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KB-6021MS

KB-6021MK

KB-6021MW

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...)

S77M284K6021M-D

MICROWAVE  DRAWER 

MODEL

 

SERVICE MANUAL

TABLE OF CONTENTS

 

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 ................................................................................................................. 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

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

SHARP ELECTRONICS CORPORATION

KB-602MS pictured

KB-6021MS/MK/MW

Summary of Contents for KB-6021MK

Page 1: ...re possibly fatal electrical shock High Voltage Capacitor High Voltage Power Transformer High Voltage Rectifier Heat Sink Magnetron and High Voltage Harness etc S77M284K6021M D MICROWAVE DRAWER MODEL SERVICE MANUAL TABLE OF CONTENTS Page PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY INSIDE FRONT COVER BEFORE SERVICING INSIDE FRONT C...

Page 2: ...ion 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 Micr...

Page 3: ...n remove neccessary covers 2 Open the drawer and keep 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 ...

Page 4: ...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 3 Set the cooking control on Full Power Cooking Mode 4 Close the drawer an...

Page 5: ...ot defective C The door packing is not damaged D The door is not deformed or warped E There is not any other visible damage with the oven Servicing and repair work must be carried out only by trained service personnel DANGER Certaininitialpartsareintentionallynotgroundedandpresent a risk of electrical shock only during servicing Service personnel Do not contact the following parts while the ap pli...

Page 6: ...ate P HI 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 START MINUTE PLUS pad Defrost pad Number selection...

Page 7: ...ng this appliance observe all applicable codes and ordinances Where a two pronged wall receptacle is encountered it is the personal responsibility and obligation of the customer to con tact 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 an extension cord must be used it should be a 3...

Page 8: ... circuits to the stir fan motor the cooling fan motor and the high voltage componentsarede energized theovenlampremainson 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 secondary interlock switch and secondary interlock relay and is mechanically associated with the drawer so that ...

Page 9: ...able power Cooking Sequence 1 Touch one of the SENSOR pads 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 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 microwaveenergyisproducedandfi...

Page 10: ...250V NO IS E F IL T E R N L 120V AC 60 Hz L O W V O L T A G E FM OL SM DM N C COM C OM N O H N WHT RED GND G R N WHT WHT R E D OR G B LK OR G WHT BLK OR G C N501 3 C N501 1 RY5 T R A NS F O R ME R C N502 2 C N502 1 C N502 3 R E D B LK R E D OR G YLW BLK BLU GR N GR N GR N GR N GR N GR N GR Y WHT BLU G R N G R N R E D R E D R E D R E D OR G OR G GR Y B LK OR G OR G BLK WHT GR Y BR N BLK WHT WHT WHT...

Page 11: ...en remove covers 2 Open the drawer and block it open 3 Discharge high voltage capacitor 4 Replace the Keyboard unit 5 Reconnect all leads removed from components during testing 6 Re install the covers 7 Reconnect the power supply cord after the covers are installed 8 Run the oven and check all functions 2 Control Unit The following symptoms indicate a defective control unit Before replacing the co...

Page 12: ...or 8 Disconnect the power supply cord and then remove outer case 9 Open the door and block it open 10 Discharge high voltage capacitor 2 Open the drawer and block it open 3 Discharge high voltage capacitor 4 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 t...

Page 13: ...he varistor has been burned replace the power unit 7 Examine the touch control transformer with a tester for the presence of layer short circuit check the primary coil resistance which is approximately 151 6Ω 10 If any abnormal condition is detected replace the touch control transformer 8 Reconnect all leads removed from components during testing 9 Re install the outer case cabinet 10 Reconnect th...

Page 14: ...y in the oven cavity 3 Close the drawer 4 Touch the TIMER CLOCK pad once the POWER LEVEL pad twice and the START pad once And touch the number pad 1 once and the number pad 4 once Now the oven is in the sensor cooking condition and AH20 and ON 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...

Page 15: ...e power supply cord 9 Check the sensor cook operation proceed as follows 9 1 Close the door Touch the TIMER CLOCK pad once the POWER LEVEL pad twice and the START pad once And touch the number pad 1 once and the number pad 4 once 9 2 The control panel is in the sensor cooking operation 9 3 Afterapproximately25seconds pushplungerofselectswitchformorethan3seconds Thiscondition is same as judgement b...

Page 16: ...e 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 28 ο to 54 ο F 16 ο to 30 ο C rise in temperature If the water temperatures are accurately measur...

Page 17: ...er is open the meter should indicate a closed circuit When the monitor switch actuator is pushed by a screw driver through the lower latch hole on the front plate of the oven cavity with the drawer 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 and both the monitor swit...

Page 18: ... TO MEASURE THE FILAMENT AND HIGH VOLTAGE 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 for those switches before replacing the blown monitor fuse CAUTION BEFOREREPLACINGABLOWNMONITO...

Page 19: ...state when power is supplied 5 Indicator Circuit A circuit to drive the Liquid Crystal Displays LCD1 6 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 7 Relay Circuit A circuit to drive ...

Page 20: ...rnal clock oscillation frequency control output Output to control oscillation input of Xin 14 VCC IN Power source voltage 5V VC voltage of power source circuit input 15 P60 IN Plus signal coming from the Microwave drawer door open close motor is input into P60 as revolution number 16 P37 IN Input signal which communicates the drawer door open information to LSI from the door position switch front ...

Page 21: ... of J 11 line key on matrix is touched 39 P15 OUT Key strobe signal Signal applied to touch key section A pulse signal is input to P20 P23 terminal while one of J 10 line key on matrix is touched 40 P14 OUT Key strobe signal Signal applied to touch key section A pulse signal is input to P20 P23 terminal while one of J 9 line key on matrix is touched 41 P13 OUT Key strobe signal Signal applied to t...

Page 22: ...V 60 INT0 IN Signal to synchronize LSI with commercial power source frequency This is the basic timing for all real time processing of LSI 61 AVSS IN A D converter power source voltage The power source voltage to drive the A D converter in the LSI 62 VREF IN Reference voltage input terminal A reference voltage applied to the A D converter in the LSI Connected to 5V 63 AN7 IN AH sensor input This i...

Page 23: ...such a way as to change the resistance values in parallel with R45 R49 Changing HUMIDITY SENSOR CIRCUIT the resistance values results in that there is the same potential at both F 3 terminal of the absolute humidity sensor and AN6 terminal of the LSI The voltage of AN7 terminal will indicate about 2 5V This initial balancing is set up about 16 seconds after the unit is put in the Sensor Cookingmod...

Page 24: ...ol 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 ...

Page 25: ... tin lead alloy solder it is recommend that a dedicated bit is used and that the iron temperature is adjusted accordingly 3 Soldering As the melting point of lead free solder Sn Ag Cu is higher and has poorer wet ability flow to prevent damage to the land of the PWB extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time Remove the bit as soon as a ...

Page 26: ...Hot parts Oven lamp Magnetron High voltage transformer and Oven cavity WARNING FOR WIRING 1 Disconnect the power supply cord 2 Make sure that a definite click can be heard when the microwave oven drawer is unlatched Hold the drawer in a closed position with one hand then pull the drawer open this causes the latch leads to rise it is then possible to hear a click as the drawer switches operate 3 Vi...

Page 27: ...o access the 4 mounting screws holding the unit on to the wall or cabinet opening Fig 1 3 Close Drawer and carefully pull the unit out from opening and unplug the power supply cord 4 Remove top cover Fig 2 5 Remove air cover from back of unit then both side panels Fig 2 6 Remove exhaust duct and back cover Fig 2 NOTE You now have access to various components for the Drawer WARNING Follow all safet...

Page 28: ...ree Fig 3 POWER CORD REPLACEMENT 1 Un hook the black and white AC terminals from the Noise Filter PWB and green ground wire from the back plate Fig 4 2 Attach the black and white AC terminals from the new Power Cord to the Noise Filter as shown in figure 4 Fig 4 Note The green ground wire terminal can be attached when reassembling the back plate to the drawer cavity Un hook Attach Black AC Wire to...

Page 29: ... 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 secondary interlock switch is activated with the drawer closed The horizontal position of the latch hook should be adjusted so that the monitor switch and drawer sensing switch are activated with the drawer closed 8 Secure the screws with washers firmly 9...

Page 30: ...that drawer sensing switch secondary interlock switch and monitor switch are operating properly Refer to chapter Test Procedures B An approved microwave survey meter should be used toassurecompliancewithpropermicrowaveradiation emission limitation standards After any servicing make sure of the following 1 Drawer latch heads smoothly catch latch hook through latch holes and that latch head goes thr...

Page 31: ...E REMOVAL ADJUSTMENT SWITCH ANGLE REMOVAL Fig S 1 Fig S 2 ACTUATOR REMOVAL ADJUSTMENT 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 Locate either the right or left actuator and remove the 2 screws holding the actuator to the door support angles 5 Relpace with the new actuator Fig A 3...

Page 32: ...re set into the cavity angle correctly before tightening screws careful not to touch PWB 1 Follow the Microwave Drawer disassembly as previously stated above 2 Open the drawer and keep it open 3 To discharge the high voltage capacitor wait for 60 seconds 4 Remove the Microwave Drawer by following steps under DRAWER SUPPORT ANGLE REMOVAL 5 Remove the 3 screws holding the Rack Gear to the bottom sli...

Page 33: ...ER BOARD N H WHT RED CONTROL UNIT CNK CNM CNN CNE SWITCHING POWER SUPPLY CN501 CN502 T1 1 2 3 4 5 GRN BLU WHT CNM RY1 N O RY1 COM RY2 N O RY2 COM 1 2 3 4 5 6 7 BLK WHT BRN CNA BLK ORG BLK RED ORG ORG ORG GRN BLK 1 2 3 CNB GRY 1 2 3 CN501 BLK GRY GRY 1 2 3 4 5 BLU BLK RED CNN YLW 1 2 3 CNE BLK RED 1 2 3 4 5 6 7 GRY WHT CNK 8 GRY GRY GRY GRY GRY GRY 1 2 3 4 5 6 7 GRY RED WHT CNH 9 8 10 11 GRY GRY GR...

Page 34: ...RY2 COM N O D7 RY1 COM N O D10 RY3 D11 RY4 D12 RY5 H 1 H 3 H 2 H 4 H 5 H 7 H 6 AC 120V MICRO COM O L FM SM 0 1uF 50V NOTE IF NOT SPECIFIED 1SS270A 10G471K A 5 A 1 H 8 1 3 8 5 B 1 C10 C11 NOT INSERT PARTS T1 VR GND INT 0 1u 250V R10 1 2W 120 R11 1 2W 120 0 1u 250V A 7 A 3 B 3 SW Reg PWR D4 D3 D2 D1 H 9 H 11 K 1 K 3 K 2 K 8 502 3 E 3 K 4 K 6 K 5 K 7 J10 SW Reg OUT 24V J11 CN H CHECK POINTS ...

Page 35: ...5 4 7K R56 C52 M 5 4 7K 10K 10K R58 C51 R55 R57 SP D19 D20 Q22 Q21 C20 C21 Q20 AN5 CF1 4MHz 1 2 3 7 5 6 CONTROL UNIT 4 7K R13 4 7K R12 P05 P51 P57 C3 S22 S23 SEG22 SEG23 COM2 10uF 35V VR GND INT 47K C5 C4 S24 R69 R68 3 3K 1 5K C3 R52 10uF 35V C8 KIA78L05BP Q4 O C I C7 C6 10uF 35V R8 KRA224S KRA117S 10uF 35V 200 1w x2 2W C12 CN K M 2 CN M KTC1027 KTC1027 AN4 K 4 KRC101S KRC101S KTC3875 LCD COM0 COM...

Page 36: ... 2 3 A B C D E F G H A B C D E F G H Figure S 4 Printed Wiring Board of Power Unit 2 5A 3 1 2 FUSE T1 4 8 D3 ZD1 J10 RY1 D12 RY5 DIP CNH Q1 R1 D2 D1 1 11 D4 1 1 R10 C10 RY2 1 3 P 3 D11 D10 7 CNA CNB C11 R11 RY4 RY3 COM COM N O N O C1 C2 R3 J11 D7 D5 VRS1 ...

Page 37: ...6 K SP C0 S0 S0 S24 C4 C5 R29 CF2 S24 C4 C5 C3 S0 C0 SP C90 C8 C6 C5 C3 C21 R27 R26 R28 C90 C90 R98 R96 R99 R95 D96 K D95 K D97 K Q97 R97 R41 J2 J1 J4 J6 K J3 C5 C6 D19 K D20 K ZD2 R7 1 1 8 6 Q26 WHA Q23 Q21 Q25 Q22 1 7 Q20 R8 Q4 C51 R56 R55 C22 C23 C52 R21 R24 R58 R20 R23 R57 R47 R48 R49 Q6 64 R45 49 48 33 17 32 R51 R52 R50 12 2 11 1 CNJ R40 R36 R38 R37 R35 IC5 IC6 C43 R44 R43 C42 Q96 Q95 LCD 5 1...

Page 38: ... 1 BP 1 2 FUNTKB498MRE0 M Key unit KB6021MS KB6021MK 1 AR 1 2 FUNTKB499MRE0 M Key unit KB6021MW 1 AR 1 3 FPNLCB533MRK0 M C P frame assy KB6021MS 1 AX 1 3 FPNLCB527MRK0 M C P frame assy KB6021MK 1 AX 1 3 FPNLCB528MRK0 M C P frame assy KB6021MW 1 AX 1 4 PCOVPB140MRP0 M C P cover 1 AM 1 5 PCUSUB106MRP0 M C P cushion 2 AA 1 6 LANGTB182MRP0 M C P angle 1 AM 1 7 XEPS730P10XS0 M Screw 4 AA 1 8 PSEL B002M...

Page 39: ... 2 7 2 7 2 2 2 4 2 3 2 1 2 7 2 7 2 6 2 5 2 8 2 7 2 1 PCOVPB168MRP0A M Bottom cover 1 AN 2 2 LANG B043MRP0 M Air guide L 1 AQ 2 3 LANG B047MRP0 M Air guide R 1 AN 2 4 PSKR B023MRP0 M Partition angle 1 AH 2 5 PCUSUB104MRP0 M Bottom cushion A 1 AB 2 6 PCUSGB063MRP0 M Bottom cushion B 1 AB 2 7 XOTS740P12000 M Screw 14 AB 2 8 PDUC B173MRF0 M Exhaust guide 1 AP REF NO PART NO DESCRIPTION Q TY CODE ...

Page 40: ...25 FC QZB052MRK0A M HVC assy 1 AP 3 26 LBNDKB007MRP0 M HVC band 1 AB 3 27 XCBS730P08000 M Screw 3 AB 3 28 XOTS740P12000 M Screw 79 AA 3 29 PCOVPB169MRP0A M Top cover 1 AE 3 30 TLAB B060MRR0 M Menu label 1 AC 3 31 XOTS740P12RV0 M Screw 4 AB 3 32 XEPS730P10XS0 M Power unit assy screw 2 AC 3 33 DDORFB134MRK0 M Door assy KB6021MS 1 BT 3 33 DDORFB135MRK0 M Door assy KB6021MK 1 BS 3 33 DDORFB136MRK0 M D...

Page 41: ...label 1 AA 3 64 FANGTB019MRK0 M Auto drawer gear assy 1 BL 3 65 LANGTB217MRP0 M Switch angle L 2 AC 3 66 MACT B003MRF0 M Actuator R 1 AD 3 67 MACT B004MRF0 M Actuator L 1 AD 3 68 DPWBFC526WRKZ M SW power supply 1 BM 3 69 NGERRB005MRF0 M Rack gear 2 AQ 3 70 LANGTB218MRP0 M Switch angle R 1 AC 3 71 LHLD B035MRF0 M Switch PSU holder 1 AC 3 72 LANGTB180MRP0 M Louver angle 1 AL 3 73 PCOVPB130MRP0 M Cov...

Page 42: ... 22 3 1 3 15 3 24 3 25 3 26 3 62 3 44 3 45 3 56 3 46 3 11 3 14 3 13 3 18 3 32 3 76 3 32 3 41 3 41 3 42 3 42 3 41 3 28 3 28 3 28 3 28 3 28 3 28 3 27 3 28 3 28 3 27 3 42 3 28 3 28 3 32 3 28 3 28 3 28 3 28 3 28 3 28 3 28 3 28 3 10 3 10 3 10 3 6 3 6 3 38 3 4 3 66 3 67 3 65 3 70 3 28 3 28 3 69 3 78 3 27 3 64 3 28 3 68 3 71 3 55 3 46 3 28 3 40 3 49 3 28 3 28 3 28 3 28 3 53 3 53 3 28 3 59 3 61 3 21 3 21 ...

Page 43: ...s Delivery Section REF NO PART NO DESCRIPTION Q TY CODE 4 1 TINSEB486MRK0 M Operation manual 1 AE 4 2 TINSEB487MRR0 M Installation instructions 1 AC 4 3 XTPS740P20000 M Wood screws 4 AA INSTALLION SHEET OPERATION MANUAL WOOD SCREWS 4 3 4 1 4 2 SUPPORT CORNERS Non replaceable items TOP FOAM SUPPORT CORNERS BOTTOM FOAM SUPPORT CORNERS SUPPORT CORNERS TOP FOAM PACKING CASE ...

Page 44: ... COPYRIGHT 2007 BY SHARP CORPORATION ALL RIGHTS RESERVED Nopartofthispublicationmaybereproduced 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 ...

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