Sharp KB-6021MS Service Manual
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Sharp KB-6021MS Service Manual

Microwave drawer
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KB-602MS pictured
In the interest of user-safety the unit should be restored to its original condition and only parts identical to those specified should
be used.
WARNING TO SERVICE PERSONNEL:
This service manual is intended for use by persons having electrical and mechanical training and a level of
knowledge of these subjects generally considered acceptable in the appliance repair trade. Sharp Electronics
Corporation cannot be responsible, nor assume any liability, for injury or damage of any kind arising from the
use of this manual.
Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with the
following parts may result in a severe, possibly fatal, electrical shock. (High Voltage Capacitor, High Voltage
Power Transformer, High Voltage Rectifier, Heat Sink, Magnetron and High Voltage Harness etc...)
BEFORE SERVICING ....................................................................................................... INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL ................................................................................................................. 3
MICROWAVE MEASUREMENT PROCEDURE ..................................................................................................... 4
FOREWORD AND WARNING ............................................................................................................................... 5
PRODUCT SPECIFICATIONS ............................................................................................................................... 6
SCHEMATICS ...................................................................................................................................................... 0
TEST PROCEDURES .......................................................................................................................................... 
TOUCH CONTROL PANEL ASSEMBLY .............................................................................................................. 9
MICROWAVE DRAWER DISASSEMBLY ............................................................................................................. 27
WIRING DIAGRAMS ............................................................................................................................................ 33
PRINTED WIRING BOARDS ............................................................................................................................... 34
PARTS LIST ......................................................................................................................................................... 38
PACKING AND ACCESSORIES .......................................................................................................................... 43
SHARP ELECTRONICS CORPORATION
This document has been published to be used for after sales service only. The contents are subject to change without notice.
SERVICE MANUAL

TABLE OF CONTENTS

MICROWAVE DRAWER
MODEL
KB-6021MS/MK/MW

KB-6021MS
KB-6021MK
KB-6021MW
S77M284K6021M-D
Page

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Summary of Contents for Sharp KB-6021MS

  • Page 1: Table Of Contents

    This service manual is intended for use by persons having electrical and mechanical training and a level of knowledge of these subjects generally considered acceptable in the appliance repair trade. Sharp Electronics Corporation cannot be responsible, nor assume any liability, for injury or damage of any kind arising from the use of this manual.

  • 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 Measure- ment Procedure outlined in this service manual. If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS CORPO- RATION immediately @-800-237-4277.

  • Page 3: Warning To Service Personnel

    KB-6021MS KB-6021MK KB-6021MW WARNING TO SERVICE PERSONNEL Microwave Oven units contain circuitry capable of producing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (Example) High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness, Heating Elements, etc..

  • Page 4: Microwave Measurement Procedure

    KB-6021MS KB-6021MK KB-6021MW MICROWAVE MEASUREMENT PROCEDURE A. Requirements: ) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed mW/cm at any point 5cm or more from the external surface of the oven, measured prior to...

  • Page 5: Foreword And Warning

    KB-6021MS / KB-6021MK / KB-6021MW SCHEMATICS FOREWORD TEST PROCEDURE This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel and Service Information for the MICROWAVE DRAWERS, KB-602MS, KB-602MK, KB-602MW. TOUCH CONTROL PANEL 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.

  • Page 6: Product Specifications

    KB-6021MS KB-6021MK KB-6021MW MICROWAVE DRAWER SPECIFICATION ITEM DESCRIPTION Power Requirements 20 Volts 4.5 Amperes, 000 watts 60 Hz Single phase, 3 wire grounded Power Output 000 watts (IEC TEST PROCEDURE) Operating frequency of 2450MHz Cooking Cavity Dimensions Width 7-/32 Height 5-7/8"...
  • Page 7 KB-6021MS GENERAL INFORMATION KB-6021MK KB-6021MW 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.
  • Page 8 KB-6021MS KB-6021MK KB-6021MW OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions dur- the secondary interlock switch and secondary interlock ing oven operation. relay and is mechanically associated with the drawer so that it will function in the following sequence.
  • Page 9 KB-6021MS KB-6021MK KB-6021MW SENSOR COOKING CONDITION 2. The coil of shut-off relay (RY-) is energized, but the Using the SENSOR function, food is cooked without figur- power transformer is not turned on. ing time, power level or quantity. When the oven senses enough steam from the food, it relays the information to its 3.
  • Page 10 KB-6021MS SCHEMATIC (OFF CONDITION) KB-6021MK KB-6021MW "TO SOURCE" "TO SOURCE" FUSE RESISTOR 470 k? 1/2W LINE CROSS CAPACITOR 1.0 ? F 275V NOISE SUPRESSION COIL LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR 0.0033 ? F 250V 0.0033 ? F 250V "TO LOAD"...

  • Page 11: Test Procedures

    KB-6021MS KB-6021MK TEST PROCEDURES KB-6021MW PROCEDURE COMPONENT TEST LETTER TOUCH CONTROL PANEL ASSEMBLY TEST The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter and ohmmeter.
  • Page 12 KB-6021MS KB-6021MK TEST PROCEDURES KB-6021MW PROCEDURE COMPONENT TEST LETTER 4) Reconnect all leads removed from components during testing. 5) Re-install the covers. 6) Reconnect the power supply cord after the covers are installed. 7) Run the oven and check all functions.
  • Page 13 KB-6021MS KB-6021MK TEST PROCEDURES KB-6021MW PROCEDURE COMPONENT TEST LETTER . Re-install the outer case (cabinet). 2. Reconnect the power supply cord after the outer case is installed. 3. Run the oven and check all function. DEFROST TEST WARNING : The oven should be fully assembled before following procedure.
  • Page 14 KB-6021MS KB-6021MK KB-6021MW TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 9) Discharge high voltage capacitor. 0) Reconnect all leads removed from components during testing. ) Re-install the outer case (cabinet). 2) Reconnect the power supply cord after the outer case is installed.
  • Page 15 KB-6021MS KB-6021MK KB-6021MW TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 9-2. Place the container on the center of tray in the oven cavity. 9-3. Close the drawer. 9-4. Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice and the START pad once. And touch the number pad  once and the number pad 4 once.
  • Page 16 KB-6021MS TEST PROCEDURES KB-6021MK KB-6021MW PROCEDURE COMPONENT TEST LETTER Refer to the disassembly instructions found on Page 27. MAGNETRON ASSEMBLY TEST . Disconnect the power supply cord. 2. Open the drawer and keep it open. 3. To discharge high voltage capacitor, wait for 60 seconds.
  • Page 17 KB-6021MS KB-6021MK TEST PROCEDURES KB-6021MW PROCEDURE COMPONENT TEST LETTER SECONDARY INTERLOCK SWITCH TEST . Disconnect the power supply cord. 2. Open the drawer and keep it open. 3. To discharge 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.
  • Page 18 KB-6021MS KB-6021MK KB-6021MW TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER BLOWN MONITOR FUSE TEST . Disconnect the power supply cord. 2. Open the drawer and block it open. 3. To discharge high voltage capacitor, wait for 60 seconds. 4. If the monitor fuse is blown when the drawer is opened, check the primary interlock switch, secondary interlock switch and monitor switch according to the "TEST PROCEDURE"...

  • Page 19: Touch Control Panel Assembly

    KB-6021MS KB-6021MK KB-6021MW TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units. 6) Power Source Circuit This circuit generates voltages necessary in the control () Key unit unit from the AC line voltage.
  • Page 20 KB-6021MS KB-6021MK KB-6021MW DESCRIPTION OF LSI (IC-1) The I/O signal of the LSIis detailed in the following table. Pin No. Signal Description Terminal to change cooking input according to the Model.  - 3 AN5- AN3 By using 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 21 KB-6021MS KB-6021MK KB-6021MW Pin No. Signal Description Common data signal. COM0 Connected to LCD signal C4. Connected VC (+5V). 29 - 3 P27- P25 Terminal not used. Segment data signal. SEG20 Connected to LCD segment S24. Signal coming from touch key.
  • Page 22 KB-6021MS KB-6021MK KB-6021MW Pin No. Signal Description Magnetron high-voltage circuit driving signal. Microwave cooking mode Other cooking mode VARI MODE ON TIME OFF TIME ON TIME OFF TIME To turn on and off the cook relay(RY2). In 00% 00% power 32 sec.
  • Page 23 KB-6021MS KB-6021MK KB-6021MW HUMIDITY SENSOR CIRCUIT (1) Structure of Humidity Sensor the resistance values results in that there is the same The humidity sensor includes two thermistors as shown potential at both F-3 terminal of the absolute humidity in the illustration. One thermistor is housed in the closed sensor and AN6 terminal of the LSI.
  • Page 24 KB-6021MS KB-6021MK KB-6021MW 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 This unit uses CMOS LSI in the integral part of the circuits.
  • Page 25 KB-6021MS KB-6021MK KB-6021MW PRECAUTIONS FOR USING LEAD-FREE SOLDER 1. Employing lead-free solder The "Main PWB" of this model employs lead-free solder. This is indicated by the "LF" symbol printed on the PWB and in the service manual. The suffix letter indicates the alloy type of the solder.
  • Page 26 KB-6021MS KB-6021MK KB-6021MW COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING AGAINST HIGH VOLTAGE: Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with the 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..

  • Page 27: Microwave Drawer Disassembly

    KB-6021MS KB-6021MK MICROWAVE DRAWER DISASSEMBLY KB-6021MW WARNING: Follow all safety precautions as stated at the beginning of this Service Manual before proceeding! . Before removing Microwave Drawer, take measures to protect the Drawer louver by either removing the louver or by letting the louver over hang off flat protected surface (Fig 1).
  • Page 28 KB-6021MS KB-6021MK KB-6021MW 7. To remove the Control Panel Frame Assembly, remove the (5) screws holding the CP frame to the C/P angle in the back (Fig 3). Fig. 3 8. Unsnap the top C/P frame assembly away from the C/P frame and unplug all wires.
  • Page 29 KB-6021MS KB-6021MK KB-6021MW STOP SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL . Follow the Microwave Drawer disassembly as previously Re-install stated . Re-install each switch in its place. The secondary interlock 2. Open the drawer and keep it open.
  • Page 30 KB-6021MS DRAWER/SLIDE RAIL REMOVAL KB-6021MK KB-6021MW DRAWER ASSEMBLY AND CHOKE REMOVAL . Follow the Microwave Drawer disassembly as previously NOTE: Fig. D-1 stated To remove only the 2. Open the drawer and keep it open. Microwave Drawer, follow steps 3. To discharge the high voltage capacitor, wait for 60 , 2, 5, 8, 9 &...
  • Page 31 KB-6021MS KB-6021MK SWITCH ANGLE REMOVAL/ADJUSTMENT KB-6021MW SWITCH ANGLE REMOVAL Fig. S-1 (Locate either the right or left switch angle) . Follow the Microwave Drawer disassembly as previously stated 2. Open the drawer and keep it open. 3. To discharge the high voltage capacitor, wait for 60 seconds.
  • Page 32 KB-6021MS KB-6021MK KB-6021MW AUTO DRAWER GEAR REMOVAL/INSTALLATION (This procedure requires a 4" or greater phillips head screwdriver) . Disengage the power supply to the unit. 2. Open the drawer and keep it open. 3. Remove the top cover and right side cabinet.

  • Page 33: Wiring Diagrams

    KB-6021MS KB-6021MK KB-6021MW Power Supply cord 120V 60Hz NOISE FILTER to Back Plate BOARD CN502 (SWITCHING POWER SUPPLY) CN502 CN501 MAGNETRON OVEN THERMAL THERMAL CUT-OUT CUT-OUT N.C. MONITOR COOLING SWITCH MOTOR COM. N.O. CN501 N.O. COM. (POWER SUPPLY) COM. STIRRER...

  • Page 34: Printed Wiring Boards

    KB-6021MS KB-6021MK KB-6021MW CN-A PA154DR D1 -- D4 2.5A 1N4002L x4 CN-H FUSE AC 120V VRS1 60Hz 10G471K SW Reg . 502-3 H- 9 SW Reg. OUT +24V H-11 N.O. MICRO N.O. (O.L) <NOTE> : IF NOT SPECIFIED, 1SS270A ( ) : NOT INSERT PARTS...
  • Page 35 KB-6021MS KB-6021MK KB-6021MW...
  • Page 36 KB-6021MS KB-6021MK KB-6021MW N.O. COM. N.O. COM. FUSE 2.5A Figure S-4. Printed Wiring Board of Power Unit...
  • Page 37 KB-6021MS KB-6021MK KB-6021MW...

  • Page 38: Parts List

    KB-6021MS KB-6021MK KB-6021MW CONTROL PANEL 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 39 KB-6021MS KB-6021MK KB-6021MW BOTTOM COVER 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 KB-6021MS KB-6021MK MICROWAVE DRAWER PARTS LIST KB-6021MW 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 41 KB-6021MS KB-6021MK KB-6021MW REF. NO. PART NO. § DESCRIPTION Q'TY CODE 3-58 JHNDPB073MRF0 M Door handle [KB6021MW] 3-59 FGLSPB002MRY0 M Oven tray assy 3-60 GCOVHB058MRF0 M Choke cover 3-61 PDIF-B062MRT0 M Louver [KB6021MS] 3-61 PDIF-B063MRF0 M Louver [KB6021MK] 3-61 PDIF-B064MRF0 M Louver [KB6021MW] 3-62 RMOTDA262WRZZ M Stirrer motor 3-63...
  • Page 42 KB-6021MS KB-6021MK KB-6021MW MICROWAVE DRAWER 3-28 3-14 3-28 3-28 3-28 3-40 3-55 3-73 3-49 3-29 3-11 3-28 3-68 3-28 3-28 3-28 3-71 3-27 3-39 3-28 3-45 3-28 3-15 3-28 3-57 3-25 3-28 3-46 3-24 3-27 3-28 3-75 3-28 3-28 3-44...

  • Page 43: Packing And Accessories

    KB-6021MS PACKING PARTS LIST KB-6021MK KB-6021MW 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 Q'TY CODE...
  • Page 44 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. 2007 SHARP CORP. (7R2.00E) Printed in U.S.A...

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