R-870B SERVICE MANUAL S8837R870BPHR DOUBLE GRILL CONVECTION MICROWAVE OVEN TURNOVER ADD STAND COVER STIR DEFROST HELP % AUTO SENSOR COOK KG CRISPY SNACK PIZZA AUTO COOK GRILL 1 2 3 ROAST Grilled Fish 1 Grilled Lobster 2 Steak 3 BAKE Beef 1 Lamb 2 Chicken 3 Cake Apple Pie Cookies SENSOR COOK RICE MENU REHEAT DISH STEAM MENU HELP GRILL DOUBLE GRIL L SLOW COOK CONVEC PREHEAT POWER LEVEL MODEL R-870B MIX EASY DEFROST CONVECTIO N STOP/ CLEAR INSTANT COOK/START Sensor In i
R-870B
R-870B SERVICE MANUAL PRODUCT SPECIFICATIONS GENERAL INFORMATION DOUBLE GRILL CONVECTION MICROWAVE OVEN APPEARANCE VIEW R-870B GENERAL IMPORTANT INFORMATION 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.
R-870B PRODUCT DESCRIPTION SPECIFICATION ITEM DESCRIPTION Power Requirements Power Consumption Power Output Grill heater Power Output (Top heater) Bottom heater Power Output Case Dimensions Cooking Cavity Dimensions Turntable diameter Control Complement 220 Volts 50 Hertz Single phase, 3 wire earthed Microwave cooking 1.6 kW Top Heater mode 1.3 kW Grill cooking Bottom heater mode 0.9 kW Double grill mode 2.1 kW Convection cooking 2.
R-870B APPEARANCE VIEW 4 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 Turntable support 11.Waveguide cover 12.Door opening button 13.Control panel 14.Digital display 15.Power supply cord Bottom heater 16.Outer cabinet 17.
R-870B OPERATION SEQUENCE OFF CONDITION Closing the door activates the 1st. latch switch and 2nd. interlock relay control switch. IMPORTANT: When the oven door is closed, the contacts COM-NC of the monitor switch must be open. When the microwave oven is plugged in a wall outlet (220V 50Hz), the line voltage is supplied to the noise filter and the control unit. Contact 1st. latch switch 2nd.
R-870B the top and bottom heaters. 3. When the oven temperature reaches the selected preheat temperature, the following operations occur: 3-1. The heater relays RY3+RY4 de-energized by the CPU unit temperature circuit and thermistor, opening the circuit to the top and bottom heaters. 3-2. The oven will continue to function for 30 minutes, turning the top and bottom heaters on and off, as needed to maintain the selected preheat temperature. The oven will shut-down completely after 30 minutes.
R-870B CONVEC MIX HIGH MODE AND CONVEC MIX LOW MODE pressed, the following operations occur: Figure O-5(b) on page 37 1. The relay RY5 + RY6 are energized. 2. The numbers of the digital read-out start the count down to zero. 3. The turntable motor, oven lamp and fan motor are energized. 4. The relay RY2 + RY3 are energized alternately within a 48 seconds time base by the control unit. 5. The top heaters operate through the relay RY3 is energized.
R-870B Cooking mode Specified cooking time (minutes) Limited power output (%) 3. Sensor detects moisture and humidity and calculates cooking time and variable power. Time base (seconds) Microwave 100% Power Top heaters 20 70 32 30 50 48 Bottom heater Top browner and Bottom browner or Oven cooking 15 50 48 10 (Top) 10 (Bottom) 50 50 48 48 AH SENSOR COOKING SEQUENCE 1.
R-870B motor, turntable motor and the oven lamp. The LSI also stops counting down. 3. Once the fire sensor feature has shut the unit down, the programmed cooking cycle may be resumed by pressing the "START" pad or the unit may be reset by pressing the "CLEAR" pad. ON/OFF TIME RATIO In grill cooking, convection cooking or mix cooking, the top heaters, bottom heater or magnetron operate whithin a 48 second time base.
R-870B FUSE M10A 250V NOISE FILTER 1. If the wire harness or electrical components are shortcircuited, this fuse blows to prevent an electric shock or fire hazard. 2. This fuse blows when the 1st. latch switch and 2nd. interlock relay (RY2) remain closed with the oven door open and when the contacts (COM-NC) of monitor switch closes. The noise filter assembly prevents radio frequency interference that might flow back in the power circuit.
R-870B SERVICING WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with following parts will result in electrocution. High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier assembly, High voltage harness. REMEMBER TO CHECK 3D REMEMBER TO CHECK 4R 1) Disconnect the supply. 2) Door opened, and wedged open. 3) Discharge high voltage capacitor. 1) Reconnect all leads removed from components during testing.
11 AH. SENSOR CONVECTION COOKING CONDITION MIX COOKING CONDITION GRILL COOKING CONDITION MICROWAVE COOKING CONDITION COOKING CONDITION (COMMON MODE) OFF CONDITION CONDITION Oven is in sensor cooking condition but AH sensor does not end 1st. stage or does not stop cooking cycle or the oven stops soon. Oven stops after 4 minutes 15 sec.. Convection motor does not operate. Temperature is lower or higher than preset. Bottom heater does not operate. Top heaters do not operate.
R-870B TEST PROCEDURES PROCEDURE LETTER A MAGNETRON TEST COMPONENT 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. To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron filament terminals, the meter should show a reading of less than 1 ohm.
R-870B 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” ..........................................
R-870B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST B. Continuity check must be carried out with measuring instrument which is set to the highest resistance range. C. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ after it has been charged. D. A short-circuited capacitor shows continuity all the time. E. An open capacitor constantly shows a resistance about 10 MΩ because of its internal 10MΩ resistance. F.
R-870B TEST PROCEDURES PROCEDURE LETTER H BLOWN FUSE 15A COMPONENT TEST CARRY OUT 3D CHECKS. If the fuse 15A 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. CARRY OUT 4R CHECKS. CAUTION: I Only replace fuse 15A with the correct value replacement. NOISE FILTER TEST N WHT L RED CARRY OUT 3D CHECKS. Disconnect the leads from the terminals of noise filter.
R-870B TEST PROCEDURES PROCEDURE LETTER L THERMISTOR TEST COMPONENT TEST 1. CARRY OUT 3D CHECKS. 2. Disconnect connector-D from the control unit. Measure the resistance of the thermistor with an ohmmeter. Connect the ohmmeter leads to Pin No’s D1 and D3. Room Temperature 68˚F(20˚C) - 86˚F(30˚C) Resistance Approx. 293kΩ - 184KΩ 3. If the meter does not indicate above resistance, replace the thermistor 4. CARRY OUT 4R CHECKS. M HIGH VOLTAGE FUSE TST CARRY OUT 3D CHECKS.
R-870B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST (stop switch) is good, disconnect the flat ribbon cable that connects the key unit to the control unit and make sure the door sensing switch is closed (either close the door or short the door sensing switch connecter). Use the Key unit matrix indicated on the control panel schematic and place a jumper wire between the pins that correspond to the STOP/CLEAR pad marking momentary contact.
R-870B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST STEPS OCCURRENCE 1 The rated AC voltage is not present at Power terminal of CPU connector (CN-A). Check supply voltage and oven power cord. CAUSE OR CORRECTION 2 The rated AC voltage is present at primary side of low voltage transformer. Low voltage transformer or secondary circuit defective. Check and repair. 3 Only pattern at "a" is broken. *Insert jumper wire J1 and solder. (CARRY OUT 3D CHECKS BEFORE REPAIR.
R-870B 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. (2) Discharge the high voltage capacitor. (3) Remove the AH sensor. (4) Install the new AH sensor. (5) Re-install the outer case.
R-870B TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL 4) ACL A circuit to generate a signal which resets the LSI to the initial state when power is supplied. The touch control section consists of the following units as shown in the touch control panel circuit. (1) Key Unit (2) Control Unit (The Control unit consists of Power unit and CPU unit.) 5) Buzzer Circuit The buzzer is responsive to signals from the LSI to emit audible sounds (key touch sound and completion sound).
R-870B DESCRIPTION OF LSI LSI(IZA936DR) The I/O signal of the LSI(IZA936DR) are detailed in the following table. Pin No. Signal I/O C1 VL1 IN IN Terminal not used. Power source voltage input terminal. Standard voltage for LCD. AN7-AN5 AN4 IN IN Heating constant compensation terminal. Terminal not used. 7 AN3 IN 8 AN2 IN Temperature measurement input: OVEN THERMISTOR.
R-870B Pin No. Signal I/O Description 25 P41 OUT 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. 26 P40 OUT 27 P77 OUT 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. Key strobe signal. Signal applied to touch-key section.
R-870B Pin No. 38 Signal XIN I/O IN 39 XOUT OUT 40 VSS IN 41 P27 OUT Bottom heater driving signal. To turn on and off the bottom relay (RY4). "L" level during grill (TOP AND BOTTOM) cooking, or Convection cooking, "H" level otherwise. The heater relay turns on and off within a 48 second time base in accordance with the special program in LSI. 42 P26 OUT Convection motor driving signal. To turn on and off shut-off relay(RY1). "L" level during CONVECTION; "H" level otherwise.
R-870B Pin No. Signal I/O SEG8-SEG0 OUT 91 VCC IN Connected to GND. 92 VREF IN Connected to GND. 93 94 AVSS COM3 IN OUT Connected to VC. Common data signal. Connected to LCD (Pin No. 36). No connection in LCD. 95 COM2 OUT 96 COM1 OUT Common data signal: COM3. Connected to LCD (Pin No. 35). Common data signal: COM2. Connected to LCD (Pin No. 34). 97 COM0 OUT VL3-VL2 IN C2 IN 82-90 98-99 100 Description Segment data signal. Connected to LCD. Signal is similar to SEG39.
R-870B ABSOLUTE HUMIDITY SENSOR CIRCUIT Then the LSI observes that voltage at AN1 terminal and compares it with its initial value, and when the comparison rate reaches the preset value (fixed for each menu to be cooked), the LSI causes the unit to stop sensor cooking; thereafter, the unit goes in the next operation automatically.
R-870B SERVICING 1. Precautions for Handling Electronic Components 6) Run the oven and check all functions. This unit uses CMOS LSI in the integral part of the circuits. When handling these parts, the following precautions should be strictly followed. CMOS LSI have extremely high impedance at its input and output terminals. For this reason, it is easily influenced by the surrounding high voltage power source, static electricity charge in clothes, etc.
R-870B 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 power supply. 2. Make sure that a definite “click” can be heard when the microwave oven door is unlatched. (Hold the door in a closed position with one hand, then push the door open button with the other, this causes the latch leads to rise, it is then possible to hear a “click” as the door switches operate.
R-870B oven cavity rear plate. 7. Release the capacitor holder from the fan duct. 8. Remove the capacitor from the capacitor holder. 9. Now, the high voltage rectifier assembly and the capacitor should be free. CAUTION: WHEN REPLACING HIGH VOLTAGE RECTIFIER ASSEMBLY, ENSURE THAT THE CATHODE (EARTH) CONNECTION IS SECURELY FIXED TO THE CAPACITOR HOLDER AND BASE PLATE WITH AN EARTHING SCREW. HIGH VOLTAGE TRANSFORMER REMOVAL 1. CARRY OUT 3D CHECKS. 2.
R-870B THERMISTOR REMOVAL 1. CARRY OUT 3D CHECKS. 2. Now, the back plate with the sub back plate should be removed. 3. Disconnect the connector CN-D from the control unit. 4. Remove the one (1) screw holding the air duct to the oven cavity rear plate. 5. Remove the air duct assembly from the oven cavity rear plate. 6. Remove the one (1) screw holding the thermistor angle to the oven cavity rear plate. 7. Remove the thermistor angle together with thermistor from the oven. 8.
R-870B • Make sure that the axis of the shaft is not slanted. 3. Install the fan duct to the oven cavity rear plate with the one (1) screw. 4. Insert the tabs of the capacitor holder to the fan duct. 5. Install the capacitor holder to the oven cavity rear plate with the one (1) screw. 6. Install the noise filter to the fan duct and the chassis support with the one (1) screw. 7. Re-connect the wire leads to the fan motor.
R-870B GRILL HEATERS (TOP HEATERS) REMOVAL 1. CARRY OUT 3D CHECKS. 2. Remove the one (1) screw holding the exhaust duct to the oven cavity. 2. Remove the exhaust duct from the oven cavity. 4. Disconnect the wire leads from the grill heaters. 5. Lay down the two (2) tabs holding the reflector to the oven cavity. 6. Remove the reflector from the oven cavity by sliding it leftward. 7. Remove the grill heaters and the short terminal together from the oven cavity top plate. 8.
R-870B DOOR REPLACEMENT tabs of door frame to seven (7) holes of door panel. 5. Hold the door panel to the door frame with four (4) screws. 6. Catch two (2) pins of door panel on two (2) hole of upper and lower oven hinges. 7. Re-install choke cover to door panel by pushing. Note: After any service to the door; (A) Make sure that door sensing switch and primary latch switch are operating properly. (Refer to chapter "Test Procedures".).
R-870B MICROWAVE MEASUREMENT After adjustment of door latch switches, monitor switch and door are completed individually or collectively, the following leakage test must be performed with a survey instrument and it must be confirmed that the result meets the requirements of the performance standard for microwave oven. 2. 3. REQUIREMENT The safety switch must prevent microwave radiation emission in excess of 5mW/cm2 at any point 5cm or more from external surface of the oven. PREPARATION FOR TESTING: 4.
N EARTH G-Y THERMAL CUT-OUT(OVEN) AH SENSOR 2ND. INTERLOCK RELAY CONTROL SWITCH 34 RY4 COM. 1ST. LATCH SWITCH Figure O-2 Oven Schematic-Microwave cooking Condition H.V. RECTIFIER CAPACITOR 1.07µF AC2200V H.V. FUSE 0.75A MONITOR SWITCH MONITOR RESISTOR 0.8/ 20W N.O. MAGNETRON T1 T2 FUSE M10A GRILL HEATER (TOP) CONTROUNIT N.O. N.O. COM. FM COM. COM. COM. N.O. A3 A5 H.V. RECTIFIER CAPACITOR 1.07µF AC2200V H.V. FUSE 0.75A MONITOR SWITCH N.O. N.O. COM. MONITOR RESISTOR 0.
N EARTH G-Y THERMAL CUT-OUT(OVEN) AH SENSOR 2ND. INTERLOCK RELAY CONTROL SWITCH 35 RY4 COM. 1ST. LATCH SWITCH Figure O-4(a) Oven Schematic-Grill cooking Condition (TOP HEATER mode) H.V. RECTIFIER CAPACITOR 1.07µF AC2200V H.V. FUSE 0.75A MONITOR SWITCH MONITOR RESISTOR 0.8/ 20W N.O. MAGNETRON T1 T2 FUSE M10A GRILL HEATER (TOP) CONTROUNIT N.O. N.O. COM. H.V. RECTIFIER CAPACITOR 1.07µF AC2200V H.V. FUSE 0.75A MONITOR SWITCH GRILL HEATER (TOP) N.O. N.O. COM. MONITOR RESISTOR 0.
N EARTH G-Y THERMAL CUT-OUT(OVEN) AH SENSOR 2ND. INTERLOCK RELAY CONTROL SWITCH 36 1ST. LATCH SWITCH Figure O-4(c) Oven Schematic-Grill cooking Condition (Double Grill mode) H.V. RECTIFIER CAPACITOR 1.07µF AC2200V H.V. FUSE 0.75A MONITOR SWITCH MONITOR RESISTOR 0.8/ 20W N.O. MAGNETRON T2 FUSE M10A GRILL HEATER (TOP) CONTROUNIT N.O. T1 H.V. RECTIFIER CAPACITOR 1.07µF AC2200V H.V. FUSE 0.75A MONITOR SWITCH GRILL HEATER (TOP) N.O. N.O. COM. MONITOR RESISTOR 0.8/ 20W N.O.
R-870B SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. MIX PAD TOUCHED ONCE/TWICE. 3. COOKING TIME PROGRAMMED. 4. STRAT PAD TOUCHED. NOTE: Indicates components with potential above 250 V. NOISE FILTER UNIT FUSE M10A H.V. RECTIFIER CAPACITOR 1.07µF AC2200V H.V. FUSE 0.75A MAGNETRON HIGH VOLTAGE TRANSFORMER MONITOR RESISTOR 0.8/ 20W BOTTOM HEATER COM. TURNTABLE MOTOR TTM OVEN LAMP GRILL HEATER (TOP) N.O. RY4 RY3 COM. COM. N.O. OL FAN MOTOR FM CM CONVECTION MOTOR 2ND.
H 1 2 3 38 4 RED 1 CN-A RY5 RY1 T1 5 ORG BRN BLK 5 RY6 CN-A 1 GRY 2 3 ORG 4 5 RED BRN ORG ORG COM 1ST. LATCH SWITCH COM. GRY 6 WHT TURNTABLE MOTOR BLK WHT RED OVEN LAMP (HALOGEN LAMP) BOTTOM HEATING ELEMENT CONNECTOR WHT RED WHT L BRN RED WHT WHT M10A GRY GRY FAN MOTOR ORG GRY RED RED BRN THERMAL CUT-OUT 125°C(MG) WHT RED CONVECTION MOTOR RED WHT HIGH VOLTAGE TRANSFORMER H.V. FUSE H.V. RECTIFIER MAGNETRON H.V.
R-870B 2 1 4 3 6 5 A A Q2 2SB1238 R4 27 C10 D1-4 11ES1 2SB1238 c R2 680 1/2w B + – C2 GND C3 VC C1 VA C9 VR C4 INT C5 BUZZER C15 FAN MOTOR C4 10µ/35v C3 0.1µ/50v HZ16-1 ZD1 R1 2.4k Q1 (J1) C D2 D4 b + 6 d 1 a LED R5 4.7k D1 D3 – 10G471K 4 D6 C2 1000µ/35v 8 A1 VRS1 AC220V 50Hz D5 C1 0.1µ/50v T1 B R3 510 1/2w SP1 C D12 RY5 FAN MOTOR R6 3.
C3 C5 C1 C10 C9 C15 C16 VC BUZZER VA LED VR FAN MOTOR CONVECTION MOTOR C7 MICRO 5 OVEN C17 THERMISTOR C13 C12 C11 C14 BOTTOM HEATER DOOR SWITCH C8 TOP HEATER C6 C2 OVEN LAMP TURNTABLE MOTOR C4 GND D30 D23 D22 + – Q20 DTA123JKA Q21 DTA123JKA C21 0.1µ/50v Q22 DTA123JKA Q23 DTA143EKA Q24 DTA143EKA Q25 DTA143EKA R31 15k F2 F3 1.8kF R101 IC2 0.
R-870B 2 1 4 3 6 5 A A DIP R3 CN - C 18 B 1 1 2 D6 3 Q1 B 3 D5 1 CN - B 4 D11 RY6 1 R1 E R2 C2 AC B 2 ZD1 C5 E Q3 SP1 C CN - D R4 E Q2 B D8 C3 C4 R6 D9 D10 B R5 C D1 D3 C1 RY3 T-H D D 1 D2 8 RY4 B-H D4 E 6 RY2 MICRO E S P 4 VRS1 F F T1 5 (J1) FAN 1 5 CON AC D7 CN - A 6 LOT NO. D12 RY1 G G RY5 F H H Figure S-4.
R-870B 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.
R-870B Note: The parts marked "∆" may cause undue microwave exposure. The parts marked "*" are used in voltage more than 250V. REF. NO. PART NO.
R-870B Note: The parts marked "∆" may cause undue microwave exposure. The parts marked "*" are used in voltage more than 250V. REF. NO. PART NO.
R-870B 2 1 4 3 6 5 OVEN AND CABINET PARTS 2-2 A A 7-9 6-12 7-8 4-45 7-9 4-33 2-1 B B 7-10 4-25 7-12 4-23 7-9 4-29 4-26 7-10 7-5 7-7 7-10 4-4 4-37 4-42 1-11 7-7 C 4-15 1-20 1-12 4-30 1-14 7-4 1-16 4-31 4-34 4-27 7-15 1-22 7-13 4-3 7-10 C 7-10 4-40 1-21 7-1 4-19 7-10 7-17 1-8 4-32 4-43 4-18 7-13 4-24 D 4-39 7-8 4-1 D 4-41 1-9 1-15 7-1 7-8 1-17 7-7 7-6 4-44 4-36 1-10 7-6 4-35 7-10 1-13 4-14 7-6 E 4-16 6-7 7-1 7-1 7-6 4-6 4-18 4-32 4-19 7-6 4
R-870B 2 1 4 3 6 5 CONTROL PANEL PARTS 3-6 3-4 A A 3-5 3-2 3-3 3-6 B B 3-3-3 6-13 3-1 C C DOOR PARTS 3-3-1 D D 5-8 3-3-2 5-9 5-1 E E 5-6 5-2 5-7 F F 5-3 5-4 MISCELLANEOUS 5-5 G G 6-1 6-10 6-9 6-11 6-2 Actual wire harness may be different than illustration. H H 1 2 4 3 5 6 '98SHARP CORP. (8K0.
