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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 and Heat sink etc., and Magnetron, High Voltage Harness etc..)
BEFORE SERVICING ...................................................................................................... INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL ............................................................................................................... 1
MICROWAVE MEASUREMENT PROCEDURE .....................................................................................................3
FOREWORD AND WARNING ................................................................................................................................5
PRODUCT SPECIFICATIONS ............................................................................................................................... 6
POWER CONNECTION .........................................................................................................................................7
ANTI-TIP DEVICE ................................................................................................................................................. 8
CONTROL LAYOUT .............................................................................................................................................. 9
SCHEMATICS ..................................................................................................................................................... 10
TEST PROCEDURES .......................................................................................................................................... 13
TOUCH CONTROL PANEL ASSEMBLY ............................................................................................................. 24
COOK TOP/MICROWAVE DRAWER DISASSEMBLY ........................................................................................ 32
WIRING DIAGRAMS ........................................................................................................................................... 39
PRINTED WIRING BOARDS ............................................................................................................................... 44
PARTS LIST ........................................................................................................................................................ 47
PACKING AND ACCESSORIES ......................................................................................................................... 55
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
MODELS

TABLE OF CONTENTS

COOK TOP
WITH
MICROWAVE DRAWER
KB-5121KS
KB-5121KK
KB-5121KW
1
KB-5121KS/K/W
S15R256KB5121
Page

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   Summary of Contents for Sharp KB-5121KS

  • 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 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

    KB-5121KS/K/W WARNING TO SERVICE PERSONNEL Range 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: Safe Servicing Practices

    6. Prior to returning the product to service, ensure that: • All electrical connections are correct and secure • All electrical leads are properly dressed and secured away from sharp edges, high-temperature components, and moving parts • All non-insulated electrical terminals, connectors, heaters, etc. are adequately spaced away from all metal parts and panels •...
  • Page 5: Microwave Measurement Procedure

    KB-5121KS/K/W 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...
  • Page 6 KB-5121KS/K/W NOTES...
  • Page 7: Foreword And Warning

    KB-5121KS / KB-5121KK / KB-5121KW ANTI-TIP DEVICE FOREWORD SCHEMATICS This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP COOK TOP WITH MICROWAVE DRAWER, KB-5121KS/JK/ TEST PROCEDURE 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 8: Product Specifications

    KB-5121KS/K/W COOK TOP SPECIFICATION ITEM DESCRIPTION Power Requirements 120 /208 - 120/240Volts / 46/50 Amperes 60 Hertz Single phase, 3 wire grounded Cook Top Heating Elements Two 6" - 1200W One 8" - 2000W One 6"/9" - 1200/2400W One 6" - 100W...
  • Page 9: Power Connection

    KB-5121KS/K/W POWER CONNECTION SELECTING 208 OR 240 VOLT CONNECTION 4-WIRE CONNECTION This appliance can be set for 208V or 240V. The voltage setting for When installing to a 4-wire electrical system, new construction, your appliance is pre-set at 240V from the factory. Follow these mobile home and recreational vehicle or when local codes do not steps to change the voltage setting.
  • Page 10: Anti-tip Device

    KB-5121KS/K/W ADJUST ANTI-TIP BRACKET Measure the thickness of the counter. See Figure 6. Locate the Anti-Tip Bracket on the backside of the appliance. See Figure 7. Loosen screws and adjust space between the glass cooktop and bracket to match the counter thickness plus 1/16”. See Figure 8.
  • Page 11: Control Layout

    KB-5121KS/K/W KB-5121KS...
  • Page 12: Schematics

    KB-5121KS/K/W Schematic-Off Condition COOK TOP BLK *3 RED *3 NOISE FILTER BOARD FUSE RESISTOR 470 kW 1/2W LINE CROSS CAPACITOR 1.0 F 250V NOISE SUPRESSION COIL LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR 0.0033 F 250V 0.0033 F 250V DOOR SENSING...
  • Page 13 KB-5121KS/K/W COOK TOP SCHEMATIC (DETAIL) CONTROL INDICATOR LIGHT P1B / INSIDE OUTSIDE P1A/ PROTECTOR RIGHT FRONT SURFACE ELEMENT YLW*2 P 1 / Y LW W H T R E D CONTROL Y LW RIGHT REAR SURFACE ELEMENT PROTECTOR P 1 /...
  • Page 14 KB-5121KS/K/W MICROWAVE DRAWER SCHEMATIC (DETAIL) NOISE FILTER BOARD FUSE RESISTOR 470 kW 1/2W LINE CROSS CAPACITOR 1.0 F 250V NOISE SUPRESSION COIL LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR 0.0033 F 250V 0.0033 F 250V DOOR SENSING SWITCH HUMIDITY SENSOR FAN MOTOR...
  • Page 15: Test Procedures

    KB-5121KS/K/W TEST PROCEDURES 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 16 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 4) Reconnect all leads removed from components during testing. 5) Re-install the covers. 6) Reconnect the power source after the outer case is installed. 7) Run the oven and check all functions. KEYBOARD UNIT TEST 1.
  • Page 17 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 8. Reconnect all leads removed from components during testing. 9. Re-install the covers. 10. Reconnect the power source after the cabinets are installed. 11. Run the drawer and check all function. DEFROST TEST WARNING : The unit should be fully assembled before following procedure.
  • Page 18 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER STEPS OCCURRENCE CAUSE OR CORRECTION The rated AC voltage is not present between Check supply voltage and oven power cord. Pin Nos. 1and 3 of the 2-pin connecter (CN-B). The rated AC voltage is present at primary Touch control transformer or secondary circuit defective.
  • Page 19 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER (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 source after the cabinets are installed. (9) Reconnect the oven to the power supply and check the sensor cook operation as follows: 9-1.
  • Page 20 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER ELEMENTCONTROL SYSTEMS SURFACE Di al Posit ion Contacts LO-MED Two types of surface elements control systems are L1 - P covered in this manual. L1 - H 1 Standard infinite switch. L2 - H 2 X - C Dual infinite switch.
  • Page 21 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER between the switch and the element are open. If the meter reads line to line voltage the element is defective. Element does not cycle: If the element does not cycle when the switch is set in a position other than high the switch is defective.
  • Page 22 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER Both elements do not heat: With the switch turned clockwise to the high position measure the voltage drop between Checking the system with a Voltmeter, if the elements terminals 4 and 2. If the meter reads zero do not heat up: the switch is defective.
  • Page 23 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER MAGNETRON ASSEMBLY TEST 1. Disconnect the power source. 2. Open the drawer and keep it open. 3. To discharge high voltage capacitor, wait for 60 seconds. 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.
  • Page 24 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER SECONDARY INTERLOCK SWITCH TEST 1. Disconnect the power source. 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 25 KB-5121KS/K/W TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER BLOWN MONITOR FUSE TEST 1. Disconnect the power source. 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 26: Touch Control Panel Assembly

    KB-5121KS/K/W TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL In addition, the synchronizing signal is available in order The touch control section consists of the following units. to compose a basic standard time in the clock circuit. (1) Keyboard unit...
  • Page 27 KB-5121KS/K/W DESCRIPTION OF LSI (IC-1) The I/O signal of the LSIis detailed in the following table. Pin No. Signal Description Signal coming from Transparent electrode (touch key on the LCD). When the 1 key of the transparent electrode is touched, a corresponding signal out of OUT1 of IC-2 will be input into P96 of IC-1.
  • Page 28 KB-5121KS/K/W Pin No. Signal Description INT0 Signal to synchronize LSI with commercial power source frequency. This is the basic timing for all real time processing of LSI. H : +5V L : GND 16.7 msec. Signal to change the rotational direction is output to the Microwave drawer door open-close motor.
  • Page 29 KB-5121KS/K/W Pin No. Signal Description Reset signal is outout to the LCD. Chip select signal is outout to the LCD. Terminal not used. Terminal not used. Signal to turn on the indicator for the Cook Top Warmer is output to the LED (LD10).
  • Page 30 KB-5121KS/K/W Pin No. Signal Description “L” level: During fan motor OFF. 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. 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.
  • Page 31 KB-5121KS/K/W HUMIDITY SENSOR CIRCUIT (1) Structure of Humidity Sensor potential at both F-3 terminal of the absolute humidity The humidity sensor includes two thermistors as shown sensor and AN5 terminal of the LSI. The voltage of AN6 in the illustration. One thermistor is housed in the closed terminal will indicate about +2.5V.
  • Page 32 KB-5121KS/K/W TOUCH CONTROL PANEL SERVICING touch control panel and the oven itself is so short that the 1. Precautions for Handling Electronic Components two can’t be separated. For those models, check and This unit uses CMOS LSI in the integral part of the repair all the controls (sensor-related ones included) of circuits.
  • Page 33 KB-5121KS/K/W 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 34: Cook Top/microwave Drawer Disassembly

    KB-5121KS/K/W COOK TOP / MICROWAVE DRAWER DISASSEMBLY WARNING: Follow all safety precautions beginning on Page 2 before proceeding! CAUTION: Before performing any of the disassembly, disconnect the power source! Fig. 1 1. Before removing Control Panel, take measures to protect the Cook Top surface and keep Microwave Drawer open to prevent scratches.
  • Page 35 KB-5121KS/K/W 10. Remove screws from Control Panel Frame (Fig 4). Fig. 4 Control Panel Frame 11. Slide Cook Top forward to unlock from shoulder screws, then remove or reposition (Fig. 5). Fig. 5 Before you can Slide the Cook Top...
  • Page 36 KB-5121KS/K/W STOP SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL 1. Disconnect the power source. Re-install 2. Open the drawer and keep it open. 1. Re-install each switch in its place. The secondary interlock 3. To discharge the high voltage capacitor, wait for 60 switch is in the lower position and the monitor switch is in seconds.
  • Page 37 KB-5121KS/K/W DRAWER/SLIDE RAIL REMOVAL DRAWER ASSEMBLY AND CHOKE REMOVAL NOTE: 1. Disconnect the power source. To remove only the Fig. D-1 2. Open the drawer and keep it open. Microwave Drawer, follow steps 3. To discharge the high voltage capacitor, wait for 60 1, 2, 5, 8, 9 &...
  • Page 38 KB-5121KS/K/W SWITCH ANGLE REMOVAL/ADJUSTMENT Fig. S-1 SWITCH ANGLE REMOVAL (Locate either the right or left switch angle) 1. 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 39 KB-5121KS/K/W AUTO DRAWER GEAR REMOVAL 1. 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. 4. Unhook wiring Auto Drawer Gear. 5. Remove the (4) screws holding the auto drawer gear to the bottom cavity angle (Fig. G-1).
  • Page 40 KB-5121KS/K/W COOK TOP RADIANT HEATERS/HOT SURFACE INDICATOR REMOVAL 1. Disconnect the power source. 2. Refer to the disassembly instructions as previously stated. 3. After Cook Top Assembly is free, turn upside down (glass side down) on a protective surface to prevent scratching (Fig.
  • Page 41: Wiring Diagrams

    KB-5121KS/K/W CONTROL PANEL WIRING DIAGRAM...
  • Page 42 KB-5121KS/K/W COOK TOP WIRING DIAGRAM...
  • Page 43 KB-5121KS/K/W MICROWAVE DRAWER WIRING DIAGRAM (N.C.) (N.O.) (COM)
  • Page 44 KB-5121KS/K/W...
  • Page 45 KB-5121KS/K/W...
  • Page 46: Printed Wiring Boards

    KB-5121KS/K/W VRS1 RY7 RY8 Figure S-4. Printed Wiring Board of Power Unit...
  • Page 47 KB-5121KS/K/W LCD1 R100 R101 R102 R103 R104 R105 LD10 QPWBFA851DRZZ B C E B C E Figure S-5. Printed Wiring Board of Control Unit...
  • Page 48 KB-5121KS/K/W Stop OPEN START Clear CLOSE Minute Kitchen Timer Plus Setup Cook top Control Lock Warm (On) On/Off (Set Off) IC44 QPWBFA850DRZZ Figure S-5. Printed Wiring Board of Keyboard Unit...
  • Page 49: Parts List

    KB-5121KS/K/W CONTROL PANEL PARTS LIST Note: The parts marked “Δ Δ Δ Δ Δ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. " §" MARK: PARTS DELIVERY SECTION REF. NO. PART NO.
  • Page 50: Control Panel

    KB-5121KS/K/W CONTROL PANEL 1-17 1-16 1-17 1-20 1-15 1-11 1-16 1-20 1-14 1-11 1-10 1-10 1-13 1-12 1-19 1-18 CONTROL PANEL HARNESS 1-12 1-19 Actual wire harness may be different from illustration.
  • Page 51 KB-5121KS/K/W COOK TOP PARTS LIST Note: The parts marked “Δ Δ Δ Δ Δ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. " §" MARK: PARTS DELIVERY SECTION REF. NO. PART NO.
  • Page 52 KB-5121KS/K/W 2-12 2-15 2-12 2-14 2-10 2-11 2-13 2-12 2-13 2-12 Actual wire harness may be different from illustration.
  • Page 53 KB-5121KS/K/W MICROWAVE DRAWER PARTS LIST Note: The parts marked “Δ Δ Δ Δ Δ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. " §" MARK: PARTS DELIVERY SECTION REF. NO. PART NO.
  • Page 54 KB-5121KS/K/W REF. NO. PART NO. § DESCRIPTION Q'TY CODE 3-59 FGLSPB002MRY0 Oven tray assy 3-60 GCOVHB052MRF0 Choke cover 3-61 PDIF-B053MRT0 Louver [KB5121KS] 3-61 PDIF-B054MRT0 Louver [KB5121KK] 3-61 PDIF-B055MRT0 Louver [KB5121KW] 3-62 RMOTDA262WRZZ Stirrer motor 3-63 TCAUHB009MRR0 User caution label 3-64...
  • Page 55 KB-5121KS/K/W MICROWAVE DRAWER 3-28 3-28 3-81 3-28 3-82 3-75 3-14 3-76 3-28 3-28 3-40 3-80 3-79 3-28 3-55 3-49 3-11 3-28 3-39 3-68 3-28 3-71 3-27 3-45 3-28 3-28 3-15 3-28 3-28 3-25 3-46 3-57 3-24 3-28 3-27 3-54 3-28...
  • Page 56 KB-5121KS/K/W BOTTOM COVER PARTS LIST Note: The parts marked “Δ Δ Δ Δ Δ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. " §" MARK: PARTS DELIVERY SECTION REF. NO. PART NO.
  • Page 57: Packing And Accessories

    KB-5121KS/K/W PACKING PARTS LIST Note: The parts marked “Δ Δ Δ Δ Δ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. " §" MARK: PARTS DELIVERY SECTION REF. NO. PART NO.
  • Page 58 KB-5121KS/K/W NOTES...
  • Page 59 KB-5121KS/K/W NOTES...
  • Page 60 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. (5R2.00E) Printed in U.S.A...

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Kb-5121kkKb-5121kw

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