Sharp R-4A56 Service Manual
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Sharp R-4A56 Service Manual

Sharp R-4A56 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 .......................................................................................................................................................... 6
TEST PROCEDURE ............................................................................................................................................ 8
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
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-4A56
R-4A56
S8406R4A56PJZ
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Summary of Contents for Sharp R-4A56

  • Page 1: Table Of Contents

    R-4A56 SERVICE MANUAL S8406R4A56PJZ MICROWAVE OVEN R-4A56 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-4A56...

  • Page 3: Caution Microwave Radiation

    MICROWAVE OVEN R-4A56 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-4A56 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 1.4 kW Power Output 900 watts nominal of RF microwave energy (IEC 705)

  • Page 5: Appearance View

    R-4A56 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-4A56 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-4A56 FUNCTION OF IMPORTANT COMPONENTS DOOR OPEN MECHANISM ture rise of the power transformer by blowing the fuse (M8A) when the high voltage rectifier is shorted. The door can be opened by pushing the door open button on the control panel. When the door open button is pushed, the latch lever is moved upward, operating the latch head.

  • Page 8: 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 9 R-4A56 CK = Check / RE = Replace A B C D E E E E F G H H I I J K M N TEST PROCEDURE RE RE CK CKCKCK CKCKCK CKCK POSSIBLE CAUSE DEFECTIVE PARTS PROBLEM CONDITION...

  • Page 10: Test Procedure

    R-4A56 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 11 R-4A56 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.
  • Page 12 R-4A56 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 13 R-4A56 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 14 R-4A56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER MONITOR RESISTOR TEST CARRY OUT 3D CHECKS. Disconnect the leads from the monitor resist. Using an ohmmeter and set on a low range. Check between the terminals of the monitor resistor. The resistance of monitor resistor is approx. 0.8 ohms.
  • Page 15 R-4A56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER 5. Close the oven door. 6. Set the power level to HIGH and set the relevant timer for about three (3) minutes. 7. Note the reading on the meter and carefully observe the motor under test to see if it is turning.
  • Page 16 R-4A56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER KEY UNIT TEST If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the ribbon is making good contact, verify that the door sensing switch(stop switch) operates properly; that is the contacts are closed when the door is closed and open when the door is open.
  • Page 17 R-4A56 TEST PROCEDURES (CONT'D) PROCEDURE COMPONENT TEST LETTER PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD (PWB) IS OPEN To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the PWB, this foil pattern acts as a fuse.

  • Page 18: Touch Control Panel

    R-4A56 TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOIUCH CONTROL PANEL The touch control section consists of the following unit as 3) Synchronizing Signal Circuit shown in the touch control panel circuit. This power source synchronizing signal is available in order to compose a basic standard time in the clock (1) Key Unit circuit.
  • Page 19 R-4A56 DESCRIPTION OF LSI LSI(IZA430DR) The I/O signal of the LSI(IZA430DR) is detailed in the following table. Pin No. Signal Description Digit selection signal. Refer to the touch control panel circuit about the relation between signals and digits. Normally, one pulse is output in every synchronized signal period, and input to the grid of the fluorescent display.
  • Page 20 R-4A56 Pin No. Signal Description Signal coming from touch key. When either one of G9 line keys on key matrix is touched, a corresponding signal out of R0 , R1 will be input into R2 . When no key is touched, the signal is held at "L"...
  • Page 21 R-4A56 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 pre- oven.

  • Page 22: Component Replacement And Adjustment Procedure

    R-4A56 COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before operating the oven. 1. Disconnect the oven from the power supply. 1. Door does not close firmly. 2. Make sure that a definite” click” can be heard when the 2.
  • Page 23 R-4A56 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 24: Control Panel Assembly Removal

    R-4A56 3) Install the fan blade to the shaft of fan motor by pushing Coil the fan blade with a small, light weight, ball peen hammer Groove joint pliers or rubber mallet. CAUTION: * Do not hit the fan blade strongly when installed because the bracket may be transformed.
  • Page 25 R-4A56 4. Remove the single (1) screw holding the green/yellow Blue wire lead of power supply cord wire of the power supply cord to the oven cavity. 5. Remove the single (1) screw holding the cord anchorage to the oven cavity.
  • Page 26 R-4A56 UPPER LATCH SWITCH, LOWER LATCH SWITCH, STOP SWITCH AND MONITOR SWITCH ADJUSTMENT If the lower latch switch, stop switch, upper latch switch and 2. The upper latch switch and lower latch switch interrupt monitor switch do not operate properly due to a mis- the circuit before the door can be opened.
  • Page 27 R-4A56 3. Install the latch head to the holes in the door panel. CHOKE COVER REMOVAL Door 1. Insert an iron plate (thickness of about 0.5mm) or flat Panel type screw driver to the gap between the choke cover Ring and door panel as shown in the figure to free the engaging part.

  • Page 28: Microwave Measurement

    R-4A56 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 29: Wiring Diagram

    R-4A56 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. CLOCK APPEARS ON DISPLAY N.O. COM. Figure O-1. Oven Schematic-OFF Condition (for Australia) Figure O-1. Oven Schematic-OFF Condition (for New Zealand)
  • Page 30 R-4A56 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. COOKING TIME PROGRAMMED 3. START KEY TOUCHED N.O. COM. Figure O-2. Oven Schematic-Cooking Condition (for Australia) Figure O-2. Oven Schematic-Cooking Condition (for New Zealand)

  • Page 31: Pictorial Diagram

    R-4A56 NEUTRAL...
  • Page 32 R-4A56 NEUTRAL LIVE...

  • Page 33: Control Panel Circuit

    R-4A56 Vdisp 3.3K OSC2 OSC1 TEST RESET AVSS INT1 AVCC (J7) (J6) (J5) (J4) 47µF/16V 0.01µF/50V 3.3µF/50V SP20 470µF/35V 0.1µF/50V 0.01µF/50V VRS1...

  • Page 34: Printed Wiring Board

    R-4A56 (R90) (R91) CF100 R100 (C9) – (J4) (J6) (Q50) (J12 R12) – (J10) SP20 – (C31) 10 GND (J11) 12 E (J33 R33) (J2) BC (Q33) (C8) (J3) C1 – (TAB4) (TAB3) (VRS2) US:BLK,CD:WHT GE:RED,AS:ORG US:RED,CD:GRY GE:BLK,AS:BRN VRS1 (TAB1) (COM.)

  • Page 35: Parts List

    R-4A56 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 36 R-4A56 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-B12EF471J Resistor 470 ohm 1/4W VRD-B12EF101J Resistor 100 ohm 1/4W VRD-B12EF512J Resistor 5.1k ohm 1/4W...
  • Page 37 R-4A56 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- 9 FW-VZB139WRE0 Low voltage harness 6-10 TSPCNC034WRR0 Rating label (for Australia)
  • Page 38 R-4A56 OVEN AND CABINET PARTS 4-13 4-12 7-10 1-11 4-19 1-11 7-10 7-12 1-19 7-12 4-24 4-25 4-27 7-14 6-15 4-23 4-14 4-26 7-11 7-12 7-12 4-28 1-14 4-30 4-17 4-21 7-23 4-10 1-18 7-20 1-10 4-15 7-24 1-17 7-13...
  • Page 39 R-4A56 CONTROL PANEL PARTS 6-10 3-2-1 DOOR PARTS 7-21 7-21...
  • Page 40 R-4A56 MISCELLANEOUS 240 mm 110 mm 220 mm 6-12 6-14 6-13 Actual wire harness may be different than illustration. PACKING AND ACCESSORIES TOP PAD *(SPADBA524WRE0) CABINET COVER (R-4X55B) *(SPAKHA003WRE0) TRAY HOLDER *(SPADFA208WRE0) PLASTIC BAG *(SSAKHA032WRE0) PACKING ADD KIT *(CPADBA113WRK0) TURNTABLE TRAY...

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