Sharp R-8470 Service Manual Download Page 13

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R-8470
R-8570

COOKING CONDITION

Oven lamp does not light in cook

Defective shut-off relay

on relay Procedure J.

cycle.

unit.

(Does light when door is opened)

Defective control unit

Procedure K

Oven lamp does not light at all.

Burned out bulb.

Replace

Open wiring of oven lamp.

Check and repair wiring

Oven lamp lights, but turntable

Open or loose wiring to turntable motor.

Check and repair wiring

motor does not operate.

Defective turntable motor.

Replace

Turntable motor operates normally

Defective cooling fan motor.

Replace.

but cooling fan motor dies not

Defective shut-off relay (RY5) on relay Replace

operate

unit.
Open or loose wiring to fan motor

Check and repair wiring

MICROWAVE

Oven des not go into a cook cycle
when START pad is touched.

Oven seems to be operating but
little or no heat is produced in
oven

load. (Food

incompletely

cooked or not cooked at all at end
of cook cycle.)

Oven does into a cook cycle but

extremely

uneven

h e a t i n g i s

produced in oven load(food).

Oven does not cook properly
when programed for MEDIUM
etc. cooking powers.

(Operates properly on HIGH)

Oven does not cook properly
when programed in COMPU DE-

FROST cooking mode

Upper and/or lower latch switches

Procedure E.

tive or out of adjustment.

Defective cook relay

) on relay unit.

Procedure J.

Defective control unit.

Procedure K.

Defective key unit.

Procedure L.

Open or loose wiring to above compo-

Check and repair wiring

nents.

Defective magnetron.

Procedure A.

Defective cook relay

on relay unit.

Procedure J.

Defective power transformer.

Procedure B.

Defective rectifier.

Procedure C.

Defective high voltage capacitor.

Procedure D.

Defective control unit.

Procedure K.

Open or loose wiring to above compo-

Check and repair wiring

nents.

Low voltage.
Dirty oven cavity.

Turntable motor does not operate.

Refer to proceding turntable

motor problem.

Defective control unit.

Procedure K.

Defective key unit.

Procedure L.

Open or loose wiring to above compo-

Check and repair wiring

nents.

Defective COMPU DEFROST function.

Refer to COMPU DEFROST

section on operation manual
and check control unit.

Summary of Contents for R-8470

Page 1: ...TS Page FOREWORD 1 CAUTION MICROWAVE RADIATION 1 PRODUCT DESCRIPTION 2 OPERATION INSTRUCTIONS 3 OPERATION I 4 SERVICING 10 TOUCH CONTORL PANEL ASSEMBLY 20 COMPORNENT REPLACEMENT AND ADJUSTMENT PROCEDURE 29 MICROWAVE MEASUREMENT PROCEDURE 34 PACKING AND ACCESSORIES 35 PICTORIAL DIAGRAM 36 CONTROL PANEL CIRCUIT R 8470 37 CONTROL PANEL CIRCUIT R 8570 39 PRINTED WIRING BOARD 41 PARTS LIST 42 SERVICE I...

Page 2: ...I R 8470 R 8570 R 8470 R 8570 ...

Page 3: ...e given to avoid electrical shock and microwave radiation hazard CAUTION 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 nicrowave ene...

Page 4: ...wever cooking by microwave energy only produces no browning or searing unless cooking a roast of sufficient thickness This microwave oven is therefore equipped with a sheath heater to provide browning of the food The combination of the heater plus high speed circu lation of air by a circulating fan around the food pro vides fast cooking and browning of foods conventionally with or without the addi...

Page 5: ...oking time cooking instruction or time of day INDICATORS CONYECTlON not _ A _ LOW MIX T L ye 7 IYGHAS SL35 ym GRlli A SLOW COOK 5 mot A ow lyiiz MEDLOW I E of ml __ Med aare 17 E 1 8 22x t Lki l Te E i 9 i y 0W s I 0 25592 iMEP 1 AT STAR I HOLD CLOCK CONVECTION COOKING FUNCTION PADS Touch to cook with each function SENSOR COOK PAD Touch to select Sensor Cook settings COMPU COoKTM PAD Touch to sele...

Page 6: ...neled through the waveguide into the cavity feed box and then into the cavity where the food is placed to be cooked 5 6 Upon completion of the cooking time the power transformer oven lamp etc are turned off and the generation of microwave energy is stopped The oven will revert to the OFF condition When the door is opened during a cook cycle monitor switch stop switch upper latch switch are activat...

Page 7: ...tor circuit to continue operation of the cooling fan motor until the temperature drops below 100 OC at which time the relay will be de energized turn ing off the fan motor Relay RY3 will however open as soon sa the convection cycle has ended turning off the convection fan motor This will now cool and allow the damper door to open At the end of the convection cook cycle shut off relay RY6 is energi...

Page 8: ...emaining cooking time and the timer counts down to zero At this time the door may be opened to stir food turn it or season etc 6 When the timer reaches zero an audible signal sounds The shut offrelay and cook relay are de energized and the power transformer oven light etc are turned off 7 Opening the door or touching the STOP CLEAR pad the time of day will reappear on the display and the oven will...

Page 9: ...IF E 4j ZI i 0 T z 211 i Il z L p 2 5 oooo i O I Q E z so o pq G Wok 3 gyzyp Z 5 5 y Z gpP otwvJt z o 2X Lu JQ 5 oLL QaOL u4ak w OOCCYU a I Lip ggz OVL Uv z N 0 s 5 a 1 L s cu 0 5 4 2 a 0 Y iy 25 m _ 8 k z g i 2 6 5 IC Via C 0 0 5 E 0 2 e a G ao r iiF Eye 66 vi 6 7 m IA 0 c c 00 c J F G E 0 I g E EY 4 50 v L 0 Eg Yi hi 6 2 3 m IA E w z s t 0 I 0 c E z ci E 6 6 E L 7 ...

Page 10: ...inversely 3 In the door is opened and the upper latch switch contacts fail to open the fuse blows simultaneously with the closing of the monitor switch contacts CAUTION BEFORE REPLACING A BLOWN FUSE TEST THE MONITOR SWITCH UPPER LATCH SWITCH FOR PROPER OPERA TION REFER TO CHAPTER TEST PRO CEDURE DOOR OPEN MECHANISM The door can be opened by grasping the door handle and pulling strong When the door...

Page 11: ... a sig nal is sensed in the control unit and operates the shut off relay RY6 Contacts of shut off relay RY6 close then the damper motor is energized opening the damper door When damper is moved to the open position by the damper cam damper switch is closed ON position The signal of damper switch is re sensed in the control unit and shut off relay RY6 is turned off The 240 volts A C to the damper m...

Page 12: ...ord is plugged into wall recepta ness and repair harness I de Defective monitor switch Procedure F 88 88 do not appear in display No power at outlet Check home fuse when power cord is first plugged Blown monitor fuse Psocedure G into wall outlet Blown magnetron temp fuse Psocedure H Open wire in power cord wiring harness Replace or repair wiring or wiring between control panel assembly units Defec...

Page 13: ...o a cook cycle but extremely uneven heating is produced in oven load food Oven does not cook properly when programed for MEDIUM etc cooking powers Operates properly on HIGH Oven does not cook properly when programed in COMPU DE FROST cooking mode Upper and or lower latch switches defec Procedure E tive or out of adjustment Defective cook relay RYI on relay unit Procedure J Defective control unit P...

Page 14: ...oose wire connection to the Check and repair wiring above components Temperature in the oven cavity is Defective heating element Procedure I 1 lower or higher than preset Defective control unit Porcedure K Defective convection mortor Replace motor Defective thermistor Procedure N Defective cooling fan motor Replace Defective dumper motor Procedure 0 Defective drive mechanism of convection Check I ...

Page 15: ...V x AT t Our condition for the water load is as follows Water load 2000 ml Heating time I20 seconds 2 minutes P 7Ox A T Measuring method 1 Put the water load of two 2 litres on the center of the oven shelf The water load should be arranged in two 2 Pyrex beakers the size of which is one 1 litre and be placed at right and left side by side on the oven shelf 2 Measure the temperature of water before...

Page 16: ...O NENTS OR WIRING If the capacitor is open no high voltage will be available to the magnetron Disconnect input leads and check for short or open between the terminals using an ohmmeter Checking with a high ohm scale if the high voltage capacitor is normal the meter will indicate continuity for a short time and should indicate an open circuit once the capacitor is charged If the above is not the ca...

Page 17: ...A continuity check across the temp fuse terminal should indicate a closed circuit If the temperature of the magnetron reaches 115 OC thne temp fuse opens If the temp fuse has opened replace the fuse An open temp fuse indicates overheating of the magnetron assembly Check for restricted air flow to the magnetron through the opening in the chassis especially the cooling duct I HEATING ELEMENT TEST Ma...

Page 18: ...anel assembly is di vided into three units Control Unit Key Unit and Relay Unit and troubleshooting by unit re placement is described according to the symptoms indicated 1 Key Unit The following symptoms indicate a defective key unit Replace the key un it a When touching the pads a certain pad produces no signal at all b When touching a number pad two figures or more are displayed c When touching ...

Page 19: ...xample chicken pieces would be at refrigerator temperature and canned soup at room temperature 7 Foods weighing less than 3 ounces should be cooked by time and vaiper power 8 Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings The sensor will detect the vapor given of by the spray and turn off befor food is propary cooked 9 After 30 minutes it the sensor has n...

Page 20: ...ads to Pin No s E l and E 2 Room Temp Resistance 68 F 20 C 86 F 30 C 1 Approx 350 f2 155k n If the meter does not indicate above resistance replace the thermistor 0 DAMPER MOTOR TEST When the power cord is plugged into the wall receptacle the 240 volts A C is supplied to the damper motor and the motor operates until the damper is opened and the damper switch closes Then the damper motor stops oper...

Page 21: ...oximately 5 minutes after the preheat temperature is reached audible signal sounds four times The temperature experienced may be approximately 20 C more or less than indicated on the display however in most cases the food cooking results will be satisfactory Difference in power supply voltage will also affect the oven temperature The household power supply voltage may sometimes become lower than t...

Page 22: ...2 R 8570 only 34v Fluorescent display tube Grid and anode voltage VFI 25V Filament of fluorescent display tube VF2 28V VFI VF2 voltage Synchronizing Signal Circuit The power source synchronizing signal is available in order to compose a basic standard time in the clock circuit It accompanies a very small error because it works on commercial frequency ACL Circuit Cirucit to generate signals resetti...

Page 23: ...R 8470 R 8570 1 I 2 3 4 5 6 1 2 Figure T l Block Daigram 3 4 5 I I 6 21 ...

Page 24: ...ey matrix is touched PIN NO 9 Segment data sianal Signal similar to E6 1 SIGNAL E8 I I O j O U T Kev strobe siqnal R 8570 onlv Signal applied to touch key section A pulse signal is input to AN4 AN7 terminal while one of G 3 line keys on key matrix is touched PIN NO j IO 11 Segment data siqnal Signal similar to E6 S I G N A L E9 ElO I I O j OUT PIN NO 12 1 S I G N A L El1 I I I O j OUT Segment data...

Page 25: ... line keys on key matrix is touched PIN NO 19 20 1 S I G N A L 1 El8 E19 I l O 1 OUT Seqment data siqnal Signal similar to E6 PIN NO 21 24 1 SIGNAL E20 E23 I I O 1 OUT R 8470 Terminal not used Connected to GND R 8570 Used for initial balancing of the bridge circuit absolute himidity sensor PIN NO 25 1 SIGNAL 1 EX I I O 1 IN Internal clock oscillation frequency settinq input The internal clock freq...

Page 26: ...ooking and H level while not cooking In other cooking modes MED HIGH MED MED LOW LOW the signal turns to H level and L level in repetition according to the power level PIN NO j 34 1 SIGNAL 1 RI I I O OUT Oven lamp and turntable motor driving signal Sauare Waveform 50Hz To turn on and off the control relay The pulse signai 50Hz is delivered to the control relay driving circuit and cook relay and he...

Page 27: ...verter in the LSI The reference voltage is generally maintained at 5V I I O 1 IN PIN NO 45 1 SIGNAL AVR I I O IN Reference voltage input terminal A reference voltage applied to the A D converter in the LSI Connectd to GND PIN NO 1 46 Connected to GND 1 SIGNAL j AVcc I I O IN PIN NO 47 1 SIGNAL A N 7 I l O IN Signal coming from touch key When either one of G l 3 line keys on key matrix is touched a...

Page 28: ...L j A N 1 I I O j IN Temperature measurement input OVEN THERMISTOR By inputting DC voltage corresponding to the temperature detected by the thermistor this input is converted into temperature by the A D converter built into the LSI PIN NO 1 54 1 SIGNAL 1 AN0 I I O IN Terminal not used Connected to GND PIN NO 55 1 SIGNAL R8 Terminal not used Connected to VC I I O j OUT PIN NO 5 6 6 0 Terminal not u...

Page 29: ... sensor cooking of the unit When the unit is set in the sensor cooking mode 16 seconds later the detector circuit starts to func tion and the LSI observes the initial voltage availabel at its AN2 terminal With this voltage given the switches SW1 to SW5 in the LSI are turned on in such a way as to change the resistance values in parallel with R50 1 Changing the resistance values results in that the...

Page 30: ...some models on the other hand the power supply cord between the touch control panel and the oven proper is so long that they may be separated from each other For those mod els therefore it is allowed to check and repair the controls of the touch control panel while keeping it apart from the oven proper in this case you must short both ends of the stop switch on PWB of the touch control panel with ...

Page 31: ...ling the transformer secure the transformer with two screws to the cabinet base one is with outertooth washer and the other is without outer tooth washer Re connect the wire leads primary and high voltage to the transformer and filament leads of transformer to the magnetron referring to the Pictorial Diagram Re install the outer case and check that the oven is operating properly SILICON RECTIFIER ...

Page 32: ...te with the convection motor should be installed in close contact with the waveguide flange Otherwise the revolution of the convection fan belt may be disrupted COOLING FAN MOTOR REMOVAL 1 Disconnect oven from power supply and remove outer case 7 Remove the duct A with the cooling fan motor attached from the unit 2 Discharge the high voltage capacitor 3 Disconnect wire leads from the cooling fan m...

Page 33: ...Disconnect oven from power supply and remove outer case Discharge the high voltage capacitor Disconnect the wire connectors and wire leads from the relay unit Disconnect a connector from the control unit Remove single 1 screw holding the control panel back plate to the chassis support Remove the two 2 screws holding the bottom edge of the back plate to the cabinet base Remove single 1 screw holdin...

Page 34: ...ure the screws with washers firmly 4 Now make sure of the upper latch switch opera tion If the upper latch switch has not activated with the door closed loose the one 1 screw holding the upper latch hook to the oven cavity front flange and adjust the upper latch hook position After the adjustment make sure of the following points 1 The in and out play of the door remains less than 0 5 mm at latche...

Page 35: ...oor is adjusted to meet the fol lowing three conditions before tightening the hinge screws 1 Adjust door latch heads at a position where they smoothly catch the latch hooks through the latch holes Refer to primary and secondary interlock switches adjustment 2 Deviation of the door alignment from the horizontal line of cavity face to be less than IOmm 3 Door should be adjusted with its face depress...

Page 36: ...he per formance standard for microwave ovens must be used for testing Recommended instruments are NARDA 8100 NARDA 8200 HOLDADYA HI 1500 SIMPSON 3800M 2 Place the turntabel tray into the oven cavity 3 Place the load of 275 fl5ml of water initially at 20 5 C in the centre of the oven tray The water container should be a low form of 600 ml beaker with inside diameter of approx 8 5cm and made of an e...

Page 37: ...R 8470 R 8570 1 2 3 4 5 6 PACKING AND ACCESSORIES TRAY PACKING FOAM s SPADP0328WREO N o t Replaceble Items c C D E 35 ...

Page 38: ...GL CN I 101 I 3 618 N A CN BI lCN ii 1 COOLING FANMOTOR 3 p W Ii I R 857 u rAt C I I I c CONTROL PANEL ASS Y TO 3PIN CONNECTOR CN F THERMISTOR HEATING ELEMENT i ION ZP N CONNECTOR Al 1L _ o __ bin __ _ _ _ _ _ _ __ _ _ ___ r T 0 0 W D m ...

Page 39: ... I VI TURNTABLE MOTOR OVEN LAMP r4 yB 4 IDT FAN MOTOR A 9 dc aC A 7 i A 5 fN CTlON DAMPER MOTOR DTA143 A x5 IF NOT SPECIFIED 1 4W 5 j I F NOT SPECIFIED 0 015 25V IF NOT SPECIFIED US1060 I t R76 l k R71 lk f R66 l k fvc t R65 130 F C65 l 7 DAMPER STOP SWITCH SWITCH DOOR SWITCH TERMISTER Figure S 2 Contorol Panel Circuit Mot 1 I 2 I 3 4 I 5 6 I 7 37 ...

Page 40: ... 8570 R66 l k f R65 G 130 F C65 T 1 KEY UNIT 1 I 1 10k t j t jR99 fR96 R 9 7 R96 R95 fR94 fR9l r F U OS ln0V l C C c B 1 7 8 I 9 10 11 12 l A C VP 9 D E OVEN TERMISTER Ii I Panel Circuit Model R 8470 I 7 8 I 9 I 10 11 12 38 ...

Page 41: ...POWER TRANSFORMER IIf AKt HEATING ELEMENT FAN MOT01 c IUU CTION DAMPER MOTOF 5 DTA143 A x I F N O T SPECIFIED 1 4W 5 4 b IF NOT SPECIFIED 0 015 25V IF NOT SPECIFIED US1060 I J I I I R76 l k R75 27k i iI R52 i BkF KfT STOP OVEN THERMISTOR DO TC Figure S 3 I 1 I 2 1 3 4 5 39 ...

Page 42: ...8470 R 8570 7 8 9 10 11 I 12 I 1 NAL VP 2 D91 10k xt H I G H MEDHIGH AUTO s im S T O P I N S T A N T T I M E R START HOLD DEFROST KEY UNIT I AH SENSOR 11 Panel Circuit Model R 8570 I 7 8 I 9 10 I 11 12 40 ...

Page 43: ... lOlOl K E I ggzr z Y7 O Rmo f f Ll Lx I 71 I r J ggo g pa3 g f 1 II I 1 fi g j iti E 0 ec g kn L 0 0 I e 4 I gj zm 52 1 i yfycJ 3 I a Ad 53 g a g a Fz i Li _ z 4 I 3 I mR r IIAFI _ I 0184 n Control Unit Figure S 4 Printed Wiring Board Relay Unit rl B C D E F G H I 1 II 2 3 4 5 6 I 41 ...

Page 44: ...8570 LBNDK0035WRPO Capacitor holder PCUSU0242YBPO Cushion LHLDK0005YBFO Cord holder GCABUAO56WRPO Outer case cabinet PCUSUOl 12YBPO Shading cushion A LANGQ0255WRWO Capacitor mounting bracket PSPAGQ002YBEO Vibration proof cushion P C A S 0017WRFO Plug case LANGQ0225WRWO Cord mounting bracket LBSHC0032WREO Cord bushing LSTPP0009YBFO Cord anchorage lower LSTPP0008YBFO Cord anchorage upper CONTROL PAN...

Page 45: ... R E O R R DZl 5 1 P D R E O R R DZl 2 1 P D R E O R R D Z 2 7 1 P D R E O R R DZ473DDREO AC A A A A A A A A A A R R DZ473DDREO Transistor 2SB91 OMR Resistor 3 3 0 n Resistor 150 n Resistor 120n Resistor 270 n Resistor 47k n Resistor 47k n Resistor 15kn Resistor 4 7 0 c2 Resistor block RNAFST Resistor 330 n Resistor IOkn 1 4w 1 2w lj2W 1 2w 1 4W R 8470 1 4W R 8570 A A R R DZl 5 3 D D R E C I 1 l4W...

Page 46: ...2WRWO FFANMA002WRYO NBLTKAOO5WREO NPLYBOO3OWRFO Relay unit 12 pin connector A pin wire connector 0 13 pin wire connector C 8 pin connector I Fuse holder Capacitor 0 1 PF Capacitor 1000 FF Capacitor 0 1 PF Capacitor 10 FF Diode 11 El Diode US1 060 5 o v 3 5 v 25V 5 o v Fuse Filter coil 22 PH Transistor 2SA937Q Resistor 18kn Resistor 10kn Resistor 150k n Resistor 470 n Relay D C 14V Buzzer Varistor ...

Page 47: ...pper 1 LANGTAO48WRWO Sash mounting plate lower 1 F H N G 0078WREO Door hinge ass y 1 HDECQA028WRFO Door sash left 1 PGLSPAO45WREO Door glass R 8470 1 PGLSPAO46WREO Door glass R 8570 1 P C U S G 0 2 1 3 W R P 0 Door sushion short 2 P C U S G 0 2 1 2 W R P 0 Door cushion long 2 PSLDMAO38WREO Door ferrite upper 2 L X CZAOl 7 W R E 0 Screw sash mounting plate mtg 6 L X CZOO26WREO Screw door hinge ass ...

Page 48: ...ght left upper thermal 21 AA protection plate right left thermal protection cover oven lamp mounting plate sensor cover and air guide duct mtg X C P S D4 0 P 2 7 0 0 0 Screw cord anchorage upper mtg 2 A A XCPWW3OPl o x u o Screw heating element holder and heating element insulator mtg 4 AA XCTSD40P08000 Screw convection motor mounting plate and damper duct mtg 4 AA XCTSD40Pl 0 0 0 0 Screw cord anc...

Page 49: ...1 4 3 A l R H T Z A 0 2 5 D R E O VS2SC2021 f 1 A R H T Z A 0 2 1 D R E O VS2SB851 R 1 REF NO RI R2 RS R4 R22 etc R23 eic R 3 0 R 5 5 e c R66 e c R70 etc R83 R 8 4 R113 R 2 0 0 R 2 0 4 LISTED PART NO USED PART NO R 1 DZ331 N D R E O L R D ST2EF331 J R R DZl 5 1 P D R E O S D ST2HAl 5 1 J R R DZl 2 1 P D R E O x R D S72HAl 2 1 J RR D Z 2 7 7 P D R E O RD ST2HA271 J R R DZ473DDREO RD ST2EF473J R R D...

Page 50: ...R 8470 R 8570 1 2 3 j 4 5 6 I CABINET PARTS I 1 I 1 I 2 I 3 I 4 I I 5 6 48 ...

Page 51: ...R 8470 R 8570 1 2 3 4 5 6 I i E I I 1 2 49 ...

Page 52: ...R 8470 R 8570 1 2 I 3 4 5 6 1 I 1 I 2 3 4 5 I 6 50 ...

Page 53: ...R 8470 R 8570 1 2 I 3 I 4 5 6 DOOR ASSEMBLY MISCELLANEOUS 6 3 Trans m I I I I I I i I t ...

Page 54: ...refore it must be fixed correctly and firmly 1 The cord anchorage which is used to secure the mains supply cord can be fixed in two different ways 2 If you fix them s shown in Figure 2 the mains supply cord will not be secured firmly 3 Therefore make sure to fix them as shown in figure 1 LSTFFOOO8Y BFO SUPPLY CDRD ANCHORAGE WPPER LBTPPWlO8YBFO Figure 1 Correct Fixing Figure 2 Wrong Fixing 3 m m 86...

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Sharp R-8470, Service Manual

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