Sharp R-426LS Service Manual
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Sharp R-426LS Service Manual

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TopPage
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE EXPO-
SURE TO EXCESSIVE MICROWAVE ENERGY
CHAPTER 1. WARNING TO SERVICE PERSONNEL
CHAPTER 2. MICROWAVE MEASUREMENT PRO-
CEDURE
CHAPTER 3. FOREWORD AND WARNING
CHAPTER 4. PRODUCT DESCRIPTION
CHAPTER 5. GENERAL INFORMATION
CHAPTER 6. OPERATION
CHAPTER 7. TROUBLESHOOTING GUIDE
SERVICE MANUAL
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 TO SERVICE PERSONNEL: Microwave ovens con-
tain circuitry capable of producing very high voltage and cur-
rent, contact with following parts may result in a severe,
possibly fatal, electrical shock. (High Voltage Capacitor, High
Voltage Power Transformer, Magnetron, High Voltage Rectifier
Assembly, High Voltage Harness etc..)
CONTENTS
CHAPTER 8. TEST PROCEDURES
CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY
CHAPTER 10. PRECAUTIONS FOR USING LEAD-
FREE SOLDER
CHAPTER 11. COMPONENT REPLACEMENT AND
ADJUSTMENT PROCEDURE
CHAPTER 12. CIRCUIT DIAGRAMS
Parts List
S9608R426LPST

MICROWAVE OVEN

R-426LS
This document has been published to be used for
after sales service only.
The contents are subject to change without notice.
R426LS

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Do you have a question about the R-426LS and is the answer not in the manual?

Questions and answers

Diane Neubauer
May 20, 2025

would like to replace glass turntable for model R-426L

0
1 comments:
Mr. Anderson
May 24, 2025

To replace the glass turntable for the Sharp model R-426LS:

1. Open the microwave door and remove the existing glass turntable and turntable support.
2. Clean the area if needed using a soft cloth and warm water; avoid abrasive cleaners.
3. Place the new NTNT-A108 replacement glass turntable on the turntable support, aligning it with the motor shaft.
4. Ensure the turntable is seated properly and rotates freely.

Note: The NTNT-A108 is a compatible replacement part, not an original manufacturer product.

This answer is automatically generated

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Summary of Contents for Sharp R-426LS

  • Page 1: Microwave Oven

    TopPage R426LS SERVICE MANUAL S9608R426LPST 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 TO SERVICE PERSONNEL: Microwave ovens con-...

  • Page 2: Table Of Contents

    CONTENTS PRECAUTIONS TO BE OBSERVED BEFORE [11] Procedure J: TOUCH CONTROL PANEL AND DURING SERVICING TO AVOID POSSIBLE ASSEMBLY TEST........8-4 EXPOSURE TO EXCESSIVE MICROWAVE ENER- [12] Procedure K: KEY UNIT TEST ....8-5 [13] Procedure L: RELAY TEST......8-6 [14] Procedure M: DEFROST TEST .....

  • Page 3: Precautions To Be Observed Before

    Before servicing an operative unit, perform a microwave emission check as per the Microwave Measurement Procedure outlined in this service manual. If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS CORPORATION immediately @1-800-237-4277. If the unit operates with the door open, service person should 1) tell the user not to operate the oven and 2) contact SHARP ELECTRONICS CORPORATION and Food and Drug Administration's Center for Devices and Radiological Health immediately.

  • Page 4: When The Testing Is Completed

    R426LS CHAPTER 1. R426LS WARNING TO SERVICE PERSONNEL Service Manual Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in a severe, possibly fatal, electrical shock. (Example) High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. Read the Service Manual carefully and follow all instructions.

  • Page 5: Chapter 2. Microwave Measurement Procedure

    R426LS CHAPTER 2. R426LS MICROWAVE MEASUREMENT PROCEDURE Service Manual [1] Requirements: 1. Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/ at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the use- ful life of the oven), 5 mW/cm at any point 5cm or more from the external surface of the oven.

  • Page 6: Chapter 3. Foreword And Warning

    Service Manual [1] FOREWORD This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVEN, R-426LS. It is recommended that service personnel carefully study the entire text of this manual so that they will be qualified to render satisfactory customer service.

  • Page 7: Chapter 4. Product Description

    R426LS CHAPTER 4. R426LS PRODUCT DESCRIPTION Service Manual [1] SPECIFICATIONS ITEM DESCRIPTION 120 Volts Power Requirements 60 Hertz Single phase, 3 wire grounded Power Consumption 1600W / Approx. 13.5 Amperes 1100 W nominal of RF microwave energy (IEC Test procedure) Power Output Operating frequency 2450 MHz Width 21-5/8"...

  • Page 8: Chapter 5. General Information

    R426LS CHAPTER 5. R426LS GENERAL INFORMATION Service Manual [1] 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 accor- dance with the National Electrical Code and local codes and ordinances. In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the electric current.

  • Page 9: Chapter 6. Operation Description Of Operating Se- Quence

    R426LS CHAPTER 6. R426LS OPERATION Service Manual [1] DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions during oven operation. 1. OFF CONDITION 3. POWER LEVEL P-0 TO P-90 COOKING Closing the door activates the door sensing switch and primary inter- When Variable Cooking Power is programmed, the 120 volts A.C.

  • Page 10: Oven Schematic

    R426LS 2. The coil of shut-off relay (RY-1) is energized, the turntable motor, oven lamp and cooling fan motor are turned on, but the power AH SENSOR 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.

  • Page 11: Description And Function Of Components

    R426LS 2. Cooking Condition SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. COOKING TIME PROGRAMMED. 3. VARIABLE COOKING CONTROL "P-HI". 4. START PAD TOUCHED. DOOR SENSING SWITCH POWER TRANSFORMER (RY2) SECONDARY INTERLOCK RELAY 120VAC 60Hz CONTROL UNIT (RY1) HIGH OVEN LAMP VOLTAGE RELAY...
  • Page 12 R426LS 4. 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. 5. COOLING FAN MOTOR The cooling fan motor drives a blade which draws external cool air.

  • Page 13: Troubleshooting Chart

    R426LS CHAPTER 7. R426LS TROUBLESHOOTING GUIDE Service Manual Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected. When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many of the possible causes of trouble will require that a specific test be performed.

  • Page 14: Chapter 8. Test Procedures

    R426LS CHAPTER 8. R426LS TEST PROCEDURES Service Manual [1] Procedure A: MAGNETRON ASSEMBLY 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. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across the magnetron filament leads should indicate less than 1 ohm.

  • Page 15: Procedure D: High Voltage Capacitor Test

    R426LS 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. NOTE: Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3 volts. [4] Procedure D: HIGH VOLTAGE CAPACITOR TEST 1.

  • Page 16: Procedure F: Secondary Interlock System Test

    R426LS [7] Procedure F: SECONDARY INTERLOCK SYSTEM TEST 1. 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. Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal of the switch. The meter should indicate an open circuit with the door open and a closed circuit with the door closed.

  • Page 17: Procedure H: Blown Monitor Fuse Test

    R426LS [9] Procedure H: BLOWN MONITOR FUSE 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 monitor fuse is blown when the door is opened, check the primary interlock switch, secondary interlock relay (RY2), relay (RY1) and monitor switch according to the “TEST PROCEDURE”...

  • Page 18: Procedure K: Key Unit Test

    R426LS 2. Control Unit. The following symptoms indicate a defective control unit. 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) In connection with indicators a) At a certain digit, all or some segments do not light up.

  • Page 19: Procedure L: Relay Test

    R426LS [13] Procedure L: RELAY 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. Disconnect the leads to the primary of the power transformer. 5.

  • Page 20: Procedure O: Ah Sensor Test

    R426LS 6) Reconnect all leads removed from components during testing. 7) Re-install the outer case (cabinet). 8) Reconnect the power supply cord after the outer case is installed. 9) Run the oven and check all functions. 2. Follow the troubleshooting guide given below, if indicator does not light up after above check and repairs are finished.
  • Page 21 R426LS 6) After approximately 16 seconds, microwave energy is produced. If ERROR is displayed or the oven does not turn off, replace the AH sensor or check the control unit, refer to explanation below. 1. 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.

  • Page 22: Chapter 9. Touch Control Panel Assembly

    R426LS CHAPTER 9. R426LS TOUCH CONTROL PANEL ASSEMBLY Service Manual [1] OUTLINE OF TOUCH CONTROL PANEL This circuit generates voltage necessary in the control unit from the AC line voltage. The touch control section consists of the following units. In addition, the synchronizing signal is available in order to com- (1) Key Unit pose a basic standard time in the clock circuit.

  • Page 23: Servicing For Touch Control Panel

    R426LS Then the LSI observes that voltage at AN1 terminal and compares it with its initial value, and when the comparison rate reaches the preset value (fixed for each menu to be cooked), the LSI causes the unit to 620k stop sensor cooking;...
  • Page 24 R426LS 4. Other Precautions 1) Before turning on the power source of the control unit, remove the aluminium foil applied for preventing static electricity. 2) Connect the connector of the key 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.

  • Page 25: Chapter 10. Precautions For Using Lead-Free Solder

    R426LS CHAPTER 10. R426LS PRECAUTIONS FOR USING LEAD-FREE SOLDER Service Manual [1] Employing lead-free solder The “Main PWB” of this model employs lead-free solder. This is indicated by the “LF” symbol printed on the PWB and in the service manual. The suffix letter indicates the alloy type of the solder.

  • Page 26: And Adjustment Procedure 1] Warnings

    1. Door does not close firmly. 4. If the outer case (cabinet) is not fitted. WARNING FOR WIRING To prevent an electric shock, take the following precau- 3) Sharp edge: tions. Bottom plate, Oven cavity, Waveguide flange, 1. Before wiring, Chassis support and other metallic plate.

  • Page 27: Outer Case Removal

    R426LS [2] OUTER CASE REMOVAL To remove the outer case, procedure as follows. NOTE: When replacing the outer case, the 2 special Torx screws must be reinstalled in the same locations. 1. Disconnect the power supply cord. 2. Open the oven door and block it open. 3.

  • Page 28: Oven Lamp Removal

    R426LS 3. Hold the chassis support to the oven cavity front plate and the mag- 5. Reinstall outer case and check that the oven is operating properly. netron with the two (2) screws. CAUTION: WHEN REPLACING MAGNETRON, BE SURE THE R.F. 4.

  • Page 29: Turntable Motor Removal

    4. Where the corners have been snipped off bend corner areas flat. 8. After replacement use the one (1) screw XOTS740P10000 to fit the No sharp edges must be evident after removal of the turntable turntable motor cover. motor cover.

  • Page 30: Door Sensing Switch/Primary Interlock Switch And Monitor Switch Removal

    R426LS Coil Shaft Groove joint pliers Shaft These are the positions Axis that should be pinched Stator with pliers. Stator Table Center of bracket Rotor Bracket Rotor Side View Rear View [12] DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL 1.
  • Page 31 R426LS 3. Insert a putty knife (thickness of about 0.5mm) into the gap NOTE: After any service to the door; between the door stopper and the choke cover to free engaging 1) Make sure that door sensing switch and primary interlock parts as shown in Figure C-4.

  • Page 32: Chapter 12. Circuit Diagrams

    R426LS CHAPTER 12. R426LS CIRCUIT DIAGRAMS Service Manual [1] Pictorial Diagram (Figure S-1) SWITCH MONITOR Figure S-1. Pictorial Diagram 12 – 1...

  • Page 33: Control Panel Circuit (Figure S-2)

    R426LS [2] Control Panel Circuit (Figure S-2) SEG24 SEG23 SEG8 SEG22 SEG7 SEG21 SEG6 SEG5 SEG20 SEG19 SEG4 SEG18 SEG3 SEG17 SEG2 SEG16 SEG1 SEG0 SEG15 SEG14 SEG13 SEG12 VREF XOUT SEG11 AVSS SEG10 SEG9 COM3 SEG8 COM2 SEG7 COM1 COM0 SEG6 RESET...

  • Page 34: Printed Wiring Board (Figure S-3)

    R426LS [3] Printed Wiring Board (Figure S-3) Figure S-3. Printed Wiring Board 12 – 3...

  • Page 35: Parts List

    R426LS PARTS LIST MICROWAVE OVEN HOW TO ORDER REPLACEMENT PARTS To have your order filled promptly and correctly, please furnish the following information. R-426LS MODEL 1. MODEL NUMBER 2. REF. NO. 3. PART NO. 4. DESCRIPTION Parts marked "*" may cause undue microwave exposure.
  • Page 36 R426LS [1] OVEN PARTS 7-10 7-10 4-13 4-11 4-16 1-14 1-10 4-15 7-10 4-12 7-10 1-11 4-10 1-12 4-14 1-13 7-10 7-10...
  • Page 37 R426LS PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK [1] OVEN PARTS ELECTRIC PARTS Noise filter assembly FPWBFA417WRKZ Noise filter assembly (Interchangeable) FPWBFA389WRKZ Monitor fuse 20A and monitor switch(V-5220Q) FFS-BA033WRKZ Monitor fuse 20A and monitor switch(D3V-1G-2C25) (Interchangeable) FFS-BA037WRKZ Temp. fuse 150C (Magnetron) QFS-TA013WRE0 Primary interlock switch/ door sensing switch QSW-MA085WRE0...
  • Page 38 R426LS [2] DOOR AND CONTROL PANEL PARTS 3-2-1 Actual wire harness may be different from illustration. 3-2-2 3-1-2 3-1-1...
  • Page 39 R426LS PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK [2] DOOR AND CONTROL PANEL PARTS CONTROL PANEL PARTS Open button assembly FBTN-A162WRKZ 3-1-1 Button decoration HDECQA320WRPZ 3-1-2 Open button JBTN-B379WRFZ Panel sub assy FPNLCB918WRKZ 3-2-1 Key sheet PSHEPB211WREZ 3-2-2 QSW-KA074DRZZ Open button spring MSPRCA157WREZ Control unit...
  • Page 40 [ N ] NFANJA053WRFZ 1-4-3 NTNT-A108WREZ 1-6-2 COPYRIGHT © 2006 BY SHARP CORPORATION ALL RIGHTS RESERVED. No part of this publication may be reproduced, stored in retrieval systems, or transmitted in anyform or by any means, electronic, mechanical, photocopying, re- cording, or other wise, without prior written permission of the publisher.

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