Sharp R-370EK Service Manual Download Page 10

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R- 370EK
R - 37 0ES

Figure O-1. Oven Schematic-Off Condition

SCHEMATIC

NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY

120V AC
60 Hz

OVEN
LAMP

AH SENSOR

OVEN LAMP
RELAY

TURN-
TABLE
MOTOR

FAN
MOTOR

POWER
TRANSFORMER

MONITOR

SWITCH

RECTIFIER

MAGNETRON

PRIMARY
INTERLOCK
SWITCH

TTM

FAN
MOTOR

MONITOR
FUSE 20A

N.O.

COM.

DOOR
SENSING
SWITCH

(RY1)

(RY2)

CONTROL UNIT

SECONDARY
INTERLOCK
RELAY

OVEN THERMAL
CUT-OUT

MG. THERMAL CUT-OUT

GRN

CAPACITOR
0.94

AC 2200V

NOTE: " " indicates components with potential above 250V.

SCHEMATIC

NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. COOKING TIME PROGRAMMED
3. VARIABLE COOKING CONTROL "P-HI" (100%)
4. "START" PAD TOUCHED

Figure O-2. Oven Schematic-Cooking Condition

120V AC
60 Hz

OVEN
LAMP

OVEN LAMP
RELAY

TURN-
TABLE
MOTOR

FAN
MOTOR

POWER
TRANSFORMER

MONITOR

SWITCH

RECTIFIER

MAGNETRON

PRIMARY
INTERLOCK
SWITCH

TTM

FAN
MOTOR

MONITOR
FUSE 20A

N.O.

COM.

DOOR
SENSING
SWITCH

(RY1)

(RY2)

CONTROL UNIT

SECONDARY
INTERLOCK
RELAY

OVEN THERMAL
CUT-OUT

MG. THERMAL CUT-OUT

GRN

CAPACITOR
0.94

AC 2200V

AH SENSOR

NOTE: " " indicates components with potential above 250V.

Summary of Contents for R-370EK

Page 1: ...T COVER WARNING TO SERVICE PERSONNEL 1 MICROWAVE MEASUREMENT PROCEDURE 2 FOREWORD AND WARNING 3 PRODUCT SPECIFICATIONS 4 GENERAL INFORMATION 4 OPERATION 6 TROUBLESHOOTING GUIDE 10 TEST PROCEDURE 12 TOUCH CONTROL PANEL 21 COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE 26 PICTORIAL DIAGRAM 33 POWER UNIT CIRCUIT 34 CPU UNIT CIRCUIT 35 PRINTED WIRING BOARD 36 PARTS LIST 37 PACKING AND ACCESSORIES 39 S...

Page 2: ...tion and transmission systems shall be repaired replaced or adjusted by procedures described in this manual before the oven is released to the owner e A microwave leakage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner BEFORE SERVICING Before servicing an operative unit perform a microwave emission check as per the Mic...

Page 3: ...capacitor 4 Disconnect the leads to the primary of the power transformer 5 Ensure that the leads remain isolated from other components and oven chassis by using insulation tape 6 After that procedure reconnect the power supply cord When the testing is completed 1 Disconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Recon...

Page 4: ...ter initially at 20 5 C 68 F in the center of the oven cavity The water container shall be a low form of 600 ml 20 oz beaker with an inside diameter of approx 8 5 cm 3 1 2 in and made of an electrically nonconductive material such as glass or plastic The placing of this standard load in the oven is important not only to protect the oven but also to insure that any leakage is measured accurately 4 ...

Page 5: ...ing is not damaged D The door is not deformed or warped E There is no other visible damage with the oven Servicing and repair work must be carried out only by trained service personnel DANGER Certaininitialpartsareintentionallynotgroundedandpresent a risk of electrical shock only during servicing Service personnel Do not contact the following parts while the appliance is energized HighVoltageCapac...

Page 6: ...CK pad STOP CLEAR pad MINUTE PLUS START pad Oven Cavity Light Yes Safety Standard UL Listed FCC Authorized DHHS Rules CFR Title 21 Chapter 1 Subchapter J SPECIFICATION GENERAL INFORMATION GROUNDING INSTRUCTIONS This oven is equipped with a three prong grounding plug It must be plugged into a wall receptacle that is properly installed and grounded in accordance with the National Electrical Code and...

Page 7: ...inges 7 Door seals and sealing surface 8 Turntable motor shaft 9 Removable turntable support Carefullyplacetheturntablesupportinthecenter of the oven floor 10 Removable turntable Place the turntable on the turntable support cecurely The turntable will rotate clockwise or counterclockwise Only remove for cleaning 11 Ventilation openings Rear 12 Oven light It will light when oven is operating or doo...

Page 8: ...itor switch electrically monitors the operation of the primary interlock switch and secondary interlock relay RY2 andismechanicallyassociatedwiththedoor so that it will function in the following sequence 1 When the door opens from the closed position the secondary interlock relay RY2 and primary interlock switch open their contacts And contacts of the relay RY1 remains closed Then the monitor swit...

Page 9: ...ing on SENSOR 2 Thecoilofshut offrelay RY 1 isenergized theturntable motor oven lamp and cooling fan motors are turned on but the power transformer is not turned on 3 After about 16 seconds the cook relay RY 2 is energized The power transformer is turned on microwave energy is produced and first stage is started The 16 seconds is the cooling time required to remove any vapor from the oven cavity a...

Page 10: ...TOR 0 94µF AC 2200V F1 F3 F2 NOTE indicates components with potential above 250V SCHEMATIC NOTE CONDITION OF OVEN 1 DOOR CLOSED 2 COOKING TIME PROGRAMMED 3 VARIABLE COOKING CONTROL P HI 100 4 START PAD TOUCHED Figure O 2 Oven Schematic Cooking Condition 120V AC 60 Hz OVEN LAMP OVEN LAMP RELAY TURN TABLE MOTOR FAN MOTOR POWER TRANSFORMER MONITOR SWITCH RECTIFIER MAGNETRON PRIMARY INTERLOCK SWITCH T...

Page 11: ... INTERLOCK RELAY RY2 RELAY RY1 PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION REFER TO CHAP TER TEST PROCEDURE NOTE MONITOR FUSE AND MONITOR SWITCH ARE REPLACED AS AN ASSEMBLY TURNTABLE MOTOR The turntable motor rotates the turntable located on the bottom of the oven cavity so that the foods on the turntable cook evenly during cooking The turntable may turn in either direction CO...

Page 12: ...S BA023WRK0 as an assembly IMPORTANT Whenever troubleshooting is performed with the power supply cord disconnected It may in some cases be necessary to connect the power supply cord after the outer case has been removed in this event 1 Disconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Disconnect the leads to the prima...

Page 13: ... ex tremely uneven heating is produced in oven load food Oven does not cook properly when programmedforCookingPowerP 50 mode Operates properly on Cook ing Power HIGH 100 mode Oven goes into COMPU DEFROST but food is not defrosted well AH sensor does not end during sen sor cooking condition Oven does not shut off after a cup of water is boiling by sensor cooking Oven stops at 16 sec after starting ...

Page 14: ...URING THE COOK CYCLE SO EXTREME CAUTION SHOULD BE OBSERVED Power output of the magnetron can be measured by performing a water temperature rise test This test shouldonlybeusedifabovetestsdonotindicateafaultymagnetronandthereisnodefectinthefollowing componentsorwiring siliconrectifier highvoltagecapacitorandpowertransformer Thistestwillrequire a 16 ounce 453cc measuring cup and an accurate mercury ...

Page 15: ...air flow through the vent holes of the oven cavity especially the cooling fan and air guide 5 Reconnect all leads removed from components during testing 6 Reinstall the outer case cabinet 7 Reconnect the power supply cord after the outer case is installed 8 Run the oven and check all functions MAGNETRON THERMAL CUT OUT TEST 1 Disconnect the power supply cord and then remove outer case 2 Open the d...

Page 16: ...nect the power supply cord after the outer case is installed 8 Run the oven and check all functions SECONDARY INTERLOCK SYSTEM TEST DOOR SENSING SWITCH 1 Disconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 To discharge the high voltage capacitor wait for 60 seconds 4 Isolatetheswitchandconnecttheohmmetertothecommon COM andnormallyopen NO terminal of the ...

Page 17: ... with only a voltmeter and ohmmeter In this service manual the control panel unit is divided into three units CPU Unit Key Unit and Power Unit and troubleshooting by unit replacement is described according to the symptoms indicated Before testing 1 Disconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 To discharge high voltage capacitor wait for 60 seconds...

Page 18: ...r supply cord and then remove outer case 2 To discharge the high voltage capacitor wait for 60 seconds 3 If the display fails to clear when the STOP CLEAR pad is depressed first verify the flat ribbon cable is making 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 If the door sensi...

Page 19: ...ter The meter should indicate 120 volts if not check oven circuit RY1 and RY2 Relay Test These relays are operated by D C voltage Check voltage at the relay coil with a D C voltmeter during the microwave cooking operation DC voltage indicated Defective relay DC voltage not indicated Check diode which is connected to the relay coil If diode is good control unit is defective RELAY SYMBOL OPERATIONAL...

Page 20: ... repair STEPS OCCURRENCE CAUSE OR CORRECTION The rated AC voltage is not present between 1 the normal open terminal of the relay RY1 and Check supply voltage and oven power cord the normal open terminal of the relay RY2 2 The rated AC voltage is present at primary Low voltage transformer or secondary circuit defective side of low voltage transformer Check and repair 8 Disconnect the power supply c...

Page 21: ... AH sensor or check the control unit refer to explanation below If the oven stops after 5 minutes and ERROR is displayed the AH sensor is normal Check other parts except the AH sensor 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 the power supply cord and then remove outer cas...

Page 22: ...f the above is proper the AH sensor is probably defective 10 Disconnect the power supply cord and then remove outer case 11 Open the door and block it open 12 Discharge high voltage capacitor 13 Disconnect the dummy resistor circuit from the sensor connector of control panel 14 Carry out necessary repair 15 Reconnect all leads removed from components during testing and repairing 16 Re install the ...

Page 23: ...er to compose a basic standard time in the clock circuit Symbol Voltage Application VC 5V LSI IC1 4 Relay Circuit A circuit to drive the magnetron fan motor turntable motor and light the oven lamp 5 Buzzer Circuit The buzzer is responsive to signals from the LSI to emit audiblesounds keytouchsoundandcompletionsound 6 Synchronizing Signal Circuit The power source synchronizing signal is available i...

Page 24: ...and OFF times for other power level 20 P46 IN Signal coming from touch key When either G11 line on key matrix is touched a corresponding signal out of P20 P26 will be input into P46 When no key is touched the signal is held at H level 21 P45 IN Signal similar to P46 When either G10 line on key matrix is touched a corresponding signal will be input into P45 22 P44 IN Signal similar to P46 When eith...

Page 25: ...o P43 P46 terminal while one of G2 line keys on key matrix is touched 40 P20 OUT Key strobe signal Signal applied to touch key section A pulse signal is input to P43 P46 terminal while one of G1 line keys on key matrix is touched 41 47 P17 P11 OUT Terminal not used 48 72 SEG24 SEG0 OUT Segment data signal Connected to LCD The relation between signals are as follows LSI signal Pin No LCD Pin No LSI...

Page 26: ... change the resistance values in parallel with R53 R57 Changing the resistance values results in that there is the same potential at both F 3 terminal of the absolute humidity sensor and AN0 terminal of the LSI The voltage of AN1 terminal will indicate about 2 5V This initial balancing is set up about 16 seconds after the unit is put in the SensorCookingmode Asthesensorcookingproceeds the food is ...

Page 27: ...te that is equivalent to the oven door being closed Connect an external power source to the power input terminal of the touch control panel then it is possible to check and repair the controls of the touch control panel it is also possible to check the sensor related controls of the touch control panel by using the dummy resistor s 4 Servicing Tools Tools required to service the touch control pane...

Page 28: ...citor and High voltage rectifier assembly 2 Hot parts Oven lamp Magnetron High voltage transformer WARNING FOR WIRING 1 Disconnect the power supply cord 2 Visuallycheckthedoorandcavityfaceplatefordamage dents cracks signs of arcing etc Carry out any remedial work that is necessary before operating the oven Do not operate the oven if any of the following conditions exist 1 Door does not close firml...

Page 29: ...nd block it open 3 It is recommended that the door is removed from the oven cavity Refer to DOOR REPLACEMENT 4 Disconnect the wire leads from the power supply cord turntable motor thermal cut out oven thermal cut out MG all switches on the latch hook magnetron and oven lamp 5 Release the two 2 snap bands of the main wire harness from the oven cavity 6 Remove the two 2 screws holding the front leg ...

Page 30: ...UND SIDE TERMINAL OF THE HIGH VOLTAGE RECTIFIER MUST BE SECURED FIRMLY WITH A GROUNDING SCREW 4 Disconnect the wire leads from the oven lamp 5 Remove the one 1 screw holding the oven lamp to the lamp angle 6 Remove the oven lamp from the lamp angle 7 Now the oven lamp socket is free REMOVAL 1 Disconnect the power supply cord and then remove the outer case 2 Remove the oven cavity assembly from the...

Page 31: ...e rotates smooth after installation Make sure that the axis of the shaft is not slanted 6 Catch two holes of fan duct on two tabs of the base plate 7 Hold the fan duct assembly to the base plate with the two 2 screws 8 Re install the separete angles A B and C to the base plate with each one 1 screw 9 Insert the main wire harness and switch harness into the holes of the fan duct 10 Connect the wire...

Page 32: ...install outer case and check for microwave leakage around door with an approved microwave survey meter Refer to Microwave Measurement Procedure Figure C4 Latch Switch Adjustments 1 Disconnect the power supply cord and remove outer case 2 Open the door and block it open 3 To discharge the high voltage capacitor wait for 60 seconds 4 Disconnect the wire leads from the switches 5 Push outward on the ...

Page 33: ...fter any service make sure of the following 1 Door latch heads smoothly catch latch hook through latch holes and that latch head goes through center of latch hole 2 Deviation of door alignment from horizontal line of cavity face plate is to be less than 1 0mm 3 Door is positioned with its face pressed toward cavity face plate 4 Check for microwave leakage around door with an approvedmicrowavesurve...

Page 34: ... and the latch spring are free CPU UNIT 7 Remove the two 2 screws holding the PWB cover to the door frame assembly 8 Remove the PWB cover from the door frame assembly 9 Remove the one 1 screw holding the CPU unit to the door frame assembly 10 Releasing the two 2 tabs remove the CPU unit with the LCD holder from the door frame assembly 11 Releasing the two 2 tabs release the LCD from the LCD holder...

Page 35: ...cord GRY BLK GRY RED WHT WHT WHT BLK WHT 1 2 BLK BLK GRY GRN RED RED BLK RED WHT GRY BLK BLK WHT RED BLK BLK ORG THERMAL CUT OUT MG THERMAL CUT OUT OVEN MONITOR FUSE HOLDER WHT WHT GRY WHT BLK BLK RED RED GRN GRY 2 3 1 WHT WHT WHT WHT WHT BLK RY2 RY1 SECONDARY INTERLOCK RELAY CN C CN B CN F CN B T1 1 1 1 2 3 9 POWER UNIT CPU UNIT H N NOTE The grounding conductor of the power supply cord has been g...

Page 36: ...EN LAMP TURNTABLE MOTOR FAN MOTOR AC H MICRO DOOR SENSING SWITCH NOTE IF NOT SPECIFIED 1 4W 5 CN B CN C CN F D1 D4 1N4002 RY1 RY2 D20 1SS270A D40 1SS270A Q1 2SB1238 C21 10µ 35v SP1 PKM22EPT Q21 DTD143ES Q22 DTA143ES R2 330 1w R53 1 8kF 1 4w R54 360kF 1 4w IC2 BA4558 5 8 7 4 6 R50 330 1w 3 a b c d 7 D3 D4 D2 D1 1 4 C1 0 1µ 50v C50 0 1µ 50v C2 1000µ 35v C3 10µ 35v C51 0 1µ 50v ZD1 HZ16 1 VRS1 10G471...

Page 37: ... 270k R73 270k R71 270k R72 270k R100 15k R66 15k R65 15k R64 15k R63 15k R62 15k R61 15k R60 15k R80 1M R4 1k J10 J12 J11 4 7k J13 4 7k J15 4 7k J17 4 7k J14 J16 R5 15k R8 4 7k R7 4 7k R6 4 7k R2 4 7k LD4 CPU UNIT KEY UNIT LIQUID CRYSTAL DISPLAY VL3 COM0 COM0 COM1 COM2 SEG0 SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8 SEG8 SEG9 SEG10 COM0 LCD COM0 LCD COM1 LCD COM2 LCD COM3 LCD COM1 LCD COM2 LCD COM3 ...

Page 38: ...N B 1 R52 R50 R4 SP1 CN A D22 D4 D2 J1 R51 D40 C51 IC2 D20 R2 C21 R1 Q1 D21 C1 S 7 1 3 4 P D3 D1 OM OM DU DU J2 E E B B Q2 RY1 RY2 T1 VRS1 R3 ZD2 2 R54 R53 CN F 1 4 3 1 5 8 C50 Q22 Q21 B B E E C3 C2 ZD1 DIP 9 1 1 2 1 2 6 4 5 1 2 3 6 4 5 1 2 3 A B C D E F G H A B C D E F G H ...

Page 39: ...31DRE0 2 pin connector CN B 1 AC 3 1B QCNCMA470DRZZ 9 pin connector CN C 1 AF 3 1C QCNCMA237DRE0 3 pin connector CN F 1 AD C1 RC KZA087DRE0 Capacitor 0 1 uF 50V 1 AA C2 VCEAB31VW108M Capacitor 1000 uF 35V 1 AF C3 VCEAB31VW106M Capacitor 10 uF 35V 1 AA C12 VCEAB31VW106M Capacitor 10 uF 35V 1 AA C50 51 RC KZA087DRE0 Capacitor 0 1 uF 50V 2 AA D1 4 RH DZA006PRE0 Diode 1N4002 4 AD D20 22 VHD1SS270A 1 D...

Page 40: ...RFZ LCD holder 1 AC 5 8 PSHEPA786WREZ LED sheet 1 BB 5 9 FW VZA272DREZ 9 pin wire harness 1 AL 5 10 PCOVPA372WRWZ PWB cover 1 AF 5 11 PCUSUA567WRPZ Cushion 1 AE 5 12 XEPSD38P08000 Screw 3 8mm x 8mm 4 AA 5 13 XEPSD30P08XS0 Screw 3mm x 8mm 3 AA 5 14 LHLD A237WRFZ Light guide 1 AL MISCELLANEOUS 6 1 FROLPA079WRK0 Turntable support 1 AP 6 2 NTNT A079WRF0 Turntable tray 1 AR 6 3 FW VZB827WREZ Main wire ...

Page 41: ... requiring return should be returned as indicated in the Service Policy PACKING AND ACCESSORIES DOOR PROTECTION SHEET SPADPA204WRE0 TOP PAD ASSEMBLY FPADBA451WRKZ WRAP COVER SSAKHA072WREZ Not replaceable items PACKING CASE SPAKCD578WREZ R 370ES SPAKCD580WREZ R 370EK BOTTOM PAD ASSEMBLY FPADBA453WRKZ 6 2 TURNTABLE TRAY 6 7 INSTRUCTION BOOK PRINTING MATTER 6 1 TURNTABLE SUPPORT TRAY PAD SPADFA499WRE...

Page 42: ...6 7 3 1 10 7 7 7 7 1 12 7 1 4 16 7 5 4 20 4 12 4 13 x2 1 4 4 22 7 1 7 9 7 11 7 11 7 13 7 15 7 10 1 9 4 4 4 11 7 3 7 2 1 8 1 8 4 1 1 1 4 25 4 6 4 24 4 28 4 28 4 17 4 18 6 6 7 14 7 14 7 12 7 13 7 8 4 19 4 21 4 31 7 7 1 5 1 4 1 3 4 5 4 30 1 2 1 3 3 1 4 14 4 8 1 11 4 15 7 5 2 5 4 4 7 1 2 1 7 3 2 2 4 9 6 1 6 2 7 13 4 3 7 1 x2 7 1 x2 4 23 1 13 4 26 6 5 4 27 2 4 7 11 ...

Page 43: ... 3 A B C D E F G H A B C D E F G H DOOR PARTS MISCELLANEOUS Actual wire harness may be different from illustration CAPACITOR 5 13 5 11 5 12 5 12 5 12 5 10 5 9 5 6 5 13 4 7 5 7 5 1 5 14 5 6 6 3 6 4 5 2 5 8 5 4 5 12 5 3 2 5 3 1 5 3 6 8 6 9 5 5 ...

Page 44: ...T 2001 BY SHARP CORPORATION ALL RIGHTS RESERVED No part of this publication may be reproduced stored in retrieval systems or transmitted in any form or by any means electronic mechanical photocopying recording orotherwise withoutprior written permission of the publisher ...

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