Sharp R-870B Service Manual

R-870BTABLE OF CONTENTSPageCAUTION, MICROWAVE RADIATION...

8R-870BDOOR OPEN MECHANISMThe door can be opened by pushing the open button on thecontrol panel. When the open button is pushed, the switchlever is mo

R-870B9NOISE FILTERThe noise filter assembly prevents radio frequency inter-ference that might flow back in the power circuit.TOP HEATERSThe top heate

10R-870BWhen troubleshooting the microwave oven, it is helpful tofollow the Sequence of Operation in performing the checks.Many of the possible causes

R-870B11Fuse 15A blows when power cord is plugged into wall outlet.Fuse M10A blows when the door is opened.Home fuse blows when power cord is plugge

12R-870BA MAGNETRON TESTTEST PROCEDURESPROCEDURELETTER COMPONENT TESTCARRY OUT 3D CHECKS.Isolate the magnetron from high voltage circuit by removing a

R-870B13Initial temperature ... T1 = 11°CTemperature af

14R-870BTEST PROCEDURESPROCEDURELETTER COMPONENT TESTE SWITCH TESTCARRY OUT 3D CHECKS.Isolate the switch to be tested and using an ohmmeter check betw

R-870B15CARRY OUT 3D CHECKS.Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the twoterminals as described in the

16R-870BTEST PROCEDURESPROCEDURELETTER COMPONENT TESTL THERMISTOR TEST1. CARRY OUT 3D CHECKS.2. Disconnect connector-D from the control unit. Measure

R-870B17TEST PROCEDURESPROCEDURELETTER COMPONENT TEST(stop switch) is good, disconnect the flat ribbon cable that connects the key unit to the control

R-870B

18R-870BSTEPS OCCURRENCE CAUSE OR CORRECTION1The rated AC voltage is not present at Check supply voltage and oven power cord.Power terminal of CPU con

R-870B19TEST PROCEDURESPROCEDURELETTER COMPONENT TESTTESTING METHOD FOR AH SENSOR AND/OR CONTROL UNITTo determine if the sensor is defective, the simp

20R-870BTOUCH CONTROL PANEL ASSEMBLYOUTLINE OF TOUCH CONTROL PANEL4) ACLA circuit to generate a signal which resets the LSI to theinitial state when p

R-870B21DESCRIPTION OF LSILSI(IZA936DR)The I/O signal of the LSI(IZA936DR) are detailed in the following table.Pin No. Signal I/O Description20 msec.H

22R-870B25 P41 OUT Key strobe signal.Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminalwhile one of G8 line key on mat

R-870B2338 XIN IN Internal clock oscillation frequency input setting.The internal clock frequency is set by inserting the crystal oscillation circuit

24R-870BPin No. Signal I/O Description82-90 SEG8-SEG0 OUT Segment data signal.Connected to LCD. Signal is similar to SEG39.91 VCC IN Connected to GND.

R-870B25(1) Structure of Absolute Humidity SensorThe absolute humidity sensor includes two thermistorsas shown in the illustration. One thermistor is

26R-870BSERVICING6) Run the oven and check all functions.A. On some models, the power supply cord between thetouch control panel and the oven itself i

R-870B271. Disconnect the oven from power supply.2. Make sure that a definite “click” can be heard when themicrowave oven door is unlatched. (Hold the

R-870B1SERVICE MANUALDOUBLE GRILLCONVECTIONMICROWAVE OVEN R-870BGENERAL IMPORTANT INFORMATIONThis Manual has been prepared to provide Sharp Corp. Ser

28R-870BPOSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL1. CARRY OUT 3D CHECKS.2. Push the lever of positive lock® connector.3. Pull down on the posit

R-870B29REMOVAL1. CARRY OUT 3D CHECKS.2. Remove the one (1) screw holding the noise filter to thechassis support.3. Release the noise filter from the

30R-870BRemoval1. CARRY OUT 3D CHECKS.2. Remove the one (1) screw holding the green/yellowwire to the cavity rear plate.3. Disconnect the leads of the

R-870B31If the 1st. latch switch, 2nd. interlock relay control switchand monitor switch do not operate properly due to a mis-adjustment, the following

32R-870BUpper OvenHingeUpper OvenHingeLower OvenHingeLower OvenHingePinPinChoke CoverDoorPanelFigure C-6. Door ReplacementREMOVAL1. CARRY OUT

R-870B33MICROWAVE MEASUREMENTAfter adjustment of door latch switches, monitor switchand door are completed individually or collectively, thefollowing

34R-870BSCHEMATICNOTE: CONDITION OF OVEN1. DOOR CLOSED.2. COOKING TIME PROGRAMMED.3. START PAD TOUCHED.Figure O-2 Oven Schematic-Microwave cooking Con

R-870B35NOTE: Indicates components with potential above 250 V.SCHEMATICNOTE: CONDITION OF OVEN1. DOOR CLOSED.2. GRILL PAD TOUCHED ONCE.3. COOKING TIM

36R-870BSCHEMATICNOTE: CONDITION OF OVEN FOR GRILL COOKING1. DOOR CLOSED.2.GRILL PAD THREE TIMES.3. COOKING TIME PROGRAMMED.4. STRAT PAD TOUCHED.Fig

R-870B37SCHEMATICNOTE: CONDITION OF OVEN1. DOOR CLOSED.2. MIX PAD TOUCHED ONCE/TWICE.3. COOKING TIME PROGRAMMED.4. STRAT PAD TOUCHED.Figure O-5(a) Ove

2R-870BGENERAL INFORMATIONWARNINGTHIS APPLIANCE MUST BE EARTHEDIMPORTANTTHE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING COD

38R-870B645123645123ABCDEFGHABCDEFGHFigure S-1. Pictrorial DiagramREDWHTWHTTHERMAL CUT-OUT(OVEN)OVEN LAMP (HALOGEN LAMP)MONITOR RESISTORTHERMALCU

R-870B39Figure S-2. Power Unit Circuit645123645123ABCDEFGHABCDEFGH+–+–+–COMN.O.COMN.O.COMN.O.COMN.O.A 3OVEN LAMPTURNTABLEMOTORBOTTOMHEATERTOPHEA

40R-870B645123645123ABCDEFGHABCDEFGHFigure S-3. Control Panel CircuitC 4INTGNDVCBUZZER: IF NOT SPECIFIED, 1/10w ± 5% NOTEVALEDVRFANMOTORCONVECTION

R-870B41645123645123ABCDEFGHABCDEFGHFigure S-4. Printed Wiring BoardDIPD8 3 2 312 1115184 D6 R4 CN - C CN - D CN - B CN - A D5 R5 AC AC VRS16FANCONRY1

42R-870BPARTS LISTNote: The parts marked "∆" may cause undue microwave exposure.The parts marked "*" are used in voltage more than

R-870B43∆∆∆∆∆Note: The parts marked "∆" may cause undue microwave exposure.The parts marked "*" are used in voltage more than 250V

44R-870BPACKING AND ACCESSORIESHOW TO ORDER REPLACEMENT PARTSTo have your order filled prompty and correctly, please furnish the following information

R-870B45645123645123ABCDEFGHABCDEFGHOVEN AND CABINET PARTS7-97-54-14-307-107-107-92-16-127-97-17-67-61-104-354-414-387-147-117-167-134-414-254-334-297

46R-870B'98SHARP CORP. (8K0.12E) Printed in Japan645123645123ABCDEFGHABCDEFGHDOOR PARTSMISCELLANEOUSCONTROL PANEL PARTS5-85-35-65-45-55-15-96-133

R-870B3TOUCH CONTROL PANEL14u30005526w798qertyTurntable Turntablesupport High rackLow rackTurntable motor shaft Bottom heaterAPPEARANCE VIEW1. TOP

4R-870BOPERATION SEQUENCEOFF CONDITIONClosing the door activates the 1st. latch switch and 2nd.interlock relay control switch.IMPORTANT:When the oven

R-870B5the top and bottom heaters.3. When the oven temperature reaches the selectedpreheat temperature, the following operations occur:3-1. The heater

6R-870BCONVEC MIX HIGH MODE AND CONVEC MIX LOWMODEIn these modes, the food is cooked by the convection andthe microwave energy. Press the MIX pad once

R-870B7Specified cooking Limited power Time baseCooking mode time (minutes) output (%) (seconds)Microwave100% Power20 70 32Top heaters 30 50 48Bottom