Sharp R-520KS Service Manual
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Sharp R-520KS Service Manual

Sharp R-520KS Service Manual

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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..)
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 ............................................................................................................................................ 11
TOUCH CONTROL PANEL .................................................................................................................................. 21
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE .................................................................. 27
PICTORIAL DIAGRAM ........................................................................................................................................ 34
CPU UNIT CIRCUIT ............................................................................................................................................. 35
PRINTED WIRING BOARD ................................................................................................................................. 36
PARTS LIST ........................................................................................................................................................ 37
PACKING AND ACCESSORIES ......................................................................................................................... 41
SHARP ELECTRONCS CORPORATION
Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135
SERVICE MANUAL
MODEL

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This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
S45M251R520KE
MICROWAVE OVEN
R-520KS
R - 520KS
Page

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  • Page 1: Table Of Contents

    PARTS LIST ................................ 37 PACKING AND ACCESSORIES ......................... 41 This document has been published to be used for after sales service only. SHARP ELECTRONCS CORPORATION The contents are subject to change without notice. Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135...

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

    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-520KS 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 - 5 2 0 K S 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: Foreword And Warning

    MICROWAVE OVEN R-520KS GENERAL INFORMATION FOREWORD This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP OPERATION MICROWAVE OVEN R-520KS. It is recommended that service personnel carefully study the entire text...

  • Page 6: Product Specifications

    SPECIFICATION R - 5 2 0 K S ITEM DESCRIPTION Power Requirements 120 Volts 14.3 Amperes, 1700 watts 60 Hertz Single phase, 3 wire grounded Power Output 1200 watts (IEC TEST PROCEDURE) Operating frequency of 2450MHz Case Dimensions Width 24" Height 13-3/8"...
  • Page 7 R-520KS 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. Grounded A short power-supply cord is provided to reduce risks of becoming Receptacle Box entangled in or tripping over a longer cord.

  • Page 8: Operation

    R - 5 2 0 K S OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions during and is mechanically associated with the door so that it will oven operation. function in the following sequence. (1) When the door opens from the closed position, the OFF CONDITION secondary interlock relay (RY2) and primary interlock switch open their contacts.
  • Page 9 R-520KS SENSOR COOKING CONDITION 2. The coil of shut-off relay (RY-1) is energized, the Using the SENSOR function, food is cooked without figuring turntable motor are turned on, but the power transformer time, power level or quantity. When the oven senses enough is not turned on.
  • Page 10 R - 5 2 0 K S Note:* Indicates component SCHEMATIC NOTE: CONDITION OF OVEN 1. Door Closed 2. CLOCK APPEARS ON DISPLAY N.O. COM. DOOR SENSING POWER SWITCH TRANSFORMER HUMIDITY SENSOR (RY2) SECONDARY INTERLOCK RELAY CONTROL UNIT (RY1) COM. N.O.
  • Page 11 R-520KS DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM 3. If the door is opened, and the secondary interlock relay (RY2) and primary interlock switch contacts fail to open, The door is opened by pushing the open button on the control the monitor fuse blows simultaneously with closing of the panel, refer to the Figure D-1.

  • Page 12: Troubleshooting Guide

    R - 5 2 0 K S 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 13: Test Procedure

    R-520KS CK = Check / RE = Replace RE RE A B C D E E F F G H RE RE CK I CK CK CK J K L M N TEST PROCEDURE PROBLEM CONDITION Home fuse or circuit breaker blows...
  • Page 14 R - 5 2 0 K S TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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.
  • Page 15 R-520KS 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. 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.
  • Page 16 R - 5 2 0 K S TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER CAUTION: IF THE TEMPERATURE FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERA- TURE, REPLACE TEMPERATURE FUSE. PRIMARY INTERLOCK SWITCH TEST 1. Disconnect the power supply cord, and then remove outer case. 2.
  • Page 17 R-520KS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER MONITOR SWITCH TEST 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. 4. Before performing this test, make sure that the primary interlock switch and the secondary interlock relay are operating properly, according to the above Switch Test Procedure.
  • Page 18 R - 5 2 0 K S TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER Control Unit The following symptoms indicate a defective control unit. 2-1 In connection with pads. a) When touching the pads, a certain group of pads do not produce a signal. b) When touching the pads, no pads produce a signal.
  • Page 19 R-520KS TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER NO. G1 NO. G13 FROZEN POWER BONE-IN Key unit ribbon cable ROLLS/ POULTRY LEVEL MUFFINS GROUND FRESH BAKED CUSTOM START KEEP WARM STOP RICE MEAT ROLLS/ POTATOES CLEAR MINUTE PLUS HELP PLUS (DEFROST)
  • Page 20 R - 5 2 0 K S TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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.
  • Page 21 R-520KS 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 95½F (35½C).
  • Page 22 R - 5 2 0 K S 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.

  • Page 23: Touch Control Panel

    R-520KS TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL 3) Power Source Circuit The touch control section consists of the following units. This circuit generates voltages necessary in the control unit from the AC line voltage. (1) Key Unit...
  • Page 24 R - 5 2 0 K S DESCRIPTION OF LSI The I/O signal of the LSI is detailed in the following table. Pin No. Signal Description VL2-VL1 Power source voltage input terminal. Standard voltage for LCD. AN7-AN4 Terminal to change cooking input according to the Model. By using the A/D converter contained in the LSI, DC voltage in accordance with the Model in operation is applied to set up its cooking constant.
  • Page 25 R-520KS Pin No. Signal Description Signal similar to AN3. When either G11 line on key matrix is touched, a corresponding signal will be input into P41. Connected to GND through the pull-down resistor. RESET Auto clear terminal. Signal is input to reset the LSI to the initial state when power is applied.
  • Page 26 R - 5 2 0 K S Pin No. Signal Description Connected to LCD. The relation between signals are as follows: LSI signal (Pin No.) LCD (Pin No.) LSI signal (Pin No.) LCD (Pin No.) SEG0 (72) ........ SEG 0 SEG11 (61) .......
  • Page 27 R-520KS ABSOLUTE HUMIDITY SENSOR CIRCUIT (1) Structure of Absolute Humidity Sensor balance of the bridge circuit is deviated to increase the The absolute humidity sensor includes two thermistors voltage available at AN1 terminal of the LSI. as shown in the illustration. One thermistor is housed in...
  • Page 28 R - 5 2 0 K S TOUCH CONTROL PANEL SERVICING A. On some models, the power supply cord between the 1. Precautions for Handling Electronic Components touch control panel and the oven itself is so short that the This unit uses CMOS LSI in the integral part of the two can’t be separated.

  • Page 29: Component Replacement And Adjustment Procedure

    4. If the outer case (cabinet) is not fitted. WARNING FOR WIRING To prevent an electric shock, take the following pre- 3) Sharp edge: cautions: Bottom plate, Oven cavity, Waveguide flange, 1. Before wiring: Chassis support and other metallic plate.
  • Page 30 R - 5 2 0 K S CAUTION: 1. DISCONNECT OVEN FROM POWER SUP- PLY BEFORE REMOVING OUTER CASE. 2. DISCHARGE THE HIGH VOLTAGE CA- PACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING. Special screw NOTE: When replacing the outer case, the 2 special Torx screws must be reinstalled in the same locations.
  • Page 31 R-520KS OVEN LAMP AND LAMP SOCKET REMOVAL 1. Disconnect the power supply cord and remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor. 4. Remove the oven lamp from the oven lamp socket.
  • Page 32 4. Where the corners have been snipped off bend corner 7. Now the turntable motor is free. areas flat. No sharp edges must be evident after removal 8. After replacement, use the one (1) screw provided with the of the turntable motor cover.
  • Page 33 R-520KS COOLING FAN MOTOR REMOVAL REMOVAL CAUTION: 1. Disconnect the power supply cord and then remove outer * Do not reuse the removed fan blade because the hole case. (for shaft) may be larger than normal. 2. Open the door and block it open.
  • Page 34 R - 5 2 0 K S 3. Secure latch hook (with two (2) mounting screws) to oven and check continuity of the monitor circuit. Refer to chapter flange. "Test Procedure" and Adjustment procedure. 4. Make sure that the monitor switch is operating properly DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT 1.
  • Page 35 R-520KS 9. Release the door panel from twelve (12) tabs of door frame. 10.Remove the door panel from the door frame. 11.Now, door panel with sealer film is free. 12.Tear sealer film from door panel. 13.Now, door panel is free.

  • Page 36: Pictorial Diagram

    R - 5 2 0 K S...

  • Page 37: Cpu Unit Circuit

    R-520KS...

  • Page 38: Printed Wiring Board

    R - 5 2 0 K S CHIP SIDE CN-F 1 2 3 CN-B WH-2 WH-2 Q4 SP1 VRS1 Figure S-5 . Printed Wiring Board of Power Unit...

  • Page 39: Parts List

    R-520KS PARTS LIST Note: The parts marked “∆ ∆ ∆ ∆ ∆ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. "§" MARK: PARTS DELIVERY SECTION. REF. NO. PART NO. § DESCRIPTION...
  • Page 40 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.
  • Page 41 R-520KS OVEN AND CABINET PARTS 1-14 1-13 4-13 1-11 4-12 1-12 4-10 1-10 4-11...
  • Page 42 R - 5 2 0 K S CONTROL PANEL PARTS 3-11 3-10 DOOR PARTS 5-11 MISCELLANEOUS Actual wire harness may be different from illustration.

  • Page 43: Packing And Accessories

    R-520KS PACKING AND ACCESSORIES TOP PAD ASSEMBLY DOOR PROTECTION SHEET 6-3 TURNTABLE TRAY PLASTIC BAG TRAY HOLDER 6-6 OPERATION MANUAL BOTTOM PAD ASSEMBLY 6-2 TURNTABLE SUPPORT PACKING CASE...
  • Page 44 No part of this publication may be repro- duced, stored in retrieval systems, or trans- mitted in any form or by any means, elec- tronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher. 2005 SHARP CORP. (5M2.00E) Printed in U.S.A...

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