Sharp R-771 OE Service Manual
Sharp R-771 OE Service Manual

Sharp R-771 OE Service Manual

Microwave oven
Table of Contents

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SERVICE MANUAL !i
S H A R P
R - 7 7 1 OE
In the interests of user-safety the set should be restored to its original
condition and only parts identical to those specified used.

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Summary of Contents for Sharp R-771 OE

  • Page 1 SERVICE MANUAL !i S H A R P R - 7 7 1 OE In the interests of user-safety the set should be restored to its original condition and only parts identical to those specified used.
  • Page 2: Foreword

    S H A R P FOREWORD This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with complete Operation and Service Information for the Sharp Coun- ter Top Microwave Oven, R-7710E. It is recommended that service personnel carefully study the entire text of this Manual so they will be qualified to render satisfactory customer service.
  • Page 3: Table Of Contents

    TABLE OF CONTENTS Page FOREWORD..............CAUTION, MICROWAVE RADIATION .
  • Page 4 Cook Lamp ............. 20 Upper Latch Switch, Lower Latch Switch and Monitor Switch Adjustment .
  • Page 5: Chapter I Product Description

    CHAPTER I PRODUCT DESCRIPTION EXPLANATION OF MICROWAVE COOKING The Sharp Counter Top Microwave Oven uses microwave Materials with a high moisture content, like most foods, energy to produce heat in the food to be cooked. Unlike at a frequency of 2450 Megahertz enters the food, the conventional ovens microwave energy will cook foods without applying external heat.
  • Page 6: Chapter Ii Operation

    CHAPTER II OPERATION Note: To start cooking: If the oven door is opened during the cook cycle, the oven will go out of the cook cycle (no Place the food to be cooked in the oven and close the microwave energy) and the timer will stop. This is door firmly.
  • Page 7 240V 50Hz FUSE - - - - UPPER LOWER LATCH LATCH SWITCH SWITCH MAGNETRON 1 THERM0 CUT-OUT COOK SWITCH TURNTABLE MOTOR COOK LAMP I- - NOTE : CONDITION TIMER 1. DOOR CLOSED SWITCH L -------m--w- - POWER TRANSFORMER HIGH D,: SHORT PROTECTOR MAGNETRON Figure 1.
  • Page 8 240V 50Hz MONITOR SWITCH TIMER UPPER LATCH SWITCH MAGNETRON THERM0 CUT-OUT COOK TURNTABLE MOTOR VARI-MOTOR NOTE: CONDITION TIMER 1. DOOR CLOSED SWITCH POWER TRANSFORMER PROTECTOR MAGNETRON Figure 2. Oven Schematic - Idle Condition...
  • Page 9 240V 50Hz FUSE MONITOR SWITCH TIMER CONTACTS OVEN LAMP UPPER LOWER LATCH LATCH SWITCH SWITCH MAGNETRON ; THERM0 CUT-OUT COOK SWITCH TURNTABLE MOTOR COOK LAMP VARI-MOTOR SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. TIMER “ON” 3. COOK SWITCH “ON” SWITCH 4.
  • Page 10: Description And Function Of Components

    DESCRIPTION AND FUNCTION OF COMPONENTS VARIABLE COOKING CONTROL The variable cooking control consists of the vari-motor, cooking control is set at LOW, MED. LOW, MED. or vari-switch, gear, select lever bracket assembly, etc. MED. HIGH position, 240 volts A.C. is supplied to the the purpose of the vari-motor is to rotate a cam which power transformer intermittently within a 30 seconds is going to turn the vari-switch on and off within 30...
  • Page 11: Door Open Mechanism

    DOOR OPEN MECHANISM The door can be opened by pushing the open button on the control panel, refer to Figure 4. Pushing the open button, the open plate on the open device pushes the door lever on the door. Therefore, the lower and upper latch heads remove upwards, and then those latch heads are released from the lower and upper latch hooks.
  • Page 12: Chapter Iii Servicing

    CHAPTER I SERVICING TROUBLESHOOTING GUIDE When troubleshooting the microwave oven, it is helpful to IMPORTANT: If the oven becomes inoperative because follow the Sequence of Operation in performing the checks. of a blown fuse in the upper latch- Many of the possible causes of trouble will require that a monitor switch circuit, check the upper specific test be performed.
  • Page 13 TROUBLESHOOTING GUIDE (CONT’D)
  • Page 14: Test Procedures

    TEST PROCEDURES MAGNETRON ASSEMBLY TEST...
  • Page 15: Power Transformer Test

    TEST PROCEDURES (CONT’D) POWER TRANSFORMER TEST RECTIFIER TEST HIGH VOLTAGE CAPACITOR TEST SHORT PROTECTOR TEST...
  • Page 16: Fan Motor Test

    TEST PROCEDURES FAN MOTOR TEST TIMER TEST MAGNETRON THERM0 CUT-OUT TEST UPPER LATCH SWITCH TEST LOWER LATCH SWITCH TEST...
  • Page 17: Monitor Switch Test

    TEST PROCEDURES (CONT’D) PROCEDURE COMPONENT TEST LETTR MONITOR SWITCH TEST a r e o p e r a t i n g p r o p e r l y upper latch P O W E R T R A N S F O R M E R CHAPTER IV COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURES 3 ‘d.
  • Page 18: High Voltage'components Removal

    (High Voltage Capacitor, Rectifier and Short Protector) To remove the components, proceed as follows. 5. Now, the capacitor, rectifier and short protector are 1. Disconnect the oven from the power supply and remove free. the outer case. CAUTION: WHEN REPLACING THE RECTIFIER 2.
  • Page 19: Turntable Motor Removal

    TURNTABLE MOTOR REMOVAL 5. Remove the four (4) screws holding the turntable motor Disconnect the oven power supply. mounting plate to the oven cavity bottom. Remove the six (6) screws holding the base cabinet (B) 6. Disconnect the wire leads from the turntable motor. to the oven cavity and rear cabinet.
  • Page 20: Upper Latch Switch And Monitor Switch Removal

    UPPER LATCH SWITCH AND MONITOR SWITCH REMOVAL 5. Remove the single (1) screw and washer holding the the outer case. upper latch hook to the oven cavity front flange. 6. Remove the upper latch hook from the flange by moving 2.
  • Page 21: Control Panel Assembly And Components Removal

    CONTROL PANEL ASSEMBLY AND COMPONENTS REMOVAL The complete control panel should be removed for TIMER replacement of the components. To remove the control panel, refer to Figure 9 and proceed as follows: timer shaft. 1. Disconnect the oven from the power supply and re- 2.
  • Page 22: Upper Latch Switch, Lower Latch Switch And Monitor Switch Adjustment

    UPPER LATCH SWITCH, LOWER LATCH SWITCH AND MONITOR SWITCH ADJUSTMENT In case the upper and lower latch switches do not operate properly due to a misadjustment, the following adjustment should be taken. 1. Loosen the single (1) screw holding the upper latch hook to the oven cavity front flange and the single (1) screw holding the lower latch hook to the same flange.
  • Page 23: Door Replacement And Adjustment

    DOOR REPLACEMENT AND ADJUSTMENT DOOR REPLACEMENT DOOR ADJUSTMENT Disconnect the oven power supply, remove the outer When removing and/or loosening hinge such as in the case case and discharge the high voltage capacitor. of a door replacement, the following adjustment criteria Remove the four (4) screws holding the door hinge to are taken.
  • Page 24: Microwave Measurement

    MICROWAVE MEASUREMENT After the adjustment of the door interlock switches and Recommended instruments are: NARDA 8 100 door is completed individually or collectively, the follow- ing leakage test must be performed with a survey NARDA 8200 HOLADAY HI 1500 instrument and it must be confirmed that the result meets SIMPSON 380M the requirements of the performance standard for micro Place the turntable tray into the oven cavity.
  • Page 25: Schematic Diagram

    CIRCUIT SUBJECT TO CHANGE WITHOUT NOTICE RED/18 WIRE COLOUR CODE SYMBOL RED: RED B R N : B R O W N (LI BLU : BLUE IN) ORG: ORANGE(L) GRY : GRAY (N) PNK : PINK GRE : GREEN G-Y GREEN AND YELLOW STRIPE 0.75mm’ HV : HIGH- VOLTAGE WIRE : NO INDICATION SHOWS 0.5mmz : QUICK CONNECT TERMINAL...
  • Page 26: Pictorial Diagram

    0 03...
  • Page 27: Parts List

    PARTS LIST ELECTRICAL PARTS Mains supply cord Fuse (MlOA) Fuse holder QSW-M0085WREO and monitor switch Vari-motor assembly Cook lamp Cook switch QSW-M0088WREO Oven lamp Oven lamp socket Fan motor Turntable motor Magnetron therm0 cut-out l-13 Magnetron l-14 High voltage capacitor 1-15 Rectifier l-16...
  • Page 28 Cook button Mode select knob assembly Y~~~(ccioG1c_Lhr\ Timer knob assembly AG r LSUB-0117WRWO Cook lamp mounting plate Timer mounting plate Cook lamp insulator 3-10 OVEN PARTS Open cavity assembly Turntable roller Roller shaft Waveguide cover Clip Turntable tray NTNT-0036WRFO FCPL-0018WRK0 Turntable coupling assembly Oven lamp filter Fan blade assembly...
  • Page 29 Panel harness Wire harness Cook book Use and care SCREWS, NUTS AND WASHERS Screw; actuator mtg Screw; lamp access cover mtg Screw; turntable coupling mtg Screw; power transformer mtg Screw; hinge mounting plate mtg Screw; turntable motor mounting plate Screw; magnetron therm0 cut-out mtg Screw;...
  • Page 33 DOOR ASSEMBLY MISCELLANEOUS...

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