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Sharp R-4H56 Service Manual

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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 ....................................................................................................................................... 32
CONTROL PANEL CIRCUIT .............................................................................................................................. 33
PRINTED WIRING BOARD ................................................................................................................................ 34
PARTS LIST ........................................................................................................................................................ 35
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-4H56
R-4H56
S8405R4H56PJ/
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Summary of Contents for Sharp R-4H56

  • Page 1: Table Of Contents

    R-4H56 SERVICE MANUAL S8405R4H56PJ/ MICROWAVE OVEN R-4H56 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-4H56...

  • Page 3: Caution Microwave Radiation

    MICROWAVE OVEN R-4H56 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-4H56 PRODUCT SPECIFICATIONS ITEM DESCRIPTION Power Requirements 240 Volts 50 Hertz Single phase, 3 wire earthed Power Consumption 1.4 kW Power Output 900 watts nominal of RF microwave energy (IEC 705) 750 watts (2 litre water load) Operating fequency 2450 MHz...

  • Page 5: Appearance View

    R-4H56 APPEARANCE VIEW 1. Ventilation openings 2. Oven lamp 3. Door hinges 4. Safety door latches 5. See through door 6. Coupling 7. Door open button 8. Touch control panel 9. Digital readout 10.Wave guide cover 11.Access cover for oven lamp replacement 12.Power supply cord...

  • Page 6: Operation Sequence

    R-4H56 OPERATION SEQUENCE OFF CONDITION The circuits to the power transformer, fan motor and turntable motor are cut off when the upper latch switch, Closing the door activates all door interlock switches lower latch switch and stop switch are made open. The...

  • Page 7: Function Of Important Components

    R-4H56 best results. ACTION immediately after plugging in the unit. Wait When the food is cooked, water vapor is developed. The five minutes before cooking on SENSOR COOK, sensor “senses” the vapor and its resistance increases REHEAT SENSOR or SENSOR INSTANT ACTION.
  • Page 8 R-4H56 ASYMMETRIC RECTIFIER ever, when abnormally high temperatures are reached within the oven cavity, the oven thermal cut-out will open at The asymmetric rectifier is a solid state device that prevents 145˚C, causing the oven to shut down. The thermal cut-out current flow in both directions.

  • 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-4H56 CK = Check / RE = Replace A B C D E E E E F G G H H I J L M N TEST PROCEDURE RE RE CK CKCKCK CKCKCK CKCK POSSIBLE CAUSE DEFECTIVE PARTS CONDITION PROBLEM...

  • Page 11: Test Procedure

    R-4H56 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 CHECKS. Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal.
  • Page 12 R-4H56 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) = 49sec............... T2 = 21°C Temperature difference Cold-Warm ..............
  • Page 13 R-4H56 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-4H56 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-4H56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER TEMPERATURE FUSE OR THERMAL CUT-OUT TEST CARRY OUT 3D CHECKS. Disconnect the leads from the terminals of the temperature fuse or thermal cut-out. Then using an ohmmeter, make a continuity test across the two terminals as described in the table below.
  • Page 16 R-4H56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER BLOWN FUSE F M8A CARRY OUT 3D CHECKS. 1. If the fuse M8A is blown, there could be shorts or ground in electrical parts or wire harness. Check them and replace the defective parts or repair the wire harness.
  • Page 17 R-4H56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER replaced. If a specific pad does not respond, the above method may be used ( after clearing the control unit) to determine if the control unit or key pad is at fault.
  • Page 18 R-4H56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER AH SENSOR TEST Checking the initial sensor cooking condition (1) The oven should be plugged in at least five minutes before sensor cooking. (2) Room temperature should not exceed 35˚C. (3) The unit should not be installed in any area where heat and steam are generated. The unit should not be installed, for example, next to a conventional surface unit.
  • Page 19 R-4H56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER 6-1. Touch SENSOR COOK pad and number 1 pad and 0 pad. 6-2. The control panel is in the sensor cooking operation. 6-3. After approximately 20 seconds, push plunger of select switch. This condition is same as judgement by AH sensor.

  • Page 20: Touch Control Panel

    R-4H56 TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOIUCH CONTROL PANEL The touch control section consists of the following units as 3) Synchronizing Signal Circuit 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 21 R-4H56 DESCRIPTION OF LSI LSI(IZA506DR) The I/O signal of the LSI(IZA506DR) is detailed in the following table. Pin No. Signal Description Power source voltage: -5.2V VC voltage of power source circuit input. VASS Reference voltage input terminal. A reference voltage applied to the A/D converter in the LSI. The reference voltage is generally maintained at -5V.
  • Page 22 R-4H56 Pin No. Signal Description Signal similar to H0. When any one of G-11 line keys on key matrix is touched, a corresponding signal will be input into H1. Signal similar to H0. When any one of G-10 line keys on key matrix is touched, a corresponding signal will be input into H2.
  • Page 23 R-4H56 Pin No. Signal Description Segment data signal. Signal similar to B2. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to H0 - H3 terminal while one of G-4 line keys on key matrix is touched.
  • Page 24 R-4H56 ABSOLUTE HUMIDITY SENSOR CIRCUIT the resistance values in parallel with R-1. Changing the (1) Structure of Absolute Humidity Sensor resistance values results in that there is the same The absolute humidity sensor includes two thermistors potential at both F-3 terminal of the absolute humidity as shown in the illustration.
  • Page 25 R-4H56 SERVICING 1. Precautions for Handling Electronic Components repair all the controls (sensor-related ones included) of This unit uses CMOS LSI in the integral part of the the touch control panel while keeping it connected to the circuits. When handling these parts, the following oven.

  • Page 26: Component Replacement And Adjustment Procedure

    R-4H56 COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before operating the oven. 1. Disconnect oven from power supply.. 1. Door does not close firmly. 2. Make sure that a definite” click” can be heard when the 2.
  • Page 27 R-4H56 4. Remove the air duct from the oven cavity. 7. Remove the magnetron cushion from the magnetron. 5. Carefully remove four (4) screws holding magnetron to CAUTION: WHEN REPLACING THE MAGNETRON, BE waveguide, when removing the screws holding the SURE THE R.F.

  • Page 28: Control Panel Assembly Removal

    R-4H56 of the fan motor on the flat table. Coil 2) Apply the screw lock tight into the hole (for shaft) of the fan blade. Groove joint pliers 3) Install the fan blade to the shaft of fan motor by pushing the fan blade with a small, light weight, ball peen hammer or rubber mallet.
  • Page 29 R-4H56 POWER SUPPLY CORD REPLACEMENT Removal 5. Wind the conductors of Blue and White wires each other. 1. CARRY OUT 3D CHECKS. 6. Insert the stripped wire leads into the connector CE-230. 2. Disconnect the brown wire of the power supply cord from...

  • Page 30: Door Replacement And Adjustment

    R-4H56 DOOR REPLACEMENT AND ADJUSTMENT DOOR REPLACEMENT FLAT TYPE SCREW-DRIVER 1. CARRY OUT 3D CHECKS. 2. Remove two (2) screws holding the lower oven hinge to the oven cavity. The lower oven hinge is now free. 3. Release the door assembly from the upper oven hinge.
  • Page 31 R-4H56 DOOR FRAME REMOVAL Remove the door assembly, refer to “DOOR REPLACE- MENT” 1. Place the door assembly on a soft cloth with facing up. 2. Tear the door screen from the door frame. 3. Remove the two (2) screws holding the door frame to the door panel assembly.

  • Page 32: Microwave Measurement

    R-4H56 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-4H56 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. CLOCK APPEARS ON DISPLAY Figure O-1. Oven Schematic-OFF Condition SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. COOKING TIME PROGRAMMED 3. START KEY TOUCHED Figure O-2. Oven Schematic-ON Condition...

  • Page 34: Pictorial Diagram

    R-4H56 NEUTRAL...

  • Page 35: Control Panel Circuit

    R-4H56...

  • Page 36: Printed Wiring Board

    R-4H56 Figure S-3. Printed Wiring Board...

  • Page 37: Parts List

    R-4H56 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 QFS-TA014WRE0 Temp. fuse 150˚C (MG)
  • Page 38 R-4H56 ∆ 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 VRD-B12HF751J Resistor 750 ohm 1/2W VRD-B12EF102J Resistor 1k ohm...
  • Page 39 R-4H56 ∆ 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- 3 PTUBUA004WRE0 Tube 220 6- 4 QTANP0020YBE0 Connector CE 230...
  • Page 40 R-4H56 OVEN AND CABINET PARTS 4-13 7-19 1-19 4-12 7-19 4-19 1-11 7-10 7-12 4-27 7-14 4-23 4-14 4-26 7-11 7-12 7-12 4-28 6-13 1-14 4-24 4-17 4-21 7-16 4-10 1-18 4-15 1-10 7-24 1-17 7-13 4-11 4-20 7-25 4-25...
  • Page 41 R-4H56 CONTROL PANEL PARTS 6-10 3-2-1 DOOR PARTS 7-15 7-15...
  • Page 42 R-4H56 MISCELLANEOUS 220 mm 240 mm 110 mm 6-11 6-12 6-14 Actual wire harness may be different than illustration. TOP PAD *(SPADBA524WRE0) PACKING AND ACCESSORIES TRAY HOLDER *(SPADFA208WRE0) PLASTIC BAG *(SSAKHA032WRE0) PACKING ADD KIT *(CPADBA113WRK0) TURNTABLE TRAY INSTRUCTION BOOK COOK BOOK...
  • Page 43 R-4H56...
  • Page 44 R-4H56 '94SHARP CORP. (08K0.820E) Printed in Australia...

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