Sharp R426LS - 1.4 cu. Ft. 1100W Microwave Oven Service Manual Download Page 28

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R426LS

11 – 3

3. Hold the chassis support to the oven cavity front plate and the mag-

netron with the two (2) screws.

4. Reconnect the wire leads to the magnetron. Refer to “PICTORIAL

DIAGRAM”.

5. Reinstall outer case and check that the oven is operating properly.

CAUTION: WHEN REPLACING MAGNETRON, BE SURE THE R.F.

GASKET IS IN PLACE AND MOUNTING SCREWS ARE
TIGHTENED SECURELY.

[6] OVEN LAMP REMOVAL

1. Disconnect the power supply cord and then remove outer case.

2. Open the oven door and block it open.

3. Discharge high voltage capacitor.

4. Disconnect the wire leads from the oven lamp.

5. Remove the one (1) screw holding the oven lamp to the magnetron

duct.

6. Remove the oven lamp from the magnetron duct.

7. Now, the oven lamp is free.

Figure C-1. Oven lamp

[7] POSITIVE LOCK CONNECTOR (NO-CASE TYPE) REMOVAL

1. Disconnect the power supply cord, and remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

4. Push the lever of positive lock

connector.

5. Pull down on the positive lock

connector.

CAUTION: WHEN CONNECTING THE POSITIVE LOCK

CONNEC-

TORS TO THE TERMINALS, CONNECT THE POSITIVE
LOCK

SO THAT THE LEVER FACES YOU.

Figure C-2. Positive lock

connector

[8] CONTROL PANEL ASSEMBLY 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 wire leads from panel components.

5. Straighten the nail holding the control panel assembly to the oven

cavity front plate.

6. Slide the control panel assembly upward and remove it.

7. Now, individual components can be removed.

[9] GRAPHIC SHEET AND MEMBRANE SWITCH REPLACEMENT

1. 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. Remove the control panel assembly, referring to chapter of CON-

TROL PANEL ASSEMBLY REMOVAL.

5. Disconnect the ribbon cable of the membrane switch from the con-

trol unit.

6. Remove the back light PWB from the control panel frame.

7. Remove the four (4) screws holding the control unit to the control

panel frame. And remove the control unit.

8. Tear away the graphic sheet from the control panel frame.

9. Tear away the membrane switch from the control panel frame.

Oven lamp

Terminal

Push

Pull down

Lever

Positive lock¨

connector

Summary of Contents for R426LS - 1.4 cu. Ft. 1100W Microwave Oven

Page 1: ...E CHAPTER 12 CIRCUIT DIAGRAMS Parts List S9608R426LPST SERVICE MANUAL R426LS CONTENTS This document has been published to be used for after sales service only The contents are subject to change without notice TopPage MICROWAVE OVEN R 426LS MODEL In the interest of user safety the oven should be restored to its origi nal condition and only parts identical to those specified should be used WARNING T...

Page 2: ...8 4 10 Procedure I NOISE FILTER TEST 8 4 11 Procedure J TOUCH CONTROL PANEL ASSEMBLY TEST 8 4 12 Procedure K KEY UNIT TEST 8 5 13 Procedure L RELAY TEST 8 6 14 Procedure M DEFROST TEST 8 6 15 Procedure N FOIL PATTERN ON THE PRINTED WIRING BOARD TEST 8 6 16 Procedure O AH SENSOR TEST 8 7 CHAPTER 9 TOUCH CONTROL PANEL ASSEM BLY 1 OUTLINE OF TOUCH CONTROL PAN EL 9 1 2 ABSOLUTE HUMIDITY SENSOR CIR CUI...

Page 3: ...components in the interlock monitor door seal and microwave generation 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 a...

Page 4: ...h voltage capacitor 4 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 2 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 cap...

Page 5: ...he 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 M...

Page 6: ...ets and hinges are not defective C The door packing 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 3 DANGER Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing Service personnel Do not contact the followi...

Page 7: ...Control Complement Touch Control System Clock 1 00 12 59 Timer 0 99 minutes 99 seconds Microwave Power for Variable Cooking Repetition Rate P HI Full power throughout the cooking time P 90 approx 90 of FULL Power P 80 approx 80 of FULL Power P 70 approx 70 of FULL Power P 60 approx 60 of FULL Power P 50 approx 50 of FULL Power P 40 approx 30 of FULL Power P 30 approx 40 of FULL Power P 20 approx 2...

Page 8: ...a 3 wire 15 amp or higher rated cord Do not drape over a countertop or table where it can be pulled on by children or tripped over accidentally CAUTION DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE ROUND GROUNDING PRONG FROM THIS PLUG 2 OVEN DIAGRAM 1 OVEN 1 One touch door open button Push to open door 2 Door latches The oven will not operate unless the door is securely closed 3 Removable turnt...

Page 9: ...2 and primary interlock switch open their contacts And contacts of the relay RY1 remains closed Then the monitor switch contacts close b When the door is closed from the open position the monitor switch contacts open first Then the contacts of the primary interlock switch and door sensing switch close And contacts of the relay RY1 open If the primary interlock switch and secondary interlock relay ...

Page 10: ... down to zero At this time the door may be opened to stir turn or season food 5 When the timer reaches zero an audible signal sounds The shut off relay and cook relay are de energized and the power trans former oven lamp etc are turned off 6 Opening the door or touching the STOP CLEAR pad the time of day will reappear on the display and the oven will revert to an OFF condition 2 OVEN SCHEMATIC 1 O...

Page 11: ...tact close to the ON condition due to their being normally closed At this time the secondary interlock relay RY2 and primary interlock switch are in the OFF condition contacts open due to their being normally open contact switches 2 As the door goes to a closed position the monitor switch contacts are first opened and then the door sensing switch and the primary interlock switch contacts close On ...

Page 12: ...high temperatures are reached within the oven cavity the oven thermal cut out will open at 293 F 145 C causing the oven to shut down 7 MAGNETRON TEMPERATURE FUSE The magnetron temperature fuse located near the magnetron is designed to prevent damage to the magnetron if an over heated condi tion develops in the tube due to cooling fan failure obstructed air guide dirty or blocked air intake etc Und...

Page 13: ...the circuit with your hand or an uninsulated tool while the power supply is connected RE CK A B C D E F F G H RE RE CK J CK CK CK K L N O I POSSIBLE CASE AND DEFECTIVE PARTS SHORT IN POWER CORD SHORT OR OPENED WIRING MAGNETRON POWER TRANSFORMER H V RECTIFIER ASSEMBLY HIGH VOLTAGE CAPACITOR MAGNETRON TEMPERATURE FUSE SECONDARY INTERLOCK SYSTEM PRIMARY INTERLOCK SWITCH MONITOR SWITCH MONITOR FUSE OV...

Page 14: ...temperature making sure to stir the thermometer or thermocouple through the water until the maximum temperature is recorded 4 Subtract the cold water temperature from the hot water temperature The normal result should be 34 8 to 64 6 F 19 3 to 35 9 C rise in tempera ture If the water temperatures are accurately measured and tested for the required time period the test results will indicate if the ...

Page 15: ...g of the magnetron Check for restricted air flow to the magnetron especially the cool ing fan and air guide An open thermal cut out Oven indicates overheating of the oven exchange the thermal cut out and check inside of oven cavity and for improper setting of cooking time or operation of control unit Check for restricted air flow through the vent holes of the oven cavity especially the cooling fan...

Page 16: ... 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 8 Procedure G MONITOR SWITCH 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 Before performing this test m...

Page 17: ...nents 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 11 Procedure J TOUCH CONTROL PANEL ASSEMBLY TEST The touch control panel consists of circuits including semiconductors such as LSI ICs etc Therefore unlike conventional microwave ovens proper maintenance cannot be performed with only a v...

Page 18: ...ter case cabinet 6 Reconnect the power supply cord after the outer case is installed 7 Run the oven and check all functions 12 Procedure K KEY UNIT TEST 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 sens ing switch stop switch operates properly that is the contacts are closed when the door is closed...

Page 19: ...mbled before following procedure 1 Open the door 2 Place one cup of water in the center of the turntable tray in the oven cavity 3 Close the door touch the DEFROST pad once 4 Press 2 then press 5 5 Touch the START pad 6 The oven is in Defrost cooking condition 7 The oven will operate as follows 8 If improper operation is indicated the control unit is probably defective and should be checked 15 Pro...

Page 20: ...or air circulation 5 Be sure the exterior of the cooking container and the interior of the oven are dry Wipe off any moisture with a dry cloth or paper towel 6 The Sensor works with food at normal storage temperature For example chicken pieces would be at refrigerator temperature and canned soup at room temperature 7 Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor ...

Page 21: ...ge high voltage capacitor 4 Disconnect the sensor connector that is mounted to control panel 5 Then connect the dummy resistor circuit see fig to the sen sor connector of control panel 6 Disconnect the leads to the primary of the power trans former 7 Ensure that these leads remain isolated from other components and oven chassis by using insulation tape 8 After that procedure re connect the power s...

Page 22: ...tor is housed in the closed vessel filled with dry air while another in the open vessel Each sensor is provided with the protective cover made of metal mesh to be protected from the external airflow 2 Operational Principle of Absolute Humidity Sen sor The figure below shows the basic structure of an absolute humidity sensor A bridge circuit is formed by two thermistors and two resistors R1 and R2 ...

Page 23: ...rd After checking the performance of the touch control panel 1 Disconnect the power supply cord 2 Open the door and block it open 3 Re connect the leads to the primary of the power transformer 4 Re install the outer case cabinet 5 Re connect the power supply cord after the outer case is installed 6 Run the oven and check all functions a On some models the power supply cord between the touch contro...

Page 24: ...ey unit to the control unit being sure that the lead wires are not twisted 3 After aluminium foil is removed be careful that abnormal voltage due to static electricity etc is not applied to the input or output ter minals 4 Attach connectors electrolytic capacitors etc to PWB making sure that all connections are tight 5 Be sure to use specified components where high precision is required ...

Page 25: ...s adjusted accordingly 3 Soldering As the melting point of lead free solder Sn Ag Cu is higher and has poorer wettability flow to prevent damage to the land of the PWB extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time Remove the bit as soon as a good flow is achieved The high content of tin in lead free solder will cause premature corrosion of...

Page 26: ... close firmly 2 Door hinge support or latch hook is damaged 3 The door gasket or seal is damaged 4 The door is bent or warped 5 There are defective parts in the door interlock system 6 There are defective parts in the microwave generating and transmission assembly 7 There is visible damage to the oven Do not operate the oven 1 Without the RF gasket Magnetron 2 If the wave guide or oven cavity are ...

Page 27: ...ll outer case and check that oven is operating properly 4 HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL To remove the components proceed as follows 1 Disconnect the power supply cord and remove outer case 2 Open the oven door and block it open 3 Discharge high voltage capacitor 4 Disconnect the high voltage wire of the power transformer from the high voltage capacitor 5 Disconnect the ...

Page 28: ...ONNEC TORS TO THE TERMINALS CONNECT THE POSITIVE LOCK SO THAT THE LEVER FACES YOU Figure C 2 Positive lock connector 8 CONTROL PANEL ASSEMBLY 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 wire leads from panel components 5 Straighten the nail holding the control panel assembly to the oven ...

Page 29: ...OTOR REMOVAL 1 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 wire leads from the fan motor 5 Remove the two 2 screws holding the fan motor to the oven cavity back plate 6 Remove the fan blade from the fan motor shaft according to the fol lowing procedure 7 Hold the edge of the rotor of the...

Page 30: ...n In and out play of the door allowed by the upper and lower position of the latch hook should be less than 0 5mm The vertical position of the latch hook should be adjusted so that the door sensing switch and primary interlock switch are activated with the door closed The horizontal position of the latch hook should be adjusted so that the plunger of the monitor switch is pressed with the door clo...

Page 31: ... the latch spring to the latch head Reinstall the latch spring to the door frame Reinstall latch head to door frame 6 Reinstall choke cover to door panel by pushing 7 Catch two 2 pins of door panel on two 2 hole of upper and lower oven hinges as shown Figure C 5 8 Re install the door stopper to the door assembly NOTE After any service to the door 1 Make sure that door sensing switch and primary in...

Page 32: ... POWER SUPPLY CORD 120V 60Hz NOTE The neutral WHT wire must be connected to the terminal with N mark on the power supply cord RED WHT WHT H N NOTE The grounding conductor of the power supply cord has been grounded by power supply cord fixing screw The screw must always be kept tight COM N O DOOR SENSING SWITCH GRY GRN GRN to Chassis support GRN GRY GRN 2 1 CN B BRN WHT ORG RED WHT ORG ORG GRY WHT ...

Page 33: ...1 COM2 COM3 COM3 COM0 COM1 COM2 COM0 COM1 COM2 COM3 SEG0 SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8 SEG9 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 SEG16 SEG17 SEG18 SEG19 SEG20 SEG21 SEG22 SEG23 SEG24 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 SEG16 SEG17 SEG18 SEG19 SEG20 SEG21 SEG22 SEG23 SEG24 SEG25 P12 P13 P14 P15 P16 GND LIQUID CRYSTAL DISPLAY J10 AN4 AN5 AN6 AN7 C14 0 01uF 50V C13 C11 0 1uF 50V 0 01uF 50V J...

Page 34: ...R426LS 12 3 3 Printed Wiring Board Figure S 3 Figure S 3 Printed Wiring Board ...

Page 35: ...O 4 DESCRIPTION Parts marked may cause undue microwave exposure Parts marked are used in voltage more than 250V PartsGuide 1 OVEN PARTS 2 DOOR AND CONTROL PANEL PARTS INDEX CONTENTS DOOR PROTECTION SHEET SPADPA204WRE0 TOP PAD ASSEMBLY FPADBA632WRKZ PLASTIC BAG SSAKHA032WRE0 Not replaceable items PACKING CASE FPAK A571WRKZ BOTTOM PAD ASSEMBLY FPADBA633WRKZ 6 2 TURNTABLE TRAY 6 7 OPERATION MANUAL 6 ...

Page 36: ...6 4 1 10 4 3 4 5 4 7 6 2 6 1 2 2 7 1 1 12 4 10 7 3 7 3 4 1 1 13 7 9 7 5 7 6 7 8 7 8 4 4 7 10 1 5 4 8 7 7 1 4 1 4 4 6 7 8 4 2 1 9 1 8 2 3 2 3 2 3 2 3 7 10 7 4 4 9 7 10 7 1 4 12 1 7 7 10 7 10 7 2 7 2 1 2 1 11 7 10 4 14 7 1 1 2 1 3 1 1 1 14 4 16 7 8 7 6 ...

Page 37: ...264WRZZ AT Turntable motor 1 12 RMOTDA186WRE0 AW Turntable motor Interchangeable 1 13 RTRN A746WRZZ BM Power transformer 1 13 RTRN A745WRZZ Power transformer for production use 1 14 FDTCTA225WRKZ AW AH sensor assy CABINET PARTS 2 1 GCABUB047WRPZ BF Outer case cabinet 2 2 GDAI A403WRWZ BA Base plate 2 3 GLEGPA104WREZ AF Leg OVEN PARTS 4 1 PHOK A130WRFZ AK Latch hook 4 2 LBNDKA163WRPZ AK H V capacit...

Page 38: ...AND CONTROL PANEL PARTS 3 5 3 2 3 1 3 3 3 1 1 3 2 2 3 2 1 3 1 2 3 5 3 4 5 5 5 1 5 3 7 5 4 5 6 5 2 5 3 5 3 3 5 3 6 5 3 2 5 3 8 5 3 5 5 3 4 5 3 1 5 7 Actual wire harness may be different from illustration 6 6 6 5 6 7 6 8 ...

Page 39: ... panel 5 2 PSHEPA336WRP0 AF Sealer film 5 3 FWAKPA454WRKZ BE Door frame assembly 5 3 1 FBTN A163WRKZ AS Button assy 5 3 2 GWAKPB063WRFZ AW Door frame 5 3 3 HDECQA321WRPZ AV Door decoration L 5 3 4 HDECQA322WRPZ AV Door decoration U 5 3 5 LSTPPA243WRFZ AG Glass stopper 5 3 6 MSPRCA160WREZ AC Button spring 5 3 7 PGLSPA680WREZ AX Door glass 5 3 8 XEPS740P08000 AB Screw 4mm x 8mm 5 4 GCOVHA382WRF0 AM ...

Page 40: ... AF PCUSUA191WRP0 1 4 9 AC PCUSUA410WRP0 1 4 11 AB PCUSUA455WRP0 1 4 12 AD PDUC A610WRF0 1 4 13 AR PDUC A936WRFZ 1 4 14 AV PDUC A940WRPZ 1 4 16 AV PGLSPA680WREZ 2 5 3 7 AX PHOK A130WRFZ 1 4 1 AK PPACGA084WRF0 1 4 10 AE PPACGA272WREZ 1 4 15 AG PSHEPA336WRP0 2 5 2 AF PSHEPB211WREZ 2 3 2 1 AT Q QFS TA013WRE0 1 1 3 AG QSW KA074DRZZ 2 3 2 2 AR QSW MA085WRE0 1 1 4 AF QSW MA147WRZZ 1 1 4 AG R RC QZA211WR...

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Sharp R426LS - 1.4 cu. Ft. 1100W Microwave Oven, Service Manual

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