SHARP KWK Service Manual

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R21LTF

SERVICE MANUAL

S7606R21LTFP/

LIGHT DUTY COMMERCIAL

MICROWAVE OVEN

1000W

-21L T

MODELS

R-21LTF

MME

MICR

VEN

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..)

CONTENTS

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

BEFORE SERVICING

CHAPTER 1. WARNING TO SERVICE PERSONNEL

CHAPTER 2. MICROWAVE MEASUREMENT PROCEDURE

CHAPTER 3. FOREWORD AND WARNING

CHAPTER 4. PRODUCT DESCRIPTION

CHAPTER 5. GENERAL INFORMATION

R-21LVF

CHAPTER 7. TROUBLESHOOTING GUIDE

CHAPTER 8. TEST PROCEDURES

CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY

CHAPTER 10. PRECAUTIONS FOR USING LEADFREE SOLDER

CHAPTER 11. COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

CHAPTER 12. CIRCUIT DIAGRAMS

Parts List

CHAPTER 6. OPERATION

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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CONTENTS

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

CHAPTER 1. WARNING TO SERVICE PERSONNEL

[1] Before Servicing .........................................1-1

[2] When the testing is completed, ..................1-1

[3] After repairing .............................................1-1

CHAPTER 2. MICROWAVE MEASUREMENT PROCEDURE

[1] Requirements: ............................................2-1

[2] Preparation for testing: ...............................2-1

[3] Leakage test: ..............................................2-1

CHAPTER 3. FOREWORD AND WARNING

[1] FOREWORD ..............................................3-1

[2] WARNING ..................................................3-1

[3] DANGER ....................................................3-1

CHAPTER 4. PRODUCT DESCRIPTION

[1] SPECIFICATIONS ......................................4-1

CHAPTER 5. GENERAL INFORMATION

[1] GROUNDING INSTRUCTIONS .................5-1

[2] OVEN DIAGRAM........................................5-1

CHAPTER 6. OPERATION

[1] DESCRIPTION OF OPERATING SE-

QUENCE ...................................................6-1

[2] OVEN SCHENATIC....................................6-2

[3] DESCRIPTION AND FUNCTION OF

COMPONENTS..........................................6-3

CHAPTER 7. TROUBLESHOOTING GUIDE

[1] TROUBLESHOOTING CHART .................7-1

CHAPTER 8. TEST PROCEDURES

[1] Procedure A: MAGNETRON ASSEMBLY

TEST ..........................................................8-1

[2] Procedure B: POWER TRANSFORMER

TEST ..........................................................8-1

[3] Procedure C: HIGH VOLTAGE RECTIFI-

ER TEST ....................................................8-1

[4] Procedure D: HIGH VOLTAGE CAPACI-

TOR TEST..................................................8-2

[5] Procedure E: THERMAL CUT OUT TEST.....8-2

[6] Procedure F: SECONDARY INTERLOCK

SWITCH TEST ...........................................8-2

[7] Procedure F: PRIMARY INTERLOCK

SYSTEM TEST...........................................8-3

[8] Procedure G: MONITOR SWITCH TEST.....8-3

[9] Procedure H: BLOWN MINITOR FUSE

TEST ..........................................................8-3

[10] Procedure I: NOISE FILTER TEST.............8-4

[11] Procedure J: TOUCH CONTROL PANEL

ASSEMBLY TEST ......................................8-4

[12] Procedure K: KEY UNIT TEST...................8-5

[13] Procedure L: RELAY TEST ........................8-6

[14] Procedure M: FOIL PATTERN ON THE

PRINTED WIRING BOARD TEST.............. 8-6

CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY

[1] OUTLINE OF TOUCH CONTROL PANEL ..... 9-1

[2] SERVICING FOR TOUCH CONTROL

PANEL ........................................................ 9-1

[3] PROCEDURE FOR CHECKING/CLEAR-

ING SERVICE COUNTS OF MICRO-

WAVE OVEN .............................................. 9-2

[4] OTHER SETTING AND CHECKING PRO-

CEDURE..................................................... 9-3

CHAPTER 10. PRECAUTIONS FOR USING LEADFREE SOLDER

[1] Employing lead-free solder ....................... 10-1

[2] Using lead-free wire solder ....................... 10-1

[3] Soldering................................................... 10-1

CHAPTER 11. COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

[1] WARNING..................................................11-1

[2] OUTER CASE REMOVAL .........................11-1

[3] POWER TRANSFORMER REMOVAL......11-2

[4] HIGH VOLTAGE RECTIFIER ASSEMBLY

AND HIGH VOLTAGE CAPACITOR RE-

MOVAL ......................................................11-2

[5] MAGNETRON REMOVAL .........................11-2

[6] CONTROL PANEL ASSEMBLY REMOV-

AL ..............................................................11-2

[7] OVEN LAMP AND LAMP SOCKET RE-

MOVAL ......................................................11-3

[8] POSITIVE LOCK CONNECTOR (NO-

CASE TYPE) REMOVAL .......................

[9] ANTENNA MOTOR REMOVAL .................11-3

[10] COOLING FAN MOTOR REMOVAL..........11-3

[11] POWER SUPPLY CORD REPLACE-

MENT.........................................................11-4

[12] DOOR SENSING SWITCH/SECONDARY

INTERLOCK SWITCH AND MONITOR

SWITCH REMOVAL ..................................11-4

[13] DOOR SENSING SWITCH/SECONDARY

INTERLOCK SWITCH AND MONITOR

SWITCH ADJUSTMENT ...........................11-5

[14] DOOR PARTS REMOVAL .........................11-5

[15] ANTENNA MOTOR SHAFT REPLACE-

MENT.........................................................11-6

[16] INSTALLATION OF CERAMIC SHELF......11-8

CHAPTER 12. CIRCUIT DIAGRAMS

[1] Pictorial Diagram (Figure S-1) .................. 12-1

[2] Control Panel Circuit (Figure S-2a and S-

2b)............................................................. 12-2

[3] Printed Wiring Board (Figure S-3) ............ 12-4

Parts List

....11-3

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R21LTF

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID

Service Manual

POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY

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.

BEFOR SERVICING

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/cm . 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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R21LTF

CHAPTER 1. 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.

(Example)

High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..

Read the Service Manual carefully and follow all instructions.

Service Manual

Don't Touch !

Danger High Voltage

[1] 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 shortcircuit the connection of the high-voltage capacitor (that is the connecting lead of the high-voltage 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.

[2] 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.

[3] 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 microwave leakage test should be carried out.

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R21LTF

CHAPTER 2. MICROWAVE MEASUREMENT PROCEDURE

Service Manual

[1] Requirements:

1. Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/ cm

2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the use-

ful life of the oven), 5 mW/cm

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 the external surface of the oven.

at any point 5cm or more from the external surface of the oven.

at any point 5cm or more from

[2] 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±5 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.

[3] 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/cm 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.

, and that the secondary

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R21LTF

CHAPTER 3. FOREWORD AND WARNING

Service Manual

[1] FOREWORD

This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVEN, R-21LTF and R-21LVF.

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.

[2] 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.

(D) The door is not deformed or warped.

(E) There is not any other visible damage with the oven.

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

[3] 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.

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.

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R21LTF

CHAPTER 4. PRODUCT DESCRIPTION

[1] SPECIFICATIONS

ITEM DESCRIPTION

120 Volts

Power Requirements

Power Output

Outer Case Dimensions

Cooking Cavity Dimensions

Control Complement

Oven Cavity Light Yes

Safety Standard

14 Amperes 60 Hertz Single phase, 3 wire grounded 1000 watts (IEC Test procedure) Operating frequency 2450 MHz Width 20-1/2" (520mm) Height 12-1/8" (309mm) Depth 16" (406mm)

Width 13-7/8" (353mm) NOTE: Internal capacity is calculated by measuring Height 8-1/ 8" (207mm) maximum width, depth and height. Depth 14-5/8" (370mm) Actual capacity for holding food is less.

Touch Control System Timer (0 - 99 minutes 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. 30% of FULL Power P-30 -------------------- approx. 40% 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 DOUBLE QUANTITY pad EXPRESS DEFROST pad Ten number pads SELECTATIME pad STOP/CLEAR pad SELECTAPOWER pad (R-21LTF only) START pad SET pad CHECK pad SIGNAL pad

UL Listed. FCC Authorized DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J, NSF certified

R21LTF

Service Manual

4 – 1

Page 8

R21LTF

3-Pronged Plug

Grounded Receptacle Box

Grounding Pin

3-Pronged Receptacle

R21LTF

CHAPTER 5. GENERAL INFORMATION

Service Manual

[1] 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 amp. or more protected 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 twopronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to contact a qualified electrician and have it replaced with a properly grounded threepronged 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 REMOVE THE ROUND

GROUNDING PRONG FROM THIS PLUG.

[2] OVEN DIAGRAM

1. OVEN

1. Back splash cover

2. Side splash cover

3. Oven light

4. Ceramic shelf

5. Control panel

6. Cavity face plate

7. Door latch openings

8. Door latches

9. Door hinges

10.Door seals and sealing surfaces

11.Door handle

12.Oven door with see-through window

13.Air ventilation cover and openings

14.Power supply cord

15.Air intake openings

16.Outer case cabinet

2. TOUCH CONTROL PANEL

912

3 2

DEFONNO.X2CHECK

6 8

9 10

6 8 11

R-21LTF R-21LVF

1. Digital Readout

2. DOUBLE QUANTITY pad

3. EXPRESS DEFROST pad

4. Ten number pads for time and memory programming

5. SELECTATIME pad

6. STOP/CLEAR pad; touch to stop operation of oven and clear remaining heating time

7. SELECTAPOWER pad for setting variable power level (R-21LTF only)

8. START pad; touch to operate oven after door is closed and time is set

9. SET pad for setting memory

10.CHECK pad for checking memory

11.SIGNAL pad for setting signal sound

5 – 1

Page 9

R21LTF

CHAPTER 6. OPERATION

[1] DESCRIPTION OF OPERATING SEQUENCE

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

R21LTF

Service Manual

1. OFF CONDITION

Closing the door activates 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 noise filter of the control unit (Figure O-1).

1) The display will show " . ".

2. COOKING CONDITION

Program desired cooking time by touching SELECTATIME pad and the NUMBER pads. When the START pad is touched, the following operations occur:

1) The contacts of the relays are closed and components connected to the relays are turned on as follows.

(For details, refer to Figure O-2)

RELAY CONNECTED COMPONENTS

RY-2 power transformer RY-3 oven lamp/antenna motor/fan motor

2) 120 volts A.C. is supplied to the primary winding of the power transformer and is converted to about 3.2 volts A.C. output on the filament winding, and approximately 2150 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 feed-box, 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, monitor switch, door sensing switch, secondary interlock switch, relay (RY3) and primary interlock relay (RY2) are activated with the following results. The circuits to the antenna 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 control relay (RY3) and is mechanically associated with the door so that it will function in the following sequence.

a) 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 (RY3) remains closed. Then the monitor switch contacts close.

b) 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 (RY3) 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 monitor fuse, secondary interlock switch, relay (RY3) and primary interlock relay (RY2), causing the monitor fuse to blow.

3. POWER LEVEL P-0 TO P-90 COOKING (R-21LTF only)

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:

VARI-MODE ON TIME OFF TIME Power 10 (P-HI) (100% power) 32 sec. 0 sec. Power 9 (P-90) (approx. 90% power) 30 sec. 2 sec. Power 8 (P-80) (approx. 80% power) 26 sec. 6 sec. Power 7 (P-70) (approx. 70% power) 24 sec. 8 sec. Power 6 (P-60) (approx. 60% power) 22 sec. 10 sec. Power 5 (P-50) (approx. 50% power) 18 sec. 14 sec. Power 4 (P-40) (approx. 40% power) 16 sec. 16 sec. Power 3 (P-30) (approx. 30% power) 12 sec. 20 sec. Power 2 (P-20) (approx. 20% power) 8 sec. 24 sec. Power 1 (P-10) (approx. 10% power) 6 sec. 26 sec. Power 0 (P-0) (0% power) 0 sec. 32 sec.

NOTE: The ON/OFF time ratio does not correspond with the per-

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

6 – 1

Page 10

R21LTF

[2] OVEN SCHENATIC

1. Off Condition

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. “ . “ APPEARSED

AC120V 60 Hz

THERMAL

CAPACITOR

0.0033μF / AC 250V

CAPACITOR

0.0033μF / AC 250V

CUT-OUT 125ºC (OVEN)

NOISE FILTER

FUSE

20A

LINE BYPASS

NOISE SUPPRESSION COIL

LINE CROSS CAPACITOR 0.22μF AC250V

LINE BYPASS

THERMAL CUT-OUT 145ºC (MAG.)

B1 B2

DOOR SENSING SWITCH

RY3

CONTROL

RELAY

CONTROL UNIT

OL FM AM

OVEN LAMP

SECONDARY INTERLOCK SWITCH

Figure O-1. Oven Schematic-Off Condition

2. Cooking Condition

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED.

2. SELECTATIME PAD TOUCHED.

3. COOKING TIME ENTERED.

4. START PAD TOUCHED.

RY2

PRIMARY

FAN MOTOR

INTERLOCK

RELAY

ANTENNA MOTOR

POWER TRANSFORMER

MONITOR SWITCH

CAPACITOR

1.00 μF 2300V

MAGNETRON

RECTIFIER

AC120V 60 Hz

THERMAL

CAPACITOR

0.0033μF / AC 250V

CAPACITOR

0.0033μF / AC 250V

CUT-OUT 125ºC (OVEN)

NOISE FILTER

FUSE

20A

LINE BYPASS

NOISE SUPPRESSION COIL

LINE CROSS CAPACITOR 0.22μF AC250V

LINE BYPASS

THERMAL CUT-OUT 145ºC (MAG.)

B1 B2

DOOR SENSING SWITCH

RY3

CONTROL UNIT

CONTROL

RELAY

RY2

OL FM AM

OVEN LAMP

FAN MOTOR

SECONDARY INTERLOCK SWITCH

Figure O-2. Oven Schematic-Cooking Condition

PRIMARY

INTERLOCK

RELAY

ANTENNA MOTOR

POWER TRANSFORMER

MONITOR SWITCH

CAPACITOR

1.00 μF 2300V

MAGNETRON

RECTIFIER

6 – 2

Page 11

[3] DESCRIPTION AND FUNCTION OF COMPONENTS

R21LTF

1. DOOR OPEN MECHANISM

The door is opened by grasping the door handle, refer to Figure D-1.

When the door handle is grasped, the handle lever is pulled. And then the upper and lower latch heads are moved upward by the handle lever, and they are released from the latch hook. Now the door will open.

Handle Lever

Door Handle

Latch Lever

Latch Head

Latch Switch Lever C

Latch Head

Latch Hook

Latch Switch Lever A

Secondary Interlock Switch

Latch Switch Lever B

Monitor Switch

Door Sensing Switch

CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE TEST

THE DOOR SENSING SWITCH, PRIMARY INTERLOCK RELAY (RY2), RELAY (RY3) SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROC

NOTE: MONITOR FUSE AND MONITOR SWITCH ARE REPLACED

AS AN ASSEMBLY.

4. ANTENNA MOTOR

The antenna motor rotates the stirrer antenna located on the bottom of the oven cavity, so that the food on the ceramic shelf is cooked evenly during cooking. The antenna motor may turn in either direction.

5. COOLING FAN MOTOR

The cooling fan motor drives a blade which draws external cool air. This cool air is directed through the air vanes surrounding the magnetron and cools the magnetron. This air is channelled through the oven cavity to remove steam and vapors given off from the heating food. It is then exhausted through the exhausting air vents at the oven cavity.

6. MONITOR FUSE

1) The monitor 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 monitor fuse blows to prevent an electric shock or fire hazard.

Figure D-1. Door Open Mechanism.

2. DOOR SENSING AND SECONDARY INTERLOCK SWITCHES

The secondary interlock switch is mounted in the upper position of the latch hook and the door sensing switch in the primary interlock system is mounted in the lower position of the latch hook. The secondary interlock switch is activated by the latch switch lever A. The latch switch lever A is activated by the upper latch head. The door sensing switch is activated by the latch switch lever C. The latch switch lever C is activated by the lower latch head. 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.

3. MONITOR SWITCH

The monitor switch is activated (the contacts opened) by the latch switch lever B on the latch hook while the door is closed. The latch switch lever B is activated by the lower latch head. The switch is intended to render the oven inoperative, by means of blowing the monitor 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 their 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 the secondary interlock switch contacts close. (On opening the door, each of these switches operate inversely.)

3) If the door is opened, and the primary interlock relay (RY2) and secondary interlock switch contacts fail to open, the monitor fuse blows simultaneously with closing of the monitor switch contacts.

7. THERMAL CUT-OUT 145°C (MAGNETRON)

This thermal cut-out protects the magnetron against overheating. If the temperature goes up higher than 293°F (145°C) because the fan motor is interrupted or the ventilation openings are blocked, the thermal cut-out will open and line voltages to the high voltage transformer will be cut off and the operation of the magnetron will be stopped. The thermal cutout will not resume.

8. THERMAL CUT-OUT 125°C (OVEN)

The thermal cut-out located on the top of the oven cavity is designed to prevent damage to the oven if the food in the oven catches fire due to over heating produced by improper setting of the cooking time or failure of control unit. Under normal operation, the oven thermal cutout remains closed. However, when abnormally high temperatures are reached within the oven cavity, the oven thermal cut-out will open at 257°F(125°C) causing the oven to shut down. The thermal cut-out will not resume.

9. NOISE FILER

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

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CHAPTER 7. TROUBLESHOOTING GUIDE

Service Manual

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 monitor fuse, check the monitor switch, relay (RY3), primary interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the monitor fuse. If monitor fuse is replaced, the monitor switch must also be replaced. Use part FFS-BA033WRKZ 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.

[1] TROUBLESHOOTING CHART

CONDITION

OFF CONDITION

COOKING CONDITION

ERROR MODE

TEST PROCEDURE

POSSIBLE CASE

AND

DEFECTIVE PARTS

PROBLEM

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

Monitor fuse blows when power cord is plugged into wall receptacle.

. does not appear in display when

power cord is first plugged into wall outlet.

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 antenna 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 5 mode. (Operates properly on Cooking Power 10 (HIGH) mode.)

"EE9" Maximum time is exceeded.

ABC DEF FGH JK L M

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

HIGH VOLTAGE CAPACITOR

THERMAL CUT-OUT

SECONDARY INTERLOCK SWITCH

PRIMARY INTERLOCK SYSTEM

MONITOR SWITCH

MONITOR FUSE

TOUCH CONTROL PANEL

KEY UNIT

RELAY (RY3)

RE RE RE RE RE CK CK CK I

EXCEED MAX. HEATING TIME

FOIL PATTERN ON P.W.B.

OVEN LAMP OR SOCKET

COOLING FAN MOTOR

ANTENNA MOTOR

SHORTED IN POWER CORD

SHORT OR OPENED WIRING

LOW VOLTAGE

WRONG OPERATION

DIRTY OVEN CAVITY

NOISE FILTER

7 – 1

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R21LTF

CHAPTER 8. TEST PROCEDURES

Service Manual

[1] Procedure 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.

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.

1. 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 10 (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 34.7 to 64.6°F(19.3 to 35.9°C) rise in tempera- ture. 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.

[2] Procedure 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 83.7 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.)

[3] Procedure 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 defective and should be replaced.

5. Reconnect all leads removed from components during testing.

8 – 1

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R21LTF

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.

[4] Procedure 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.

[5] Procedure E: THERMAL CUT OUT TEST

1. THERMAL CUT OUT 125°C (OVEN)

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 thermal cut-out terminals should indicate a closed circuit unless the temperature of the thermal cut-out reaches approximately 257°F(125°C). An open thermal cut-out indicates overheating of the oven, exchange the thermal cut-out 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.

2. THERMAL CUT OUT 145°C (MAGNETRON)

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 thermal cut-out terminals should indicate a closed circuit. If the temperature of the magnetron reaches approximately 293°F(145°C), the thermal cut-out opens. An open thermal cutout indicates overheating of the magnetron. Check for restricted air flow to the magnetron, especially the cooling fan 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.

CAUTION: IF THE THERMAL CUT-OUT INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE,

REPLACE THERMAL CUT-OUT.

[6] Procedure 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).

8 – 2

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R21LTF

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

8. Run the oven and check all functions.

[7] Procedure F: PRIMARY INTERLOCK SYSTEM TEST

1. 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.

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.

2. 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.

[8] Procedure 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.

MONITOR SWITCH

SCREW DRIVER

WHT/ WHT

OHMMETER

[9] Procedure H: BLOWN MINITOR 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.

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R21LTF

FUSE

LINE CROSS CAPACITOR 0.22μF AC250V

WHITE RED

NOISE SUPPRESSION COIL

LINE BYPASS

CAPACITOR

0.0033μF / AC 250V

LINE BYPASS

CAPACITOR

0.0033μF / AC 250V

20A

NOISE FILTER

4. If the monitor 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 monitor fuse.

CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK RELAY, SECONDARY INTERLOCK SWITCH,

DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION.

If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must be replaced with "monitor fuse and monitor switch assembly" part number FFS-BA033WRKZ, even if the monitor switch operates normally. The monitor fuse and monitor switch assembly is comprised of a 20 ampere fuse and 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.

[10] Procedure I: NOISE FILTER 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 lead wires from the terminal the noise filter. Using an ohmmeter, check between the terminals as described in the following table. If incorrect reading are obtained, replace the noise filter.

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.

MEASURING POINT INDICATION OF OHMMETER Between N and L Open circuit. Between terminal N and WHITE Short circuit. Between terminal L and RED Short circuit.

[11] Procedure J: TOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter and ohmmeter.

In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key Unit, and troubleshooting by 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.

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

1. Key Unit

NOTE:

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) Check key unit ribbon connection before replacement.

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.

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.

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Page 17

R21LTF

If the key 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 key unit.

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.

2. Control Unit.

The following symptoms indicate a defective control unit. Before replacing the control unit, perform the Key unit test (Procedure K) to determine if control unit is faulty.

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) 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.

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.

When 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 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.

[12] Procedure K: 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. If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable is making good contact, verify that the door sensing switch (stop switch) operates properly; that is the contacts are closed when the door is closed and open when the door is open. If the door sensing switch (stop switch) is good, disconnect the flat ribbon cable that connects the key unit to the control unit and make sure the door sensing switch is closed (either close the door or short the door sensing switch connector). Use the Key unit matrix indicated on the control panel schematic and place a jumper wire between the pins that correspond to the STOP/CLEAR pad making momentary contact. If the control unit responds by clearing with a beep the key unit is faulty and must be replaced. If the control unit does not respond, it is faulty and must be replaced. If a specific pad does not respond, the above method may be used (after clearing the control unit) to determine if the control unit or key pad is at fault.

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.

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G1 G2 G3 G4 G5 G6 G7 G8

G10

G11

G12

R-21LTF

SELECTA

POWER

SELECTA

TIME

G10

G11

G12

DOUBLE

QUANTITY

EXPRESS DEFROST

START SET

STOP/

CLEAR

11131519

12141620

G1 G2 G3 G4 G5 G6 G7 G8

CHECK

SIGNAL

DOUBLE

QUANTITY

EXPRESS

DEFROST

SELECTA

TIME

START SET

STOP/

CLEAR

R-21LVF

[13] Procedure L: 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 Pin Numbers. 3 and 7 of the connector (A) on the control unit with an A.C. voltmeter.

The meter should indicate 120 volts, if not check oven circuit.

RY2 and RY3 Relay Test

These relays are operated by D.C. voltage

Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.

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

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

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

RY2 Approx. 12.0V D.C. Power transformer RY3 Approx. 12.0V D.C. Oven lamp / Antenna motor / Cooling fan motor

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.

CHECK

SIGNAL

[14] Procedure 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

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Page 19

1 Only pattern at “a” is broken. *Insert jumper wire J1 and solder.

(17)

(C T 1)

(J 1)

(J 7)

(TB 1)

VR S1

(VR S 2)

POWER

2 Pattern at “a” and “b” are broken. *Replace control unit.

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 915Ω±10%). If any abnormal condition is detected, replace the control unit.

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.

STEPS OCCURRENCE CAUSE OR CORRECTION

The rated AC voltage is not present between Pin No. 1 of the 3-pin con-

nector (A) and the normal open terminal of the relay RY2 The rated AC voltage is present at primary side of low voltage trans-

former.

Check supply voltage and oven power cord.

Low voltage transformer or secondary circuit defective. Check and replace control unit.

R21LTF

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.

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CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY

Service Manual

[1] OUTLINE OF TOUCH CONTROL PANEL

The touch control section consists of the following units as shown in the touch control panel circuit.

(1) Key Unit (2) Control Unit

The principal functions of these units and their related signals are explained below.

1. Control Unit

Signal of key touch and oven function control are all processed by one microcomputer.

1) Power Supply Circuit

This circuit changes output voltage at the secondary side of the low voltage (T1) transformer to voltages required at each part by full wave rectifying circuit, constant voltage circuit, etc..

2) ACL Circuit

This is an Auto-clear Circuit, i.e., a reset circuit, which enables IC1 to be activated from initial state.

3) Power SYNC Signal Generating Circuit

This is a circuit for generating power SYNC signal by virtue of the secondary side output of transformer T1. This signal is used for a basic frequency to time processing and so on.

4) Clock Circuit

This is a circuit for controlling clock frequency required for operating IC1.

5) IC1 (Main Processor)

This is a one-chip microcomputer, responsible for controlling the entire control unit.

6) IC2 (Memory Processor)

This is a memory IC, responsible for memory function.

7) IC3

This is a IC for driving light emitting diode.

8) Display Circuit

This is a circuit for driving light emitting diode by IC1 output.

9) Key Input Circuit

This is a circuit for transmitting key input information to IC1.

10)Sound-body Driving Circuit

This is a circuit for driving sound body by IC1 output.

11)Relay Driving Circuit

This is a circuit for driving output relay by IC1 output.

12)Door Sensing Switch Circuit

This is a circuit for driving IC1 to detect door opening/ closing.

2. Key Unit

The key unit is composed of a matrix circuit in which when a key it touched, one of signals P30--P34 generated by the LSI, is passed through the key and returned to the LSI as one of signals P24--P27. This model has 20 Memory pads. When the oven is shipped, Memory pad 1 to 10 are set as follows: fig.1.

Memory No. Cook Time Output Power

1 10 sec. 100% 2 20 sec. 100% 3 30 sec. 100% 4 45 sec. 100% 5 1 min. 100% 6 1 min. 15 sec. 100% 7 1 min. 30 sec. 100% 8 2 min. 100% 9 2 min. 30 sec. 100% 0 3 min. 100%

This model has a double quantity pad. When the oven is shipped, Magnification "1.7" is preset in the double quantity pad. This model has an express defrost pad. When the oven is shipped, express defrost is set as follows: fig.2.

FORMULA P = 0.2T P = 0.15T P = 0.65T POWER 0.6 0.4 0.2 T : Total cooling time

When 1/2 total cooking time is passed, the signal will sound and "CHECK" indicator will flash.

(fig. 1)

1 STAGE 2 STAGE 3 STAGE

(fig. 2)

[2] SERVICING FOR TOUCH CONTROL PANEL

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 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

9 – 1

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 MICRO-

WAVE 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.

Page 21

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 so long enough that they may be separated from each other. For those models, therefore, it is possible to check and repair the controls of the touch control panel while keeping it apart from the oven proper; in this case you must short both ends of the door sensing switch (on PWB) of the touch control panel with a jumper, which brings about an operational state that is equivalent to the oven door being closed. As for the sensorrelated controls of the touch control panel, checking them is possible if the 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:

R21LTF

Disconnect the touch control panel completely from the oven proper, and short both ends of the door sensing switch (on PWB) of the touch control panel, which brings about an operational state that is equivalent to the oven door being closed. Connect an external power source to the power input terminal of the touch control panel, then it is possible to check and repair the controls of the touch control panel; it is also possible to check the sensor-related controls of the touch control panel by using the dummy resistor(s).

3. Servicing Tools

Tools required to service the touch control panel assembly.

1) Soldering iron: 60W

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

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

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

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

[3] PROCEDURE FOR CHECKING/CLEARING SERVICE COUNTS OF MICROWAVE OVEN

The following procedure enables the servicer to obtain the total using times (cook cycles) since the microwave oven is purchased and the total operation time (hours) since the microwave oven is purchased. The maximum capacity of the total using is 999,999 times, and the maximum capacity of total operation time is 999,999 hours.

1. Practice for checking total using times (Ex. 345678 times).

... Flashing / ... 0.1sec BUZZER

PAD DISPLAY INDICATOR PHONE

(Door close) .

CHECK . CHECK No. CHECK #1 82 68 CHECK

SIGNAL SIGNAL DOUBLE 34 56 QUANTITY

1 (No 1) 1 No.

(after 1 sec.) 34 56

2 (No 2) 2 No.

(after 1 sec.) 78

CHECK .

(service total count upper figure)

3456XX

(service total count upper figure)

(service total count lower figure)

(user total count)

2. Practice for checking total operation time (Ex.

4567 hours).

... Flashing / ... 0.1sec BUZZER

PAD DISPLAY INDICATOR PHONE

(Door close) .

CHECK . CHECK No. CHECK #1 82 68 CHECK

SIGNAL SIGNAL DOUBLE 34 56 QUANTITY

9 (No 9) 9 No.

(after 1 sec.) 45

0 (No 0) 0 No.

(after 1 sec.) 67

CHECK .

(service total count upper figure)

3456XX

(Total operation time upper figure)

(Total operation time lower figure)

#1 : No key entry signal.

#2 : To set -B, touch the selectapower key twice.

(user total count)

9 – 2

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R21LTF

3. Practice for inputting total using times (Ex. 310000 times).

... Flashing / ... 0.1sec BUZZER

PAD DISPLAY INDICATOR PHONE

(Door close) .

CHECK . CHECK No. CHECK 82 68 CHECK

SIGNAL SIGNAL DOUBLE 34 56 QUANTITY

2 2 No.

(after 1 sec.) 78

1 1 No.

(after 1 sec.) 34 56

SET 0

3,1,0,0 31 00 x 4

SET 31 00

2 2 No.

(after 1 sec.) 78

SET 0 00 SET 0

CHECK .

(service total count upper figure)

3456XX

(service total count lower figure)

XXXX78

(service total count 310000 set)

#1 : No key entry signal.

#2 : To set -B, touch the selectapower key twice.

4. Practice for inputting total operation time (Ex. 1234 hours).

PAD DISPLAY INDICATOR PHONE

(Door close) .

CHECK . CHECK No. CHECK 82 68 CHECK

SIGNAL SIGNAL DOUBLE 34 56 QUANTITY

9 9 No.

(after 1 sec.) 45

SET 0 1,2 12 x 2 SET 12

0 1 0 No.

(after 1 sec.) 67

SET 0 3,4 34 x 2 SET 34

CHECK .

(service total count upper figure)

3456XX

(Total operation time 1234 hours set)

(user total count)

... Flashing / ... 0.1sec BUZZER

(user total count)

5. Practice for cancelling total using times and total

operation time (user and service) and all other counter.

... Flashing / ... 0.1sec BUZZER

PAD DISPLAY INDICATOR PHONE (Door close) . SET . SET . No. (within 2.0sec.) .

DOUBLE QUANTITY . DOUBLE CHECK . SINGLE . SET .

[4] OTHER SETTING AND CHECKING PROCEDURE

1. EXPRESS DEFROST

T = STG1 + STG 2 + STG3

STG = A x T + B

1) To set the constants of Express defrost.

(Ex. 020T, 60% at 1st stage / 0.15T, 40% at 2nd stage/ 0.65T, 20% at 3rd stage )

" ": Flicker / : 0.1 sec BUZZER

PAD ORDER DISPLAY PHONE

(Door close) .

SET .

SET "NO" . (within 2 sec.) #1 START . EXPRESS DEF 0.00 DEF.

2,0 0.20 DEF x 2

#2 SELECTATIME 0 DEF

0 0 DEF

#4 SELECTAPOWER P -

6P-60 SELECTATIME

1,5 0.15 DEF x 2

SELECTATIME 0 DEF

0 0 DEF

#4 SELECTAPOWER P -

4-40 SELECTATIME 0 DEF #3 5 5 DEF

#4 SELECTAPOWER P -

2P-20 SET . DEF SET .

#1 : No key entry signal.

#2 : To set -B, touch the selectapower key twice.

#3 : Ex. defrost is paused after 50% of cooking time has lapsed when

5 key is entered, otherwise it is paused at the end of each stage.

#4 : For R-21LTF, change selectapower key to signal key.

(A)

(+-B)

DEF

0.00 DEF

(A)

(+-B)

DEF

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KEY DISPLAY PAUSE

0 0 End of each stage 1 1 After 10% of total cooking time is passed ::: 9 9 After 90% of total cooking time is passed

START A There is no pause

2) To check the constants of Express defrost.

" ": Flicker / : 0.1 sec BUZZER

PAD DISPLAY INDICATOR PHONE

. CHECK . "No." CHECK EXPRESS DEFROST 0.20 DEF

(A)

( +-B )

P-60

(PL)

0.15

(A)

( +-B )

P-40

(PL)

( pause time )

P-20

(PL)

( repeat )

CHECK .

R21LTF

3) To set user counts

Practice for inputting total number of using times (Ex. 3100 times), and using times of Memory 1 (Ex. 100 times).

" ": Flicker / : 0.1 sec BUZZER

PAD DISPLAY INDICATOR PHONE

(Door close) .

CHECK . CHECK No. CHECK 82 68 CHECK

DOUBLE QUANTITY

SIGNAL SET 0 3,1,0,0 31 00 x 4 SET 31 00

(user total count 3100 set)

#A 1 1 No.

(after 1 sec.) 1 32

SET 0 1,0,0 1 00 x 3 SET 1 00

(memory 1 count 100 set)

CHECK .

(user total count)

(memory 1 count)

NOTE: 1) To input using times of other memory, touch necessary

Memory key at above step #A.

2) To input using times of manual cooking, touch SELECTATIME key at above step #A.

3) o input using times of Express Defrost, touch EXPRESS DEFROST key at above step #A.

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R21LTF

CHAPTER 10. PRECAUTIONS FOR USING LEAD-FREE SOLDER

Service Manual

[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:

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.

10 – 1

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R21LTF

CHAPTER 11. COMPONENT REPLACEMENT AND ADJUSTMENT PROCE-

Service Manual

DURE

[1] WARNING

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:

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

1. Disconnect the power supply cord.

2. 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 operat-

ing the oven.

Do not operate the oven if any of the following conditions exist;

1. Door does not close firmly.

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

3. The door gasket or seal is damaged.

4. The door is bent or warped.

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.

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 Chassis supportand other metallic plate.

4) Movable parts (to prevent a fault) Fan blade, Fan motor, Switch, Switch lever, and Antenna motor

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:

[2] OUTER CASE REMOVAL

To remove the outer case, procedure as follows.

1. Disconnect the power supply cord.

2. Open the oven door and block it open.

3. Remove the five (5) screws from rear and along the side edge of case.

4. Slide the entire case back about 3cm to free it from retaining clips on the cavity face plate.

5. Lift entire outer case from the unit.

6. Discharge the H.V. capacitor before carrying out any further work.

7. Do not operate the oven with the outer case removed.

CAUTION: DISCONNECT OVEN FROM POWER SUPPLY BEFORE

REMOVING OUTER CASE.

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

11 – 1

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R21LTF

[3] POWER TRANSFORMER REMOVAL

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

2. Open the oven door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the filament leads of power transformer from high voltage capacitor and the magnetron.

5. Disconnect the H.V. wire from the power transformer.

6. Disconnect the main wire harness from the power transformer.

7. Remove the two (2) screws and two (2) VCP caps holding the transformer to base plate.

8. Remove the transformer.

9. Now the power transformer is free.

[4] HIGH VOLTAGE RECTIFIER ASSEMBLY AND HIGH VOLTAGE CAPACITOR REMOVAL

To remove the components, proceed as follows.

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

2. Open the oven door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect H.V. wire of the high voltage rectifier assembly from the magnetron and the power transformer.

5. Disconnect the filament lead of the power transformer from the high voltage capacitor.

6. Remove one (1) screw holding earth side terminal of the high voltage rectifier assembly.

7. Disconnect all the leads and terminals of high voltage rectifier assembly from the high voltage capacitor.

8. Now, the high voltage rectifier assembly should be free.

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

10.Remove one (1) screw holding the fan duct to the oven cavity rear plate.

11.Release the capacitor holder from the fan duct.

12.Remove the capacitor from the capacitor holder.

13.Now, the capacitor should be free.

CAUTION: WHEN REPLACING HIGH VOLTAGE RECTIFIER AND

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

[5] MAGNETRON REMOVAL

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

2. Open the oven door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the high voltage wire of the high voltage rectifier assembly and filament lead of the transformer from the magnetron.

5. Remove the one (1) screw holding the airguide to the magnetron and remove the airguide.

6. Remove the one (1) screw holding the insertion plate A to the magnetron and remove the insertion plate A.

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

[6] CONTROL PANEL ASSEMBLY REMOVAL

CONTROL PANEL ASSEMBLY

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the main wire harness from the control unit.

5. Remove the one (1) screw holding the control panel assembly to the oven cavity front plate.

6. Lift up the control panel assembly.

7. Now, the control panel assembly is free.

8. Release the tabs of air intake duct from the chassis support and the oven cavity.

9. Move the air intake duct to the left.

10.Carefully remove four (4) screws holding magnetron to waveguide, when removing the screws hold the magnetron to prevent it from falling.

11.Remove the magnetron from the waveguide with care so the magnetron antenna is not hit by any metal object around the antenna.

CAUTION: WHEN REPLACING THE MAGNETRON, BE SURE THE

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

CONTROL UNIT

8. Disconnect the flat ribbon cable from the connector CN-G.

9. Remove the six (6) screws holding the control unit to the control panel frame.

10.Release the two (2) tabs of the control panel frame holding the control unit to the control panel frame.

11.Now, the control unit is free.

NOTE: 1) Before attaching a new key unit, wipe off remaining adhe-

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

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

3) Stick the key unit firmly to the control panel frame by rubbing with a soft cloth so not to cause scratches.

11 – 2

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[7] OVEN LAMP AND LAMP SOCKET REMOVAL

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Lift up the oven lamp socket from air intake duct.

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

6. Now, the oven lamp socket is free.

Figure C-1. Oven lamp socket

Oven lamp socket

Terminal

Wire lead

[8] POSITIVE LOCK CONNECTOR (NO-CASE TYPE) REMOVAL

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Push the lever of positive lock

5. Pull down on the positive lock

CAUTION: WHEN CONNECTING THE POSITIVE LOCK

TORS TO THE TERMINALS, NSTALL THE POSITIVE

LOCK

SO THAT THE LEVER FACES YOU.

connector.

CONNEC-

Positive lock connector

Lever

R21LTF

Terminal hole

Flat type small screw driver

Terminal

Push

[9] ANTENNA MOTOR REMOVAL

1. Disconnect the power supply cord.

2. Remove the one (1) screw holding the base plate cover to the base plate and remove the base plate cover.

[10] COOLING FAN MOTOR REMOVAL

1. REMOVAL

1. Disconnect the power supply cord and 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 one (1) screw holding the capacitor holder to the oven cavity rear plate.

6. Remove the one (1) screw holding the fan duct to the oven cavity rear plate.

7. Release the tabs of the capacitor holder from fan duct.

8. Remove the fan duct from the oven.

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

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

Pull down

Figure C-1. Positive Lock

3. Disconnect the wire leads from the antenna motor and remove the one (1) screw holding the antenna motor.

4. Remove the antenna motor shaft from the antenna motor.

5. Now, the antenna motor is free.

CAUTION: MAKE SURE THAT ANY PIECES DO NOT ENTER THE

GAP BETWEEN THE ROTOR AND THE STATOR OF THE FAN MOTOR. BECAUSE THE ROTOR IS EASY TO BE 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.

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

12.Now, the fan blade will be free.

CAUTION: DO NOT RE-USE THE REMOVED FAN BLADE

BECAUSE THE HOLE (FOR SHAFT) MAY BE LARGER THAN NORMAL.

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

14.Now, the fan motor is free.

Connector

11 – 3

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R21LTF

Power Supply Cord

Chassis Support

WHT

RED

Screw

Green Wire

Noise Filter

White Wire

Oven Cavity Rear Plate

Black Wire

2. INSTALLATION

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

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

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

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.

CAUTION: DO not hit the fan blade hard when installing because the

bracket may be disfigured.

MAKE SURE THAT THE FAN BLADE ROTATES SMOOTH AFTER INSTALLED.

MAKE SURE THAT THE AXIS OF THE SHAFT IS NOT SLANTED.

5. Install the fan duct to the oven cavity rear plate with the one (1) screw.

6. Insert the tabs of the capacitor holder to the fan duct.

7. Install the capacitor holder to the oven cavity rear plate with the one (1) screw.

8. Re-connect the wire leads to the fan motor.

Coil

Groove joint pliers

Shaft

Stator

Gap

Bracket

Rotor

Rear View

Axis

Stator

Rotor

Side View

[11] POWER SUPPLY CORD REPLACEMENT

1. 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 one (1) screw holding the green wire to the cavity rear plate.

5. Disconnect the wire leads of the power supply cord from the noise filter.

6. Release the power supply cord from the oven cavity rear plate.

7. Now, the power supply cord is free.

These are the positions that should be pinched with pliers.

Table

Shaft

Center of bracket

2. REINSTALL

1. Insert the moulding cord stopper of power supply cord into the square hole of the oven cavity rear plate, referring to the Figure C3b.

2. Install the earth wire lead of power supply cord to the cavity rear plate with one (1) screw and tighten the screw.

3. Connect the wire leads of power supply cord to the noise filter, referring to the Pictorial Diagram.

Figure C-3a. Power Supply Cord Replacement

Moulding Cord Stopper

Power Supply Cord

Oven Cavity Rear Plate

Square Hole

Figure C-3b. Power Supply Cord Replacement

[12] DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL

1. REMOVAL

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

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

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R21LTF

5. Disconnect the leads from all switches.

6. Remove the two (2) screws holding the latch hook to the oven cavity.

7. Remove the latch hook.

8. Push the retaining tab outward slightly and remove the switch.

2. REINSTALL

1. Re-install each switch in its place. The door sensing switch and monitor switch are in the lower position and the secondary interlock switch is in the upper position.

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

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

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

Tab

Figure C-4. Switches

Latch Hook

Tabs

Secondary Interlock Switch

Tab

Monitor Switch

Tab

Door Sensing Switch

[13] DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT

1. 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.

2. 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 opened.

3. Monitor switch contacts close when door is opened.

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

Handle Lever

Door Handle

Latch Lever

Latch Head

Latch Switch Lever C

Figure C-5. Latch Switch Adjustments

Latch Head

Latch Hook

Latch Switch Lever A

Secondary Interlock Switch

Latch Switch Lever B

Monitor Switch

Door Sensing Switch

[14] DOOR PARTS REMOVAL

1. REMOVAL

CHOKE COVER

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-6 to free engaging parts.

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

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.

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R21LTF

Choke Cover

Putty Knife

Door Frame

Figure C-6. Door Disassembly

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

8. Remove the one (1) cushion (ferrite) from the lower opening between the door panel and the door frame.

9. Now, door sub assembly is free from oven cavity.

DOOR PANEL REMOVAL

10.Remove the four (4) screws holding the door panel to the door frame.

11.Release door panel from seven (7) tabs of door frame by sliding door panel downward.

12.Now, the door panel is free.

DOOR HANDLE REMOVAL

13.Release the latch spring from the tab of the latch angle assembly.

14.Remove the two (2) screws holding the door handle and the latch angle assembly through the door frame.

15.Now, door handle is free.

LATCH HEADS REMOVAL

16.Remove the one (1) screw holding the latch angle assembly to the door frame.

17.Remove the latch angle assembly together with the latch lever, latch spring and the upper and lower latch heads from the door frame.

18.Release the latch lever together with the latch spring and the latch heads from the latch angle assembly.

19.Release the two (2) latch heads from the latch lever.

20.Now, the upper and lower latch heads are free.

FRONT DOOR GLASS OR SEALER PLATE REMOVAL

(After DOOR PANEL REMOVAL)

1) Remove the four (4) screws holding the glass stopper U to the door frame and remove the glass stopper U.

2) Remove the two (2) screws holding the glass stopper R to the door frame and remove the glass stopper R.

3) Slide the front door glass and the sealer plate left at first and then slide upwards to release them from the tabs holding it.

4) Now, the front door glass or the sealer plate free.

DOOR CASE REMOVAL

(After DOOR PANEL REMOVAL)

1) Straighten all tabs of the door case holding the door case to the door frame.

2) Release door case from the door frame.

3) Now, the door case is free

NOTE: At this moment, the door badge is attached on the door case.

2. REINSTALL OF THE DOOR

1. Reinstall all door parts except the choke cover

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

3. Insert the one (1) cushion (ferrite) into the lower opening between the door panel and the door frame.

4. Reinstall choke cover to door panel by pushing.

NOTE: After any service to the door;

1) Make sure that door sensing switch, secondary inter-

lock switch and monitor switch are operating properly. (Refer to chapter “Test Procedures”.).

2) An approved microwave survey meter should be used

to assure compliance with proper microwave radiation emission limitation standards. (Refer to chapter “Test Procedures”.)

3. After any service, make sure of the following:

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

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

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

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

NOTE: The door on a microwave oven is designed to act as an

electronic seal preventing the leakage of microwave energy from oven cavity during cook cycle. This function does not require that door be air-tight, moisture (condensation)-tight or 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.

Upper

Oven Hinge

Upper Oven Hinge

Lower Oven

Door

Hinge

Panel

Slit Chok

Choke Cover

Cushion (Ferrite)

Lower

Oven Hinge

Figure C-7. Door Replacement

[15] ANTENNA MOTOR SHAFT REPLACEMENT

1. REMOVAL

1. Disconnect the power supply cord.

11 – 6

2. Open the door and block it open.

3. To discharge the high voltage capacitor, wait for 60 seconds.

Page 31

4. Remove the antenna motor from the oven cavity bottom plate, referring to "ANTENNA MOTOR REMOVAL".

5. Remove the ceramic shelf from the oven cavity bottom plate.

6. Remove the one (1) screw and the one (1) washer holding the antenna holder of the stirrer antenna assembly to the oven cavity bottom plate through the square hole of the stirrer antenna. Refer to Figure C-8.

7. Release the antenna holder from the one (1) tab of the oven cavity bottom plate.

8. Remove the stirrer antenna assembly from the oven cavity bottom plate.

9. Remove the antenna motor shaft from the hole of the oven cavity bottom plate.

10.Now, the antenna motor shaft is free.

Screw

Washer

Square hole

Antenna holder

R21LTF

2. Set the direction of the stirrer antenna and antenna holder so that the hole of the antenna holder fit to the centre of the stirrer antenna's big blade. Refer to Figure C-9.

3. Hook the hole of the antenna holder on the tab of the oven cavity bottom plate. Refer to Figure C-10.

4. Insert the antenna holder into the hole of the oven cavity bottom plate and fit the hole of the antenna holder with an antenna motor shaft. Refer to Figure C-10.

5. Install the antenna holder to the oven cavity bottom plate with the one (1) screw and the one (1) washer. Refer to Figure C-8.

6. Install the antenna motor to the oven cavity bottom plate with one (1) screw. Refer to Figure C-8.

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

8. Install the base plate cover to the base plate with one (1) screw.

9. Install the ceramic shelf to the oven cavity bottom plate. Refer to "INSTALLATION OF CERAMIC SHELF".

Stirrer antenna

Antenna motor shaft

Tab

Oven cavity bottom plate

Antenna motor

Screw

Figure C-8. Antenna Motor Shaft Removal

2. INSTALLATION

1. Install the antenna motor shaft into the hole of the oven cavity bottom plate, and turn the flat faces of antenna motor shaft to the left and right side walls of oven cavity (to fit the stirrer antenna holder). Refer to Figure C-9.

To left wall of oven cavity

Antenna holder

Stirrer antenna

Figure C-9. Derection of Antenna Motor Shaft and Stirrer Antenna

Assembly

Stirrer antenna assembly

Flat face

Hole

Antenna motor shaft

To right wall of oven cavity

Flat face

Centre

Stirrer antenna's big blade

Tab

Antenna motor shaft

Oven cavity bottom plate

Antenna holder

Figure C-10. Stirrer Antenna Assembly Installation

Stirrer antenna

Tab

Antenna motor shaft

Antenna holder

Stirrer antenna

Tab

Oven cavity bottom plate

11 – 7

Page 32

R21LTF

[16] INSTALLATION OF CERAMIC SHELF

1. Disconnect the power supply cord.

2. Open the door and block it open.

3. Make sure that the smooth surface of the ceramic shelf face up.

4. Make sure that the rubber packing without a fin of the ceramic shelf faces the front of the oven.

NOTE: The three (3) rubber packings with the fins and the one (1)

rubber packing without a fin are attached to the four (4) edges of the ceramic shelf. The one (1) rubber packing without a fin is the front edge of the ceramic shelf.

5. Put the front edge of the ceramic shelf into the front edge of the oven cavity bottom plate.

6. Push down the rear edge of the ceramic shelf into the oven cavity bottom plate.

7. Now, the ceramic shelf is installed.

WARNING: Make sure that the rubber packing is not caught

between the oven door and the oven cavity front plate, to avoid possible exposure to excessive microwave energy.

Oven Cavity

Rear Edge

Push

Ceramic

Front Edge

Shelf

11 – 8

Page 33

R21LTF

CHAPTER 12. CIRCUIT DIAGRAMS

[1] Pictorial Diagram (Figure S-1)

WHT

NOISE

FILTER

RED

THERMAL

CUT-OUT

145¡C(MAG.)

BLU

BRN

POWER SUPPLY

CORD

FUSE

GRN

EARTH

HOT

BLK

NEUTRAL

WHT

Service Manual

WHT

ORG

FAN MOTOR

MAGNETRON

HIGH VOLTAGE COMPONENTS

WHT

H.V.

CAPACITOR

RECTIFIER H.V.

RED

WHT

R21LTF

POWER TRANSFORMER

THERMAL

CUT-OUT

125ûC(OVEN)

SECONDARY

INTERLOCK

SWITCH

RED

BRN

N.O.

WHT

COM.

WHT

CN-B

WHT

GRY 2

GRY

GRN 1

OVEN LAMP

& SOCKET

BLUE MARK

GRY

CN-A

ORG

NOTE:

Hot (GRY) wire must be

GRY

connected to the terminal

with blue mark on the

oven light socket.

MONITOR

SWITCH

BLU

COM

CONNECTOR

WHT

N.C.

RED

ANTENNA

GRY

N.O.

DOOR SENSING SWITCH

YLW

MOTOR

WHT

GRN

COM.

CONTROL UNIT

Figure S-1. Pictorial Diagram

IC1

CN-G

RED

CN-B

YLW

RY2

YLW

ORG

RY3

YLW

BLU

CN-A

RELAY

RY2: PRIMARY INTERLOCK

12 – 1

Page 34

R21LTF

[2] Control Panel Circuit (Figure S-2a and S-2b)

1. R21LTF

100 X 9

R58 R57 R56

CHECK

LED 1

DEF. ON. X2

R40 2.7K

R55 R54 R53 R52 R51 R50

IC3

KD65004AP

161

GND

P30

P31

P32

P33

P34

P35

VEE

AN7

AN6

VCC

AVSS

VREF

4.7K X 5

R84

SET

CHECK

SIGNAL

R85

START

R86

DOUBLE

QUANTITY

R87

POWER

SELECTA

R88

G1 G2 G3 G4 G5 G6 G7 G8

CN-G

R80

P12

P13

P14

P15

P16

P04

P05

P06

P07

P10

P36

P37

P00

P01

P02

P03

AN5

AN4

AN3

AN2

AN1

AN0

P11

P55

P54

P53

P52

P51

P50

P17

P20

P21

P22

P23

P24

P25

IC1

IZA897

XIN

P71

P47

P46

P45

P44

P70

P43

P42

INTI

INTO

RESET

STOP/

CLEAR

EXPRESS

DEFROST

TIME

SELECTA

R81

P26

P27

VSS

XOUT

R82

KEY UNIT

G12 G11 G10 G9

R83

4.7K x 4

SP1

Q1 KIA7805API

1N40024

4.7K

DTA123ESA

ZD2 HZ4A2

C4 0.1u/50V

C3 47u/10V

C2 0.1u/50V

C1 2200u/25V

DTC143ESA

C9 0.1u/50V

(J4)

(J3)

0.1u/50V

R4 4.7K

(J6)

(J5)

C21

10u/25V

C20 0.1u/50V

Q21

DTC143ESA

Q20

DTB143ES

D20D21

CF1

R5 4.7K

CSTLS4M00G56P18

0.1u/50V

47u/10V

R33 4.7K

IF NOT SPECIFIED 1/4W J(±5%)

IF NOT SPECIFIED 0.01uF 16V

IF NOT SPECIFIED 1SS133 or 1SS270A

R30 100

15K

R31

R32 2.7K

C70

123

R71 4.7K

R70 4.7K

SCL

SDA

VCC

TEST

IC2

A0A1A2

VSS

Q22

DTD143ES

C31

C3047u/10V

D70

D23

1N4002

CN-B

B2P-VH

DOOR SW

B1 B2

CN-A

B3P5-VH

VRS1

AC120V

60Hz

Figure S-2. Control Panel Circuit for R-21LTF

(J1)

RY3

RY2

OMIF-S-112LM

DU12D1-1P(M)R

G5JS-1A-S 12VDC

TTM

MICRO

12 – 2

Page 35

2. R-21LVF

R84

R85

R86

R87

R88

R21LTF

4.7K X 5

SET

SIGNAL

CHECK

STOP/

CLEAR

EXPRESS

DEFROST

TIME

SELECTA

KEY UNIT

START

DOUBLE

QUANTITY

SP1

CHECK

DEF. ON. X2

R40 2.7K

DTA123ESA

Q1 KIA7805API

1N40024

100 X 9

R58 R57 R56 R55 R54 R53 R52 R51 R50

GND

LED 1

IC3

KD65004AP

161

P30

P31

P32

P33

P34

P35

AN7

AN6

VEE

VCC

VREF

AVSS

P04

P36

P37

P00

P01

P02

P03

P55

AN5

AN4

AN3

AN2

AN1

AN0

P12

P13

P05

P06

P07

P10

P11

P54

P53

P52

P51

P50

P47

P46

G1 G2 G3 G4 G5 G 6 G7 G8

CN-G

R80

R81

P14

P15

P16

P17

P20

P21

P22

P23

P24

P25

IC1

IZA897

P45

P44

P43

P42

XIN

P71

P70

INTI

INTO

RESET

G12 G11 G10 G9

R83

R82

4.7K x4

P26

P27

VSS

XOUT

CF1

4.7K

(J4)

(J3)

(J6)

(J5)

R5 4.7K

CSTLS4M00G56P18

0.1u/50V

47u/10V

ZD2 HZ4A2

R30 100

IC2

R33 4.7K

15K

R31

VCC

TEST

A0A1A2

SCL

C31

IF NOT SPECIFIED 1/4W J(±5%)

IF NOT SPECIFIED 0.01uF 16V

IF NOT SPECIFIED 1SS133 or 1SS270A

R32 2.7K

C70

123

R71 4.7K

R70 4.7K

SDA

VSS

CN-B

C30 47u/10V

D70

B2P-VH

D23

1N4002

DOOR SW

B1 B2

C4 0.1u/50V

C3 47u/10V

0.1u/50V

C20 0.1u/50V

R4 4.7K

Q21

Q20

DTB143ES

DTC143ESA

C21

C2 0.1u/50V

C1 2200u/25V

C9 0.1u/50V

10u/25V

Q22

D20D21

DTD143ES

CN-A

B3P5-VH

VRS1

60Hz

AC120V

Figure S-2. Control Panel Circuit for R-21LVF

(J1)

RY3

RY2

OMIF-S-112LM

DU12D1-1P(M)R

G5JS-1A-S 12VDC

TTM

MICRO

12 – 3

Page 36

R21LTF

[3] Printed Wiring Board (Figure S-3)

R83

(C83)

R82

112

CN - G

(C82)

R81

(C81)

R80

(C80)

R58 R57 R56 R55 R54 R53 R52

R50

(R 91)

(C60)

R84

(R 69)

(R 60)

(R 90) (R 89)

R88 R87 R86

R85

D70

CN - B

MIC R O 1 MIC R O 2

D23

(C62)

(J F )

(CN - H)

113

DIP

R30

(J D)

(C63)

D21

IC2

C30

32 25 20 15

(4)

(R 68)

(C60)

C70

(J C )

R70

(D10)

Q22

(R 102)

(C10)

R31

R32

R33

ZD2

16 9

(CN - D)

IC3

(R 67)

(J J )

(J 3)

(J 4)

(J H)

(C101)

(J 5)

(J 6)

(J B )

(J 9)

(R 66)

(C64)

(R 65)

R40

SP1

(J G )

R51

C31

(Q60)

40 50 55 64

IC1

(R 62)

(R 61)

R71

(J E )

(R 64)

(R 63)

RY2

RY3

(14)

(TB 2)

(15) (16)

(TB 1)

(17)

(CT 1)

(J 1)

POWER

VRS 1

(VR S 2)

(J 7)

POWER

SM TTM

CN - A

(R Y 1)

(D20)

C20

C21

Q21

Q20

D22

(Q23)

(D100)

(R 100)

(C10)

(C13)

(J A )

(R 101)

(C100)

(Q24)

(R 1)

(R 2)

(D5)

(R 6)

(ZD3)

(ZD1)

CER TAIN PART IS INTENTIONALLY NOT

DANG E R -

GROUNDED AND MAY PRESENT A RISK OF

ELECTRICAL SHOCK DURING SERVICING. SERVICE

PER S ONNE L - DO NOT CONTACT THE FOLL OWING

PARTS WHILE THE APPLIANCE IS E NERGIZED ;

(C11)

(13)

(C12)

Figure S-3. Printed Wiring Board

12 – 4

Page 37

PartsGuide

PARTS LIST

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

Parts marked "*" may cause undue microwave exposure. Parts marked " " are used in voltage more than 250V.

CONTENTS

LIGHT DUTY COMMERCIAL

MICROWAVE OVEN

MODELS

R-21LTF R-21LVF

R21LTF

[1] OVEN PARTS

[2] DOOR AND CONTROL PANEL

TRAY HOLDER

(SPADFA435WRE0)

Into

INSTRUCTION BOOK

6-7

Oven Cavity

PARTS

 INDEX

TOP PAD ASSEMBLY

(FPADBA385WRK0)

WRAP COVER

(SSAKHA034WRE0)

DOOR PROTECTION SHEET

(SPADPA204WRE0)

BOTTOM PAD ASSEMBLY

(FPADBA386WRK0)

Not Replaceable Items.

PACKING CASE

SPAKCE434WREZ [R-21LTF] SPAKCE425WREZ [R-21LVF]

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

Page 38

R21LTF

[1] OVEN PARTS

7-3

2-1

4-14

4-40

4-23

4-34

7-6

6-1

4-19

4-2

4-27

4-24

4-26

7-3

7-12

7-3

4-36

7-3

4-25

1-10

1-13

1-9

1-4

7-1

6-4

4-28

4-26

6-5

4-10

4-32

4-16

7-11

7-12

7-13

6-3

7-9

1-12

7-7

7-13

4-15

7-10

4-9

1-4

6-6

7-13

1-1

7-1

1-8

4-18

4-21

4-22

4-1

4-21

4-38

4-37

4-20

7-12

4-20

6-2

2-4

4-29

4-30

2-2

7-1

1-11

4-39

4-8

4-31

1-2

7-4

7-7

4-6

7-7

4-33

4-6

1-3

4-3

4-4

4-5

1-1

4-7

7-7

4-11

7-8

4-24

7-7

1-15

1-6

4-12

1-14

7-1

1-5

4-13

7-2

1-7

7-5

4-35

2-3

7-8

2-4

7-12

4-24

7-12

4-17

2-5

7-11

Page 39

R21LTF

NO. PARTS CODE

[1] OVEN PARTS

ELECTRIC PARTS

1-1

FFS-BA033WRKZ

1-2

QSW-MA085WRE0

1-3

QSW-MA135WRE0

1-4

FACCDA116WREZ

1-5

CABINET PARTS

OVENPARTS

* 4-2

* 4-8

MISCELLANEOUS

FH-DZA119WRKZ

1-6

RC-QZA235WRE0

1-6

RC-QZA336WRZZ

1-7

RMOTEA376WRE0

1-8

FPWBFA389WRKZ

1-8

FPWBFA417WRKZ

1-9

QSOCLA021WRE0

1-10

RLMPTA086WRZZ

1-11

RMOTDA233WRE0

1-12

RTHM-A138WRZZ

1-12

RTHM-A080WRE0

1-12

RTHM-A120WRE0

1-13

RTHM-A137WRZZ

1-13

RTHM-A096WRE0

1-13

RTHM-A123WRZZ

1-14

RTRN-A751WRZZ

1-15

RV-MZA347WRZZ

2-1

GCABUA672WRP0

2-2

GDAI-A311WRW0

2-3

GCOVHA406WRW0

2-4

GLEGPA074WRE0

2-5

GLEGPA076WRF0

4-1

FGLSPA062WRE0 *************

4-3

MLEVPA227WRF0

4-4

MLEVPA228WRF0

4-5

MLEVPA229WRF0

4-6

MSPRCA108WRE0

4-7

MSPRTA191WRE0 PHOK-A160WRFZ

4-9

FDUC-A341WRY0

4-10

PSKR-A351WRP0

4-11

LBNDKA136WRP0

4-12

NFANJA029WRE0

4-13

PDUC-A888WRFZ

4-14

FPLT-A007WRY0

4-15

PCUSGA504WRP0

4-16

PSKR-A348WRW0

4-17

GCOVHA509WREZ

4-18

LANGFA199WRWZ

4-19

NSFTPA035WRFZ

4-20

PCLICA032WRE0

4-21

PCLICA033WRE0

4-22

PCOVPA344WRF0

4-23

PCOVPA345WRF0

4-24

PCUSGA249WRP0

4-25

PCUSUA511WRP0

4-26

PCUSUA194WRP0

4-27

PCUSUA514WRP0

4-28

PDUC-A966WRFZ

4-29

PFILWA060WRP0

4-30

PSHEPA644WRE0

4-31

PSKR-A347WRW0

4-32

PSKR-A349WRP0

4-33

PSKR-A359WRW0

4-34

PSPA-A112WRE0

4-35

PCUSGA378WRP0

4-36

PCUSUA507WRP0

4-37

PCUSUA517WRP0

4-38

PSHEPA674WRE0

4-39

PCUSUA518WRP0

4-40

PSHEPA673WRE0

6-1

TMAPCA780WRRZ

6-2

TCAUAA249WRR0

6-3

TCAUAA250WRR0

6-4

TCAUAA295WRRZ

6-5

TCAUAA243WRR0

PRICE

RANK

NEW

MARK

-- Monitor fuse20A and monitor switch (V-5220Q) AF Door sensing switch AH Secondary interlock switch AV Power supply cord AU High voltage rectifier assembly AU High voltage capacitor

-- High voltage capacitor for production use (Interchangeable) AU Fan motor AW Noise filter AY Noise filter (Interchangeable) AG Oven lamp socket AL Oven lamp AQ Antenna motor AH Thermal cut-out 145 deg. (MAG) AP Thermal cut-out 145 deg. (MAG) (Interchangeable) AH Thermal cut-out 145 deg. (MAG) (Interchangeable) AH Thermal cut-out 125 deg. (OVEN) AK Thermal cut-out 125 deg. (OVEN) (Interchangeable) AK Thermal cut-out 123 deg. (OVEN) (Interchangeable) BP Power transformer

BH Magnetron

BH Outer case cabinet AS Base plate AQ Base plate cover AC Foot AF Leg

BL Ceramic shelf

-- Oven cavity (Not a replaceable part) AF Latch switch lever A AF Latch switch lever B AF Latch switch lever C AC Latch lever spring AC Switch lever B spring AN Latch hook BL Steam duct sub assembly AY Steam guide AQ HV capacitor holder AK Fan blade AM Fan duct BB Stirrer antenna assembly AB Insertion cushion AN Insertion plate A AG VCP cap AH Chassis support AQ Antenna motor shaft AD Hand clip 4 AD Hand clip 5 AF Side splash cover AF Back splash cover AA Cushion AC Cushion AC Cushion AB Cushion AT Air intake duct AD Lamp filter AD Insertion sheet AL Insertion plate B AF Steam duct barrier AM Air guide AC Mica washer AL Cushion AC Cushion AE Cushion AL Cover AC Cushion AD S/Film

AH Schematic diagram AE Caution label AF DHHS caution label AH Monitor caution AC Earth caution

PAR T

RANK

DESCRIPTION

Page 40

R21LTF

NO. PARTS CODE

[1] OVEN PARTS

6-6

SCREWS, NUTS AND WASHERS

TCAUAA245WRR0

7-1

XHPS740P08K00

7-2

XEPS740P25000

7-3

LX-CZA038WRE0

7-4

LX-CZ0052WRE0

7-5

LX-EZA042WRE0

7-6

XBPWW40P04000

7-7

XHPS740P08000

7-8

XHTS740P08000

7-9

XHPS730P06000

7-10

XHTS740P08RV0

7-11

XOTS740P12000

7-12

XOTS740P08000

7-13

XOTWW40P10000

PRICE

RANK

NEW

MARK

AC Cover caution

AB Screw : 4mm x 8mm AB Screw : 4mm x 25mm AA Special screw AA Special screw AB Special screw AB Screw : 4mm x 4mm AB Screw : 4mm x 8mm AC Screw : 4mm x 8mm AB Screw : 3mm x 6mm AG Screw : 4mm x 8mm AA Screw : 4mm x 12mm AA Screw : 4mm x 8mm AA Screw : 4mm x 10mm

PAR T

RANK

DESCRIPTION

Page 41

[2] DOOR AND CONTROL PANEL PARTS

3-1

3-2

3-2-3

3-2-2

3-3

R21LTF

3-4

5-3

5-1-5

5-1-4

3-2-1

5-1-18

5-1-4-3

5-1

5-1-4-4

5-1-4-2

5-1-12

5-1-4-5

5-1-14

5-1-4-1

5-1-9

5-1-8

5-1-16

5-1-4-5

5-1-8

5-1-2

5-1-13

5-1-7

5-1-15

5-1-12

5-1-16

5-1-3

5-1-17

5-1-11

5-1-17

5-1-16

5-1-1

5-1-16

5-2

5-4

5-1-10

5-1-6

6-7

Actual wire harness may be different from illustration.

6-8

6-9

Page 42

R21LTF

NO. PARTS CODE

PRICE

RANK

[2] DOOR AND CONTROL PANEL PARTS

CONTROL PANEL PARTS

3-1 3-1 3-2

3-2 3-2-1 3-2-1 3-2-2 3-2-3

3-3

3-4

DOOR PARTS

* 5-1 * 5-1-1

5-1-2

* 5-1-3 * 5-1-4

5-1-4-1 5-1-4-2 5-1-4-3 5-1-4-4 5-1-4-5

5-1-5 5-1-6

* 5-1-7 * 5-1-8

5-1-9

5-1-10 5-1-11 5-1-12 5-1-13 5-1-14 5-1-15 5-1-16 5-1-17 5-1-18

* 5-2

5-3

* 5-4

MISCELLANEOUS

6-7

6-8

6-9

DPWB-A417DRKZ DPWB-A418DRKZ FPNLCB912WRKZ FPNLCB913WRKZ FUNTKB173WREZ FUNTKB174WREZ GCOVAA260WRP0 GMADIA109WRF0 TCAUAA076WRR0 XEPS730P08XS0

CDORFB052WRKZ FDORFA322WRT0 PSHEPA649WRE0 FANGKA206WRY0 FCOV-A012WRKZ LSTPPA180WRF0 LSTPPA182WRF0 PGLSPA516WRE0 PSLDMA198WREZ XETS740P08000 GWAKPA580WRM0 JHNDMA040WRW0 LANGKA874WRW0 LSTPPA181WRF0 MSPRTA190WRE0 PCUSUA506WRP0 XEPS740P06000 PSHEPA686WRE0 PSHEPA687WRE0 PCUSGA514WRP0 PCUSUA505WRP0 XEBS738P08000 XEPS740P25K00 PCUSUA508WRP0 GCOVHA407WRF0 HBDGCA124WREZ HBDGCA122WREZ PPACGA171WRE0

TINSEB126WRRZ FW-VZC074WREZ LHLDWA013WRE0

BQ Control unit [R-21LTF] BQ Control unit [R-21LVF] BB Control panel frame with key unit [R-21LTF] BB Control panel frame with key unit [R-21LVF] AU Key unit [R-21LTF] AU Key unit [R-21LVF] BA C/P case AE Display window AB User caution label AA Screw; 3mm x 8mm

BT Door assembly AZ Door panel assembly AB Sealer film AW Latch angle assembly BQ Door case assembly AK Glass stopper R AN Glass stopper U AU Front door glass BB Sealer plate AA Screw : 4mm x 8mm AQ Door handle AN Handle lever AR Latch lever AL Latch head AD Latch spring AC Cushion AA Screw : 4mm x 6mm AK Panel sheet AK Panel sheet AK Cushion AC Cushion AB Screw : 3.8mm x 8mm AC Screw : 4mm x 25mm AC Cushion AM Choke cover AK Door badge [R-21LTF] AK Door badge [R-21LTF] AK Cushion (ferrite)

AM Instruction book AX Main wire harness AC Purse lock LL

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INDEX

PARTS CODE No.

[ C ]

CDORFB052WRKZ 2-5-1 BT

[ D ] DPWB-A417DRKZ 2-3-1 BQ DPWB-A418DRKZ 2-3-1 BQ

[ F ] FACCDA116WREZ 1-1-4 AV FANGKA206WRY0 2-5-1-3 AW FCOV-A012WRKZ 2-5-1-4 BQ FDORFA322WRT0 2-5-1-1 AZ FDUC-A341WRY0 1-4-9 BL FFS-BA033WRKZ 1-1-1 -FGLSPA062WRE0 1-4-1 BL FH-DZA119WRKZ 1-1-5 AU FPLT-A007WRY0 1-4-14 BB FPNLCB912WRKZ 2-3-2 BB FPNLCB913WRKZ 2-3-2 BB FPWBFA389WRKZ 1-1-8 AW FPWBFA417WRKZ 1-1-8 AY FUNTKB173WREZ 2-3-2-1 AU FUNTKB174WREZ 2-3-2-1 AU FW-VZC074WREZ 2-6-8 AX

[ G ] GCABUA672WRP0 1-2-1 BH GCOVAA260WRP0 2-3-2-2 BA GCOVHA406WRW0 1-2-3 AQ GCOVHA407WRF0 2-5-2 AM GCOVHA509WREZ 1-4-17 AG GDAI-A311WRW0 1-2-2 AS GLEGPA074WRE0 1-2-4 AC GLEGPA076WRF0 1-2-5 AF GMADIA109WRF0 2-3-2-3 AE GWAKPA580WRM0 2-5-1-5 AQ

[ H ] HBDGCA122WREZ 2-5-3 AK HBDGCA124WREZ 2-5-3 AK

[ J ] JHNDMA040WRW0 2-5-1-6 AN

[ L ] LANGFA199WRWZ 1-4-18 AH LANGKA874WRW0 2-5-1-7 AR LBNDKA136WRP0 1-4-11 AQ LHLDWA013WRE0 2-6-9 AC LSTPPA180WRF0 2-5-1-4-1 AK LSTPPA181WRF0 2-5-1-8 AL LSTPPA182WRF0 2-5-1-4-2 AN LX-CZ0052WRE0 1-7-4 AA LX-CZA038WRE0 1-7-3 AA LX-EZA042WRE0 1-7-5 AB

[ M ] MLEVPA227WRF0 1-4-3 AF MLEVPA228WRF0 1-4-4 AF MLEVPA229WRF0 1-4-5 AF MSPRCA108WRE0 1-4-6 AC MSPRTA190WRE0 2-5-1-9 AD MSPRTA191WRE0 1-4-7 AC

[ N ] NFANJA029WRE0 1-4-12 AK NSFTPA035WRFZ 1-4-19 AQ

[ P ] PCLICA032WRE0 1-4-20 AD PCLICA033WRE0 1-4-21 AD PCOVPA344WRF0 1-4-22 AF PCOVPA345WRF0 1-4-23 AF PCUSGA249WRP0 1-4-24 AA PCUSGA378WRP0 1-4-35 AL PCUSGA504WRP0 1-4-15 AB PCUSGA514WRP0 2-5-1-14 AK PCUSUA194WRP0 1-4-26 AC PCUSUA505WRP0 2-5-1-15 AC PCUSUA506WRP0 2-5-1-10 AC PCUSUA507WRP0 1-4-36 AC PCUSUA508WRP0 2-5-1-18 AC PCUSUA511WRP0 1-4-25 AC PCUSUA514WRP0 1-4-27 AB PCUSUA517WRP0 1-4-37 AE PCUSUA518WRP0 1-4-39 AC PDUC-A888WRFZ 1-4-13 AM PDUC-A966WRFZ 1-4-28 AT

PRICE RANK

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PARTS CODE No.

PFILWA060WRP0 1-4-29 AD PGLSPA516WRE0 2-5-1-4-3 AU PHOK-A160WRFZ 1-4-8 AN PPACGA171WRE0 2-5-4 AK PSHEPA644WRE0 1-4-30 AD PSHEPA649WRE0 2-5-1-2 AB PSHEPA673WRE0 1-4-40 AD PSHEPA674WRE0 1-4-38 AL PSHEPA686WRE0 2-5-1-12 AK PSHEPA687WRE0 2-5-1-13 AK PSKR-A347WRW0 1-4-31 AL PSKR-A348WRW0 1-4-16 AN PSKR-A349WRP0 1-4-32 AF PSKR-A351WRP0 1-4-10 AY PSKR-A359WRW0 1-4-33 AM PSLDMA198WREZ 2-5-1-4-4 BB PSPA-A112WRE0 1-4-34 AC

[ Q ] QSOCLA021WRE0 1-1-9 AG QSW-MA085WRE0 1-1-2 AF QSW-MA135WRE0 1-1-3 AH

[ R ] RC-QZA235WRE0 1-1-6 AU RC-QZA336WRZZ 1-1-6 -RLMPTA086WRZZ 1-1-10 AL RMOTDA233WRE0 1-1-11 AQ RMOTEA376WRE0 1-1-7 AU RTHM-A080WRE0 1-1-12 AP RTHM-A096WRE0 1-1-13 AK RTHM-A120WRE0 1-1-12 AH RTHM-A123WRZZ 1-1-13 AK RTHM-A137WRZZ 1-1-13 AH RTHM-A138WRZZ 1-1-12 AH RTRN-A751WRZZ 1-1-14 BP RV-MZA347WRZZ 1-1-15 BH

[ T ] TCAUAA076WRR0 2-3-3 AB TCAUAA243WRR0 1-6-5 AC TCAUAA245WRR0 1-6-6 AC TCAUAA249WRR0 1-6-2 AE TCAUAA250WRR0 1-6-3 AF TCAUAA295WRRZ 1-6-4 AH TINSEB126WRRZ 2-6-7 AM TMAPCA780WRRZ 1-6-1 AH

[ X ] XBPWW40P04000 1-7-6 AB XEBS738P08000 2-5-1-16 AB XEPS730P08XS0 2-3-4 AA XEPS740P06000 2-5-1-11 AA XEPS740P25000 1-7-2 AB XEPS740P25K00 2-5-1-17 AC XETS740P08000 2-5-1-4-5 AA XHPS730P06000 1-7-9 AB XHPS740P08000 1-7-7 AB XHPS740P08K00 1-7-1 AB XHTS740P08000 1-7-8 AC XHTS740P08RV0 1-7-10 AG XOTS740P08000 1-7-12 AA XOTS740P12000 1-7-11 AA

XOTWW40P10000 1-7-13 AA

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R21LTF

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No part of this publication may be reproduced, stored in retrieval systems, or transmitted in anyform or by any means, electronic, mechanical, photocopying, recording, or other wise, without prior written permission of the publisher.

No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher.

SHARP KWK Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

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

CHAPTER 1. WARNING TO SERVICE PERSONNEL

[1] Before Servicing

[2] When the testing is completed,

[3] After repairing

CHAPTER 2. MICROWAVE MEASUREMENT PROCEDURE

[1] Requirements:

[2] Preparation for testing:

[3] Leakage test:

CHAPTER 3. FOREWORD AND WARNING

[1] FOREWORD

[2] WARNING

[3] DANGER

CHAPTER 4. PRODUCT DESCRIPTION

[1] SPECIFICATIONS

CHAPTER 5. GENERAL INFORMATION

[1] GROUNDING INSTRUCTIONS

[2] OVEN DIAGRAM

1. OVEN

2. TOUCH CONTROL PANEL

CHAPTER 6. OPERATION

[1] DESCRIPTION OF OPERATING SEQUENCE

1. OFF CONDITION

2. COOKING CONDITION

3. POWER LEVEL P-0 TO P-90 COOKING (R-21LTF only)

[2] OVEN SCHENATIC

1. Off Condition

2. Cooking Condition

[3] DESCRIPTION AND FUNCTION OF COMPONENTS

1. DOOR OPEN MECHANISM

4. ANTENNA MOTOR

5. COOLING FAN MOTOR

6. MONITOR FUSE

2. DOOR SENSING AND SECONDARY INTERLOCK SWITCHES

3. MONITOR SWITCH

7. THERMAL CUT-OUT 145°C (MAGNETRON)

8. THERMAL CUT-OUT 125°C (OVEN)

9. NOISE FILER

CHAPTER 7. TROUBLESHOOTING GUIDE

[1] TROUBLESHOOTING CHART

CHAPTER 8. TEST PROCEDURES

[1] Procedure A: MAGNETRON ASSEMBLY TEST

1. MICROWAVE OUTPUT POWER

[2] Procedure B: POWER TRANSFORMER TEST

[3] Procedure C: HIGH VOLTAGE RECTIFIER TEST

[4] Procedure D: HIGH VOLTAGE CAPACITOR TEST

[5] Procedure E: THERMAL CUT OUT TEST

1. THERMAL CUT OUT 125°C (OVEN)

2. THERMAL CUT OUT 145°C (MAGNETRON)

[6] Procedure F: SECONDARY INTERLOCK SWITCH TEST

[7] Procedure F: PRIMARY INTERLOCK SYSTEM TEST

1. DOOR SENSING SWITCH

2. PRIMARY INTERLOCK RELAY (RY2)

[8] Procedure G: MONITOR SWITCH TEST

[9] Procedure H: BLOWN MINITOR FUSE TEST

[10] Procedure I: NOISE FILTER TEST

[11] Procedure J: TOUCH CONTROL PANEL ASSEMBLY TEST

1. Key Unit

2. Control Unit.

[12] Procedure K: KEY UNIT TEST

[13] Procedure L: RELAY TEST

[14] Procedure M: FOIL PATTERN ON THE PRINTED WIRING BOARD TEST

CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY

[1] OUTLINE OF TOUCH CONTROL PANEL

1. Control Unit

2. Key Unit

[2] SERVICING FOR TOUCH CONTROL PANEL

1. Precautions for Handling Electronic Components

2. Servicing of Touch Control Panel

3. Servicing Tools

4. Other Precautions

[3] PROCEDURE FOR CHECKING/CLEARING SERVICE COUNTS OF MICROWAVE OVEN

1. Practice for checking total using times (Ex. 345678 times).

3. Practice for inputting total using times (Ex. 310000 times).

4. Practice for inputting total operation time (Ex. 1234 hours).

1. EXPRESS DEFROST