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Sharp R-880B Service Manual

Double grill convection microwave oven
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See also: Operation Manual and Cookbook , Operating Manual
DO UB LE G RI
LL CO NV EC
TI O N
Se ns or
CAUTION, MICROWAVE RADIATION.................................................................................................... 1
WARNING .................................................................................................................................................1
PRODUCT SPECIFICATIONS ................................................................................................................ 2
GENERAL INFORMATION....................................................................................................................... 2
APPEARANCE VIEW .............................................................................................................................. 3
OPERATION SEQUENCE....................................................................................................................... 4
FUNCTION OF IMPORTANT COMPONENTS ....................................................................................... 8
SERVICING .............................................................................................................................................. 8
TROUBLESHOOTING GUIDE ............................................................................................................... 10
TEST PROCEDURE .............................................................................................................................. 12
TOUCH CONTROL PANEL ASSEMBLY .............................................................................................. 20
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE .................................................. 27
MICROWAVE MEASUREMENT ........................................................................................................... 33
WIRING DIAGRAM ................................................................................................................................ 34
PICTORIAL DIAGRAM .......................................................................................................................... 38
POWER UNIT CIRCUIT ......................................................................................................................... 39
CONTROL PANEL CIRCUIT .................................................................................................................. 40
PRINTED WIRING BOARD .................................................................................................................... 41
PARTS LIST .......................................................................................................................................... 42
SERVICE MANUAL
COOK
HELP
Info Display
HELP
MULTI
CONVENIEN CE
COOK
/PIZZA
REHEAT
EASY
SENSOR
DEFPST
Fresh
Vegetab les
Reheat Pie
Jacket
Potato
Frozen
Vegetab les
Rice
Pasta
MODEL
MIX
GRILL
CONV EC REHE
AT
POWE R
LESS
MIX
LEVE L
MORE
40˚ C
70˚ C
130˚ C
150˚ C
160˚ C
180˚ C
200˚ C
220˚ C
230˚ C
250˚ C
STOP
INSTAN T COOK
CLOCK
CLEAR
START
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
DOUBLE GRILL
CONVECTION
MICROWAVE OVEN
R-880B
R-880B
S7810R880BPJ/
Page

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Summary of Contents for Sharp R-880B

  • Page 1: Table Of Contents

    R-880B SERVICE MANUAL S7810R880BPJ/ DOUBLE GRILL CONVECTION MICROWAVE OVEN COOK HELP Info Display HELP MULTI CONVENIEN CE COOK /PIZZA REHEAT EASY SENSOR DEFPST R-880B Fresh Vegetab les Reheat Pie Jacket Potato Frozen Vegetab les Rice Pasta MODEL GRILL CONV EC REHE...
  • Page 2 R-880B...

  • Page 3: Caution Microwave Radiation

    APPEARANCE VIEW R-880B GENERAL IMPORTANT INFORMATION OPERATING SEQUENCE 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 FUNCTION OF IMPORTANT text of this manual, so they will be qualified to render satisfactory COMPONENTS customer service.

  • Page 4: General Information

    R-880B PRODUCT DESCRIPTION SPECIFICATION ITEM DESCRIPTION Power Requirements 230 - 240 Volts 50 Hertz Single phase, 3 wire earthed Power Consumption Microwave cooking 1.6 kW Top Heater mode 1.3 kW Grill cooking Bottom heater mode 0.9 kW Top and Bottom heater mode 2.1 kW...

  • Page 5: Appearance View

    R-880B APPEARANCE VIEW OVEN 1. Oven lamp 2. Top heaters (Grill heaters) 3. See through door 4. Door hinges 5. Door safety latches 6. Door seals and sealing surfaces 7. Bottom heater 8. Oven cavity 9. Turntable motor shaft 10.Ventilation openings High rack 11.Waveguide cover...

  • Page 6: Operation Sequence

    Shown in the display is remaining time. Figure O-1 on page 34 6. MONITOR SWITCH CIRCUIT 1. The oven display will show " SHARP MICRO- WAVE The monitor switch is mechanically controlled by the OVEN " . oven door, and monitors the operation of the 1st. latch 2.
  • Page 7 R-880B 1. The relay RY3 + RY5 + RY6 are energized. In these modes, the food is cooked by the top heaters and the microwave energy. Press the MIX pad once for HIGH 2. The numbers of the digital read-out start the count MIX TOP GRILL mode.
  • Page 8 R-880B energized. NOTE: 4. The relay RY2 + RY4 are energized alternately within 1. In case of Automatic operations, the limitations of a 48 seconds time base by the control unit. power output are not carried out. 5. The bottom heater operate through the relay RY4 is 2.
  • Page 9 R-880B 3. Sensor detects moisture and humidity and calculates Selected Temp- Top Heaters Bottom Heater cooking time and variable power. erature (˚C) Power (%) Power (%) AH SENSOR COOKING SEQUENCE 1. In case the AH sensor cooking condition is started, the...

  • Page 10: Function Of Important Components

    R-880B judgment that there is a fire in the oven cavity and will ON/OFF TIME RATIO switch off the relays to the power transformer, fan In grill cooking, convection cooking or mix cooking, the top motor, turntable motor and the oven lamp. The LSI heaters, bottom heater or magnetron operate whithin a 48 also stops counting down.
  • Page 11 R-880B rotate the turntable. ASYMMETRIC RECTIFIER The asymmetric rectifier is a solid state device that pre- FAN MOTOR vents current flow in both directions. And it prevents the The fan motor drives a blade which draws external cool air. temperature rise of the high voltage transformer by blowing This cool air is directed through the air vanes surrounding the fuse M10A when the high voltage rectifier is shorted.

  • Page 12: Servicing

    If the water remains cold carry out 3D checks and re-examine the Sharp recommend that wherever possible fault-finding is connections to the component being tested. carried out with the supply disconnected. It may in, some...
  • Page 13 R-880B SWITCHES MIS-ADJUSTMENT HARNESS WIRE OPENED HARNESS WIRE SHORTED LAMP OVEN CORD SUPPLY POWER SENSOR P.W.B. PATTERN FOIL RELAY RELAY RELAY RELAY RELAY RELAY UNIT PANEL CONTROL TOUCH THERMISTOR HEATER BOTTOM HEATERS MOTOR CONVECTION MOTOR TURNTABLE MOTOR FILTER NOISE FUSE...

  • Page 14: Test Procedure

    R-880B 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 15 R-880B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST Initial temperature ....................T1 = 11 C Temperature after (47 + 2) = 49 sec ..............T2 = 21 C Temperature difference Cold-Warm ............... T1 = 10C Measured output power The equation is “P = 90 x T” ............P = 90 x 10 C = 900 Watts JUDGMENT: The measured output power should be at least 15 % of the rated output power.
  • Page 16 R-880B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF THE MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6 VOLTS, BE- CAUSE OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIREC- TIONS.
  • Page 17 R-880B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST BLOWN FUSE M10A CARRY OUT 3D CHECKS. If the fuse M10A is blown when the door is opened, check the 1st. latch switch, 2nd. latch switch, monitor switch and monitor resistor. If the fuse M10A is blown, there could be a short or ground in electrical parts or wire harness. Check them and replace the defective parts or repair the wire harness.
  • Page 18 R-880B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST Check the resistance across the terminals of the heater as described in the following table. Table: Resistance of heater Parts name Resistance Top heaters Approximately 24 x 2 = 48 Bottom heater Approximately 72 2.
  • Page 19 R-880B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST KEY UNIT TEST If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable is marking 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 20 R-880B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST STEPS OCCURRENCE CAUSE OR CORRECTION The rated AC voltage is not present at Check supply voltage and oven power cord. Power terminal of CPU connector (CN-A). The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective.
  • Page 21 R-880B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT To determine if the sensor is defective, the simplest method is to replace it with a new replacement sensor. (1) Disconnect oven from power supply and then remove outer case.

  • Page 22: Touch Control Panel Assembly

    R-880B TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units as 8) Back Light Circuit shown in the touch control panel circuit. A circuit to drive the back light (Light emitting diodes LD1 - LD10).
  • Page 23 R-880B DESCRIPTION OF LSI LSI(IZA927DR) The I/O signal of the LSI(IZA927DR) are detailed in the following table. Pin No. Signal Description Terminal not used. Power source voltage input terminal. Standard voltage for LCD. AN7-AN5 Heating constant compensation terminal. Terminal not used.
  • Page 24 R-880B Pin No. Signal Description Key strobe signal. Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal while one of G8 line key on matrix is touched. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal while one of G7 line key on matrix is touched.
  • Page 25 R-880B Pin No. Signal Description Internal clock oscillation frequency input setting. The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to XIN terminal. XOUT Internal clock oscillation frequency control output. Output to control oscillation input of XOUT.
  • Page 26 R-880B Pin No. Signal Description SEG9 Segment data signal. Connected to LCD. No connection in LCD. 82-90 Segment data signal. SEG8-SEG0 Connected to LCD. Signal is similar to SEG39. Connected to GND. VREF Connected to GND. AVSS Connected to VC.
  • Page 27 R-880B ABSOLUTE HUMIDITY SENSOR CIRCUIT With this voltage given, the switches SW1 to SW5 in (1) Structure of Absolute Humidity Sensor the LSI are turned on in such a way as to change the The absolute humidity sensor includes two thermistors resistance values in parallel with R107 ~ R111 of IC2.
  • Page 28 R-880B SERVICING 1. Precautions for Handling Electronic Components A. On some models, the power supply cord between the This unit uses CMOS LSI in the integral part of the circuits. touch control panel and the oven itself is so short that When handling these parts, the following precautions the two can't be separated.

  • Page 29: Component Replacement And Adjustment Procedure

    High voltage transformer and Oven cav- To prevent an electric shock, take the following ity. manners. 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 R-880B CAUTION: WHEN REPLACING HIGH VOLTAGE 5. Release the capacitor holder from the fan duct. RECTIFIER ASSEMBLY, ENSURE THAT 6. Remove the capacitor from the capacitor holder. THE CATHODE (EARTH) CONNECTION 7. Now, the capacitor should be free. IS SECURELY FIXED TO THE CAPACI- 8.

  • Page 31: Fan Motor Replacement

    R-880B THERMISTOR REMOVAL 1. CARRY OUT 3D CHECKS. 6. Remove the one (1) screw holding the thermistor angle 2. Now, the back plate with the sub back plate should be to the oven cavity rear plate. removed. 7. Remove the thermistor angle together with thermistor from the oven.
  • Page 32 3. Where the corners have been snipped off, bend corner cover. areas flat. No sharp edge must be evident after re- moval of turntable motor cover. NOTE: The one (1) screw to fit the turntable motor cover 4.
  • Page 33 R-880B GRIL HEATERS (TOP HEATERS) REMOVAL 1. CARRY OUT 3D CHECKS. 6. Remove the reflector from the oven cavity by sliding it 2. Remove the one (1) screw holding the exhaust duct to leftward. the oven cavity. 7. Remove the grill heaters and the short terminal to- 2.
  • Page 34 R-880B DOOR REPLACEMENT tabs of door frame to seven (7) holes of door panel. REMOVAL 5. Hold the door panel to the door frame with four (4) 1. CARRY OUT 3D CHECKS. screws. 2. Push the open button and open the door slightly.

  • Page 35: Microwave Measurement

    R-880B MICROWAVE MEASUREMENT Recommended instruments are: After adjustment of door latch switches, monitor switch NARDA 8100 and door are completed individually or collectively, the NARDA 8200 following leakage test must be performed with a survey instrument and it must be confirmed that the result meets...

  • Page 36: Wiring Diagram

    R-880B SCHEMATIC NOTE: Indicates components with potential above 250 V. NOTE: CONDITION OF OVEN 1. DOOR CLOSED. OR CLOCK APPEAR ON DISPLAY. NOISE FILTER UNIT 2ND. FUSE THERMAL CUT-OUT LATCH SWITCH M10A (MG.) CONTROUNIT THERMAL 1ST. CUT-OUT(OVEN) LATCH SWITCH Figure O-1 Oven Schematic-OFF Condition...
  • Page 37 R-880B NOTE: Indicates components with potential above 250 V. SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. GRILL PAD TOUCHED ONCE. 3. COOKING TIME PROGRAMMED. 4. STRAT PAD TOUCHED. NOISE FILTER UNIT 2ND. FUSE THERMAL CUT-OUT LATCH SWITCH M10A (MG.)
  • Page 38 R-880B SCHEMATIC NOTE: CONDITION OF OVEN FOR GRILL COOKING NOTE: Indicates components with potential above 250 V. 1. DOOR CLOSED. 2. GRILL PAD THREE TIMES. 3. COOKING TIME PROGRAMMED. 4. STRAT PAD TOUCHED. NOISE FILTER UNIT 2ND. FUSE THERMAL CUT-OUT...
  • Page 39 R-880B SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. NOTE: Indicates components with potential above 250 V. 2. MIX PAD TOUCHED ONCE/TWICE. 3. COOKING TIME PROGRAMMED. NOTE: The microwave relay RY2 and heater relay RY3 could not turn on simultaneously.

  • Page 40: Pictorial Diagram

    R-880B RESISTOR MONITOR NEUTRAL LIVE EARTH...

  • Page 41: Power Unit Circuit

    R-880B Q2 2SB1238 R4 27 D1-4 R5 4.7k 11ES1 AC230-240V 50Hz R3 510 1/2w 2SB1238 R2 680 1/2w BUZZER R6 3.3k FAN MOTOR FAN MOTOR CONVECTION CONVECTION MOTOR MOTOR N.O. OVEN LAMP TURNTABLE DTD143ES MOTOR OVEN LAMP TURNTABLE MOTOR 10 /35v BOTTOM N.O.

  • Page 42: Control Panel Circuit

    R-880B SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8 SEG9 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 SEG16 SEG17 SEG18 SEG19 SEG20 SEG21 SEG22 SEG23 SEG24 SEG25 SEG26 SEG27 SEG28 SEG29 SEG30 SEG31 SEG15 COM1 COM2 COM3 SEG9 COM4 SEG8 COM5...

  • Page 43: Printed Wiring Board

    R-880B CN - C VRS1 CN - A LOT NO. Figure S-4. Printed Wiring Board...

  • Page 44: Parts List

    R-880B 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 ELECTRIC PARTS 1- 1 QSW-MA131WRE0 1st. latch switch, 2nd. latch switch and stop switch 1st.
  • Page 45 R-880B 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 OVEN PARTS 4- 1 DOVN-A513WRY0 Oven cavity 4- 2 PHOK-A106WRF0...
  • Page 46 R-880B 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- 2 XEPSD40P25000 Screw : 4mm x 25mm 7- 3...
  • Page 47 R-880B OVEN AND CABINET PARTS 6-11 4-45 4-33 7-10 4-25 7-12 4-23 4-29 4-26 7-10 7-10 4-37 4-42 1-11 1-20 4-15 1-12 7-17 1-22 7-15 4-30 4-31 7-10 7-13 1-14 7-10 4-34 1-16 7-10 4-40 4-27 1-21 4-19 4-43 4-32...
  • Page 48 R-880B CONTROL PANEL PARTS 3-3-3 6-12 DOOR PARTS 3-3-1 3-3-2 MISCELLANEOUS Actual wire harness may be different than illustration. 6-10 '98SHARP CORP. (7K0.730E) Printed in Australia...

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