SHARP R-370EK, R-370ES Service Manual

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R-370EK R-370ES

SERVICE MANUAL

S4112R370EPS/

MICROWAVE OVEN

lls

ffin

12345 6

7890

MODELS

R-370EK R-370ES

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

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

Page PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO

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

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

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

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

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

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

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

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

TROUBLESHOOTING GUIDE ............................................................................................................................10

TEST PROCEDURE............................................................................................................................................12

TOUCH CONTROL PANEL.................................................................................................................................21

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE................................................................26

PICTORIAL DIAGRAM ........................................................................................................................................33

POWER UNIT CIRCUIT ......................................................................................................................................34

CPU UNIT CIRCUIT ............................................................................................................................................35

PRINTED WIRING BOARD .................................................................................................................................36

PARTS LIST ........................................................................................................................................................37

PACKING AND ACCESSORIES .........................................................................................................................39

SHARP CORPORATION

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

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R-370EK R-370ES

PRECAUTIONS TO BE OBSER VED BEFORE AND DURING SERVICING T O AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROW A VE ENERGY

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

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

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

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

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

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

performed on each oven prior to release to the owner.

BEFORE SERVICING

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

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

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

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W ARNING TO SER VICE PERSONNEL

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

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

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

Read the Service Manual carefully and follow all instructions.

may result in a severe, possibly

Don't Touch ! Danger High Voltage

R-370EK R-370ES

Before Servicing

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

WARNING:RISK OF ELECTRIC SHOCK.

DISCHARGE THE HIGH-VOLTAGE CAPACITOR BEFORE SERVICING.

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

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

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

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

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

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

When the testing is completed,

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

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

5. Reinstall the outer case (cabinet).

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

7. Run the oven and check all functions.

After repairing

1. Reconnect all leads removed from components during testing.

2. Reinstall the outer case (cabinet).

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

4. Run the oven and check all functions.

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

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

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R-370EK R-370ES

MICROWAVE MEASUREMENT PROCEDURE

A. Requirements:

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

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

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

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

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

2) Place the oven tray in the oven cavity.

3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5˚C (68˚F) in the center of the oven cavity. The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made of an electrically nonconductive material such as glass or plastic. The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage is measured accurately.

4) Set the cooking control on Full Power Cooking Mode.

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

C. Leakage test:

Closed-door leakage test (microwave measurement)

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

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

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

4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2.

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

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SERVICE MANUAL

R-370EK R-370ES

MICROWAVE OVEN

R-370EK/ R-370ES

FOREWORD

This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVEN, R-370EK, R-370ES.

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

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

WARNING

Never operate the oven until the following points are ensured. (A) The door is tightly closed. (B) The door brackets and hinges are not defective. (C) The door packing is not damaged. (D) The door is not deformed or warped. (E) There is no other visible damage with the oven.

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

DANGER

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

PRODUCT DESCRIPTION

GENERAL INFORMATION

OPERATION

TROUBLESHOOTING GUIDE AND TEST PROCEDURE

TOUCH CONTROL PANEL

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WIRING DIAGRAM

PARTS LIST

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

Removal of the outer wrap gives access to voltage above 250V. All the parts marked “∆” on parts list may cause undue microwave

exposure, by themselves, or when they are damaged, loosened or removed.

SHARP ELECTRONICS CORPORATION

SHARP PLAZA, MAHWAH,

NEW JERSEY 07430-2135

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R-370EK R-370ES

SPECIFICATION

ITEM DESCRIPTION

Power Requirements 120 Volts / 13.5 Amperes

60 Hertz Single phase, 3 wire grounded

Power Output 1000 watts (IEC TEST PROCEDURE)

Operating frequency of 2450MHz

Case Dimensions Width 17-1/4"

Height 13-3/8" Depth 18-3/8"

Cooking Cavity Dimensions Width 13-3/4"

Height 7-1/4"

1.4 Cubic Feet Depth 16-1/2" Control Complement Touch Control System

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

Microwave Power for Variable Cooking Repetition Rate;

HIGH................................................Full power throughout the cooking time

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

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

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

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

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

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

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

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

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

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

SENSOR COOKING pads , INSTANT ACTION pads COMPU DEFROST pads, Number selection pads CUSTOM HELP PAD, POWER LEVEL pad, KITCHEN TIMER/CLOCK pad STOP/CLEAR pad, MINUTE PLUS /START pad

Oven Cavity Light Yes Safety Standard UL Listed FCC Authorized

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

GENERAL INFORMATION

GROUNDING INSTRUCTIONS

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

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

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

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R-370EK

;;

R-370ES

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

CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR RE-

MOVE THE ROUND GROUNDING PRONG FROM THIS PLUG.

OVEN DIAGRAM

1. Door handle Pull to open door.

2. Auto-Touch control panel

3. Display: 99 minutes, 99 seconds

4. Oven door with see-through window

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

6. Door hinges

7. Door seals and sealing surface

8. Turntable motor shaft

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

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

11.Ventilation openings (Rear)

12.Oven light It will light when oven is operating or door is opened.

13.Wave guide cover: DO NOT REMOVE.

3-Pronged Plug

Grounding Pin

3-Pronged Receptacle

Grounded Receptacle Box

TOUCH CONTROL PANEL

Baked

Popcorn

Reheat Sensor

Potatoes

Ground

Meat

Fresh

Vegetables

Frozen

Vegetables

Rice

Chicken

Breast

Frozen Entree

Fish

Seafood

Rolls & Muffins

Beverage

Compu Defrost

Kitchen Timer

Clock

COOK SENSOR LBS DEF HELP

12345 67890

Power

Level

STOP Clear

Custom

Help

Minute Plus

START

NOTE: The directed features are disabled after three minutes when the oven is not in use. These features are automatically enabled when the door is opened and closed or the STOP/ CLEAR pad is pressed.

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R-370EK R-370ES

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

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

OFF CONDITION

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

1. The display will show "SHARP SIMPLY THE BEST PRESS CLEAR AND PRESS CLOCK".To set any program or set the clock, you must first touch the STOP/ CLEAR pad. The display will clear, and " : " will appear.

COOKING CONDITION

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

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

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

2. 120 volts A.C. is supplied to the primary winding of the power transformer and is converted to about 3.4 volts A.C. output on the filament winding, and approximately 2300 volts A.C. on the high voltage winding.

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

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

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

6. When the door is opened during a cook cycle, the monitor switch, door sensing switch, primary interlock switch, relay (RY1) and secondary interlock relay (RY2) are activated with the following results. The circuits to the turntable motor, the cooling fan motors, 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 primary interlock switch and secondary interlock relay (RY2) and is mechanically associated with the door

so that it will function in the following sequence.

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

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

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

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

close. And contacts of the relay (RY1) open. If the primary interlock switch and secondary 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, primary interlock switch, relay (RY1) and secondary interlock relay (RY2), causing the monitor fuse to blow.

POWER LEVEL P-0 TO P-90 COOKING

When Variable Cooking Power is programmed, the 120 volts A.C. is supplied to the power transformer intermittently through the contacts of relay (RY2) which is operated by the control unit within a 32 second time base. Microwave power operation is as follows:

VARI-MODE DISPLAY ON TIME OFF TIME

100% HIGH 32 sec. 0 sec. approx. 90% power P-90 30 sec. 2 sec. approx. 80% power P-80 26 sec. 6 sec. approx. 70% power P-70 24 sec. 8 sec. approx. 60% power P-60 22 sec. 10 sec. approx. 50% power P-50 18 sec. 14 sec. approx. 40% power P-40 16 sec. 16 sec. approx. 30% power P-30 12 sec. 20 sec. approx. 20% power P-20 8 sec. 24 sec. approx. 10% power P-10 6 sec. 26 sec.

0% power P-0 0 sec. 32 sec.

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

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

POWER OUTPUT REDUCTION

If the oven is set for more than 30 minutes at 80, 90 or 100% power level, after the first 30 minutes the power level will automatically adjust itself to 70% power to avoid overcooking.

SENSOR COOKING CONDITION

Using the SENSOR function, the food is cooked without figuring time, power level or quantity. When the oven senses enough steam from the food, it relays the information to its microprocessor which will calculate the remaining cooking time and power level needed for best results. When the food

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R-370EK R-370ES

is cooked, water vapor is developed. The sensor “senses” the vapor and its resistance increases gradually. When the resistance reaches the value set according to the menu, supplementary cooking is started. The time of supplementary cooking is determined by experiment with each food category and inputted into the LSI. An example of how sensor works: (POTATOES)

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

MICROWAVE

2. Heat Potates. Moisture and humidity is emitted rapidly. You can smell the aroma as it cooks.

AH SENSOR

MICROWAVE

3. Sensor detects moisture and humidity and calculates cooking time and variable power.

Cooking Sequence.

1. Operate the oven in sensor cooking mode by referring to the operation manual.

NOTE: The oven should not be operated on SENSOR

immediately after plugging in the unit. Wait two minutes before cooking on SENSOR.

2. The coil of shut-off relay (RY-1) is energized, the turntable motor, oven lamp and cooling fan motors are turned on, but the power transformer is not turned on.

3. After about 16 seconds, the cook relay (RY-2) is energized. The power transformer is turned on, microwave energy is produced and first stage is started. The 16 seconds is the cooling time required to remove any vapor from the oven cavity and sensor.

NOTE: During this first stage, do not open the door or touch

STOP/CLEAR pad.

4. When the sensor detects the vapor emitted from the food, the display switches over to the remaining cooking time and the timer counts down to zero. At this time, the door may be opened to stir, turn, or season food.

5. When the timer reaches zero, an audible signal sounds. The shut-off relay and cook relay are de-energized and the power transformer, oven lamp, etc. are turned off.

6. Opening the door or touching the STOP/CLEAR pad, the time of day will reappear on the display and the oven will revert to an OFF condition.

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R-370EK R-370ES

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. CLOCK APPEARS ON DISPLAY

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

AH SENSOR

OVEN THERMAL CUT-OUT

OVEN LAMP RELAY

(RY1)

COM.

MG. THERMAL CUT-OUT

CONTROL UNIT

OVEN LAMP

TTM

PRIMARY INTERLOCK SWITCH

TURNTABLE MOTOR

120V AC 60 Hz

GRN

MONITOR FUSE 20A

N.O.

Figure O-1. Oven Schematic-Off Condition

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. COOKING TIME PROGRAMMED

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

4. "START" PAD TOUCHED

POWER

MONITOR

SWITCH

TRANSFORMER

CAPACITOR

0.94µF AC 2200V

RECTIFIER

FAN MOTOR

N.O.

COM.

FAN MOTOR

SECONDARY INTERLOCK RELAY

B2 B1

DOOR SENSING SWITCH

(RY2)

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

MAGNETRON

120V AC 60 Hz

GRN

MONITOR FUSE 20A

N.O.

OVEN THERMAL CUT-OUT

OVEN LAMP RELAY

(RY1)

COM.

AH SENSOR

MG. THERMAL CUT-OUT

CONTROL UNIT

OVEN LAMP

PRIMARY INTERLOCK SWITCH

TTM

TURNTABLE MOTOR

FAN MOTOR

N.O.

COM.

FAN MOTOR

SECONDARY INTERLOCK RELAY

B2 B1

DOOR SENSING SWITCH

(RY2)

Figure O-2. Oven Schematic-Cooking Condition

MONITOR

SWITCH

POWER TRANSFORMER

CAPACITOR

0.94µF AC 2200V

RECTIFIER

MAGNETRON

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DESCRIPTION AND FUNCTION OF COMPONENTS

R-370EK R-370ES

DOOR OPEN MECHANISM

The door is opened by pulling the door. Refer to the Figure D-1.

Door

Latch Heads

Latch Hook

Door Sensing Switch

Monitor Switch

Primary Interlock Switch

Figure D-1. Door Open Mechanism

DOOR SENSING AND PRIMARY INTERLOCK SWITCHES

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

MONITOR SWITCH

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

Functions:

1. When the door is opened, the monitor switch contact close (to the ON condition) due to their being normally closed. At this time the secondary interlock relay (RY2) and primary 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 primary interlock switch contacts close. (On opening the door, each of these switches operate inversely.)

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

CAUTION: BEFORE REPLACING A BLOWN MONITOR

FUSE TEST THE DOOR SENSING SWITCH, SECONDARY INTERLOCK RELAY (RY2),

RELAY (RY1), PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").

NOTE: MONITOR FUSE AND MONITOR SWITCH ARE

REPLACED AS AN ASSEMBLY.

TURNTABLE MOTOR

The turntable motor rotates the turntable located on the bottom of the oven cavity, so that the foods on the turntable cook evenly during cooking. The turntable may turn in either direction.

COOLING FAN MOTOR

The cooling fan motor drives a blade which draws external cool air. This cool air is directed through the air 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 foods. It is then exhausted through the exhausting air vents at the oven cavity.

MONITOR FUSE

1. The monitor fuse blows when the contacts (COM-NO) of the secondary interlock relay (RY2) and primary 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.

OVEN THERMAL CUT-OUT

The thermal cut-out, located on the top of the oven cavity, is designed to prevent damage to the oven by fire. If the food load is overcooked, by either error in cook time or defect in the control unit, the thermal cut-out will open. Under normal operation, the oven thermal cut-out remains closed. However, when abnormally high temperatures are reached within the oven cavity, the oven thermal cut-out will open at 257˚F(125˚C), causing the oven to shut down.

MAGNETRON THERMAL CUT-OUT

The thermal cut-out located near the magnetron is designed to prevent damage to the magnetron if an over heated condition develops in the tube due to cooling fan failure, obstructed air guide, dirty or blocked air intake, etc. Under normal operation, the thermal cut-out remains closed. However, when abnormally high temperatures are reached within the magnetron, the thermal cut-out will open at 257˚F(125˚C) causing the oven to shut down.

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R-370EK R-370ES

TROUBLESHOOTING GUIDE

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

When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which will be found in the "Test Procedure "section.

IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, relay (RY1)

secondary interlock relay (RY2), door sensing switch and primary interlock switch before replacing the monitor fuse. If the monitor fuse is replaced, the monitor switch must also be replaced. Use part FFSBA023WRK0 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 all leads removed from components during testing.

5. Reinstall the outer case (cabinet).

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

7. Run the oven and check all functions.

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R-370EK R-370ES

CK = Check / RE = Replace

CONDITION

OFF CONDITION

COOKING CONDITION

SENSOR COOKING CONDITION

TEST PROCEDURE

AND

POSSIBLE CAUSE

DEFECTIVE PARTS

PROBLEM

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

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

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

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

Oven lamp does not light when door is opened.

Oven lamp does not go out when door is closed.

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

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

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

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

Oven does not cook properly when programmed for Cooking Power P-50 mode. (Operates properly on Cooking Power HIGH (100%) mode.)

Oven goes into COMPU DEFROST but food is not defrosted well.

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

Oven stops at 16 sec. after starting.

RE RE

ABCDEFFGH

SHORT IN POWER CORD

SHORT OR OPENED WIRING

MAGNETRON

POWER TRANSFORMER

H.V. RECTIFIER ASSEMBLY

RERE

HIGH VOLTAGE CAPACITOR

THERMAL CUT-OUT

SECONDARY INTERLOCK SYSTEM

PRIMARY INTERLOCK SWITCH

MONITOR SWITCH

MONITOR FUSE

OVEN LAMP

CKICK CKCK

COOLING FAN MOTOR

TURNTABLE MOTOR

CONTROL UNIT

WRONG OPERATION

LOW VOLTAGE

DIRTY OVEN CAVITY

JKLMN

KEY UNIT

RELAY (RY1)

COMPU DEFROST

FOIL PATTERN ON PWB.

AH SENSOR

Page 14

R-370EK R-370ES

TEST PROCEDURES

PROCEDURE

LETTER

A MAGNETRON ASSEMBLY TEST

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

2. Open the door and block it open.

3. Discharge the 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.

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:

COMPONENT TEST

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

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

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

4. Subtract the cold water temperature from the hot water temperature. The normal result should be 30.7 to 57.1˚F(17.1 to 31.7˚C) rise in temperature. If the water temperatures are accurately measured and tested for the required time period the test results will indicate if the magnetron tube has low power output (low rise in water temperature) which would extend cooking time or high power output (high rise in water temperature) which would reduce cooking time. Because cooking time can be adjusted to compensate for power output, the magnetron tube assembly should be replaced only if the water temperature rise test indicates a power output well beyond the normal limits. The test is only accurate if the power supply line voltage is 120 volts and the oven cavity is clean.

B POWER TRANSFORMER TEST

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

2. Open the door and block it open.

3. Discharge the 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 85 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.

Page 15

TEST PROCEDURES

R-370EK R-370ES

PROCEDURE

LETTER

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

C HIGH VOLTAGE RECTIFIER TEST

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

2. Open the door and block it open.

3. Discharge the 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.

6. Reinstall the outer case (cabinet).

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

8. Run the oven and check all functions.

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

D HIGH VOLTAGE CAPACITOR TEST

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

2. Open the door and block it open.

3. Discharge the high voltage capacitor.

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

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

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

8. Run the oven and check all functions.

COMPONENT TEST

E OVEN THERMAL CUT-OUT TEST

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

2. Open the door and block it open.

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

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 oven 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.

MAGNETRON THERMAL CUT-OUT TEST

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

2. Open the door and block it open.

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

4. A continuity check across the thermal cut-out terminals should indicate a closed circuit unless the temperature of the magnetron reaches approximately 257˚F(125˚C). An open thermal cut-out indicates overheating of the magnetron. Check for restricted air flow to the magnetron, especially the cooling fan air guide.

Page 16

R-370EK R-370ES

TEST PROCEDURES

PROCEDURE

LETTER

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.

F PRIMARY INTERLOCK SWITCH TEST

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

2. Open the door and block it open.

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

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 primary interlock switch.

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

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

8. Run the oven and check all functions.

SECONDARY INTERLOCK SYSTEM TEST

DOOR SENSING SWITCH

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

2. Open the door and block it open.

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

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

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

8. Run the oven and check all functions.

NOTE: If the door sensing switch contacts fail in the open position and the door is closed, the cooling

fan, turntable and oven light will be activated by RY1.

COMPONENT TEST

SECONDARY INTERLOCK RELAY (RY2)

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

2. Open the door and block it open.

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

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

5. Reconnect all leads removed from components during testing.

6. Reinstall the outer case (cabinet).

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

8. Run the oven and check all functions.

G MONITOR SWITCH TEST

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

2. Open the door and block it open.

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

4. Before performing this test, make sure that the primary interlock switch and the secondary 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

Page 17

TEST PROCEDURES

Primary Interlock Switch

Monitor Switch

Screw Driver

Ohmmeter

RED

WHT

R-370EK R-370ES

PROCEDURE

LETTER

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.

H BLOWN MONITOR FUSE TEST

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

2. Open the door and block it open.

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

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

COMPONENT TEST

CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE SECONDARY INTER-

LOCK RELAY, PRIMARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONI-

TOR 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-BA023WRK0, 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.

I CONTROL UNIT TEST

The control unit 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 control panel unit is divided into three units, CPU Unit, Key Unit and Power Unit, and troubleshooting by unit replacement is described according to the symptoms indicated.

Before testing,

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

2) Open the door and block it open.

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

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

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

insulation tape.

1. Key Unit. 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.

Page 18

R-370EK R-370ES

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

If the Key unit is defective, replace the key unit.

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

2-1 In connection with pads.

a) When touching the pads, a certain group of pads do not produce a signal. b) When touching the pads, no pads produce a signal.

2-2 In connection with indicators

a) At a certain digit, all or some segments do not light up. b) At a certain digit, brightness is low. c) Only one indicator does not light. d) The corresponding segments of all digits do not light up; or they continue to light up. e) Wrong figure appears. f) A certain group of indicators do not light up. g) The figure of all digits flicker.

2-3 Other possible 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 and/or replacement is completed,

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

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

3) Re-install all removed parts.

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.

J KEY UNIT TEST

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

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

3. 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 connecter). 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.

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.

G 7 G 6 G 5 G 4 G 3 G 2 G 1

G 8

G 9G10G11

Frozen

Entrees

Rice Fish

Seafood Chicken

Breast

Rolls &

Muffins

Compu Defrost

Beverage

Kitchen Timer

Clock

Fresh

Vegetables

Baked

Potatoes

Ground

Meat

Frozen

Vegetables

1 8

Popcorn

Reheat Sensor

2 3

7 6

4 5 9 0

Power

Level

Custom

Help

Minute Plus

START

STOP

Clear

Page 19

TEST PROCEDURES

R-370EK R-370ES

PROCEDURE

LETTER

K RELAY TEST

COMPONENT TEST

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

2. Open the door and block it open.

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

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

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

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

7. Remove the outer case and check voltage between the normal open terminal of the relay RY1 and the normal open terminal of the relay RY2 on the control unit with an A.C. voltmeter. The meter should indicate 120 volts, if not check oven circuit.

RY1 and RY2 Relay Test

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

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

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

control unit is defective.

RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS

RY1 Approx. 24.0V D.C. Oven lamp / Turntable motor / Cooling fan motor RY2 Approx. 23.0V D.C. Power transformer

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

9. Open the door and block it open.

10.To discharge the high voltage capacitor. wait for 60 seconds.

11.Reconnect all leads removed from components during testing.

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

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

14.Run the oven and check all functions.

L COMPU DEFROST TEST

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

(1) Place one cup of water in the center of the turntable tray in the oven cavity. (2) Close the door, touch the " COMPU DEFROST " pad once. (3) Touch " COMPU DEFROST " pad twice. (4) Touch the Number pad " 5 " and then touch the " START " pad. (5) The oven is in Compu Defrost cooking condition. (6) The oven will operate as follows.

MENU 1ST STAGE 2ND STAGE

Steaks/Chops LEVEL TIME LEVEL TIME

0.5lb 60% 40sec. 40% 40sec.

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

M FOIL PATTERN ON THE PRINTED WIRING BOARD TEST

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

1. Foil pattern check and repairs.

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

2) Open the door and block it open.

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

4) Follow the troubleshooting guide given below for repair.

Page 20

R-370EK R-370ES

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

STEPS OCCURRENCE CAUSE OR CORRECTION

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

5) Make a visual inspection of the varistor. Check for burned damage and examine the

RY1

transformer with a tester for the presence of layer short-circuit (check the primary coil resistance which is approximately 212Ω ± 10%). If any abnormal condition is detected, replace the defective parts.

6) Reconnect all leads removed from components during testing.

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

8) Reconnect the power supply cord after the

CN - A

(J1)

RY2

VRS1

outer case is installed.

9) Run the oven and check all functions.

2. Follow the troubleshooting guide given below, if the 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) To discharge the high voltage capacitor, wait for 60 seconds.

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

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

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

side of low voltage transformer. Check and repair.

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

9) Open the door and block it open.

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

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.

N AH SENSOR TEST

Checking the initial sensor cooking condition WARNING : The oven should be fully assembled before following procedure.

(1) The oven should be plugged in at least two minutes before sensor cooking. (2) Room temperature should not exceed 95˚F (35˚C). (3) The unit should not be installed in any area where heat and steam are generated. The unit should

not be installed, for example, next to a conventional surface unit. Refer to the “INSTALLATION INSTRUCTIONS” of the operation manual.

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

permit adequate ventilation, be sure to install so as not to block these vents. There should be some space for air circulation.

Page 21

TEST PROCEDURES

R-370EK R-370ES

PROCEDURE

LETTER

COMPONENT TEST

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

with a dry cloth or paper towel.

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

at refrigerator temperature and canned soup at room temperature.

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

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

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

Water load cooking test WARNING : The oven should be fully assembled before following procedure.

Make sure the oven has been plugged in at least two minutes before checking sensor cook operation. The cabinet should be installed and screws tightened. (1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup. (2) Place the container on the center of tray in the oven cavity. (3) Close the door. (4) Touch the KITCHEN TIMER/CLOCK once, the POWER LEVEL pad twice, the START pad once, the

number pad 1 once and the number pad 4 once. Now, the oven is in the sensor cooking condition,

and "AH20", "SENSOR" and "COOK" will appear in the display. (5) The oven will operate for the first 16 seconds, without generating microwave energy. NOTE: ERROR will appear if the door is opened or STOP/CLEAR pad is touched during first stage of

sensor cooking. (6) After approximately 16 seconds, microwave energy is produced. If ERROR is displayed or the oven does not turn off, replace the AH sensor or check the control unit, refer to explanation below. If the oven stops after 5 minutes and ERROR is displayed, the AH sensor is normal. Check other parts except the AH sensor.

TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT

To determine if the sensor is defective, the simplest method is to replace it with a new replacement sensor. (1) Disconnect 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 AH sensor. (5) Install the new AH sensor. (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) Reconnect the oven to the power supply and check the sensor cook operation as follows:

9-1. Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup. 9-2. Place the container on the center of tray in the oven cavity. 9-3. Close the door. 9-4. Touch the KITCHEN TIMER/CLOCK pad once, the POWER LEVEL pad twice, the START pad

once, the number pad 1 once and the number pad 4 once.

9-5. The control panel is in automatic Sensor operation.

9-6. The oven turns off automatically, and the time for detecting moisture will be displayed. If new sensor dose not operate properly, the problem is with the control unit, and refer to explanation below.

CHECKING CONTROL UNIT

(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 sensor connector that is mounted to control panel. (5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel. (6) Disconnect the leads to the primary of the power transformer. (7) Ensure that these leads remain isolated from other components and oven chassis by using insulation

tape.

Page 22

R-370EK

Plunger

NC NO

COM

R3 R4

1 2 3

F-1 F-2

F-3

To connector (F) on Control Unit.

CONNECTOR

R-370ES

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

(8) After that procedure, re-connect the power supply cord. (9) Check the sensor cook operation proceed as follows:

9-1. Touch the KITCHEN TIMER/CLOCK pad once, the POWER LEVEL pad twice, the START pad

once, the number pad 1 once and the number pad 4 once. 9-2. The control panel is in the sensor cooking operation. 9-3. After approximately 25 seconds, push plunger of select switch for more than 3 seconds. This

condition is same as judgement by AH sensor. 9-4. After approximately 3 seconds, the display shows “ X X . X X “ which is the time for detecting

moisture.

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

If the above is proper, the AH sensor is probably defective. (10) Disconnect the power supply cord, and then remove outer case. (11) Open the door and block it open. (12) Discharge high voltage capacitor. (13) Disconnect the dummy resistor circuit from the sensor connector of control panel. (14) Carry out necessary repair. (15) Reconnect all leads removed from components during testing and repairing. (16) Re-install the outer case (cabinet). (17) Reconnect the power supply cord after the outer case is installed. Run the oven and check all

functions.

(18) Carry out "Water load cooking test" again and ensure that the oven works properly.

R1, R2 : 22Ω ± 1% 1/2W

R3 : 4.3kΩ ± 5% 1/4W R4 : 1MΩ ± 5% 1/4W

Sensor Dummy Resistor Circuit

Page 23

TOUCH CONTROL PANEL ASSEMBLY

OUTLINE OF TOUCH CONTROL PANEL

R-370EK R-370ES

The control unit section consists of the following units. (1) Key Unit

(2) Control Unit (The Control Unit consists of Power Unit and

CPU Unit).

The principal functions of these units and the signals communicated among them are explained below.

Key Unit

The key unit is composed of a matrix, signals generated in the LSI are sent to the key unit through P20, P21, P22, P23, P24, P25 and P26. When a key pad is touched, a signal is completed through the key unit and passed back to the LSI through P43, P44, P45 and P46 to perform the function that was requested.

Control Unit

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

1) ACL

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

2) Indicator Circuit

This circuit consists of 25 segments and 4 common electrodes using a Liquid Crystal Display.

3) Power Source Circuit

This circuit generates voltages necessary in the control unit from the AC line voltage.

In addition, the synchronizing signal is available in order to compose a basic standard time in the clock circuit.

Symbol Voltage Application

VC -5V LSI(IC1)

4) Relay Circuit

A circuit to drive the magnetron, fan motor, turntable motor and light the oven lamp.

5) Buzzer Circuit

The buzzer is responsive to signals from the LSI to emit audible sounds (key touch sound and completion sound).

6) Synchronizing Signal Circuit

The power source synchronizing signal is available in order to compose a basic standard time in the clock circuit. It accompanies a very small error because it works on commercial frequency.

7) Door Sensing Switch

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

8) Back Light Circuit

A circuit to drive the back light (Light emitting diodes LD1- LD4).

9) Absolute Humidity Sensor Circuit

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

LSI(IXA102DR)

The I/O signal of the LSI(IXA102DR) is detailed in the following table.

Pin No. Signal I/O Description

1-2 VL2-VL1 IN Power source voltage input terminal.

Standard voltage for LCD.

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

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

in operation is applied to set up its cooking constant. 7 AN3 OUT Back light circuit (Light emitting diodes) driving signal. 8 AN2 IN To input signal which communicates the door open/close information to LSI.

Door close "H" level signal (0V). Door open "L" level signal (-5V).

Page 24

R-370EK R-370ES

Pin No. Signal I/O Description

9 AN1 IN AH sensor input.

This input is an analog input terminal from the AH sensor circuit, and connected to the A/D converter built into the LSI.

10 AN0 IN Used for initial balancing of the bridge circuit (absolute humidity sensor). This input is an

analog input terminal from the AH sensor circuit, and connected to the A/D converter built into the LSI.

11-13 P57-P55 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor).

14 CNTR0 OUT

Signal to sound buzzer (2.0 kHz).

A: key touch sound. B: Completion sound.

0.1 sec.

2.0 sec.

15 P53 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor). 16 P52 OUT

Oven lamp, fan motor and turntable motor driving signal

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

16.7 msec.

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

During cooking

H : GND

L : -5V H : GND

L : -5V

H : GND

L : -5V

17 P51 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor). 18 P50 OUT Terminal not used. 19 P47 OUT Magnetron high-voltage circuit driving signal.

OFF

To turn on and off the cook relay (RY2). The signals holds "L" level during microwave cooking and "H" level while not cooking. In other cooking modes (variable cooking) the signal turns to "H" level and "L" level in repetition

P-HI

P-70

OFF OFF

24 sec.

8 sec.

according to the power level.

(ON and OFF times for other power level.)

20 P46 IN Signal coming from touch key.

When either G11 line on key matrix is touched, a corresponding signal out of P20 - P26 will be input into P46. When no key is touched, the signal is held at "H" level.

21 P45 IN Signal similar to P46.

When either G10 line on key matrix is touched, a corresponding signal will be input into P45.

22 P44 IN Signal similar to P46.

When either G9 line on key matrix is touched, a corresponding signal will be input into P44.

23 P43 IN Signal similar to P46.

When either G8 line on key matrix is touched, a corresponding signal will be input into P43.

24 INT0 IN Signal synchronized with commercial power source frequency.

This is the basic timing for time processing of LSI.

16.7 msec.

H : GND

L : -5V H : GND

L : -5V

H : GND

L : -5V

25 P41 OUT Terminal not used. 26 P40 IN Connected to GND through the pull-down resistor R100. 27

RESET

IN Auto clear terminal.

Signal is input to reset the LSI to the initial state when power is applied. Temporarily set "L" level the moment power is applied, at this time the LSI is reset. Thereafter set at "H" level.

28-29 P71-P70 OUT Terminal not used.

30 XIN IN Internal clock oscillation frequency input setting.

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

Page 25

Pin No. Signal I/O Description

31 XOUT OUT Internal clock oscillation frequency control output.

Output to control oscillation input of XIN.

32 VSS IN Power source voltage: -5.0V.

VC voltage of power source circuit input.

33 P27 OUT Terminal not used. 34 P26 OUT

Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one

of G7 line keys on key matrix is touched.

35 P25 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one

of G6 line keys on key matrix is touched.

36 P24 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one

of G5 line keys on key matrix is touched.

37 P23 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one

of G4 line keys on key matrix is touched.

38 P22 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one

of G3 line keys on key matrix is touched.

39 P21 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one

of G2 line keys on key matrix is touched.

40 P20 OUT Key strobe signal.

Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one

of G1 line keys on key matrix is touched.

41-47 P17-P11 OUT Terminal not used. 48-72

SEG24-SEG0

OUT Segment data signal.

Connected to LCD.

The relation between signals are as follows:

LSI signal (Pin No.) LCD (Pin No.) LSI signal (Pin No.) LCD (Pin No.)

SEG 24 (48) ....................... SEG 24 (29) SEG 11 (61) ...................... SEG 11 (16)

SEG 23 (49) ....................... SEG 23 (28) SEG 10 (62) ...................... SEG 10 (15)

SEG 22 (50) ....................... SEG 22 (27) SEG 9 (63) ...................... SEG 9 (14)

SEG 21 (51) ....................... SEG 21 (26) SEG 8 (64) ...................... SEG 8 (13)

SEG 20 (52) ....................... SEG 20 (25) SEG 7 (65) ...................... SEG 7 (12)

SEG 19 (53) ....................... SEG 19 (24) SEG 6 (66) ...................... SEG 6 (11)

SEG 18 (54) ....................... SEG 18 (23) SEG 5 (67) ...................... SEG 5 (10)

SEG 17 (55) ....................... SEG 17 (22) SEG 4 (68) ...................... SEG 4 ( 9)

SEG 16 (56) ....................... SEG 16 (21) SEG 3 (69) ...................... SEG 3 ( 8)

SEG 15 (57) ....................... SEG 15 (20) SEG 2 (70) ...................... SEG 2 ( 7)

SEG 14 (58) ....................... SEG 14 (19) SEG 1 (71) ...................... SEG 1 ( 6)

SEG 13 (59) ....................... SEG 13 (18) SEG 0 (72) ...................... SEG 0 ( 5)

SEG 12 (60) ....................... SEG 12 (17)

73/74

VCC/VREF

IN Connected to GND. 75 AVSS IN Connected to VC. 76 COM3 OUT Common data signal: COM3. Connected to LCD signal COM3. 77 COM2 OUT Common data signal: COM2. Connected to LCD signal COM2. 78 COM1 OUT Common data signal: COM1. Connected to LCD signal COM1. 79 COM0 OUT Common data signal: COM0. Connected to LCD signal COM0. 80 VL3 IN Power source voltage input terminal.

Standard voltage for LCD.

R-370EK R-370ES

Page 26

R-370EK

SW1

SW2

SW3

SW4 SW5

P57

P56 P55 P51 P53

LSI (IC1)

AN0

AN1

620k

300k 150k

75k

37.4k

17 15

47k

IC2

15k

0.01uF

0.1uF

0.01uF

VA : -15V

R50

330

F-2

1.8k

F-1

F-3

3.57k

3.32k

VC : -5V

0.1

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

R53 R54

R52

R51

360k

R54

R53

R50

R51

D90

R55 R56

R57

R52

R-370ES

ABSOLUTE HUMIDITY SENSOR CIRCUIT

1) Structure of Absolute Humidity Sensor

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

ventilation opening for sensing

Sensing part (Open vessel)

Thermistors

Sensing part (Closed vessel)

(2)Operational Principle of Absolute Humidity Sensor

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

increase the voltage available at AN1 terminal of the LSI. Then the LSI observes that voltage at AN1 terminal and compares it with its initial value, and when the comparison rate reaches the preset value (fixed for each menu to be cooked), the LSI causes the unit to stop sensor cooking; thereafter, the unit goes in the next operation automatically. When the LSI starts to detect the initial voltage at AN1 terminal 16 seconds after the unit has been put in the Sensor Cooking mode, if it is not possible to balance the bridge circuit due to disconnection of the absolute humidity sensor, ERROR will appear on the display and the cooking is stopped.

1) Absolute humidity sensor circuit

Absolute humidity vs,

Operational amplifier

S : Thermistor open vessel

C : Thermistor closed vessel

Output voltage

utput voltage O

output voltage characteristic

Absolute humidity (g/m )

(3)Detector Circuit of Absolute Humidity Sensor Circuit

This detector circuit is used to detect the output voltage of the absolute humidity circuit to allow the LSI to control sensor cooking of the unit. When the unit is set in the sensor cooking mode, 16 seconds clearing cycle occurs than the detector circuit starts to function and the LSI observes the initial voltage available at its AN1 terminal. With this voltage given, the switches SW1 to SW5 in the LSI are turned on in such a way as to change the resistance values in parallel with R53 ~ R57. Changing the resistance values results in that there is the same potential at both F-3 terminal of the absolute humidity sensor and AN0 terminal of the LSI. The voltage of AN1 terminal will indicate about -2.5V. This initial balancing is set up about 16 seconds after the unit is put in the Sensor Cooking mode. As the sensor cooking proceeds, the food is heated to generate moisture by which the resistance balance of the bridge circuit is deviated to

Page 27

TOUCH CONTROL PANEL SERVICING

R-370EK R-370ES

1. Precautions for Handling Electronic Components

This unit uses CMOS LSI in the integral part of the circuits. When handling these parts, the following precautions should be strictly followed. CMOS LSI have extremely high impedance at its input and output terminals. For this reason, it is easily influenced by the surrounding high voltage power source, static electricity charge in clothes, etc. and sometimes it is not fully protected by the built-in protection circuit. In order to protect CMOS LSI.

1) When storing and transporting, thoroughly wrap them in aluminium foil. Also wrap all PW boards containing them in aluminium foil.

2) When soldering, ground the technician as shown in the figure and use grounded soldering iron and work table.

approx. 1M ohm

2. Shapes of Electronic Components

Transistor DTA143ES DTD143ES

Transistor 2SB1238

3. Servicing of Touch Control Panel

We describe the procedures to permit servicing of the touch control panel of the microwave oven and the precautions you must take when doing so. To perform the servicing, power to the touch control panel is available either from the power line of the oven itself or from an external power source.

(1)Servicing the touch control panel with power supply

of the oven: CAUTION: THE HIGH VOLTAGE TRANSFORMER OF THE MICROWAVE OVEN IS STILL LIVE DURING SERVICING AND PRESENTS A HAZARD.

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

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

2) Open the door and block it open.

3) Discharge high voltage capacitor.

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

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

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

After checking the performance of the touch control panel,

1) Disconnect the power supply cord.

2) Open the door and block it open.

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

transformer.

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

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

6) Run the oven and check all functions.

A. On some models, the power supply cord between the

touch control panel and the oven itself is so short that the two can’t be separated. For those models, check and repair all the controls (sensor-related ones included) of the touch control panel while keeping it connected to the oven.

B. On some models, the power supply cord between the

touch control panel and the oven proper is long enough that they may be separated from each other. For those models, it is possible to check and repair the controls of the touch control panel while keeping it apart from the oven proper; in this case you must short both ends of the door sensing switch (on PWB) of the touch control panel with a jumper, which activates an operational state that is equivalent to the oven door being closed. As for the sensor-related controls of the touch control panel, checking them is possible if dummy resistor(s) with resistance equal to that of the controls are used.

(2)Servicing the touch control panel with power supply

from an external power source:

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

4. Servicing Tools

Tools required to service the touch control panel assembly.

1) Soldering iron: 30W (It is recommended to use a soldering iron with a grounding terminal.)

2) Oscilloscope: Single beam, frequency range: DC-10MHz type or more advanced model.

3) Others: Hand tools

5. Other Precautions

1) Before turning on the power source of the control unit, remove the aluminium foil applied for preventing static electricity.

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

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

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

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

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R-370EK R-370ES

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

W ARNING AGAINST HIGH VOL T AGE:

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

1. Door does not close firmly.

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

3. The door gasket or seal is damaged.

W ARNING 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) To discharge the high voltage capacitor, wait for 60 seconds.

2. Don’t let the wire leads touch to the following parts;

1) High voltage parts: Magnetron, High voltage transformer, High voltage capacitor and High voltage rectifier assembly.

2) Hot parts: Oven lamp, Magnetron, High voltage transformer

4. The door is bent or warped.

5. There are defective parts in the door interlock system.

6. There are defective parts in the microwave generating and transmission assembly.

7. There is visible damage to the oven.

Do not operate the oven:

1. Without the RF gasket (Magnetron).

2. If the wave guide or oven cavity are not intact.

3. If the door is not closed.

4. If the outer case (cabinet) is not fitted.

and Oven cavity.

3) Sharp edge:

Base plate, Oven cavity, Waveguide flange, Angles, Guides and other metallic plates.

4) Movable parts (to prevent a fault)

Fan blade, Fan motor, Switch.

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

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

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

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

OUTER CASE REMOVAL

To remove the outer case, proceed as follows.

1. Disconnect the power supply cord.

2. Open the oven door and block it open.

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

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

5. Remove the remaining three (3) screws from rear and two (2) screws along the right and left sides of outer case.

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

Special screw

Screw driver (Type: TORX T1120H or GTXH20-100)

Figure C-1. Special screw position

Page 29

R-370EK R-370ES

6. Lift entire outer case from the unit. CAUTION: 1. DISCONNECT OVEN FROM POWER SUP

PLY BEFORE REMOVING OUTER CASE.

2. DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN

OVEN CAVITY ASSEMBLY REMOVAL

Before removal of the power transformer, high voltage capacitor, high voltage rectifire, magnetron, fan motor and turntable motor, the oven cavity must be removed from base plate as follows.

Removal

1. Disconnect the power supply cord and then remove outer case (refer to "OUTER CASE REMOVAL").

2. Open the oven door and block it open.

3. It is recommended that the door is removed from the oven cavity. Refer to "DOOR REPLACEMENT".

4. Disconnect the wire leads from the power supply cord, turntable motor, thermal cut-out (oven), thermal cut-out (MG.), all switches on the latch hook, magnetron and oven lamp.

5. Release the two (2) snap bands of the main wire harness from the oven cavity.

6. Remove the two (2) screws holding the front leg to the base plate.

7. Remove the front cover from the oven cavity by releasing the three (3) tabs.

8. Remove the two (2) screws holding the waveguide flange of the oven cavity to the base plate.

9. Remove the three (3) screws holding the base plate to the oven cavity front plate.

10.Remove the three (3) screws holding the base plate to the oven cavity back plate.

11.Lift up the oven cavity assembly and remove it from the base plate.

12.Now the power transformer, high voltage capacitor, high

COMPONENTS OR WIRING.

NOTE: When replacing the outer case, the 2 special

Torx screws must be reinstalled in the same locations.

voltage rectifier and fan motor can be found on the base plate.

13.The magnetron can be found at wavegide flange of the oven cavity.

14. The turntable motor can be found under the oven cavity bottom plate.

Reinstallation

1. Make sure that the electrical parts on the base plate are reinstalled at their positions.

2. Make sure that the wire leads are reconnected to their correct positions. Refer to the "PICTORIAL DIAGRAM".

3. Reinstall the oven cavity assembly on the base plate.

4. Hold the base plate to the oven cavity back plate with three (3) screws.

5. Hold the base plate to the oven cavity front plate with three (3) screws.

6. Hold the waveguide flane of the oven cavity to the base plate with two (2) screws.

7. Reinstall the front leg to the oven cavity front plate.

8. Hold the front cover to the base plate with two (2) screws.

9. Insert the two (2) snap bands of main wire harness to the two (2) holes of oven cavity.

10. Reconnect the wire leads to the magnetron, all switches, thermal cut-out (MG.), thermal cut-out (oven.), oven lamp, turntable motor and power supply cord. Refer to the "PICTORIAL DIAGRAM" on page 32.

11. If the door has been removed, reinstall the door to the oven cavity. Refer to "DOOR REPLACEMENT".

12. Now, the oven cavity assembly should be reinstalled.

POWER TRANSFORMER REMOVAL

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

2. Remove the oven cavity assembly from the base plate. Refer to "OVEN CAVITY ASSEMBLY REMOVAL".

3. Discharge the high voltage capacitor.

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

5. Remove four (4) screws holding transformer to base plate.

6. Remove transformer from base plate.

HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL

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

2. Remove the oven cavity assembly from the base plate. Refer to "OVEN CAVITY ASSEMBLY REMOVAL".

Reinstallation

1. Rest transformer on the base plate with its primary terminals toward the left side.

Secure transformer with four screws to base plate.

3. Re-connect wire leads (primary and high voltage) to power transformer and filament leads of transformer to magnetron and high voltage capacitor. Refer to "PICTORIAL DIAGRAM".

4. Reinstall the oven cavity assembly to the base plate. Refer to "OVEN CAVITY ASSEMBLY REMOVAL".

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

3. Discharge the high voltage capacitor.

4. Disconnect the high voltage wire B from the high voltage capacitor.

5. Disconnect the filament lead (short one) of the power

Page 30

R-370EK R-370ES

transformer from the high voltage capacitor.

6. Remove one (1) screw holding capacitor holder to base plate.

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

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

MAGNETRON REMOVAL

Removal

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

2. Remove the oven cavity assembly from the base plate. Refer to "OVEN CAVITY ASSEMBLY REMOVAL".

3. Discharge the high voltage capacitor.

4. Now, the wire leads should be disconnected from the magnetron and thermal cut-out (MG).

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

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

7. Remove the one (1) screw holding the magnetron duct assembly to the magnetron.

8. Remove the magnetron duct assembly with thermal cutout (MG) from magnetron.

9. Now, the magnetron is free.

9. Remove the capacitor holder. The capacitor is now free. CAUTION: WHEN REPLACING HIGH VOLTAGE RECTI-

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

Reinstallation

1. Re-install the magnetron thermal duct assembly with thermal cut-out (MG) to magnetron with the one (1) screw.

2. Re-install the magnetron to waveguide flange with the four (4) screws.

3. Re-install the oven cavity assembly to the base plate. Refer to "OVEN CAVITY ASSEMBLY REMOVAL".

4. Reconnect the wire leads to the magnetron and thermal cut-out (MG). Refer to "PICTORIAL DIAGRAM" on page

32.

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

CAUTION: WHEN REPLACING MAGNETRON, BE SURE

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

OVEN LAMP REMOVAL

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

2. Open the door and block it open.

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

FAN MOTOR REMOVAL

REMOVAL

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

2. Remove the oven cavity assembly from the base plate. Refer to "OVEN CAVITY ASSEMBLY REMOVAL".

3. Discharge the high voltage capacitor.

4. Disconnect the wire leads from the fan motor.

5. Release the main wire harness and the switch harness from the holes of the fan duct.

6. Remove each one (1) screw holding the separate angles A, B and C to the base plate. And remove them from base plate.

7. Remove two (2) screws holding the fan duct to the base plate. And remove it from the base plate.

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

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

CAUTION: * Make sure that no metal pieces enter the gap between

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

4. Disconnect the wire leads from the oven lamp.

5. Remove the one (1) screw holding the oven lamp to the lamp angle.

6. Remove the oven lamp from the lamp angle.

7. Now, the oven lamp socket is free.

* 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.

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

11. Now, the fan blade will be free.

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

hole (for shaft) may be larger than normal.

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

13.Now, the fan motor is free.

14.Another fan motor can be removed in a same way.

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

Page 31

R-370EK

Terminal

Push

Pull down

Lever

Positive lock® connector

Shaft

Table

Center of bracket

Needle nose pliers

Power unit

PC support clip

R-370ES

fan blade.

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

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

because the bracket may be disfigured.

* Make sure that the fan blade rotates smooth after

installation.

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

6. Catch two holes of fan duct on two tabs of the base plate.

Coil

Groove joint pliers

Stator

Gap Bracket

Rotor

Rear View

Shaft

Axis

Stator

Rotor

Side View

POWER UNIT REMOVAL

7. Hold the fan duct assembly to the base plate with the two (2) screws.

8. Re-install the separete angles A, B and C to the base plate with each one (1) screw.

9. Insert the main wire harness and switch harness into the holes of the fan duct.

10.Connect the wire leads to the fan motor. Referre to "PICTORIAL DIAGRAM".

11.Re-install the oven cavity assembly to the base plate. Refere to "OVEN CAVITY ASSEMBLY REMOVAL".

12.Reconnect all wire leads removed from components. Referre to "PICTORIAL DIAGRAM".

These are the positions that should be pinched with pliers.

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

2. Open the door and back it open.

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

4. Disconnect the wire leads and the connectors from the power unit.

5. Remove two (2) screws holding power unit to the base plate.

6. With needle nose pliers, nip and push the head of the one (1) PC support clip which holds the power unit. And

POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL

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

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Push the lever of positive lock® connector.

5. Pull down on the positive lock® connector.

CAUTION: WHEN CONNECTING THE POSITIVE LOCK

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

TURNTABLE MOTOR REMOVAL

1. Disconnect the power supply cord.

2. Remove turntable and turntable support from oven cavity.

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

4. Where the corners have been snipped off bend corner areas flat.

then release the clip from the hole of the power unit.

7. Now the power unit is free.

Figure C-2. PC support clip

Figure C-3. Positive lock® connector

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

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

7. Remove the TTM packing from the turntable motor shaft.

Page 32

R-370EK R-370ES

8. Now the turntable motor is free.

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

CAUTION: NO SHARP EDGES MUST BE EVIDENT AF-

TER REMOVAL OF THE TURNTABLE MOTOR COVER.

DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL

Disconnect the power supply cord and remove outer case.

2. Open the door and block it open.

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

4. Disconnect the wire leads from the switches.

5. Push outward on the one (1) retaining tabs holding switch in place.

6. The switch is now free.

Reinstallation

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

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

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

DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT

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

2. Open the door and block it open.

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

If the door sensing switch, primary 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 primary interlock switch are activated with the door closed. The horizontal position of the latch hook should be adjusted so that the plunger of the monitor switch is pressed with the door closed.

6. Secure the screws with washers firmly.

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

After adjustment, check the following.

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

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

2. The contacts of door sensing switch and primary interlock switch open within 1.6mm gap between right side of cavity face plate and door when door is open.

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.)

Door

Latch Heads

Latch Hook

Door Sensing Switch

Monitor Switch

Primary Interlock Switch

Figure C4. Latch Switch Adjustments

DOOR REPLACEMENT

REMOVAL

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

2. Open the door slightly.

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

4. Remove the two (2) screws holding the front leg to the base plate.

5. Remove the front leg from the oven cavity by releasing the three (3) tabs.

6. Remove the harness cover from the front leg.

7. Disconnect the 9-pin wire harness from the power unit on the base plate.

8. Insert a putty knife (thickness of about 0.5mm) into the gap between the choke cover and door frame as shown in Figure C-5 to free engaging parts.

9. Pry the choke cover by inserting a putty knife as shown Figure C-5.

10.Release choke cover from door panel.

11.Now choke cover is free.

Page 33

R-370EK

Door frame

Front leg

9-pin wire harness

Power unit

Base plate

Hole

Door

R-370ES

Putty Knife

Choke Cover

Door Frame

Figure C-5. Door Disassembly

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.

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

13.With pulling out the 9-pin wire harness from the hole of the oven cavity front plate, remove the door from the oven cavity.

14.Now, the door is free from the oven cavity.

REINSTALLATION

1. Re-install the front leg to the oven cavity front plate.

2. Hold the front leg to the base plate with (2) screws.

3. Insert the 9-pin wire harness to the holes of the front leg and the oven cavity front plate.

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

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

6. Connect the 9-pin wire harness to the power unit on the base plate.

7. Re-install the harness cover to the front leg.

8. Now the door is installed.

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

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

(B) An approved microwave survey meter should be

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

After any service, make sure of the following :

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

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

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

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

Note:

The door on a microwave oven is designed to act as an electronic seal preventing the leakage of microwave energy from oven cavity during cook cycle. This function does not require that door be 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.

Door frame assembly

Upper oven hinge

Lower oven hinge

Upper oven hinge

Slit choke of door panel

Lower oven hinge

Choke cover

Figure C-6. Door Replacement

Figure C-7. Routing of 9-pin wire harness

SEALER FILM

Installation

1. Put the adhesive tape on the backing film of the sealer film as shown in Fig. C-8.

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

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

Sealer film

Backing film

Adhesive tape

Figure C-8. Sealer film

Page 34

R-370EK R-370ES

INDIVIDUAL DOOR PARTS REMOVAL

DOOR PANEL

1. Disconnect the power supply cord.

2. Remove the door from the oven. Refer to "DOOR REPLACEMENT".

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

4. The choke cover should have been removed.

5. Remove the four (4) screws holding the door panel to the door screen.

6. Now, door panel is free.

LATCH HEAD AND LATCH SPRING

7. Slide the latch head and remove it from the door frame assembly with releasing the latch spring from the door frame assembly and the latch head.

8. Now, the latch head and the latch spring are free.

CPU UNIT

7. Remove the two (2) screws holding the PWB cover to the door frame assembly.

8. Remove the PWB cover from the door frame assembly.

9. Remove the one (1) screw holding the CPU unit to the door frame assembly.

10.Releasing the two (2) tabs, remove the CPU unit with the LCD holder from the door frame assembly.

11.Releasing the two (2) tabs, release the LCD from the LCD holder.

12.Releasing the four (4) tabs, remove the LCD holder from the CPU unit.

13.Disconnect the 9-pin wire harness from the CPU unit.

14.Disconnect the ribbon cable of the key unit from the CPU unit.

15.Now the CPU unit is free.

DOOR FRAME ASSEMBLY

16.Releasing the four (4) tabs, remove the 9-pin wire harness from the door frame assembly.

19.Now, the door frame assembly is free.

NOTE: For 9-pin wire harness

1. Before the PWB cover is reinstalled to the door frame

assembly, route the 9-pin wire harness under the tab of LCD holder as shown in Figure C-9(a). And when the PWB cover is reinstalled, route the 9-pin wire harness under the hole of the PWB cover.

2. Before the door panel is reinstalled to the door frame

assembly, make sure that the 9-pin wire harness is held by the four (4) tabs and two (2) holes on the door frame assembly as shown in Figure C-9(b).

PWB Cover

CPU unit

Door frame

Hole of PWB cover

9-pin wire harness

Tab of LCD holder

Figure C-9(a). Routing of 9-pin wire harness

PWB Cover

Hole on door frame

9-pin wire harness

Hole on door frame

Tab

Hole of PWB Cover

Tab

Door frame

Figure C-9(b). Routing of 9-pin wire harness

NOTE: For key unit

1. Before attaching a new key unit, wipe off remaining adhesive on the door frame surfaces completely with a soft cloth soaked in alcohol.

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

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

NOTE: For CPU unit

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

Ribbon cable

Liquid Crystal

Display (LCD)

of CPU unit

Printed wiring board

Figure C-10. CPU unit

Page 35

R-370EK R-370ES

WHT

GRY

PRIMARY

INTERLOCK

WHT

COM.

SWITCH

WHT

THERMAL

CUT-OUT (MG)

GRN

COM.

BLK

OVEN LAMP

TURNTABLE

MOTOR

RED

ORG

BLK

WHT

BLK

FAN

RED

MOTOR

RED

WHT

COM.

N.C.

MONITOR

SWITCH

WHT

ORG

MAGNETRON

RECTIFIER

HIGH VOLTAGE

CAPACITOR

H.V.

GRY

N.O.

DOOR

SENSING

SWITCH

THERMAL

CUT-OUT (OVEN)

HIGH VOLTAGE

WIRE B

HIGH VOLTAGE COMPONENTS

NOTE:

The neutral (WHT) wire must be

connected to the terminal with "N"

mark on the power supply cord.

POWER SUPPLY

GRY

BLK

WHT

CORD 120V 60Hz

WHT

POWER

TRANSFORMER

BLK

WHT

WHT1

WHT

BLK 2

BLK

RED

RY2

COM.

SECONDARY

INTERLOCK

RELAY

RED

N.O.

GRY

BLK

WHT

MONITOR

WHT

N.O.

COM.

RY1

FUSE

RED

FAN

MOTOR

BLK

HOLDER

CN-F

POWER UNIT

CN-B

CN-C

BRN

IC1

(on the door)

CPU UNIT

GRY

231

RED

ORG

YLW

CN-C

CN-G

GRN

RED

ORG

7895

CN-C

AH SENSOR

CN-B

BLK

RED

CN-F

123

789

PPL

BLU

GRY

WHT

W N U L

Y T

Figure S-1. Pictorial Diagram

9-PIN WIRE HARNESS

WHT

NOTE:

The grounding conductor of

the power supply cord has

been grounded by power

supply cord fixing screw.

The screw must allways be

kept tight.

Page 36

R-370EK R-370ES

AC(N) OVEN LAMP

TURNTABLE MOTOR FAN MOTOR

AC(H)

MICRO

DOOR SENSING SWITCH

CN-B

VRS1

10G471K

(J1)

D1-D4 1N4002

C1 0.1µ/50v

N.O

D21

COM

RY1

1SS270A

Q21 DTD143ES

N.O

D22

COM

B-2

RY2

D20 1SS270A

D40 1SS270A

1SS270A

CN-C

C 1

+ –

C2 1000µ/35v

R1 2.4k

Q1 2SB1238

R2 330 1w

–

C21 10µ/35v

ZD1

HZ16-1

–

C3 10µ/35v

C 2

C 3

C 4

R4 3.3k

C 6

C 5

Q22 DTA143ES

SP1 PKM22EPT

C 7

C 9

GND

INT

OVEN LAMP TURNTABLE MOTOR FAN MOTOR

BUZZER

MICRO

DOOR SENSING SWITCH

AHR

B-1

IC2

R52

3.57kD

1/4w

R51

3.32kD 1/4w

BA4558

C50

0.1µ/50v

R53 1.8kF 1/4w R54 360kF 1/4w

C51

0.1µ/50v

C 8

AHA

R50 330 1w

F-2

NOTE

: IF NOT SPECIFIED, 1/4W, 5%

F-1

F-3

CN-F

Figure S-2. Power Unit Circuit

Page 37

R-370EK R-370ES

15k R60

Help

Level

Power

15k R61

15k R62

15k

P16

P17

P20 P21 P22 P23 P24 P25 P26 P27 VSS

XOUT XIN P70 P71

RESET P40 P41

25 40

P43

INT0

15k R100

R63

15k R64

15k R65

15k R66

G 7 G 6 G 5 G 4 G 3 G 2 G 1

Fresh

Vegetables

Rolls &

Muffins

Frozen

Entrees

C60 330pF/50v

Custom

Baked

Potatoes

Defrost

Compu

Rice

G 8

G 9G10G11

START

Minute Plus

Popcorn

Meat

Ground

Beverage

Fish

Seafood

C61 330pF/50v C62 330pF/50v C63 330pF/50v

1M R80

R71 270k R72 270k

Clear

STOP

Sensor

Reheat

Frozen

Vegetables

Clock

Kitchen Timer

Breast

Chicken

KEY UNIT

CN-G

SEG24 SEG23 SEG22 SEG21 SEG20 SEG19 SEG18 SEG17 SEG16 SEG15 SEG14 SEG13 SEG12 SEG11 SEG10 SEG9 SEG8

COM3 (LCD) COM2 (LCD) COM1 (LCD) COM0 (LCD)

SEG10

SEG11

SEG12

SEG8

SEG9

SEG8VL2

SEG9

SEG10

SEG11

6580

SEG7 SEG6 SEG5 SEG4 SEG3 SEG2 SEG1 SEG0

VCC

VREF AVSS

COM3 (LCD)

COM3

COM2 (LCD)

COM2

COM1 (LCD)

COM1

COM0 (LCD)

COM0

VL3

VL1

AN7

AN6

SEG13

SEG12

AN5

SEG14

SEG13

AN4

SEG15

SEG14

AN3

SEG15

AN2

SEG16

AN1

SEG17

AN0

SEG18

P57

SEG19

SEG20

SEG21

SEG22

SEG23

SEG19

SEG20

SEG21

SEG22

IC1

IXA102DR

P56

P55

P53

CNTR0

EDCAB

SEG24

SEG23

SEG24

P52

P11

P12

P13

P14

P15

P51

P50

P47

P46

P45

P44

LIQUID CRYSTAL DISPLAY

SEG24 SEG23 SEG22 SEG21 SEG20 SEG19 SEG18 SEG17

DEF HELP

SEG16 SEG15 SEG14 SEG13 SEG12 SEG11 SEG10 SEG9 SEG8 SEG7 SEG6 SEG5 SEG4 SEG3 SEG2 SEG1 SEG0 COM3 COM2 COM1 COM0

COOK SENSORLBS

129

GND

R8 4.7k R7 4.7k R6 4.7k

(J16)

(J17) 4.7k

C50 0.01µ/25v

(J14)

(J12)

(J15) 4.7k

(J13) 4.7k

C51 0.01µ/25v

R73 270k

(J10)

(J11) 4.7k

R74 270k

0.01µ/25v C4

CPU UNIT

2SA1037AK Q2

R4 1k

R2 4.7k

R1 82

–

R3 4.7k

R5 15k

C3 0.01µ/25v

C2 47µ/16v

2SA1037AK

LD4

UDZ4.3B ZD1

D50

MA152WA

R51 47kR50 15k

C11 0.01µ/25v

R10 15k

R52 47k

R53 620k

R54 300k

R55 150kF

R56 75kF

R57 37.4kF

C20

0.1µ/50v

CF1

CSTS4.00MG

/25v

0.01µ C40

R67 15k

R68 15k

R69 15k

R70 15k

Figure S-3. CPU Unit Circuit

R20 1k

Q10

DTA143EKA

LD1 LD2 LD3

/50v

0.1µ C10

R9 680 1/2w

Q30

DTA143EKA

Q20

DTA143EKA

R41 15k

R40 4.7k

C1 0.1µ/50v

: IF NOT SPECIFIED, 1/16W ± 5%

CN-C

C 1

C 2

C 3

C 8

C 9

C 6

C 4

C 5

C 7

NOTE

OVEN LAMP

TURNTABLE

MOTOR

FAN MOTOR

DOOR

SENSING

GND

INT

AHA

AHR

BUZZER

SWITCH

MICRO

Page 38

R-370EK R-370ES

R52

CN - C

DIP

R50

C51

R51

C50

IC2

R54

R53

D40

D20

CN - F

C21

Q22

(R3)

Q21

(ZD2)

CN - B

E Q1

ZD1

(Q2)

SP1

D21

CN - A

(J1)

VRS1

RY1

(J2)

D3 D1

RY2

DU OM

D22

Figure S-4. Printed Wiring Board of Power Unit

Page 39

PARTS LIST

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

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

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

ELECTRIC PARTS

1- 1 FACCDA085WREZ Power supply cord 1 AQ 1- 2 QFSHDA024WRZZ Fuse holder 1 AG 1- 3 QSW-MA137WRE0 Primary interlock switch / door sensing switch 2 AH 1- 4 FFS-BA023WRK0 1- 5 RTHM-A116WRE0 Thermal cut-out 125 deg. C (MG) 1 AK 1- 6 FH-DZA100WRKZ High voltage rectifier assembly 1 AQ

1- 7 RC-QZA211WRE0 High voltage capacitor 1 AV

1- 7 RC-QZA286WRZZ High voltage capacitor (Interchangeable) 1 AV

1- 8 RMOTEA400WRZZ Fan motor 1 AX 1- 9 RTRN-A638WRZZ Power transformer 1 BP

1-10 RV-MZA288WRE0 Magnetron 1 BK

∆

1-10 RV-MZA308WRZZ Magnetron (Interchangeable) 1 BL

∆

1-11 RLMPTA082WRZZ Oven lamp 1 AL 1-12 RMOTDA186WRE0 Turntable motor 1 AQ 1-12 RMOTDA211WRE0 Turntable motor (Interchangeable) 1 AS 1-13 RTHM-A123WRZZ Thermal cut-out 125 deg. C (OVEN) 1 AK 1-14 FDTCTA212WRKZ AH sensor 1 AX

2- 1 GDAI-A335WRWZ Base plate 1 AW 2- 2 GLEGPA087WRFZ Front leg 1 AK 2- 3 GLEGPA081WRFZ Leg 1 AC 2- 4 GCABUA803WRPZ Outer case cabinet [R-370ES] 1 BD 2- 4 GCABUA812WRPZ Outer case cabinet [R-370EK] 1 BD 2- 5 GCOVAA291WRFZ Harness cover 1 AH

3- 1 DPWBFC179WRUZ Power unit 1 BC 3- 1A QCNCMA431DRE0 2-pin connector (CN-B) 1 AC 3- 1B QCNCMA470DRZZ 9-pin connector (CN-C) 1 AF 3- 1C QCNCMA237DRE0 3-pin connector (CN-F) 1 AD C1 RC-KZA087DRE0 Capacitor 0.1 uF 50V 1 AA C2 VCEAB31VW108M Capacitor 1000 uF 35V 1 AF C3 VCEAB31VW106M Capacitor 10 uF 35V 1 AA C12 VCEAB31VW106M Capacitor 10 uF 35V 1 AA C50-51 RC-KZA087DRE0 Capacitor 0.1 uF 50V 2 AA D1-4 RH-DZA006PRE0 Diode (1N4002) 4 AD D20-22 VHD1SS270A/-1 Diode (1SS270A) 3 AA D40 VHD1SS270A/-1 Diode (1SS270A) 1 AA IC2 VHIBA4558//-6 IC (BA4558) 1 AK Q1 VS2SB1238//-3 Transistor (2SB1238) 1 AA Q21 VSDTD143ES/-3 Transistor (DTD143ES) 1 AC Q22 VSDTA143ES/1B Transistor (DTA143ES) 1 AA R1 VRD-B12EF242J Resistor 2.4k ohm 1/4W 1 AA R2 VRS-B13AA331J Resistor 330 ohm 1W 1 AA R4 VRD-B12EF332J Resistor 3.3k ohm 1/4W 1 AA R50 VRS-B13AA331J Resistor 330 ohm 1W 1 AA R51 RR-DZA285DRZZ Resistor 3.32k ohm ±0.5% 1/4W 1 AC R52 RR-DZA286DRZZ Resistor 3.57k ohm ±0.5% 1/4W 1 AC R53 VRN-B12EK182F Resistor 1.8k ohm ±1.0% 1/4W 1 AA R54 VRN-B12EK364F Resistor 360k ohm ±1.0% 1/4W 1 AA RY1 RRLY-A076DRE0 Relay (OMIF-S-124LM) 1 AK RY2 RRLY-A113DRE0 Relay (DU24D1-1P(M)-R) 1 AM SP1 RALM-A014DRE0 Buzzer (PKM22EPT) 1 AG T1 RTRNPA111DRE0 Transformer 1 AP VRS1 RH-VZA032DRE0 Varistor (10G471K) 1 AE ZD1 VHEHZ161///-1 Zener diode (HZ16-1) 1 AA

4- 1 PHOK-A118WRFZ Latch hook 1 AH

∆

4- 2 LBNDKA099WRW0 Capacitor holder 1 AD 4- 3 PDUC-A772WRWZ Fan duct 1 AN 4- 4 NFANJA047WREZ Fan blade 1 AL 4- 5 PPACGA084WRF0 TTM packing 1 AE 4- 6 ************* Oven cavity (Not a replaceable part) 1--

∆

4- 7 GCOVHA423WRFZ Choke cover 1 AL 4- 8 LANGQA531WRWZ Lamp angle 1 AP

Monitor fuse 20A and monitor switch (AM51620C53Y1) assembly

CABINET PARTS

POWER UNIT PARTS

OVEN PARTS

1AS

R-370EK R-370ES

Page 40

R-370EK R-370ES

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

4- 9 PCOVPA361WREZ Waveguide cover 1 AD 4-10 LANG-A084WRFZ Separate angle A 1 AG 4-11 LANG-A085WRFZ Separate angle B 1 AG 4-12 LANG-A086WRFZ Separate angle C 1 AG 4-13 PCLI-A002WREZ PC support clip 2 AD 4-14 FANG-A013WRYZ Magnetron duct assembly 1 AP 4-15 LANGFA200WRPZ Support angle 1 AD 4-16 NCPL-A053WRFZ Coupling 1 AE 4-17 PCUSUA571WRPZ Cushion 1 AH 4-18 PDUC-A775WRTZ Exhaust duct 1 AP 4-19 PPACGA181WREZ Cushion 1 AH 4-20 PPACGA182WREZ Cushion 1 AC 4-21 PCUSUA573WRPZ Cushion 1 AC 4-22 PCUSUA313WRP0 Cushion 1 AF 4-23 PCUSUA578WRPZ Cushion 1 AG 4-24 PCUSUA577WRPZ Cushion 1 AC 4-25 PCUSGA561WREZ Cushion 1 AC 4-26 PCUSUA583WRPZ Cushion 1 AG 4-27 PCUSUA375WRP0 Cushion 1 AH 4-28 PCUSGA560WREZ Cushion 2 AB 4-29 PCUSUA157WRP0 Cushion 1 AC 4-30 PCUSGA563WREZ Cushion 1 AH 4-31 PCUSGA564WREZ Cushion 1 AH

DOOR PARTS

5- 1 FDORFA347WRTZ Door panel 1 AX

∆

5- 2 PSHEPA775WREZ Sealer film 1 AH 5- 3 FWAKPA316WRKZ Door frame assembly [R-370ES] 1 BF

∆

5- 3 FWAKPA318WRKZ Door frame assembly [R-370EK] 1 BF

∆

5-3-1 FUNTKB060WREZ Key unit 1 AV 5-3-2 HPNL-A762WRRZ Door screen 1 AU 5- 4 LSTPPA193WRFZ Latch head 1 AE

∆

5- 5 MSPRTA202WREZ Latch spring 1 AD 5- 6 DPWBFC176WRKZ CPU unit 1 BD 5- 7 LHLD-A236WRFZ LCD holder 1 AC 5- 8 PSHEPA786WREZ LED sheet 1 BB 5- 9 FW-VZA272DREZ 9-pin wire harness 1 AL 5-10 PCOVPA372WRWZ PWB cover 1 AF 5-11 PCUSUA567WRPZ Cushion 1 AE 5-12 XEPSD38P08000 Screw : 3.8mm x 8mm 4 AA 5-13 XEPSD30P08XS0 Screw : 3mm x 8mm 3 AA 5-14 LHLD-A237WRFZ Light guide 1 AL

MISCELLANEOUS

6- 1 FROLPA079WRK0 Turntable support 1 AP 6- 2 NTNT-A079WRF0 Turntable tray 1 AR 6- 3 FW-VZB827WREZ Main wire harness 1 AW 6- 4 QW-QZA242WRZZ High voltage wire B 1 AF

6- 5 TCAUAA265WRRZ DHHS caution label 1 AC 6- 6 TCAUAA254WRR0 Monitor caution label 1 AC 6- 7 TINSEA888WRRZ Instruction book 1 AF 6- 8 FW-VZB828WREZ Switch harness 1 AK 6-12 FW-VZB802WREZ T.T. motor harness 1 AF

SCREWS,NUTS AND WASHERS

7- 1 XHPSD40P08K00 Screw : 4mm x 8mm 8 AA 7- 2 XHPSD40P08000 Screw : 4mm x 8mm 1 AA 7- 3 XOTSD40P08000 Screw : 4mm x 8mm 6 AA 7- 4 LX-CZA073WRE0 Special screw 1 AC 7- 5 XOTSD40P12000 Screw : 4mm x 12mm 2 AA 7- 6 XHPSD30P08XS0 Screw : 3mm x 8mm 2 AB 7- 7 XHTSD40P08RV0 Screw : 4mm x 8mm 9 AA 7- 8 LX-CZA070WRE0 Special screw (Torx tamper proof screw) 2 AC 7- 9 LX-CZ0052WRE0 Special screw 2 AA 7-10 XHPSD30P06000 Screw : 3mm x 6mm 1 AA 7-11 XHTSD40P08000 Screw : 4mm x 8mm 4 AA 7-12 XHTSD40P12RV0 Screw : 4mm x 12mm 1 AA 7-13 XOTSD40P12RV0 Screw : 4mm x 12mm 7 AA 7-14 XOTSE40P08000 Screw : 4mm x 8mm [R-370ES] 2 AA 7-14 XOTSF40P08000 Screw : 4mm x 8mm [R-370EK] 2 AA 7-15 LX-EZA060WREZ Special screw 4 AA 7-16 XOTSD40P12000 Screw : 4mm x 12mm 1 AA 7-17 XHBWW30P08000 Screw : 3mm x 8mm 2 AB

Page 41

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

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

PACKING AND ACCESSORIES

HOW TO ORDER REPLACEMENT PARTS

1. MODEL NUMBER

2. REF. NO.

3. PART NO.

4. DESCRIPTION

DOOR PROTECTION SHEET SPADPA204WRE0

TOP PAD ASSEMBLY FPADBA451WRKZ

R-370EK R-370ES

INTO THE OVEN CAVITY

FORM SHEET SPAKHA017WREZ

6-7 INSTRUCTION BOOK & PRINTING MATTER

6- 2 TURNTABLE TRAY

6- 1 TURNTABLE SUPPORT

TRAY PAD SPADFA499WREZ

Not replaceable items.

WRAP COVER SSAKHA072WREZ

CABINET COVER SPAKHA018WREZ

BOTTOM PAD ASSEMBLY FPADBA453WRKZ

PACKING CASE SPAKCD578WREZ [R-370ES] SPAKCD580WREZ

[R-370EK]

Page 42

R-370EK R-370ES

OVEN AND CABINET PARTS

7-4

4-27

4-6

7-17 1-14

4-28

7-13

4-28

4-17

7-14

2-4

4-18

7-8

4-26

6-6

4-25

1-13

4-24

1-1

7-12

7-14

4-19

7-13

6-5

7-7

7-11

4-21

1-9

7-11

4-23

4-9

7-9

7-15

7-7

7-1

7-3

4-44-11

7-1

4-3

4-4

7-7

7-3

4-12

7-7

4-22

4-16

4-30

4-5

1-12

4-15

2-2

7-1

7-7

2-5

7-5

7-11

1-11

4-8

4-1

1-5

7-1

1-3

4-31

1-4

7-2

1-2

1-8

1-4

7-5

4-14

7-7

7-10

1-3

7-6

4-20

3-1

1-10

6-2

4-10

4-13

7-1

1-6

1-7

4-2

4-29

6-1

2-1

7-13

7-3

2-3

7-16

Page 43

R-370EK R-370ES

DOOR PARTS

5-10

5-11

5-9

5-13

5-7

5-6

5-14

5-8

5-6

5-3

5-3-1

5-1

5-13

5-12

5-2

5-12

4-7

5-12

5-4

5-3-2

5-5

MISCELLANEOUS

6-8

6-3

6-4

(CAPACITOR)

6-9

Actual wire harness may be different from illustration.

Page 44

R-370EK R-370ES

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

2001 SHARP CORP. (4S2.530E) Printed in U.S.A

SHARP R-370EK, R-370ES Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

TABLE OF CONTENTS

BEFORE SERVICING

W ARNING TO SER VICE PERSONNEL

MICROWAVE MEASUREMENT PROCEDURE

FOREWORD

SPECIFICATION

GENERAL INFORMATION

GROUNDING INSTRUCTIONS

OVEN DIAGRAM

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

SCHEMATIC

DESCRIPTION AND FUNCTION OF COMPONENTS

TROUBLESHOOTING GUIDE

TEST PROCEDURES

A MAGNETRON ASSEMBLY TEST

B POWER TRANSFORMER TEST

C HIGH VOLTAGE RECTIFIER TEST

D HIGH VOLTAGE CAPACITOR TEST

E OVEN THERMAL CUT-OUT TEST

MAGNETRON THERMAL CUT-OUT TEST

F PRIMARY INTERLOCK SWITCH TEST

SECONDARY INTERLOCK SYSTEM TEST

G MONITOR SWITCH TEST

H BLOWN MONITOR FUSE TEST

I CONTROL UNIT TEST

J KEY UNIT TEST

K RELAY TEST

L COMPU DEFROST TEST

M FOIL PATTERN ON THE PRINTED WIRING BOARD TEST

N AH SENSOR TEST

TOUCH CONTROL PANEL ASSEMBLY

OUTLINE OF TOUCH CONTROL PANEL

ABSOLUTE HUMIDITY SENSOR CIRCUIT

TOUCH CONTROL PANEL SERVICING

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

W ARNING AGAINST HIGH VOL T AGE:

W ARNING FOR WIRING

OUTER CASE REMOVAL

OVEN CAVITY ASSEMBLY REMOVAL

POWER TRANSFORMER REMOVAL

HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL

MAGNETRON REMOVAL

OVEN LAMP REMOVAL

FAN MOTOR REMOVAL

POWER UNIT REMOVAL

POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL

TURNTABLE MOTOR REMOVAL

DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL

DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT

DOOR REPLACEMENT

INDIVIDUAL DOOR PARTS REMOVAL

PARTS LIST

PACKING AND ACCESSORIES

HOW TO ORDER REPLACEMENT PARTS

OVEN AND CABINET PARTS