Sharp R-3C57 Service Manual
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Sharp R-3C57 Service Manual

Sharp R-3C57 Service Manual

Microwave oven
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CAUTION, MICROWAVE RADIATION ................................................................................................................ 1
WARNING .............................................................................................................................................................. 1
PRODUCT SPECIFICATIONS ............................................................................................................................. 2
GENERAL INFORMATION ................................................................................................................................... 2
APPEARANCE VIEW ........................................................................................................................................... 3
OPERATION SEQUENCE ................................................................................................................................... 4
FUNCTION OF IMPORTANT COMPONENTS .................................................................................................... 5
SERVICING .......................................................................................................................................................... 7
TEST PROCEDURE ............................................................................................................................................ 9
TOUCH CONTROL PANEL ................................................................................................................................ 16
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ............................................................... 20
MICROWAVE MEASUREMENT ........................................................................................................................ 26
WIRING DIAGRAM ............................................................................................................................................. 27
PICTORIAL DIAGRAM ....................................................................................................................................... 29
CONTROL PANEL CIRCUIT .............................................................................................................................. 31
PRINTED WIRING BOARD ................................................................................................................................ 32
PARTS LIST ........................................................................................................................................................ 33
SERVICE MANUAL
MODEL
In interests of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.

TABLE OF CONTENTS

SHARP CORPORATION
MICROWAVE OVEN
R-3C57
R-3C57
S7501R3C57PJZ
Page

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Summary of Contents for Sharp R-3C57

  • Page 1: Table Of Contents

    R-3C57 SERVICE MANUAL S7501R3C57PJZ MICROWAVE OVEN R-3C57 MODEL In interests of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used. TABLE OF CONTENTS Page CAUTION, MICROWAVE RADIATION ........................ 1 WARNING ................................
  • Page 2 R-3C57...

  • Page 3: Caution Microwave Radiation

    MICROWAVE OVEN R3C57 GENERAL IMPORTANT INFORMATION APPEARANCE VIEW This Manual has been prepared to provide Sharp Corp. Service engineers with Operation and Service Information. OPERATING SEQUENCE It is recommended that service engineers carefully study the entire text of this manual, so they will be qualified to render satisfactory customer service.

  • Page 4: Product Specifications

    R-3C57 PRODUCT SPECIFICATIONS ITEM DESCRIPTION Power Requirements 240 Volts (for Australia) / 230 - 240 Volts (for New Zealand) 50 Hertz Single phase, 3 wire earthed Power Consumption 1.37kW Power Output 900 watts nominal of RF microwave energy (IEC 705)

  • Page 5: Appearance View

    R-3C57 APPEARANCE VIEW 1. Ventilation openings 2. Oven lamp 3. Door hinges 4. Door safety latches 5. See through door 6. Door seals and sealing surfaces 7. Coupling 8. Door open button 9. Touch control panel 10.Digital readout 11.Wave guide cover 12.Power supply cord...

  • Page 6: Operation Sequence

    A3+A5 in the control unit. MONITOR SWITCH CIRCUIT The monitor switch is mechanically controlled by oven Figure O-1 on page 27 door, and monitors the operation of the 1st and 2nd. 1. The display shows SHARP , MICRO- , WAVE latch switches. OVEN .

  • Page 7: Function Of Important Components

    R-3C57 FUNCTION OF IMPORTANT COMPONENTS ASYMMETRIC RECTIFIER DOOR OPEN MECHANISM The asymmetric rectifier is a solid state device that prevents The door is opened by pushing the open button on the current flow in both directions. And it prevents the tempera- control panel, refer to the Figure D-1.
  • Page 8 R-3C57 FAN MOTOR operation, the oven thermal cut-out remains closed. How- ever, when abnormally high temperatures are reached The fan motor drives a blade which draws external cool air. within the oven cavity, the oven thermal cut-out will open at This cool air is directed through the air vanes surrounding 145˚C, causing the oven to shut down.

  • Page 9: Servicing

    3D checks and re-examine the connections to the component being tested. Sharp recommend that wherever possible fault-finding is carried out with the supply disconnected. It may in, some cases, be necessary to connect the supply after...
  • Page 10 R-3C57 CK = Check / RE = Replace TEST PROCEDURE A B C D E E E E G F F H H I J K L M RECK CKRE CK CKCK CK CK POSSIBLE CAUSE DEFECTIVE PARTS PROBLEM CONDITION...

  • Page 11: Test Procedure

    R-3C57 TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST MAGNETRON TEST NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION. CARRY OUT 3D CHECK. Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal.
  • Page 12 R-3C57 TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 6. Measure the final water temperature. (Example: The final temperature T2 = 21 C) 7. Calculate the microwave power output P in watts from above formula. Initial temperature ....................T1 = 11 C Temperature after (47 + 2) = 49 sec.
  • Page 13 R-3C57 TEST PROCEDURES (CONT'D) PROCEDURE LETTER COMPONENT TEST Example Initial temperature ................T1 = 23˚C T2 = 24˚C Temperature after 1 min. 51 sec............T1 = 33˚C T2 = 34˚C Temperature difference Cold-Warm ..........T1 = 10˚C T2 = 10˚C Mean temperature rise T ......
  • Page 14 R-3C57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER CARRY OUT 4R CHECKS. ASYMMETRIC RECTIFIER TEST ASYMMETRIC RECTIFIER CARRY OUT 3D CHECKS. HIGH VOLTAGE RECTIFIER Isolate the high voltage rectifier assembly from the HV circuit. The asymmetric can be tested using an ohmmeter set to its highest range across the terminals A+B of the asymmetric rectifier and note the reading obtained.
  • Page 15 R-3C57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER If incorrect readings are obtained, replace the thermal cut-out. An open circuit thermal cut-out 145˚C (MG) indicates that the magnetron has overheated, this may be due to resistricted ventilation, cooling fan failure or a fault condition within the magnetron or HV circuit.
  • Page 16 R-3C57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER 1. Key Unit Note : Check key unit ribbon connection before replacement. The following symptoms indicate a defective key unit. Replace the key unit. a) When touching the pads, a certain pad produces no signal at all.
  • Page 17 R-3C57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS APPROX. 25.0V D.C. Oven lamp / Turntable motor / Cooling fan motor APPROX. 29.0V D.C. Power transformer CARRY OUT 4R CHECKS. PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD...

  • Page 18: Touch Control Panel

    R-3C57 TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units 3) Synchronizing Signal Circuit as shown in the touch control panel circuit. The power source synchronizing signal is available in order to compose a basic standard time in the clock (1) Key Unit circuit.
  • Page 19 R-3C57 DESCRIPTION OF LSI LSI(IZA655DR) The I/O signal of the LSI(IZA655DR) is detailed in the following table. Pin No. Signal Description Vdisp Anode (segment) of Fluorescent Display light-up voltage: -34V Vp voltage of power source circuit input. Signal coming from touch key.
  • Page 20 R-3C57 Pin No. Signal Description BUZZ Signal to sound buzzer. A: key touch sound (0.12 sec.). B: Completion sound (2.4 sec.). 26-27 D4-D5 Segment data signal. Refer to the touch control panel circuit for the relationship between signals and indicators. Normally, one pulse is output in every synchronized signal period, and input to the anode of the fluorescent display.
  • Page 21 R-3C57 SERVICING 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. When handling these parts, the following pre- the touch control panel while keeping it connected to the cautions should be strictly followed.

  • Page 22: Component Replacement And Adjustment Procedure

    R-3C57 COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before operating the oven. 1. CARRY OUT 3D CHECKS. 1. Door does not close firmly. 2. Make sure that a definite” click” can be heard when the 2.
  • Page 23 R-3C57 MAGNETRON REMOVAL Removal 4. Re-install outer case and check that the oven is operating 1. CARRY OUT 3D CHECKS. properly. 2. Disconnect wire leads from magnetron. CAUTION: WHEN REPLACING MAGNETRON, BE SURE 3. Remove the two (2) screws holding chassis support to THE R.F.
  • Page 24 4. Where the corners have been snipped off bend corner areas flat. No sharp edge must be evident after removal NOTE: The one (1) screw to fit the turntable motor cover of the turntable motor cover.
  • Page 25 R-3C57 OVEN LAMP AND LAMP SOCKET REMOVAL Oven lamp socket 1. CARRY OUT 3D CHECKS. Terminal 2. Pull the wire leads from the oven lamp socket by pushing the terminal hole of the oven lamp socket with the small Wire lead flat type screw driver.
  • Page 26 R-3C57 1ST. LATCH SWITCH, 2ND. LATCH SWITCH AND MONITOR SWITCH REMOVAL 1. CARRY OUT 3D CHECKS. Re-install 1. Re-install each switch lever and latch switch in its place. 2. Disconnect wire leads from the switches. The 1st. latch /monitor switches are in the lower position 3.
  • Page 27 R-3C57 cycle. This function does not require that door be air- tight, moisture (condensation)-tight or light-tight. Therefore, occasional appearance of moisture, light or sensing of gentle warm air movement around oven door is not abnormal and do not of themselves, indicate a leakage of microwave energy from oven cavity.

  • Page 28: Microwave Measurement

    R-3C57 MICROWAVE MEASUREMENT After adjustment of door latch switches, monitor switch standard for microwave ovens must be used for testing. and door are completed individually or collectively, the Recommended instruments are: NARDA 8100 following leakage test must be performed with a survey...

  • Page 29: Wiring Diagram

    R-3C57 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED NOTE: " " indicates components with potentials above 250V. 2. CLOCK APPEARS ON DISPLAY COM. N.O. Figure O-1. Oven Schematic-OFF Condition (for Australia) COM. N.O. Figure O-1. Oven Schematic-OFF Condition (for New Zealand)
  • Page 30 R-3C57 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. COOKING TIME PROGRAMMED NOTE: " " indicates components with potentials above 250V. 3. START KEY TOUCHED COM. N.O. Figure O-2. Oven Schematic-Cooking Condition (for Australia) COM. N.O. Figure O-2. Oven Schematic-Cooking Condition (for New Zealand)

  • Page 31: Pictorial Diagram

    R-3C57 RECTIFIER H.V. RECTIFIER ASYMMETRIC...
  • Page 32 R-3C57 RECTIFIER H.V. RECTIFIER ASYMMETRIC...

  • Page 33: Control Panel Circuit

    R-3C57 UNIT 100K 100K IZA655DR 100K 4.7K 4.7K 4.7K 4.7K HZ4C3 4MHz 47µ/16V SP40 3.3K 0.1µ/50V 330µ/35V 0.01µ/25V 0.1µ/50V 10µ/35V VRS1 (J1) (J2)

  • Page 34: Printed Wiring Board

    R-3C57 Figure S-3. Printed Wiring Board...

  • Page 35: Parts List

    R-3C57 PARTS LIST Note: The parts marked " " may cause undue microwave exposure. The parts marked "*" are used in voltage more than 250V. REF. NO. PART NO. DESCRIPTION Q'TY CODE ELECTRICAL PARTS 1- 1 QSW-MA110WRE0 1st. 2nd. and stop switches...
  • Page 36 R-3C57 Note: The parts marked " " may cause undue microwave exposure. The parts marked "*" are used in voltage more than 250V. REF. NO. PART NO. DESCRIPTION Q'TY CODE R70-72 VRD-B12EF472J Resistor 4.7k ohm 1/4W R73-75 VRD-B12EF104J Resistor 100k ohm 1/4W...
  • Page 37 R-3C57 Note: The parts marked " " may cause undue microwave exposure. The parts marked "*" are used in voltage more than 250V. REF. NO. PART NO. DESCRIPTION Q'TY CODE 7- 6 XOTSD40P12000 Screw : 4mm x 12mm 7- 7 XVPSD40P20000 Screw;...
  • Page 38 R-3C57 OVEN AND CABINET PARTS 1-13 1-12 4-13 4-12 4-11 4-19 6-13 4-10 4-14 4-18 1-14 4-15 6-11 Australia 1-17 1-10 1-16 4-17 1-15 1-10 4-16 1-11 For New Zealand...
  • Page 39 R-3C57 CONTROL PANEL PARTS 3- 1 3- 2 3- 5 3-2-1 6-10 DOOR PARTS 3- 3 3- 4 MISCELLANEOUS Actual wire harness may be different than illustration. 6-12...
  • Page 40 R-3C57 '95SHARP CORP. (07K0.820E) Printed in Australia...

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