTIC BAG SSAKHA034WRE0

CABINET COVER SPAKHA011WRE0

(only for R-305HK)

BOTTOM PAD ASSEMBLY FPADBA517WRKZ

INTO THE OVEN CAVITY

TRAY PAD ASSY

(CPADBA317WRKZ)

6-1 TURNRTABLE SUPPORT

PACKING CASE FPAK-A466WRKZ [R-305HW] FPAK-A471WRKZ [R-305HK]

Not replaceable items.

Page 35

R-305HK R-305HW

OVEN AND CABINET PARTS

4-13

4-6

4-4

1-7

2-1

4-9

4-3

7-10

6-5

7-3

7-6

1-2

7-8

4-15

1-6

7-10

7-2

7-10

7-2

7-12

7-11

4-16

7-9

1-3

6-4

7-10

7-3

1-8

7-7

7-8

4-8

1-11

4-7

6-2

7-4

4-10

6-1

1-9

7-1

1-10

2-2

4-12

4-11

7-5

4-14

7-8

4-17

4-2

4-1 4-5

7-7

1-1

1-2

1-1

7-1

1-5

1-4

2-3

7-10

2-3

7-10

Page 36

R-305HK R-305HW

3-4

CONTROL PANEL PARTS

3-2

3-1

3-4

DOOR PARTS

3-6

5-7

3-5

3-3

5-2

5-1

5-3

5-4

5-6

5-5

MISCELLANEOUS

6-3

Actual wire harness may be different from illustration.

2003 SHARP CORP. (2S1.700E) Printed in U.S.A

SHARP R-305HK, R-305HW Service Manual

TABLE OF CONTENTS

BEFORE SERVICING

WARNING TO SERVICE PERSONNEL

MICROWAVE MEASUREMENT PROCEDURE

SPECIFICATION

GENERAL INFORMATION

GROUNDING INSTRUCTIONS

OVEN DIAGRAM

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

DESCRIPTION AND FUNCTION OF COMPONENTS

TROUBLESHOOTING GUIDE

A MAGNETRON ASSEMBLY TEST

TEST PROCEDURES

B POWER TRANSFORMER TEST

C HIGH VOLTAGE RECTIFIER TEST

D HIGH VOLTAGE CAPACITOR TEST

E TEMPERATURE FUSE TEST

F SECONDARY INTERLOCK SWITCH TEST

PRIMARY INTERLOCK SYSTEM TEST

G MONITOR SWITCH TEST

H BLOWN C/T FUSE TEST

I TOUCH CONTROL PANEL ASSEMBLY TEST

J KEY UNIT TEST

K RELAY TEST

L DEFROST TEST

M FOIL PATTERN ON THE PRINTED WIRING BOARD TEST

TOUCH CONTROL PANEL ASSEMBLY

OUTLINE OF TOUCH CONTROL PANEL

DESCRIPTION OF LSI

TOUCH CONTROL PANEL SERVICING

PRECAUTIONS FOR USING LEAD-FREE SOLDER

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WARNING AGAINST HIGH VOLTAGE:

WARNING FOR WIRING

OUTER CASE REMOVAL

POWER TRANSFORMER REMOVAL

HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL

MAGNETRON REMOVAL

POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL

CONTROL PANEL ASSEMBLY REMOVAL

CONTROL UNIT ASSEMBLY REPLACEMENT

TURNTABLE MOTOR REMOVAL

COOLING FAN MOTOR REMOVAL

DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL

DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT

DOOR REPLACEMENT

Sealer film

PARTS LIST

HOW TO ORDER REPLACEMENT PARTS

PACKING AND ACCESSORIES

OVEN AND CABINET PARTS