Sharp R-204EWA Service Manual
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Sharp R-204EWA Service Manual

Sharp R-204EWA Service Manual

Service manual
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BEFORE SERVICING ...................................................................................................... INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL ................................................................................................................ 1
MICROWAVE MEASUREMENT PROCEDURE ................................................................................................... 2
FOREWORD AND WARNING ............................................................................................................................... 3
PRODUCT SPECIFICATIONS .............................................................................................................................. 4
GENERAL INFORMATION ................................................................................................................................... 4
OPERATION .......................................................................................................................................................... 6
TROUBLESHOOTING GUIDE .............................................................................................................................. 9
TEST PROCEDURE ............................................................................................................................................ 10
TOUCH CONTROL PANEL ................................................................................................................................. 18
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ................................................................ 22
PICTORIAL DIAGRAM ........................................................................................................................................ 28
CONTROL PANEL CIRCUIT ............................................................................................................................... 29
PARTS LIST ........................................................................................................................................................ 31
PACKING AND ACCESSORIES ......................................................................................................................... 32
SHARP CORPORATION
SERVICE MANUAL
MODEL
ON
DEF. LBS.
QTY. CHECK
EXP RES S
MIN UTE
DEF ROS T
PLU S
In the interest of user-safety the oven should be restored to its original
POW ER
LEV EL
TIM ER
CLO CK
STO P
condition and only parts identical to those specified should be used.
CL EA R
WARNING TO SERVICE PERSONNEL: Microwave ovens con-
tain 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 Recti-
fier Assembly, High Voltage Harness etc..)

TABLE OF CONTENTS

MICROWAVE OVEN
R-204EWA
This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
R-204EWA
S6115R204EPWA
Page

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  • Page 1: Table Of Contents

    R-204EWA SERVICE MANUAL S6115R204EPWA MICROWAVE OVEN R-204EWA MODEL DEF. LBS. QTY. CHECK EXP RES S MIN UTE DEF ROS T PLU S In the interest of user-safety the oven should be restored to its original POW ER LEV EL TIM ER...

  • Page 2: Precautions To Be Observed Before And During Servicing To Avoid Possible Exposure To Excessive Microwave Energy

    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.

  • Page 3: Warning To Service Personnel

    R-204EWA WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of pro- ducing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (Example) High Voltage Capacitor, High Voltage Power Trans- former, Magnetron, High Voltage Rectifier Assem- bly, High Voltage Harness etc..

  • Page 4: Microwave Measurement Procedure

    R - 2 0 4 E W A 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/cm 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/cm at any point 5cm or more from the external surface of the oven.
  • Page 5 MICROWAVE OVEN R-204EWA GENERAL INFORMATION FOREWORD This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the OPERATION SHARP MICROWAVE OVEN, R-204EWA. It is recommended that service personnel carefully study the entire...

  • Page 6: General Information

    R - 2 0 4 E W A PRODUCT DESCRIPTION SPECIFICATIONS ITEM DESCRIPTION Power Requirements 120 Volts 60 Hertz Single phase, 3 wire grounded Power Consumption 1250W / Approx. 10.6 Amperes Power Output 800 W nominal of RF microwave energy (IEC Test procedure) Operating frequency 2450 MHz Case Dimensions Width 18-1/8"...

  • Page 7: Oven Diagram

    R-204EWA 15 or 20 amp. fused electrical supply. It is recommended that a separate circuit Grounded serving only this appliance be provided. When installing this appliance, observe all Receptacle Box applicable codes and ordinances. A short power-supply cord is provided to reduce risks of becoming entangled in or 3-Pronged tripping over a longer cord.

  • Page 8: Operation

    R - 2 0 4 E W A OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions during relay (RY2) and is mechanically associated with the door oven operation. so that it will function in the following sequence. (1) When the door opens from the closed position, the OFF CONDITION secondary interlock switch, door sensing switch and...

  • Page 9: Oven Schematic-Cooking Condition

    R-204EWA SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. CLOCK APPEARS ON DISPLAY NOTE: " " indicates components with potential above 250V. C/T FUSE MAGNETRON THERMAL CUT-OUT COM. POWER TRANSFORMER N.O. (RY-1) (RY-2) PRIMARY INTERLOCK RELAY CAPACITOR CONTROL UNIT 0.86 F...
  • Page 10 R - 2 0 4 E W A DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM ARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (RE- The door is opened by pulling the door, refer to the Figure FER TO CHAPTER "TEST PROCEDURE"). D-1.

  • Page 11: Troubleshooting Guide

    R-204EWA 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.

  • Page 12: Test Procedure

    R - 2 0 4 E W A CK = Check / RE = Replace A B C D E F F G H TEST PROCEDURE RE CK RE RE CK CK CK CK J POSSIBLE CAUSE DEFECTIVE PARTS PROBLEM CONDITION Home fuse blows when power cord is plugged into wall receptacle.
  • Page 13 R-204EWA TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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.
  • Page 14 R - 2 0 4 E W A TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER HIGH VOLTAGE RECTIFIER TEST 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. 4.
  • Page 15 R-204EWA TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 6. Reinstall the outer case (cabinet). 7. Reconnect the power supply cord after the outer case is installed. 8. Run the oven and check all functions. PRIMARY INTERLOCK SYSTEM TEST DOOR SENSING SWITCH 1.
  • Page 16 R - 2 0 4 E W A TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER BLOWN C/T FUSE TEST 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. 4.
  • Page 17 R-204EWA TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 2) Open the door and block it open. 3) Discharge high voltage capacitor. 4) Replace the key unit. 5) Reconnect all leads removed from components during testing. 6) Re-install the outer case (cabinet).
  • Page 18 R - 2 0 4 E W A TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER DINNER MINUTE BEVERAGE PLATE PLUS FRESH EXPRESS POWER VEGETABLES DEFROST LEVEL TIMER STOP ROLLS & BAKED MUFFINS POTATOES CLOCK CLEAR START POPCORN RELAY TEST 1. Disconnect the power supply cord and then remove outer case. 2.
  • Page 19 R-204EWA TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 1. Foil pattern check and repairs. 1) Disconnect the power supply cord and then remove outer case. 2) Open the door and block it open. 3) Discharge high voltage capacitor. 4) Follow the troubleshooting guide given below for repair.

  • Page 20: Touch Control Panel

    R - 2 0 4 E W A TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL 3) Power Source Circuit The touch control section consists of the following units as This circuit generates voltage necessary in the control shown in the touch control panel circuit. unit from the AC line voltage.

  • Page 21: Description Of Lsi

    R-204EWA DESCRIPTION OF LSI The I/O signal of the LSI are detailed in the following table. Pin No. Signal Description RESET Auto clear terminal. Signal is input to reset the LSI to the initial state when power is supplied. Temporarily set to “L”...
  • Page 22 R - 2 0 4 E W A Pin No. Signal Description Signal similar to K02. When either G7 line on key matrix is touched, a corresponding signal will be input into P23. Signal similar to K02. When either G8 line on key matrix is touched, a corresponding signal will be input into K00. Signal similar to K02.
  • Page 23 R-204EWA SERVICING 1. Precautions for Handling Electronic Components A. On some models, the power supply cord between the This unit uses CMOS LSI in the integral part of the touch control panel and the oven itself is so short that the circuits.

  • Page 24: Component Replacement And Adjustment Procedure

    WARNING FOR WIRING To prevent an electric shock, take the following pre- and Oven cavity. cautions. 3) Sharp edge: 1. Before wiring, Bottom plate, Oven cavity, Waveguide flange, 1) Disconnect the power supply cord. Chassis support and other metallic plate.
  • Page 25 R-204EWA CAUTION: 1. DISCONNECT OVEN FROM POWER SUP- NOTE: When replacing the outer case, the 2 special PLY BEFORE REMOVING OUTER CASE. Torx screws must be reinstalled in the same 2. DISCHARGE THE HIGH VOLTAGE CA- locations. PACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING.

  • Page 26: Control Panel Assembly Removal

    Reinstallation 3. Turn the oven over. 1. Remove the any sharp edges on the turntable motor 4. Cut the four (4) bridges holding the turntable motor cover cover and the bottom plate with the cutting pliers. to the bottom plate with the cutting pliers as shown in 2.

  • Page 27: Pictorial Diagram

    R-204EWA CAUTION: • Make sure that no metal pieces enter the gap 5. Install the fan blade to the shaft of fan motor by pushing between the rotor and the stator of the fan the fan blade with a small, light weight, ball peen hammer motor.
  • Page 28 R - 2 0 4 E W A 3. Secure latch hook (with two (2) mounting screws) to Latch Hook oven flange. 4. Re-install the control panel assembly to the oven cavity front flange. 5. Re-connect wire leads to the control unit. Refer to Door chapter "Pictorial Diagram".
  • Page 29 R-204EWA upper and lower oven hinges by lifting up. Therefore, occasional appearance of moisture, light 8. Now, door panel is free from oven cavity. or sensing of gentle warm air movement around 9. Release door panel from ten (10) tabs of door frame and oven door is not abnormal and do not of themselves, remove door frame by sliding the door panel downward.
  • Page 30 R - 2 0 4 E W A...
  • Page 31 R-204EWA SEG13 COM1 SEG14 COM0 SEG15 SEG16 SEG17 SEG18 SEG19 /25v 0.01 220k 220k 220k 20kF 220k HZ4C3 /25v 0.01 /25v 0.01 /25v 0.01 /25v 4.7k /10v /35v /50v /25v 1/4w 3.3k PKM22EPT (J1) 10G471K VRS1...

  • Page 32: Parts List

    R-204EWA PARTS LIST Note: The parts marked “ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. REF. NO. PART NO. DESCRIPTION Q'TY CODE ELECTRIC PARTS 1- 1 QSW-MA137WRE0 Secondary interlock switch & door sensing switch...

  • Page 33: Packing And Accessories

    To have your order filled promptly and correctly, please furnish the following information. 1. MODEL NUMBER 2. REF. NO. 3. PART NO. 4. DESCRIPTION Order Parts from the authorized SHARP parts Distributor for your area. Defective parts requiring return should be returned as indicated in the Service Policy. PACKING AND ACCESSORIES...
  • Page 34 R-204EWA OVEN AND CABINET PARTS 7-10 7-12 7-10 7-11 4-17 4-14 4-14 4-11 1-11 4-16 1-10 4-10 4-15 4-13 4-12...
  • Page 35 R-204EWA Befor attaching Control unit to Control panel, foil side of Control CONTROL PANEL PARTS unit must be cleaned by ethyl- alcohol. 3-2-2 6-10 DOOR PARTS 3-2-1 MISCELLANEOUS Actual wire harness may be different than illustration.
  • Page 36 No part of this publication may be reproduced, stored in retrieval systems, or transmitted in any form or by any means, electronic, mechanical, pho- tocopying, recording, or otherwise, without prior written permission of the publisher. 2001 SHARP CORP. (6S1.700E) Printed in U.S.A...

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