Sharp R-3A56 Service Manual
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Sharp R-3A56 Service Manual

Sharp R-3A56 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 ............................................................... 21
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-3A56
R-3A56
S7403R3A56PJZ
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  • Page 1: Table Of Contents

    R-3A56 SERVICE MANUAL S7403R3A56PJZ MICROWAVE OVEN R-3A56 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-3A56...

  • Page 3: Caution Microwave Radiation

    MICROWAVE OVEN R3A56 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-3A56 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 1.35 kW Power Output 850 watts nominal of RF microwave energy (IEC 705)

  • Page 5: Appearance View

    R-3A56 APPEARANCE VIEW 1. Ventilation opening 1 (Rear) 2. Oven lamp 3. Door hinges 4. Door safety latches 5. See through door 6. Coupling 7. Door open button 8. Touch control panel 9. Digital readout 10.Wave guide cover 11.Rating label 12.Turntable...

  • Page 6: Operation Sequence

    R-3A56 OPERATION SEQUENCE OFF CONDITION The circuits to the power transformer, fan motor and turntable motor are cut off when the 1st. latch switch, Closing the door activates all door interlock switches 2nd. latch switch, and stop switch are made open. The (1st.

  • Page 7: Function Of Important Components

    R-3A56 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-3A56 operation, the oven thermal cut-out remains closed. How- FAN MOTOR 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-3A56 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-3A56 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-3A56 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 (49 + 2) = 51 sec.
  • Page 13 R-3A56 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-3A56 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-3A56 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-3A56 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-3A56 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-3A56 TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units 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-3A56 DESCRIPTION OF LSI LSI(IZA593DR) The I/O signal of the LSI(IZA593DR) is detailed in the following table. Pin No. Signal Description Vdisp Anode (segment) of Fluorescent Display illumination voltage: -30V Vp voltage of power source circuit input. Signal coming from touch key.
  • Page 20 R-3A56 Pin No. Signal Description BUZZ Signal to sound buzzer. A: key touch sound(0.12sec.). B: Completion sound(2.4sec.). 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 21 R-3A56 Pin No. Signal Description Segment data signal. Signal similar to D8. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to R0 terminal while one of G5 line keys on key matrix is touched. Segment data signal.
  • Page 22 R-3A56 SERVICING 1. Precautions for Handling Electronic Components B. On some models, the power supply cord between the This unit uses CMOS LSI in the integral part of the touch control panel and the oven proper is long circuits. When handling these parts, the following enough that they may be separated from each other.

  • Page 23: Component Replacement And Adjustment Procedure

    R-3A56 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 24: Fan Motor Replacement

    R-3A56 POSITIVE LOCK ® CONNECTOR REMOVAL Terminal ® Positive lock 1. CARRY OUT 3D CHECKS. connector ® 2. Pushing the lever of positive lock connector. Push 3. Pull out the positive lock ® connector. Lever CAUTION: WHEN YOU (SERVICE ENGINEERS) CON- ®...
  • Page 25 R-3A56 TURNTABLE MOTOR REMOVAL 1. Disconnect oven from power supply. 4. Disconnect wire leads from turntable motor. 2. Remove turntable and turntable support from oven cavity. (See "Positive lock connector removal") 3. Remove two (2) screws holding turntable motor cover to 5.
  • Page 26 R-3A56 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-3A56 side of oven cavity using a Special screw-driver (LHSTIX UPPER DOOR "LR-4").. SCREWS HINGE 8. Secure two (2) screws holding the upper oven hinge to UPPER the top of the oven cavity. OVEN RE-INSTALL HINGE Note: After any service to the door;...

  • Page 28: Microwave Measurement

    R-3A56 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-3A56 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. CLOCK APPEARS ON DISPLAY COM. N.O. Figure O-1. Oven Schematic-OFF Condition (for Australia) N.O. COM. Figure O-1. Oven Schematic-OFF Condition (for New Zealand)
  • Page 30 R-3A56 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. COOKING TIME PROGRAMMED 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-3A56...
  • Page 32 R-3A56...

  • Page 33: Control Panel Circuit

    R-3A56 IZA593DR IC-1 4.00MGW 47µ/16V 1/2W 330µ/35V 0.1µ/50V VRS1 (J1)

  • Page 34: Printed Wiring Board

    R-3A56 IC-1 SP40 (J6) (J5) (RB) (ZD3) (Q23) R20 B (J13) (D22) VRS1 (VRS2) POWER (J1) CN - A Figure S-3. Printed Wiring Board...

  • Page 35: Parts List

    R-3A56 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-3A56 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 VHEHZ4C3///-1 Zener diode (HZ4C-3) 3- 2 FPNLCB104WRK0 Control panel frame with key unit...
  • Page 37 R-3A56 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- 7 LX-CZA038WRE0 Special screw 7- 8 LX-CZ0052WRE0 Special screw...
  • Page 38 R-3A56 OVEN AND CABINET PARTS 1-13 1-12 4-21 4-23 4-12 4-20 4-22 6-10 7-12 4-13 4-14 4-27 4-24 4-11 4-16 4-18 4-25 7-10 4-26 1-14 7-13 Australia 4-15 7-10 1-16 4-10 1-17 1-10 4-19 7-11 1-15 1-10 4-17 1-11 For New...
  • Page 39 R-3A56 CONTROL PANEL PARTS 3-1E 3-2-1 6-11 DOOR PARTS...

  • Page 40: Packing And Accessories

    R-3A56 MISCELLANEOUS 6-12 6-13 Actual wire harness may be different than illustration. PACKING AND ACCESSORIES PACKING PAD KIT CPADBA162WRK0 DOOR PROTECTION SHEET 6- 2 TURNTABLE TRAY SPADPA204WRE0 6- 3 OPERATION MANUAL POLYETHYLENG BAG SSAKHA034WRE0 6- 1 TURNTABLE SUPPORT MICROWAVE OVEN...

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