Sharp R-895(AL)M Service Manual
  1. Manuals
  2. Brands
  3. Sharp Manuals
  4. Microwave Oven
  5. R-895(AL)M
  6. Service manual

Sharp R-895(AL)M Service Manual

Microwave oven with grill and convection
Hide thumbs
Table of Contents

Advertisement

Quick Links

®
CAUTION, MICROWAVE RADIATION .................................................................................................... 2
WARNING ................................................................................................................................................. 2
SERVICING ............................................................................................................................................. 3
PRODUCT SPECIFICATIONS ................................................................................................................. 4
GENERAL INFORMATION ....................................................................................................................... 4
APPEARANCE VIEW .............................................................................................................................. 5
OPERATION SEQUENCE ........................................................................................................................ 6
FUNCTION OF IMPORTANT COMPONENTS ....................................................................................... 9
TROUBLESHOOTING GUIDE ............................................................................................................... 12
TEST PROCEDURES ........................................................................................................................... 13
TOUCH CONTROL PANEL ASSEMBLY .............................................................................................. 19
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE .................................................. 24
MICROWAVE MEASUREMENT ........................................................................................................... 30
SCHEMATIC DIAGRAMS ...................................................................................................................... 31
PICTORIAL DIAGRAM .......................................................................................................................... 35
POWER UNIT CIRCUIT DIAGRAM ........................................................................................................ 36
CPU UNIT CIRCUIT DIAGRAM .............................................................................................................. 37
PRINTED WIRING BOARD OF POWER UNIT DIAGRAM .................................................................... 38
PARTS LIST .......................................................................................................................................... 39
EXPLODED DIAGRAM OF OVEN PARTS ........................................................................................... 41
CONTROL PANEL & DOOR PARTS ..................................................................................................... 42
MISCELLANEOUS/PACKING & ACCESSORIES .................................................................................. 43
SERVICE MANUAL
MICROWAVE OVEN WITH
GRILL AND CONVECTION
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
R-895M - 1
R-895(AL)M
S70224R895M//
Page

Advertisement

Table of Contents
loading

Related Manuals for Sharp R-895(AL)M

Summary of Contents for Sharp R-895(AL)M

  • Page 1: Table Of Contents

    SERVICE MANUAL ® S70224R895M// MICROWAVE OVEN WITH GRILL AND CONVECTION R-895(AL)M 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 ....................2 WARNING ..............................
  • Page 2 OVEN PARTS OVEN PARTS 7-18 7-18 7-18 4-21 4-24 7-18 7-11 4-28 4-26 4-25 4-30 7-18 7-16 7-15 4-32 4-14 7-18 7-18 7-18 7-12 4-18 7-17 7-13 4-19 1-12 7-15 4-32 1-11 1-18 4-18 7-18 4-27 7-18 1-10 4-16 7-17 7-18 1-13 7-10...
  • Page 3 CONTROL PANEL AND DOOR PARTS CONTROL PANEL PARTS DOOR PARTS 5-11 5-12 5-10 5-10 R-895M - 42...
  • Page 4 MISCELLANEOUS / PACKING & ACCESSORIES MISCELLANEOUS Actual wire harness may be different than illustration. ® COPYRIGHT © 2002 BY SHARP CORPORATION ALL RIGHTS RESERVED. No part of this publication may be reproduced, stored in retrieval systems, or transmitted in any...
  • Page 5 PARTS LIST Note: The parts marked " ∆ " may cause undue microwave exposure. / The parts marked "*" are used in voltage more than 250V. / "§" Mark: Spare parts delivery section REF. NO. PART NO. § DESCRIPTION Q'TY CODE ELECTRIC PARTS 1- 1 FH-HZA075WRE0...
  • Page 6 PARTS LIST Note: The parts marked " ∆ " may cause undue microwave exposure. / The parts marked "*" are used in voltage more than 250V. / "§" Mark: Spare parts delivery section REF. NO. PART NO. § DESCRIPTION Q'TY CODE 4-13 PDUC-A637WRF2 Fan duct...

  • Page 7: Caution, Microwave Radiation

    GENERAL IMPORTANT INFORMATION This Manual has been prepared to provide Sharp Corp. Service engineers with Operation and Service Information. 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 8: Servicing

    If the water remains cold carry out 3D checks and re-examine the connections to the compo- Sharp recommend that wherever possible fault-finding is nent being tested. carried out with the supply disconnected. It may in, some...

  • Page 9: Product Specifications

    PRODUCT DESCRIPTION SPECIFICATION ITEM DESCRIPTION Power Requirements 230 - 240 Volts / 50 Hertz / Single phase, 3 wire earthed Power Consumption Microwave cooking 1.50 kW Approx. 6.5 A Convection cooking 1.91 kW Approx. 8.0 A Top Grill mode ...... 1.25 kW Approx.

  • Page 10: Appearance View

    APPEARANCE VIEW OVEN 1. Control panel 2. Oven lamp 3. Waveguide cover 4. Bottom grill heating ele- ment (Bottom Grill) 5. Turntable motor shaft 6. Oven cavity 7. Door seals and sealing surfaces 8. Door latches 9. Door opening handle 10.Top grill heating element (Top Grill) 11.Ventilation openings...

  • Page 11: Operation Sequence

    OPERATION SEQUENCE The circuit to the high voltage transformer is cut off when OFF CONDITION the contacts of relay RY2, and the contacts (COM-NO) of Closing the door activates the monitored latch switch and the monitored latch switch and monitor switch are made the stop switch.
  • Page 12 OPERATION SEQUENCE convection temperature by touching the CONVECTION 3. The relay RY3 is energized and the main supply TEMPERATURE key . When the START key is touched, voltage is applied to the top grill heating element . the following operations occur: 4.

  • Page 13: Automatic Cooking

    OPERATION SEQUENCE POWER OUTPUT ON TIME OFF TIME MICROWAVE AND BOTTOM GRILL (Figure O-5c) 100% 54 sec. 0 sec. Programme the desired cooking time by touching the 49 sec. 5 sec. TIME keys. Touch the DUAL CONVECTION/GRILL three 45 sec. 9 sec.

  • Page 14: Function Of Important Components

    OPERATION SEQUENCE 3. COOLING FAN OPERATION OPERATION MODE DEVICE POWER CONTROL PREHEAT Cooling CONV. Cooling fan 60% 60 min. then 100% Others Cooling fan 100% The cooling fan continues to rotate when Oven temperature is more than 120˚C. Then, After cooking Cooling fan it stops when it is less than 105˚C NOW COOLING is indicated during the cooling fan movement after operation is finished.
  • Page 15 FUNCTION OF IMPORTANT COMPONENTS STOP SWITCH THERMAL CUT-OUT 145˚C (OVEN) 1. When the oven door is closed, the contacts (COM-NO) This thermal cut-out protects against overheat ing /fire inside of the switch must be closed. the oven. The cut-out contacts will open when temperatures 2.
  • Page 16 FUNCTION OF IMPORTANT COMPONENTS BOTTOM GRILL HEATING ELEMENT FIRE SENSING FEATURE The grill heating element is provided to brown the food and The oven will stop its operation when there is a fire in the is located at the base of the oven cavity. oven cavity in microwave cooking condition.

  • Page 17: Troubleshooting Guide

    TROUBLESHOOTING GUIDE BLOCKED COOLING FAN BLOCKED CONVECTION FAN NO POWER AT WALL OUTLET HOME FUSE OR BREAKER MIS-ADJUSTMENT OF SWITCHES BLOCKED VENTILATION OPENINGS OPENED WIRE HARNESS SHORTED WIRE HARNESS OVEN LAMP OR SOCKET POWER SUPPLY CORD FOIL PATTERN ON P.W.B. RELAY RY7 RELAY RY6 RELAY RY5...

  • Page 18: Test Procedures

    The power output of this oven is rated using the method specified by IEC 60705. Full details of how to curry out this procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre (part number SERV-LITMW01).
  • Page 19 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER HIGH VOLTAGE TRANSFORMER TEST WARNING: High voltage and large currents are present at the secondary winding and filament winding of the high voltage transformer. It is very dangerous to work near this part when the oven is on. NEVER make any voltage measurements of the high-voltage circuits, including the magnetron filament.
  • Page 20 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER SWITCH TEST CARRY OUT 3D CHECKS. Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the following table. Table: Terminal Connection of Switch Plunger Operation COM to NO COM to NC COM;...
  • Page 21 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER NOISE FILTER TEST CARRY OUT 3D CHECKS. Disconnect the leads from the terminals of noise filter. Using an ohmmeter, check between the terminals as described in the following table. L (min) Cx ± 20% Cy ±...
  • Page 22 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER TOUCH CONTROL PANEL ASSEMBLY TEST The control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and ohmmeter.
  • Page 23 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER RELAY TEST CARRY OUT 3D CHECKS. Remove the outer case and check voltage between Pin Nos. 1 and 3 of the 4 pin connector (E) on the control unit with an A.C. voltmeter. The meter should indicate 230-240 volts, if not check oven circuit. Relay Test Check voltage at the relay coil with a D.C.

  • Page 24: Touch Control Panel Assembly

    TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units as 4) Reset Circuit shown in the touch control panel circuit. A circuit to generate a signal which resets the LSI to the initial state when power is supplied.

  • Page 25: Description Of Lsi

    DESCRIPTION OF LSI The I/O signal of the LSI are detailed in the following table. Pin No. Signal Description Terminal not used. Power source voltage input terminal. Standard voltage for LCD. Terminal to change the on timing of the cook relay (RY2). AN6-AN5 Heating constant compensation terminal.
  • Page 26 DESCRIPTION OF LSI The I/O signal of the LSI are detailed in the following table. Pin No. Signal Description Key strobe signal. Signal applied to touch-key section. A pulse signal is input to P50-P53 terminal while one of G7 line key on matrix is touched. Key strobe signal.
  • Page 27 DESCRIPTION OF LSI The I/O signal of the LSI are detailed in the following table. Pin No. Signal Description Magnetron high-voltage circuit driving signal. To turn on and off the cook relay ON/OFF time ratio in Micro ON/OFF time ratio in Micro (RY2).
  • Page 28 SERVICING 1. Precautions for Handling Electronic Components 5) Re-connect the power supply cord after the outer This unit uses CMOS LSI in the integral part of the circuits. case is installed. When handling these parts, the following precautions 6) Run the oven and check all functions. should be strictly followed.

  • Page 29: Component Replacement And Adjustment Procedure

    Oven lamp, Magnetron, High voltage transformer To prevent an electric shock, take the following and Oven cavity. measures. 3) Sharp edge: 1. Before wiring, Bottom plate, Oven cavity, Waveguide flange, 1) Disconnect the power supply. Chassis support and other metallic plate.

  • Page 30: Magnetron Removal

    COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE HIGH VOLTAGE TRANSFORMER REMOVAL 4. Disconnect the main wire harness from the high volt- 1. CARRY OUT 3D CHECKS. age transformer. 2. Disconnect the filament leads of high voltage trans- 5. Remove the two (2) screws and one (1) washer holding former from high voltage capacitor and the magnetron.

  • Page 31: Turntable Motor Replacement

    4. Cut the four (4) bridges holding the turntable motor Re-install cover to the base plate with cutting pliers as shown in 1. Remove the any sharp edges on the turntable motor Figure C-2(a). cover and the base plate with the cutting pliers.

  • Page 32: Oven Lamp Socket Removal

    COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE OVEN LAMP SOCKET REMOVAL 1. CARRY OUT 3D CHECKS. 2. Remove the two(2)wires leads as Positive lock ® LOCK BULB connector removal above. 3. Lift up the oven lamp from its retaining clips. 4. Now, the oven lamp is free. Figure C-3.

  • Page 33: Door Replacement

    COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE MONITORED LATCH SWITCH, STOP SWITCH AND MONITOR SWITCH ADJUSTMENT If the monitored latch switch, stop switch and monitor should be less than 0.5mm. switch do not operate properly due to a mis-adjustment, the following adjustment should be made. 2.
  • Page 34 COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE to door frame. 3. Door is positioned with its face pressed toward cavity 4. Re-install door panel to door frame by fitting two (2) face plate. tabs of glass stopper to two (2) holes of door panel. 4.

  • Page 35: Microwave Measurement

    MICROWAVE MEASUREMENT After any repair, the microwave oven must be checked for PROCEDURE microwave leakage to ensure continued safe operation. 1. Place the beaker containing the water load in the oven BS EN 60335-2-25 specifies that the maximum permitted cavity at the centre of the turntable. The placing of this leakage with a load of 275 ml is 50 W/m (equivalent to 5 standard load in the oven is important, not only to...

  • Page 36: Schematic Diagrams

    SCHEMATIC DIAGRAMS Note: SCHEMATIC AC CORD CONNECTION NOTE: CONDITION OF OVEN BRN : BROWN 1. DOOR CLOSED. BLU : BLUE 2. PLUGGED IN OVEN. G-Y : GREEN AND YELLOW STRIPE 3. NOTHING APPEARS ON DISPLAY. /15 : SECTIONAL AREA OF 1.5mm MIN.
  • Page 37 SCHEMATIC DIAGRAMS SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. COOKING TIME ENTERED. 3. STRAT KEY TOUCHED. NOISE FUSE F8A FILTER THERMAL CUT-OUT OVEN THERMAL STOP SWITCH THERMISTOR CUT-OUT MONITOR ASYMMETRIC MONITORED LATCH SWITCH SWITCH RECTIFIER Figure O-2 Oven Schematic-Microwave cooking Condition SCHEMATIC NOTE: CONDITION OF OVEN 1.
  • Page 38 SCHEMATIC DIAGRAMS SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. COOKING TIME ENTERED. 3. TOP & BOTTOM GRILL MODE SELECTED. 4. STRAT KEY TOUCHED. NOISE FUSE F8A FILTER THERMAL CUT-OUT OVEN THERMAL STOP SWITCH THERMISTOR CUT-OUT MONITOR MONITORED LATCH SWITCH ASYMMETRIC SWITCH RECTIFIER...
  • Page 39 SCHEMATIC DIAGRAMS SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. COOKING TIME ENTERED. 3. DUAL KEY TOUCHED TWICE. 4. MICROWAVE POWER LEVEL ENTERED. 5. STRAT KEY TOUCHED. NOISE FUSE F8A FILTER THERMAL CUT-OUT OVEN THERMAL STOP SWITCH THERMISTOR CUT-OUT MONITOR MONITORED LATCH SWITCH ASYMMETRIC...

  • Page 40: Pictorial Diagram

    PICTORIAL DIAGRAM R-895M - 35...

  • Page 41: Power Unit Circuit Diagram

    POWER UNIT CIRCUIT DIAGRAM D11-D14 1N4005E 1N4004S OVEN WH1-4 THERMISTOR WH1-3 – – R4 510 1w WH1-6 R3 510 1w R5 3.3k WH1-9 BUZZER AC230-240V 50Hz WH1-10 WH1-5 POWER WH1-11 CONTROL WH1-8 FAN MOTOR CONVECTION WH1-7 MOTOR R6 200 1w OVEN LAMP TURNTABLE MOTOR...

  • Page 42: Cpu Unit Circuit Diagram

    CPU UNIT CIRCUIT DIAGRAM COOK SENSOR DEFROST AUTO ˚C R-895M - 37...

  • Page 43: Printed Wiring Board Of Power Unit Diagram

    PRINTED WIRING BOARD OF POWER UNIT DIAGRAM (J2) VRS1 POWER CONT Figure S-4. Printed Wiring Board of Power Unit R-895M - 38...

Table of Contents