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Sharp R-3H57 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 ................................................................................................................................ 18
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ............................................................... 24
MICROWAVE MEASUREMENT ........................................................................................................................ 30
WIRING DIAGRAM ............................................................................................................................................. 31
PICTORIAL DIAGRAM ....................................................................................................................................... 33
CONTROL PANEL CIRCUIT .............................................................................................................................. 35
PRINTED WIRING BOARD ................................................................................................................................ 36
PARTS LIST ........................................................................................................................................................ 37
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-3H57
R-3H57
S8502R3H57PJZ
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Summary of Contents for Sharp R-3H57

  • Page 1: Table Of Contents

    R-3H57 SERVICE MANUAL S8502R3H57PJZ MICROWAVE OVEN R-3H57 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-3H57...

  • Page 3: Caution Microwave Radiation

    MICROWAVE OVEN R-3H57 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-3H57 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-3H57 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.Waveguide 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 31 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-3H57 sensor “senses” the vapor and its resistance increases NOTE: The oven should not be operated on SENSOR gradually. When the resistance reaches the value set ac- COOK or SENSOR INSTANT ACTION immediately cording to the menu, supplementary cooking is started.
  • Page 8 R-3H57 ASYMMETRIC RECTIFIER THERMAL CUT-OUT TC 145˚C (OVEN) The asymmetric rectifier is a solid state device that prevents The thermal cut-out located on the top of the oven cavity is current flow in both directions. And it prevents the tempera-...

  • 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-3H57 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 CKRECK CKCKCKCK POSSIBLE CAUSE DEFECTIVE PARTS PROBLEM CONDITION Home fuse blows when power sup- ply cord is plugged into wall outlet.

  • Page 11: Test Procedure

    R-3H57 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-3H57 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-3H57 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-3H57 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-3H57 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-3H57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER 1. Key Unit 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. b) When touching a number pad, two figures or more are displayed.
  • Page 17 R-3H57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER RELAY TEST CARRY OUT 3D CHECKS. Remove the outer case and check voltage between Pin Nos. 3 and 5 of the 3-pin connector (A) on the control unit with an A.C. voltmeter. The meter should indicate 230~240 volts, if not check oven circuit.
  • Page 18 R-3H57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER NOISE FILTER TEST CARRY OUT 3D CHECKS. Disconnect the leads from the terminals of the noise filter. Using an ohmmeter, check between the terminals as described in the following table. L (min) 1.0 mH...
  • Page 19 R-3H57 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER (1) Disconnect oven from power supply and remove outer case. (2) Discharge the high voltage capacitor. (3) Remove the AH sensor. (4) Install the new AH sensor. (5) Re-install the outer case.

  • Page 20: Touch Control Panel

    R-3H57 TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL 3) Synchronizing Signal Circuit The touch control section consists of the following units The power source synchronizing signal is available in as shown in the touch control panel circuit. order to compose a basic standard time in the clock circuit.
  • Page 21 R-3H57 DESCRIPTION OF LSI LSI(IZA657DR): The I/O signals of the LSI(IZA657DR) are detailed in the following table. Pin No. Signal Description Connected to GND. P90-P91 Terminal not used. Magnetron high-voltage circuit driving signal. HIGH To turn on and off the cook relay(RY2). In...
  • Page 22 R-3H57 Pin No. Signal Description Terminal not used. Signal to sound buzzer. 0.12 sec A: key touch sound. 2.4 sec B: Completion sound. Terminal not used. Terminal not used. Segment data signals. The relation between signals and indicators are as follows:...
  • Page 23 R-3H57 Pin No. Signal Description Digit selection signal. The relationship between digit signal and digit are as follows; Digit signal Digit (50Hz) P50 ......1st. ß P51 ......2nd. P52 ......3rd. P53 ......4th. P54 ......5th. P55 ......6th.
  • Page 24 R-3H57 ABSOLUTE HUMIDITY SENSOR CIRCUIT (1) Structure of Absolute Humidity Sensor LSI are turned on in such a way as to change the The absolute humidity sensor includes two thermistors resistance values in parallel with R3 - R7 of IC2.
  • Page 25 R-3H57 SERVICING For those models, check and repair all the controls 1. Precautions for Handling Electronic Components (sensor-related ones included) of the touch control panel This unit uses CMOS LSI in the integral part of the while keeping it connected to the oven.

  • Page 26: Component Replacement And Adjustment Procedure

    R-3H57 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 27 R-3H57 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 28 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 29 R-3H57 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 30 R-3H57 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 31 R-3H57 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 32: Microwave Measurement

    R-3H57 MICROWAVE MEASUREMENT After adjustment of door latch switches, monitor switch standard for microwave ovens must be used for testing. Recommended instruments are: and door are completed individually or collectively, the NARDA 8100 following leakage test must be performed with a survey...

  • Page 33: Wiring Diagram

    R-3H57 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED NOTE: " " indicates components with potentials above 250V. 2. CLOCK APPEARS ON DISPLAY N.O. COM. RY-2 RY-1 Figure O-1. Oven Schematic-OFF Condition (for Australia) COM. N.O. RY-1 RY-2 Figure O-1. Oven Schematic-OFF Condition (for New Zealand)
  • Page 34 R-3H57 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. COOKING TIME PROGRAMMED NOTE: " " indicates components with potentials above 250V. 3. START KEY TOUCHED N.O. COM. RY-2 RY-1 Figure O-2. Oven Schematic-Cooking Condition (for Australia) COM. N.O. RY-2 RY-1 Figure O-2.

  • Page 35: Pictorial Diagram

    R-3H57 RECTIFIER H.V. RECTIFIER ASYMMETRIC...
  • Page 36 R-3H57 RECTIFIER H.V. RECTIFIER ASYMMETRIC...

  • Page 37: Control Panel Circuit

    R-3H57 IZA657DR 0.01µ/16v 0.01µ/16v 4.7k /16v HZ4A2 0.01µ 47µ/16v IZA495DR 4.7k 47µ/16v 4.7k HZ5C2 0.01µ/16v 0.1µ/50v 0.1µ/50v 10µ/35v 10µ/35v HZ16-1 2.4k 1000µ/35v 0.1µ/50v 10G471K (J1) VRS1...

  • Page 38: Printed Wiring Board

    R-3H57 QKITPB018MRE0 FLR. DISPLAY TAPE (R71) (R70) ,BFB (J5) LEAD WIRE (Q60) (D6) (J10) (D5) (J14) (J11) (D3) (D4) (R7) (J15) (J8) (D23) (VH) (TY3) CN - A POWER FM TTM Figure S-3. Printed Wiring Board...

  • Page 39: Parts List

    R-3H57 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 40 R-3H57 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 R30-31 VRD-B12EF472J Resistor 4.7k ohm 1/4W VRD-B12EF332J Resistor 3.3k ohm 1/4W...
  • Page 41 R-3H57 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 6-12 QTANP0020YBE0 Connector (for Australia) 6-13 TCAUHA185WRR0 Micro caution (for New Zealand)
  • Page 42 R-3H57 OVEN AND CABINET PARTS 1-13 1-18 1-12 4-21 4-13 4-20 4-22 4-11 4-23 4-12 4-24 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 43 R-3H57 3- 2 CONTROL PANEL PARTS 3- 1 3- 5 3-2-1 3- 5 6-10 DOOR PARTS 3- 3 3- 4 MISCELLANEOUS Actual wire harness may be different than illustration. 6-12...
  • Page 44 R-3H57 '95SHARP CORP. (08K0.820E) Printed in Australia...

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