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15

R-305EW

c) When touching the pads, sometimes a pad produces no signal.
If the Key unit is defective.
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) Replace the Key unit.
5) Reconnect all leads removed from components during testing.
6) Re-install the outer case (cabinet).
7) Reconnect the power supply cord after the outer case is installed.
8) Run the oven and check all functions.

2. Control Unit

The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the Key unit test (Procedure J) to determine if control unit is faulty.

2-1 In connection with pads.

a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.

2-2 In connection with indicators

a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.

2-3  Other possible problems caused by defective control unit.

a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.

When 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) Reconnect all leads removed from components during testing.
5) Re-install the outer case (cabinet).
6) Reconnect the power supply cord after the outer case is installed.
7) Run the oven and check all functions.

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

J

KEY UNIT TEST

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. 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 sensing
switch (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 connector). 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 making momentary contact.
If the control unit responds by clearing with a beep the key unit is faulty and must be replaced. If the
control unit does not respond, it is faulty and must be replaced. If a specific pad does not respond,
the above method may be used (after clearing the control unit) to determine if the control unit or key
pad is at fault.

5. Reconnect all leads removed from components during testing.
6. Re-install the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.

Summary of Contents for R-305EW

Page 1: ...RSONNEL 1 MICROWAVE MEASUREMENT PROCEDURE 2 FOREWORD AND WARNING 3 PRODUCT SPECIFICATIONS 4 GENERAL INFORMATION 4 OPERATION 6 TROUBLESHOOTING GUIDE 9 TEST PROCEDURE 10 TOUCH CONTROL PANEL 18 COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE 22 PICTORIAL DIAGRAM 28 POWER UNIT CIRCUIT 29 CPU UNIT CIRCUIT 30 PRINTED WIRING BOARD 31 PARTS LIST 32 PACKING AND ACCESSORIES 36 S2104R305EPW MICROWAVEOVEN MODE...

Page 2: ... 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 Microwa...

Page 3: ...or 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 Reconnect th...

Page 4: ...e 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 Set the cooking control on Full Power Cooking Mo...

Page 5: ...amaged 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 HighVoltageCapacitor PowerTr...

Page 6: ...LEAR pad 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 local codes and ordinanc...

Page 7: ...urntable The turntable will rotate clockwise or counterclockwise 5 Oven lamp It will light when oven is operating or door is opened 6 Oven door with see through window 7 Ventilation openings Rear 8 Auto Touch control panel 9 Timedisplay Digitaldisplay 99minutes99seconds 10 Coupling 4 3 1 12 7 2 8 9 6 10 5 11 11 Wave guide cover 12 Power supply cord TOUCH CONTROL PANEL NOTE The directed features ar...

Page 8: ...circuits to the turntable motor the cooling fan motor and the high voltage components are de energized the oven lamp remains on and the digital read out displays the time still remaining in the cook cycle when the door was opened 7 The monitor switch electrically monitors the operation of the secondary interlock switch and primary interlock relay and is mechanically associated with the door so tha...

Page 9: ...RANSFORMER CAPACITOR 0 94µF AC 2200V MONITOR SWITCH RECTIFIER MAGNETRON SECONDARY INTERLOCK SWITCH TTM OL FM MONITOR FUSE 20A A1 A2 N O COM COM N O DOOR SENSING SWITCH RY 1 RY 2 CONTROL UNIT PRIMARY INTERLOCK RELAY THERMAL CUT OUT OVEN THERMAL CUT OUT MG SH B SH A GRN OVEN LAMP TURN TABLE MOTOR FAN MOTOR POWER TRANSFORMER MONITOR SWITCH RECTIFIER SECONDARY INTERLOCK SWITCH TTM OL FM N O N O DOOR S...

Page 10: ...ERLOCK RELAY RY2 RELAY RY1 SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OP ERATION REFERTOCHAPTER TESTPRO CEDURE 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 COOLIN...

Page 11: ...021WRK0 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 primary o...

Page 12: ...ing but little or no heat is produced in oven load Food incompletely cooked or not cooked at all at end of cook cycle Oven goes into a cook cycle but extremely uneven heating is pro duced in oven load food Oven does not cook properly when programmed for Cooking Power P 50 mode Operates properly on Cooking Power P HI 100 mode Oven goes into COMPU DEFROST but food is not defrosted well OFF CONDITION...

Page 13: ...EME 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 thermometer or thermocouple ...

Page 14: ...ty 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 door and block it open 3 Discharge high voltage c...

Page 15: ...tch 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 PRIMARY 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 Discharge high voltage capacitor 4 Isolatethe...

Page 16: ...al microwave ovens proper maintenance cannot be performed with only a voltmeter and ohmmeter In this service manual the touch control panel assembly is divided into two units Control Unit and Key Unit and also the Control Unit is divided into two units CPU Unit and Power Unit and troubleshooting by unit replacement is described according to the symptoms indicated Before testing 1 Disconnect the po...

Page 17: ...and block it open 3 Discharge high voltage capacitor 4 Reconnect all leads removed from components during testing 5 Re install the outer case cabinet 6 Reconnect the power supply cord after the outer case is installed 7 Run the oven and check all functions TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST J KEY UNIT TEST 1 Disconnect the power supply cord and then remove outer case 2 Open the door a...

Page 18: ... A andthenormal open terminal of the relay RY1 on the control unit with an A C voltmeter 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 ...

Page 19: ... the troubleshooting guide given below if indicator does not light up after above check and repairs are finished 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 primary of the power transformer 5 Ensure that these leads remain isolated from other components and oven chassis by using ins...

Page 20: ...rough the pull down resistor R78 9 AN1 IN To input signal which communicates the door open close information to LSI Door close H level signal 0V Door open L level signal 5V 10 AN0 IN Input terminal to judge the model The signal out of P22 will be input into AN0 through G3 line on key matrix The LSI will judge the model by this signal TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The ...

Page 21: ... corresponding signal will be input into P44 23 P43 IN Signal similar to P45 When either G10 line on key matrix is touched a corresponding signal will be input into P43 24 INT0 IN Signal synchronized with commercial power source frequency This is the basic timing for time processing of LSI 25 P41 IN Signal similar to P45 When either G9 line on key matrix is touched a corresponding signal will be i...

Page 22: ... signal Signal applied to touch key section A pulse signal is input to P41 P43 P44 and P45 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 P41 P43 P44 and P45 terminal while one of G1 line keys on key matrix is touched 41 48 P17 P10 OUT Terminal not used 49 50 P07 P06 OUT Terminal not used 51 72...

Page 23: ...he 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 3 Servicing Tools Tools required to service the touch control panel assembly 1 Soldering iron 30W It is recommended to use a soldering iron with a grounding terminal 2 Oscilloscope Si...

Page 24: ...tor 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 firmly ...

Page 25: ...GE THE HIGH VOLTAGE CA PACITORBEFORETOUCHINGANYOVEN COMPONENTS OR WIRING HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL 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 high voltage wire B from the power transformer 5 Disconnect the high voltage wire of high voltage rectifier assembly from...

Page 26: ... magnetron and thermal cut out MG Refer to PICTORIAL DIAGRAM on page 28 5 Re installoutercaseandcheckthattheovenisoperating properly CAUTION WHEN REPLACING MAGNETRON BE SURE THE R F GASKET IS IN PLACE AND MOUNT ING SCREWS ARE TIGHTENED SECURELY 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 wire leads ...

Page 27: ...ocedure 3 Hold the center of the bracket which supports the shaft of the fan motor on the flat table 4 Apply the screw lock tight into the hole for shaft of the fan blade 5 Install the fan blade to the shaft of fan motor by pushing thefanbladewithasmall lightweight ballpeenhammer or rubber mallet CAUTION Do not hit the fan blade strongly when installed because the bracket may be disfigured Make su...

Page 28: ...itch contacts close when door is opened 4 Re install outer case and check for microwave leakage around door with an approved microwave survey meter Refer to Microwave Measurement Procedure Figure C 3 Latch Switch Adjustments 1 Disconnect the power supply cord and remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Disconnect wire leads from the switches 5 Remov...

Page 29: ...er microwave radiation emission limitation standards After 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 microw...

Page 30: ...MER COM NO NOTE The neutral WHT wire must be connected to the neutral WHT wire of the power supply cord GRY RED RED RED WHT YLW WHT BLK BLK BLK YLW YLW RED GRN RED GRN GRN WHT GRY BLK BLK WHT BLUE MARK BLK BLK BLK THERMAL CUT OUT MG FAN MOTOR THERMAL CUT OUT OVEN MONITOR FUSE HOLDER BLK BLK BLK BLK GRY WHT WHT 2 1 WHT WHT WHT GRY YLW RED GRN RY2 RY1 SP1 IC1 SH A SH B PRIMARY INTERLOCK RELAY To ove...

Page 31: ... 4 C 6 C 8 C 1 C 7 C 2 A 2 NO SH A COM COM GND D1 S1NB10 T1 AC AC GND INT VR BUZZER MICRO NC DOOR SENSING SWITCH OVEN LAMP TURNTABLE MOTOR FAN MOTOR CN C 9PIN LEAD WIRE HARNESS OVEN LAMP TURNTABLE MOTOR FAN MOTOR MICRO DOOR SENSING SWITCH CN A RY1 RY2 a b c d 1 3 4 7 J1 VRS1 SP1 C1 1000µ 25v 10G471K SH B NO C 9 ...

Page 32: ... R7 4 7k R10 15k R12 4 7k R41 15k R90 15k J17 4 7k J16 47k J15 4 7k J13 4 7k J11 4 7k 1 25 64 41 1 24 25 40 65 80 J14 J12 J10 Q1 2SA1037AK IC1 IXA096DR Q30 DTA143EKA Q20 DTA143EKA Q22 DTA123JKA D40 MA152WA D20 MA152WA Q21 DTD143EKA Q10 DTA143EKA Q2 2SA1037AK GND LD1 LD2 LD3 LD4 R4 560 1 2w VR INT BUZZER OVEN LAMP TURNTABLE MOTOR FAN MOTOR NC MICRO NOTE IF NOT SPECIFIED 1 10W 5 DOOR SENSING SWITCH ...

Page 33: ...Figure S 4 Printed Wiring Board of Power Unit 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 1 1 2 1 1 3 7 4 2 9 CN C D1 D2 D3 SP1 OM DU RY2 XA VH CN A SH B SH A CN B D I P VH RY1 VRS1 T1 P S J1 C1 OM DU ...

Page 34: ...E0 Thermal cut out 145 deg Interchangeable 1 AP 1 14 RTRN A576WRE0 Power transformer 1 BM CABINET PARTS 2 1 GCABUA690WRP0 Outer case cabinet 1 AZ 2 2 GDAI A316WRW0 Bottom plate 1 AX 2 3 GLEGPA074WRE0 Foot 2 AC 2 4 GLEGPA077WRF0 Leg 1 AH CONTROL PANEL PARTS 3 1 DPWBFC021WRKZ Power unit 1 BA 3 1A QCNCMA446DRE0 2 pin connector CN A 1 AC 3 1B FW VZA250DRE0 9pin wire harness CN C 1 AW 3 1C FW VZA195DRE...

Page 35: ...ch head 1 AE 5 6 MSPRTA187WRE0 Latch spring 1 AC 5 7 XEPSD40P08000 Screw 4mm x 8mm 6 AA 5 8 PCUSUA461WRP0 Cushion 1 AB 5 9 PCUSUA553WRPZ Cushion 2 AC 5 10 PCUSUA554WRPZ Cushion 2 AB 5 11 GCOVHA417WRFZ Choke cover 1 AG MISCELLANEOUS 6 1 FROLPA079WRK0 Turntable support 1 AQ 6 2 NTNT A079WRF0 Turntable tray 1 AR 6 3 FW VZB787WREZ Main wire harness 1 AU 6 4 QW QZA242WRZZ High voltage wire B 1 AF 6 5 P...

Page 36: ... 10 6 7 2 1 4 13 4 17 1 11 4 14 4 2 1 12 7 1 7 5 1 7 4 16 1 8 7 6 4 11 4 19 1 6 1 1 7 1 2 3 2 3 7 6 7 6 7 6 7 6 1 9 4 6 7 6 4 21 4 22 4 9 7 3 7 2 4 8 7 4 4 4 4 15 4 18 7 6 7 6 1 4 4 7 7 7 4 20 7 10 7 6 4 10 4 16 4 23 4 12 6 2 6 1 4 1 7 6 1 13 1 3 1 2 1 1 4 3 2 4 4 5 2 2 7 3 7 6 7 3 7 1 1 14 1 5 6 6 7 9 4 18 ...

Page 37: ...ELLANEOUS 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 5 7 5 7 5 10 5 10 5 9 5 9 Actual wire harness may be different from illustration 6 4 6 3 CAPACITOR 6 5 3 3 1 5 11 5 1 5 3 5 4 3 4 3 2 3 1 3 6 3 3 5 7 5 7 5 6 5 7 5 2 3 5 3 6 5 5 5 8 ...

Page 38: ...R PROTECTION SHEET SPADPA204WRE0 TOP PAD ASSEMBLY FPADBA416WRKZ PLASTIC BAG SSAKHA034WRE0 Not replaceable items PACKING CASE SPAKCD553WREZ BOTTOM PAD ASSEMBLY FPADBA417WRKZ 6 2 TURNTABLE TRAY 6 8 INSTRUCTION BOOK PRINTING MATTER 6 1 TURNTABLE SUPPORT TRAY PACK SPADFA451WRE0 INTO THE OVEN CAVITY ...

Page 39: ...37 R 305EW ...

Page 40: ...BY SHARP CORPORATION ALL RIGHTS RESERVED No part of this publication may be repro duced stored in retrieval systems or trans mitted in any form or by any means elec tronic mechanical photocopying record ing or otherwise without prior written per mission of the publisher ...

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