Sharp R-872M Service Manual
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SERVICE MANUAL
MICROWAVE OVEN WITH
GRILL AND CONVECTION
R-872(W)M/ R-872(SL)M
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.
MICROWAVE RADIATION
Personnel should not be exposed to the microwave energy
which may radiate from the magnetron or other microwave
generating devices if it is improperly used or connected. All input
and output microwave connections, waveguides, flanges and
gaskets must be secured. Never operate the device without a
microwave energy absorbing load attached. Never look into an
open waveguide or antenna while the device is energized.
Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is not any other visible damage with the oven.
Servicing and repair work must be carried out only by trained
service engineers.
All the parts marked "*" on parts list are used at voltages more than
250V.
Removal of the outer wrap gives access to potentials above 250V.
All the parts marked "∆" on parts list may cause undue microwave
exposure, by themselves, or when they are damaged, loosened or
removed.
Never operate the Grill and/ or Bottom heater with the oven
outer cabinet removed. (Because air flow is eliminated, and the
excess heat generated on adjacent components). It can cause
permanent damage or a fire.
SHARP CORPORATION
OSAKA, JAPAN
WARNING
WARNING
R-872M - 1
SERVICING
PRODUCT SPECIFICATIONS
GENERAL INFORMATION
APPEARANCE VIEW
OPERATING SEQUENCE
FUNCTION OF IMPORTANT
COMPONENTS
TROUBLESHOOTING GUIDE
AND TEST PROCEDURE
TOUCH CONTROL PANEL
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
MICROWAVE MEASUREMENT
WIRING DIAGRAM
PARTS LIST

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Summary of Contents for Sharp R-872M

  • Page 1 GRILL AND CONVECTION R-872(W)M/ R-872(SL)M GENERAL INFORMATION GENERAL IMPORTANT INFORMATION This Manual has been prepared to provide Sharp Corp. Service APPEARANCE VIEW 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 2: Warning To Service Personnel

    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 3: Product Description

    Set Weight Approx. 20 kg GENERAL INFORMATION WARNING THIS APPLIANCE MUST BE EARTHED IMPORTANT THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE: GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE R-872M - 3...
  • Page 4: Appearance View

    Press to start a programme. Press to cook on and/or twice to cancel a programme. (HIGH) for 1 minute or increase time during cooking in multiples of 1 minute. TIMER key R-872 AUTO START/CLOCK key. WEIGHT CONVERSION key Use to set the clock. R-872M - 4...
  • Page 5: Operation Sequence

    In this condition the food is cooked by the top grill heating COM-NO Closed Opened element . Programme the desired cooking time by touch- Monitor Switch ing the TIME keys and touh the GRILL key once. When the COM-NC Opened Closed R-872M - 5...
  • Page 6 3-2. The oven will continue to function for 30 minutes, is generated by magnetron. turning the top and bottom heating elements on and 6. Now, the food is cooked by microwave and convection off, as needed to maintain the selected pre-heat energy simultaneously. R-872M - 6...
  • Page 7 5. If the cooking mode has the power level display, the top heater, bottom heater or magnetron operate whithin a power level is also displayed when the limitations of 48 second time base. The following table is the ON / OFF power output are carried out. R-872M - 7...
  • Page 8: Function Of Important Components

    6. The fuse F8A blows by the large electric currents. If the wire harness or electrical components are short- 7. The power supplying to the high voltage transformer is circuited, this fuse blows to prevent an electric shock or fire cut off. R-872M - 8...
  • Page 9: Troubleshooting Guide

    “Test Procedure” section. IMPORTANT: If the oven becomes inoperative because of a blown fuse F8A in the monitored latch switch - monitor switch circuit, check the monitored latch switch and monitor switch before replacing the fuse F8A. R-872M - 9...
  • Page 10 TEST PROCEDURE A B C D E E E F G G H H H I J K L L M N O O O O O O O P POSSIBLE CAUSE DEFECTIVE PARTS PROBLEM CONDITION Fuse F8A blows when the door is opened. Home fuse blows when power cord is plugged into wall outlet.
  • Page 11: Test Procedures

    The power output of this oven is rated using the method specified by IEC 705. 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 12 F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance. G. The resistance across all the terminals and the chassis must be infinite when the capacitor is normal. If incorrect reading are obtained, the high voltage capacitor must be replaced. CARRY OUT 4R CHECKS. R-872M - 12...
  • Page 13 Table: Resistance of Motor Motors Resistance 293 Ω Fan motor Approximately Turntable motor Approximately 15 kΩ 288 Ω Convection fan motor Approximately If incorrect readings are obtained, replace the motor. CARRY OUT 4R CHECKS. R-872M - 13...
  • Page 14 10 MΩ in the cold start. If the results of above test 1 and/or 2 are out of above specifications, the heating element is probably faulty and should be replaced. CARRY OUT 4R CHECKS. R-872M - 14...
  • Page 15: Key Unit Test

    RICE/PASTA OVEN CHIPS FRESH VEG. CAKE START AUTO START CONVECTION g • oz Kg • Lb AUTO MINUTE CLOCK MORE LESS ( ˚C ) PIZZA DUAL STOP/ MICROWAVE CONVECTION/ TIMER Kg / Lb CLEAR POWER LEVEL GRILL R-872M - 15...
  • Page 16 (check primary coil resistance). If any abnormal condition is detected, re- place the defective parts. CARRY OUT 4R CHECKS. VRS1 POWER R-872M - 16...
  • Page 17: Touch Control Panel Assembly

    LSI. 3) Synchronizing Signal Circuit The LSI uses this information to control the relay The power source synchronizing signal is available in and display units. order to compose a basic standard time in the clock R-872M - 17...
  • Page 18: Description Of Lsi

    H : GND of LSI. L (-5V) 20 msec. 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. R-872M - 18...
  • Page 19 32 sec. 20 % 12 sec. 36 sec. 10 % 8 sec. 40 sec. Internal clock oscillation frequency input setting. The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to XIN terminal. R-872M - 19...
  • Page 20 SEG37 (53) ....SEG 3 ( 3) SEG18 (72) ....SEG22 (22) SEG38 (52) ....SEG 2 ( 2) SEG19 (71) ....SEG21 (21) SEG39 (51) ....SEG 1 ( 1) SEG20 (70) ....SEG20 (20) SEG9 Terminal not used. R-872M - 20...
  • Page 21 Connected to LCD (Pin No. 35). COM1 Common data signal: COM2. Connected to LCD (Pin No. 34). COM0 Common data signal: COM1. Connected to LCD (Pin No. 33). 98-99 VL3-VL2 Power source voltage input terminal. Standard voltage for LCD. Terminal not used. R-872M - 21...
  • Page 22 2) Open the door and block it open. 3) Re-connect the leads to the primary of the power transformer. 4) Re-install the outer case (cabinet). 5) Re-connect the power supply cord after the outer case is installed. R-872M - 22...
  • Page 23: Component Replacement And Adjustment Procedure

    3. Disconnect the high voltage wire B from the magnetron. 2. Disconnect the filament lead of the high voltage trans- 4. Remove one (1) screw holding earth side terminal of former and the high voltage wire A from the high the high voltage rectifier assembly. R-872M - 23...
  • Page 24: High Voltage Transformer Removal

    1. Install the the fan motor to the fan duct with the two (2) a pair of groove joint pliers. screws and nuts. CAUTION: 2. Install the fan blade to the fan motor shaft according to • Make sure that no swarf from the rotor enters the following procedure. R-872M - 24...
  • Page 25: Turntable Motor Replacement

    2. Remove the turntable from the oven cavity. Re-install 3. Turn the oven over. 1. Remove the any sharp edges on the turntable motor 4. Cut the four (4) bridges holding the turntable motor cover and the base plate with the cutting pliers.
  • Page 26 BOTTOM HEATING ELEMENT REMOVAL 3. Disconnect the wire leads from the bottom heating 1. CARRY OUT 3D CHECKS. element. 2. Remove the turntable motor cover from the base plate, referring to "TURNTABLE MOTOR REPLACEMENT". R-872M - 26...
  • Page 27: Monitored Latch Switch, Monitor Switch And Stop Switch Removal

    1. In and out play of door remains less than 0.5 mm when OPEN LEVER latched position. First check the latch hook position, pushing and pulling upper portion of the door toward Figure C-6 Latch Switches Adjustment R-872M - 27...
  • Page 28: Door Replacement

    Hold the glass stopper to the door frame with the LOWER two (2) screws. OVEN HINGE 3. Re-install the latch spring to the latch head. Re-install the latch spring to the door frame. Re-install latch head Figure C-8. Door Replacement R-872M - 28...
  • Page 29: Microwave Measurement

    Dotted line indicates the path taken by the leakage detec- tor. Whilst the maximum leakage permitted in BS EN 60335-2-25 is 50 W/m (equivalent to 5 mW/cm ), it is not normal to detect any significant leakage, and therefore any detected leakage should be investigated. R-872M - 29...
  • Page 30 2. " . O" APPEARS ON DISPLAY. NOISE FUSE F8A FILTER THERMAL CUT-OUT OVEN THERMAL (SW2)STOP SWITCH THERMISTOR CUT-OUT ASYMMETRIC (SW1)MONITORED LATCH SWITCH (SW3)MONITOR RECTIFIER SWITCH Figure O-1(c) Oven Schematic-OFF Condition after the oven door is closed. R-872M - 30...
  • Page 31 230 - 240V ~ 50Hz 230 - 240V ~ 50Hz BLU/15 BRN/15 BLU/15 BRN/15 G-Y/15 NEUTRAL LIVE G-Y/15 NEUTRAL LIVE EARTH EARTH 0.22µ/250V FUSE 15A 0.22µ/250V FUSE 15A 10M/ 0.5W 10M/ 0.5W NOISE SUPPRESSION COIL NOISE SUPPRESSION COIL 680 k/ 0.5W 680 k/ 0.5W 4700p/ 250V 4700p/ 250V...
  • Page 32 3. TOP & BOTTOM GRILL MODE SELECTED. 4. START KEY TOUCHED. NOISE FUSE F8A FILTER THERMAL CUT-OUT OVEN THERMAL (SW2)STOP SWITCH THERMISTOR CUT-OUT ASYMMETRIC (SW1)MONITORED LATCH SWITCH (SW3)MONITOR RECTIFIER SWITCH Figure O-3(c) Oven Schematic-Grill cooking Condition (TOP AND BOTTOM GRILL mode) R-872M - 32...
  • Page 33 4. MICROWAVE POWER LEVEL ENTERED. microwave power level. See "Power setting" on page 7. 5. CONVECTION TEMPERATURE SELECTED. 6. START KEY TOUCHED. Figure O-5(a) Oven Schematic-Dual cooking Condition (Microwave and Convection mode) R-872M - 33...
  • Page 34 4. MICROWAVE POWER LEVEL ENTERED. 5. START KEY TOUCHED. FUSE F8A NOISE FILTER THERMAL CUT-OUT OVEN THERMAL (SW2)STOP SWITCH THERMISTOR CUT-OUT ASYMMETRIC (SW1)MONITORED LATCH SWITCH (SW3)MONITOR RECTIFIER SWITCH Figure O-5(c) Oven Schematic-Dual cooking Condition (Microwave and Buttom Grill mode) R-872M - 34...
  • Page 35 THERMISTOR CN-C POWER SUPPLY CORD TOP GRILL HEATING ELEMENT G—Y N.C. CONTROL PANEL MONITOR SWITCH OVEN THERMAL OVEN LAMP IC-1 CUT-OUT MONITORED LATCH CN-G CN-1 SWITCH CN-B CN-B F 8 A WH-1 NOISE FILTER CONVECTION CN-C MOTOR MG. THERMAL CUT-OUT CN-E CN-A STOP...
  • Page 36: Power Unit Circuit

    KRC243M WH1-15 2SB1238 – WH1-2 STOP SWITCH WH1-1 STOP SWITCH NOTE 1. NOTE 2. : IF NOT SPECIFIED, 1/4W ± 5% WH1-n 15P WIRE HARNESS : IF NOT SPECIFIED, 0.1µF / 50V : IF NOT SPECIFIED, 1SS270A R-872M - 36...
  • Page 37: Cpu Unit Circuit

    CPU UNIT CIRCUIT R-872M - 37...
  • Page 38: Printed Wiring Board Of Power Unit

    PRINTED WIRING BOARD OF POWER UNIT VRS1 POWER CONT Figure S-4. Printed Wiring Board of Power Unit R-872M - 38...
  • Page 39: Parts List

    Control panel frame [R-872(SL)M] 3- 3-2 JBTN-A017URF0 Open button [R-872(W)M] 3- 3-2 JBTN-R005URF0 Open button [R-872(SL)M] 3- 3-3 MSPRCA045WRE0 Open button spring 3- 4 LHLD-A007URF0 LED holder 3- 5 PSHEPA647WRE0 LED sheet 3- 6 XEPSD30P10XS0 Screw : 3mm x 10mm R-872M - 39...
  • Page 40: Door Parts

    FW-VZA031URE0 Stop switch harness 6- 6 QW-QZA014URE0 High voltage wire A 6- 7 QW-QZA210WRE1 High voltage wire B 6- 8 FW-VZA071URE0 Main harness 6- 9 TINS-A173URR0 Quick start guide 6-10 TINS-A174URR0 Operation manual 6-11 TCAUHA001WRR1 Caution label R-872M - 40...
  • Page 41 Washer: 5mm x 0.8mm 7-23 XOTSD40P12000 Screw: 4mm x 12mm HOW TO ORDER REPLACEMENT PARTS To have your order filled promptly and correctly, please furnish the following information. 1. MODEL NUMBER 3. PART NO. 2. REF. NO. 4. DESCRIPTION R-872M - 41...
  • Page 42: Oven Parts

    7-20 1-14 4-12 7-18 4-15 1-15 4-19 7-19 4-25 1-19 4-31 4-24 7-20 4-20 NOTE: In the event of removing the 4-29 turntable motor cover this part 7-20 should be refitted using screw connection : LX-EZA045WRE0 (7-16) R-872M - 42...
  • Page 43: Control Panel/Door Parts

    CONTROL PANEL/DOOR PARTS CONTROL PANEL PARTS 3-3-1 3-3-2 3-3-3 DOOR PARTS R-872M - 43...
  • Page 44: Miscellaneous/Packing And Accessories

    R-872(SL)M: SSAKHA047WRE0 LOW RACK OUTER WRAP COVER (for R-872(SL)M) (SPADFA353WRE0) DOOR PROTECTION SHEET HIGH RACK (SPADPA020WRE0) TURNTABLE TRAY ACCESSORY HOLDER BOTTOM PAD ASSEMBLY (SPADPA013URE0) (FPADBA004URK0) INTO THE OVEN CAVITY PACKING CASE R-872(W)M: SPAKCA312URR0 R-872(SL)M: SPAKCA337URR0 Not Replaceable Items. R-872M - 44...
  • Page 45 NOTES R-872M - 45...
  • Page 46 NOTES R-872M - 46...
  • Page 47 '99 SHARP CORP. (8S1.31E) Printed in U.K. R-872M - 47...

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