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R-120DB
R-120DK
R-120DR
R-120DW

SHARP ELECTRONICS CORPORATION

SHARP PLAZA, MAHWAH,

NEW JERSEY 07430-2135

SERVICE MANUAL

MICROWAVE OVEN

R-120DB/ R-120DK/ R-120DR/ R-120DW

FOREWORD

This Manual has been prepared to provide Sharp Electronics Corp.
Service Personnel with Operation and Service Information for the
SHARP MICROWAVE OVEN, R-120DB, R-120DK, R-120DR, R-
120DW.

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.

Check the interlock switches and the door seal carefully. Special
attention should be given to avoid electrical shock and microwave
radiation hazard.

WARNING

Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is no other visible damage with the oven.

Servicing and repair work must be carried out only by trained service
personnel.

DANGER

Certain initial parts are intentionally not grounded and present
a risk of electrical shock only during servicing. Service
personnel - Do not contact the following parts while the
appliance is energized;
High Voltage Capacitor, Power Transformer, Magnetron,
High Voltage Rectifier Assembly,  High Voltage Harness;
If provided, Vent Hood, Fan assembly, Cooling Fan Motor.

All the parts marked “*” on parts list are used at voltages more than
250V.

Removal of the outer wrap gives access to voltage above 250V.

All the parts marked “

” on parts list may cause undue microwave

exposure, by themselves, or when they are damaged, loosened
or removed.

PRODUCT DESCRIPTION

GENERAL INFORMATION

OPERATION

TROUBLESHOOTING GUIDE AND
TEST PROCEDURE

TOUCH CONTROL PANEL

COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE

WIRING DIAGRAM

PARTS LIST

Summary of Contents for R-120DB

Page 1: ...ECAUTIONS 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 1 MICROWAVE MEASUREMENT PROCEDURE 2 FOREWORD AND WARNING 3 PRODUCT SPECIFICATIONS 4 GENERAL INFORMATION 4 OPERATION 6 TROUBLESHOOTING GUIDE 8 TEST PROCEDURE 10 TOUCH CONTROL PANEL 16 COMPONENT REPLACEMENT A...

Page 2: ...e generation 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...

Page 3: ...ltage 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 outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4...

Page 4: ...center of the oven cavity The water 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 4 Set the cooking control on Full Powe...

Page 5: ...ective C The door packing is not damaged D The door is not deformed or warped E There is no 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 appliance is ener...

Page 6: ...ibility and obligation of the customer to contact 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 the extension cord must be used it should be a 3 wire 15 amp or higher rated cord Do not drape over a countertop or table where it can be pulled on by children or tripped over accidentall...

Page 7: ... 14 Stop Clear button TOUCH CONTROL PANEL 3 Pronged Plug Grounded Receptacle Box Grounding Pin 3 Pronged Receptacle NOTE 1 Open the door to program the oven 2 The STOP CLEAR and the START MINUTE PLUS pads can be used even if the door closed 3 MINUTE PLUS feature is disabled after one minute when the oven is not in use This feature is automatically enabled when the door is opened and closed or the ...

Page 8: ...then into the cavity where the food is placed to be cooked 5 Upon completion of the cooking time the power transformer oven lamp etc are turned off and the generation of microwave energy is stopped The oven will revert to the OFF condition 6 When the door is opened during a cook cycle the monitorswitch doorsensingswitch secondaryinterlock switch and primary interlock relay are activated with the f...

Page 9: ...dition due to their being normally closed At this time the primary interlock relay RY2 and secondary interlock switch are in the OFF condition contacts open due to its being normally open contact switches 2 As the door goes to a closed position the monitor switch contacts are first opened and then the door sensing switch and secondary interlock switch contacts close 3 If the door is opened and the...

Page 10: ...ubleshooting is performed with the power supply cord disconnected It may in some cases be necessary to connect the power supply cord after the outer case has been removed in this event 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 Disconnect the leads to the primary of the power transformer 5 Ensure that the lea...

Page 11: ...ged into wall outlet Display does not operate properly when STOP CLEAR key is touched Buzzer should sound and time of day should appear in display C T fuse blows when the door is opened Fan motor does not operate All other electric components function Oven lamp does not light at all All other electric components function Turntable motor does not operate All other electric components function Oven ...

Page 12: ...OULD BE OBSERVED Power output of the magnetron can be measured by performing a water temperature rise test This test shouldonlybeusedifabovetestsdonotindicateafaultymagnetronandthereisnodefectinthefollowing componentsorwiring siliconrectifier highvoltagecapacitorandpowertransformer Thistestwillrequire a 16 ounce 453cc measuring cup and an accurate mercury thermometer or thermocouple type temperatu...

Page 13: ... the thermal cut out opens The thermal cut out will reset automatically below approximately 167 F 75 C An open thermal cut out indicates overheating of the magnetron Check for restricted air flow to the magnetron especially the cooling fan air guide 5 Reconnect all leads removed from components during testing 6 Reinstall the outer case cabinet 7 Reconnect the power supply cord after the outer case...

Page 14: ...ed replace the secondary interlock switch 5 Reconnect all leads removed from components during testing 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 Disconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 Dischar...

Page 15: ...N CIRCUIT AT ROOM TEMPERATURE REPLACE THE C T FUSE 5 Reconnect all leads removed from components during testing 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 The touch control panel consists of circuits including semiconductors such as LSI ICs etc Therefore unlike conventional microwave ovens proper mai...

Page 16: ... an ohmmetershouldindicateashort circuit If improperoperationisindicated thetactswitch is probably defective and should be checked 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 Disconnect the leads to the primary of the power transformer 5 Ensure that these leads remain isolated from other components and oven ch...

Page 17: ...for repair STEPS OCCURRENCE CAUSE OR CORRECTION 1 Only pattern at a is broken Insert jumper wire J1 and solder 2 Pattern at a and b are broken Insert the coil RCILF2003YAZZ between c and d 5 Make a visual inspection of the varistor Check for burned damage and examine the transformer with a tester for the presence of layer short circuit check the primary coil resistance which is approximately 563Ω ...

Page 18: ...pplication VC 5V LSI IC1 4 Relay Circuit To drive the magnetron fan motor turntable motor and light the oven lamp 5 Buzzer Circuit The buzzer is responsive to signals from the LSI to emit audible sounds tact switch touch sound and completion sound 6 Synchronizing Signal Circuit The power source synchronizing signal is available in order to compose a basic standard time in the clock circuit It acco...

Page 19: ...ch When either one of tact switches SW4 SW5 SW6 and SW7 on switch matrix is touched a corresponding signY out of P10 P13 will be input into AIN5 16 AIN6 IN Signal coming from touch tact switch When either one of tact switch SW1 SW2 and SW3 on switch matrix is touched a corresponding signal out of P10 P13 will be input into AIN6 when no key is touched the signal is held at H level 17 AIN7 IN To inp...

Page 20: ...LSI signal Pin No LCD Pin No SEG 0 51 S1 SEG 6 45 S7 SEG 1 50 S2 SEG 7 44 S8 SEG 2 49 S3 SEG 8 43 S9 SEG 3 48 S4 SEG 9 42 S10 SEG 4 47 S5 SEG 10 41 S11 SEG 5 46 S6 SEG 11 40 S12 52 COM3 OUT Terminal not used 53 COM2 OUT Common data signal COM1 Connected to LCD Pin No C3 54 COM1 OUT Common data signal COM2 Connected to LCD Pin No C2 55 COM0 OUT Common data signal COM1 Connected to LCD Pin No C1 56 ...

Page 21: ... After aluminium foil is removed be careful that abnormal voltage due to static electricity etc is not applied to the input or output terminals 4 Attach connectors electrolytic capacitors etc to PWB making sure that all connections are tight 5 Be sure to use specified components where high precision is required 1 Precautions for Handling Electronic Components This unit uses CMOS LSI in the integra...

Page 22: ... and High voltage rectifier assembly 2 Hot parts Oven lamp Magnetron High voltage transformer and Oven cavity WARNING FOR WIRING 1 Disconnect the power supply cord 2 Visuallycheckthedoorandcavityfaceplatefordamage dents cracks signs of arcing etc Carry out any remedial work that is necessary before operating the oven Do not operate the oven if any of the following conditions exist 1 Door does not ...

Page 23: ...citor holder 8 Disconnect all the leads and terminals of high voltage rectifier assembly from high voltage capacitor 9 Now the H V rectifier assembly and H V capacitor should be free CAUTION WHEN REPLACING HIGH VOLTAGE RECTI FIER ASSEMBLY ENSURE THAT THE CATH ODE GROUND CONNECTION IS SE CURELY FIXED TO THE CAPACITOR HOLDER WITH A GROUNDING SCREW CAUTION DO NOT REPLACE ONLY HIGH VOLTAGE RECTIFIER W...

Page 24: ...hown in Figure C 4 4 Re install the turntable motor with the O ring and washer to the oven cavity with the single 1 screw 5 Re connect the wire leads to the turntable motor 6 Insert the tab of the turntable motor cover into the hole of Terminal Push Pull down 4 5 Lever Positive lock connector Oven lamp socket Terminal Wire lead Terminal hole Flate type small screw driver 7 Then lift up the control...

Page 25: ...ith your hand 18 Now the fan blade will be free CAUTION Do not re use the removed fan blade because the hole for shaft may be larger than normal 19 Remove the two 2 screws holding the fan motor to the fan duct 20 Now the fan motor is free Figure C 3 Turntable Motor Cover Figure C 4 Washer and O ring Installation and Grease Applying Washer O ring Base of turntable motor shaft Turntable motor O ring...

Page 26: ...pen 3 Themonitorswitchcontactsclosewhenthedoorisopened 5 Re install outer case and check for microwave leakage around the door with an approved microwave survey meter Refer to Microwave Measurement Procedure 1 Disconnect the power supply cord and remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Disconnect wire leads from the switches 5 Remove two 2 screws ho...

Page 27: ...install choke cover to door panel by pushing 7 Catch two 2 pins of door panel on two 2 hole of upper and lower oven hinges 8 Re install door stoper to door panel by pushing Note After any service to the door A Make sure that door 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 t...

Page 28: ...unding conductor of the power supply cord has been grounded by power supply cord fixing screw The screw must allways be kept tight NOTE The neutral WHT wire must be connected to the terminal with N mark on the power supply cord RED WHT DOOR SENSING SWITCH To fan duct BLU BLK POWER TRANSFORMER HIGH VOLTAGE WIRE BLK Blue Mark NOTE Hot RED wire must be connected to the terminal with blue mark on the ...

Page 29: ...k AIN7 VAREF AVDD P10 P11 P12 P13 P14 P15 P16 P17 P50 P51 P52 P53 P54 S12 S11 S10 S9 S8 S7 S6 S5 S4 S3 S2 S1 C1 C2 C3 SEG3 VSS XIN XOUT TEST VDD P21 P22 RESET P20 AIN0 AIN1 AIN2 INT0 AIN4 AIN5 AIN6 SEG4 SEG5 SEG6 SEG7 SEG8 SEG9 P57 P56 P55 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 P32 P33 P31 P30 C0 C1 V1 V2 V3 COM0 COM1 COM2 COM3 SEG0 SEG1 SEG2 R10 15k R40 4 7k R70 100k R71 100k R72 100k R20 15k A 1 NO...

Page 30: ...0 B B R5 R30 SP1 CN B 1 2 D22 L E 4 Q20 C21 C2 C1 D3 1 3 3 1 T1 7 4 D4 D1 D2 RY1 RY2 VRS1 CN A D20 D21 1 C20 B F 5 R4 C8 13 14 9 8 C3 CF1 J13 J11 J10 J12 J14 J15 J13 J11 R70 R71 12 11 10 C61 C11 C40 7 6 R6 R5 R10 R40 R20 D40 Q22 Q21 Q10 J1 C10 C20 B E E E B B 3 2 ZD1 C3 C4 C60 R7 CF1 R8 R9 C62 R72 C8 Q1 Q30 R30 R4 SW7 SW8 SW5 SW10 E B 4 Q20 C21 RY1 RY2 D20 D20 1 C2 VRS1 C1 D1 4 3 T1 CN A 1 3 S P 7...

Page 31: ... PPACGA175WREZ Packing 1 AF OVEN PARTS 4 1 PHOK A117WRPZ Latch hook 1 AH 4 2 PDUC A740WRWZ Air intake duct 1 AD 4 3 LBNDKA132WRP0 H V Capacitor holder 1 AD 4 4 PDUC A736WRPZ Magnetron air duct 1 AF 4 5 PDUC A743WRPZ Exhaust duct 1 AD 4 6 PCUSUA541WRPZ Cushion 1 AC 4 7 PDUC A745WRWZ Fan duct 1 AE 4 8 NFANJA029WRE0 Fan blade 1 AL 4 9 PCUSUA540WRPZ Cushion 1 AC 4 10 PDUC A752WRFZ Top air separator 1 ...

Page 32: ...ecial screw 4 AB 7 4 LX CZ0052WRE0 Special screw 2 AA 7 5 LX CZA070WRE0 Special screw Torx tamper proof screw 2 AC 7 6 LX WZA028WRE0 Special washer 1 AB 7 7 XHTSD40P12RV0 Screw 4mm x 12mm 1 AA 7 8 XHPSD40P08K00 Screw 4mm x 8mm 6 AA 7 9 XHPSD30P06000 Screw 3mm x 6mm 2 AA 7 10 XHTSD40P08RV0 Screw 4mm x 8mm 6 AA 7 11 XOTSD40P12RV0 Screw 4mm x 12mm 4 AA 7 12 XOTWW40P08000 Screw 4mm x 8mm 2 AB 7 13 XHT...

Page 33: ...7 5 7 8 1 8 4 5 4 4 7 9 1 12 1 11 4 3 4 2 4 15 6 2 6 1 7 10 7 2 4 6 2 1 7 10 1 5 1 2 7 13 7 14 7 14 7 10 7 3 6 9 6 7 4 10 7 2 7 10 7 4 4 8 6 8 4 19 1 7 7 2 4 24 4 16 7 2 7 2 7 2 4 23 7 7 1 3 4 9 4 7 4 1 1 10 7 8 4 18 7 6 4 12 7 2 4 13 7 11 4 14 4 17 4 17 7 2 1 1 1 1 2 3 7 2 7 12 1 2 7 2 7 8 1 6 7 2 4 25 4 22 4 21 4 20 1 9 1 4 4 11 ...

Page 34: ... 2 3 6 4 5 1 2 3 A B C D E F G H A B C D E F G H 6 5 6 6 Actual wire harness may be different than illustration 6 4 5 10 5 10 5 10 3 2 2 3 2 1 5 9 5 10 3 2 3 1 3 3 7 1 5 5 5 6 5 1 5 8 5 7 5 3 5 4 5 2 MISCELLANEOUS CONTROL PANEL PARTS DOOR PARTS ...

Page 35: ...ot replaceable items TRAY PAD ASSY CPADBA269WRKZ PACKING CASE MICROWAVE OVEN POLYETHYLENG BAG SSAKHA006WRE0 DOOR PROTECTION SHEET SPADPA580WRE0 SPAKCD349WREZ R 120DB SPAKCD364WREZ R 120DK SPAKCD365WREZ R 120DR SPAKCD363WREZ R 120DW BOTTOM PAD ASSEMBLY FPADBA419WRKZ TOP PAD ASSEMBLY FPADBA418WRKZ PACKING AND ACCESSORIES ...

Page 36: ...COPYRIGHT 2000 BY SHARP CORPORATION ALL RIGHTS RESERVED 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 orotherwise withoutprior written permission of the publisher ...

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