Sharp R-25JT-F Service Manual
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Sharp R-25JT-F Service Manual

Commercial microwave oven
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210 0W /R-2 5JT
BEFORE SERVICING ...................................................................................................... INSIDE FRONT COVER
WARNING TO SERVICE PERSONEL .................................................................................................................. 1
MICROWAVE MEASUREMENT PROCEDURE ................................................................................................... 2
FOREWORD .......................................................................................................................................................... 3
PRODUCT SPECIFICATIONS .............................................................................................................................. 4
GENERAL INFORMATION ................................................................................................................................... 4
OPERATION .......................................................................................................................................................... 6
TROUBLE SHOOTING GUIDE/ TEST PROCEDURE ........................................................................................ 11
TOUCH CONTROL PANEL ................................................................................................................................. 21
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ................................................................ 31
PICTORIAL DIAGRAM ........................................................................................................................................ 37
CONTROL PANEL CIRCUIT ............................................................................................................................... 38
PRINTED WIRING BOARD ................................................................................................................................. 39
PARTS LIST ........................................................................................................................................................ 40
PACKING AND ACCESSORIES ......................................................................................................................... 45
SHARP CORPORATION
SERVICE MANUAL
MODEL
DOUB LE
EXPR ESS
QUAN TITY
DEFR OST
11
1
12
2
13
3
14
4
15
5
16
6
17
7
In the interest of user-safety the oven should be restored to its original
18
8
9
19
0
20
condition and only parts identical to those specified should be used.
SELE CTATI ME
STOP /CLEA R
SELEC TAPOW ER
STAR T
SET
CHEC K
SIGNA L
WARNING TO SERVICE PERSONNEL: 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. (High Voltage Capacitor, High Voltage Power
Transformer, Magnetron, High Voltage Rectifier Assembly, High
Voltage Harness etc..)

TABLE OF CONTENTS

COMMERCIAL
MICROWAVE OVEN
R-25JT-F
This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
R-25JT-F
S0513R25JTF//
Page

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  • Page 1: Table Of Contents

    R-25JT-F SERVICE MANUAL S0513R25JTF// COMMERCIAL MICROWAVE OVEN R-25JT-F MODEL DOUB LE EXPR ESS QUAN TITY DEFR OST In the interest of user-safety the oven should be restored to its original 210 0W /R-2 5JT condition and only parts identical to those specified should be used.

  • Page 2: Precautions To Be Observed Before And During Service To Avoid Possible Exposure To Excessive Microwave Energy

    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 the Food and Drug Administration's Center for Devices and Radiological Health immediately.

  • Page 3: Warning To Service Personel

    R-25JT-F WARNING TO SERVICE PERSONNEL Microwave ovens contain circuitry capable of pro- ducing 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 Trans- former, Magnetron, High Voltage Rectifier Assem- bly, High Voltage Harness etc..

  • Page 4: Microwave Measurement Procedure

    R-25JT-F MICROWAVE MEASUREMENT PROCEDURE A. Requirements: 1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a...

  • Page 5: Foreword

    MICROWAVE OVEN GENERAL INFORMATION R-25JT-F FOREWORD This Manual has been prepared to provide Sharp Electronics Corp. OPERATION Service Personnel with Operation and Service Information for the SHARP MICROWAVE OVENS, R-25JT-F. It is recommended that service personnel carefully study the entire text of...
  • Page 6 R-25JT-F SPECIFICATION ITEM DESCRIPTION Power Requirements 230/208 Volts 3.2 kW Approx. 15.5 A at 208 V / Approx. 14.5 A at 230 V 60 Hertz / Single phase, 3 wire grounded Power Output 2100 watts (IEC 705 Test Procedure) Operating frequency of 2450MHz Case Dimensions Width 20-1/8"...
  • Page 7 R-25JT-F OVEN DIAGRAM 1. Touch control panel 2. Door latch openings 3. Ceramic shelf 4. Splash cover 5. Oven light 6. Air intake filter NO. X2 CHECK 7. Air intake openings 8. Door seals and sealing surfaces 9. Door hinges...

  • Page 8: Operation

    R-25JT-F OPERATION DESCRIPTION OF OPERATING SEQUENCE 7. The monitor switch (1) is electrically monitoring the operation The following is a description of component functions during oven operation. of the secondary interlock switch (1) and primary interlock relay (1), and monitor switch (2) is electrically monitoring the...
  • Page 9 R-25JT-F TWO MAGNETRON OPERATION SYSTEM OPERATION OF MAGNETRON Two magnetrons (1), (2) are equipped in order to get higher COMMERCIAL microwave power output. The primary windings of the power FREQUENCY (60HZ) transformers (1), (2) are connected so that each magnetron...
  • Page 10 R-25JT-F SCHEMATIC NOTE: CONDITION OF OVEN 1. FOR 1MINUTE AFTER DOOR OPENED. 2. " . " APPEARS ON DISPLAY. NOISE PRIMARY FILTER MAGNETRON INTERLOCK TEMP. FUSE (1) POWER RELAY (1) TRANSFORMER (1) MAGNETRON FUSE 20A OVEN TEMP. FUSE (2) TEMP.
  • Page 11 R-25JT-F DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM Functions: With the door shut, the contacts of the door sensing switch and 1. The door release lever is pulled. the secondary interlock switches (1), (2) are closed and the 2. The upper latch head is lifted up by the linked door release contacts of the monitor switches (1), (2) are open.
  • Page 12 R-25JT-F OVEN THERMISTOR (2) SELECT SWITCH AND ELECTRICAL COMPONENTS CONDITION This thermistor detects temperature of the oven cavity bottom plate. The thermistor is a negative temperature coefficient type. SWITCH NO. ELECTRICAL PARTS The temperature is detected through the resistance of the Touch control unit thermistor.
  • Page 13 R-25JT-F TROUBLESHOOTING GUIDE 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 R-25JT-F...
  • Page 15 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER MAGNETRON ASSEMBLY TEST 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge two high voltage capacitors. 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 16 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER (HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.) HIGH VOLTAGE RECTIFIER (1) AND/ OR (2) TEST 1. Disconnect the power supply cord, and then remove outer case.
  • Page 17 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 8. Run the oven and check all functions. NOTE:If the door sensing switch contacts fail in the open position and the door is closed, the blower motor, stirrer motors and oven light will be activated by RY1.
  • Page 18 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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 two high voltage capacitors. 4. If the monitor fuse is blown when the door is opened, check the primary interlock relays RY2, RY3, secondary interlock switches (1), (2) and monitor switches (1), (2) according to the "TEST PROCEDURE"...
  • Page 19 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER Room Temp. 59˚F (15˚C) 68˚F (20˚C) 77˚F (25˚C) Resistance Approx. 373 kΩ Approx. 292 kΩ Approx. 231 kΩ If the meter does not indicate above resistance, replace the thermistor. 4-2. OVEN THERMISTOR (1) TEST Disconnect connector-B from the CPU unit.
  • Page 20 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER Before testing, 1) Disconnect the power supply cord, and then remove outer case. 2) Open the door and block it open. 3) Discharge two high voltage capacitors. 4) Disconnect the leads to the primary of the power transformer.
  • Page 21 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER KEY UNIT TEST 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge two high voltage capacitors. 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;...
  • Page 22 R-25JT-F TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 13. Reconnect the power supply cord after the outer case is installed. 14. Run the oven and check all function. FOIL PATTERN ON THE PRINTED WIRING BOARD TEST To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the PWB, this foil pattern acts as a fuse.

  • Page 23: Touch Control Panel

    R-25JT-F TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL The touch control section consists of the following units as 15) Oven Cavity Temperature Detecting Circuit shown in the touch control panel circuit. This is a circuit for transmitting output change of thermistor (Oven thermistor (2)) to IC1.
  • Page 24 R-25JT-F VOLTAGE REGULATION FOR "ERROR" INDICATION Voltage Input to Input to regulation 208V 230V *Normal +6% excel. 208.0--220.48 230.0--243.8 *Normal -9% excel. 189.28--208.0 209.3--230.0 *Error.or +6% to 220.48 243.8 indication +13% excel. 235.04 259.9 range -9% to 189.28 209.3 -13% excel.
  • Page 25 R-25JT-F DESCRIPTION OF LSI LSI(IZA633DR) The I/O signal of the LSI(IZA633DR) is detailed in the following table. Pin No. Signal Description Power source voltage: +5V. VC voltage of power source circuit input. Connected to GND VEE/AVSS VREF Connected to VC. (+5V) Temperature measurement input: INTAKE THERMISTOR.
  • Page 26 R-25JT-F Pin No. Signal Description Digit selection signal. The relation between digit signal and digit are as ß(60Hz) follows: Digit signal Digit P42 ..... 1st. P43 ....2nd. P44 ..... 3rd. P45 ..... 4th. Normally, one pulse is output in every ß period, and input to the grid of the light-emitting diode.
  • Page 27 R-25JT-F Pin No. Signal Description 41-48 P17-P10 Segment data signal. Signal similar to P21. 49-56 P07-P00 Segment data signal. Signal similar to P21. 57-59 P37-P35 Terminal not used. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to P27, P26, P25 and P24 terminals while one of G4 line keys on key matrix is touched.
  • Page 28 R-25JT-F SERVICING 1. Precautions for Handling Electronic Components 5) Re-connect the power supply cord after the outer case This unit uses CMOS LSI in the integral part of the circuits. is installed. When handling these parts, the following precautions should 6) Run the oven and check all functions.
  • Page 29 R-25JT-F 3) Practice for inputting total using times (Ex. 310000 times). PROCEDURE FOR CHECKING/CLEARING SERVICE COUNTS OF MICROWAVE OVEN ... Flashing / ... 0.1sec BUZZER DISPLAY INDICATOR TONE The following procedure enables the servicer to obtain the total (Door close)
  • Page 30 R-25JT-F 5) Practice for cancelling total using times and total operation DISPLAY PAUSE time (user and service) and all other counter. End of each stage ... Flashing / ... 0.1sec BUZZER After 10% of total cooking time is passed DISPLAY...
  • Page 31 R-25JT-F MEMORY READJUSTMENT PROCEDURE 1. To set the standard voltage When the IC2 is changed in the control unit, the standard voltage must be set again for power supply check. The power supply must be set 230V within ± 1V, and 230V connector in control unit installed.
  • Page 32 R-25JT-F 2]. [JUDGMENT PROCEDURE FOR UPPER MAGNETRON AND ITS CIRCUIT] Disconnect the power supply cord. Disconnect lead wires to the interlock relay RY3 to avoid operation of lower magnetron circuit. Reconnect power supply Heating for one minute. If EE1 is indicated, carry out Test procedures A-J and find out the defective part.

  • Page 33: Component Replacement And Adjustment Procedure

    1. Door does not close firmly. WARNING FOR WIRING To prevent an electric shock, take the following precau- Oven cavity. tions. 3) Sharp edge: 1. Before wiring, Bottom plate, Oven cavity, Waveguide flange, Chassis 1) Disconnect the power supply cord. support and other metallic plate.
  • Page 34 R-25JT-F POWER TRANSFORMERS (1) AND/OR (2) REMOVAL 1. Disconnect the power supply cord and then remove outer from high voltage capacitors (1) and/or (2). case and rear cabinet, referring to "OUTER CASE, REAR 8. Disconnect the high voltage wire lead(s) from power CABINET AND POWER SUPPLY CORD REMOVAL".
  • Page 35 "OUTER CASE, REAR CABINET AND 3. Where the portions have been snipped off bend the portions POWER SUPPLY CORD REMOVAL". flat. No sharp edge must be evident after removal of the 2. Open the oven door and block it open. stirrer motor cover.
  • Page 36 R-25JT-F CONTROL PANEL ASSEMBLY AND CONTROL UNIT REMOVAL CONTROL PANEL ASSEMBLY REMOVAL upward. 12.Now, the control unit and control panel frame (with key) are The complete control panel should be removed for replace- free. ment of components. To remove the control panel, proceed as...

  • Page 37: Pictorial Diagram

    R-25JT-F procedure. of the latch hook. DOOR SENSING SWITCH 2) Fasten both switches together to latch hook with one (1) Push the two (2) tabs outward and pull switch forwards to screw and nut. release switch. SECONDARY INTERLOCK SWITCHES MONITOR SWITCHES OR SECONDARY INTERLOCK...
  • Page 38 R-25JT-F Note: After any service to the door; This function does not require that door be air-tight, (A) Make sure that door sensing switch, secondary moisture (condensation)-tight or light-tight. Therefore, interlock switches (1), (2) and monitor switches (1), (2) occasional appearance of moisture, light or sensing are operating properly.
  • Page 39 R-25JT-F...
  • Page 40 R-25JT-F...

  • Page 41: Printed Wiring Board

    R-25JT-F Figure S-3. Printed Wiring Board...

  • Page 42: Parts List

    Outer case cabinet 2- 7 FFPF-A016WRK0 Vibration-proof sheet 2- 8 TMAPCA778WRRZ Schematic diagram CONTROL PANEL PARTS 3- 1 DPWBFB975WRU0 Control unit [R-25JT-F] 3- 1A QCNCMA308DRE0 4-pin connector (A) 3- 1B QCNCMA312DRE0 3-pin connector (B) 3- 1C QCNCMA039DRE0 3-pin connector (H)
  • Page 43 R-25JT-F REF. NO. PART NO. DESCRIPTION Q'TY CODE LED1 VHPSL3966T/1B Light emitting diode RIC--A022BDE0 IC (KIA7805PI) VSDTA123ES/-3 Transistor (DTA123ES) RH-TZA036CBE0 Transistor (KRC101M) VSDTB143ES/-3 Transistor (DTB143ES) RH-TZA036CBE0 Transistor (KRC101M) Q22-23 VSDTD143ES/-3 Transistor (DTD143ES) RH-TZA037CBE0 Transistor (KRA101M) R1-2 VRD-Q12EF471J Resistor 470 ohm...
  • Page 44 R-25JT-F REF. NO. PART NO. DESCRIPTION Q'TY CODE 4-27 PDUC-A729WRF0 Air duct 4-28 PDUC-A564WRW0 Mg exhaust duct 4-29 PCUSUA414WRP0 Cushion 4-30 LANGKA679WRPZ Fixing angle S 4-31 HDECQA147WRM0 Corner cap right 4-32 LANGFA195WRW0 Chassis support 4-33 LBSHCA014WRE0 Cord bushing 4-34 LANGQA593WRPZ...

  • Page 45: Packing And Accessories

    1. MODEL NUMBER 2. REF. NO. 3. PART NO. 4. DESCRIPTION Order Parts from the authorized SHARP parts Distributor for your area. Defective parts requiring return should be returned as indicated in the Service Policy. PACKING AND ACCESSORIES TOP PAD ASSEMBLY...
  • Page 46 R-25JT-F OVEN AND CABINET PARTS 7-19 4-20 6-11 7-22 2-5-2 4-23 2-5-1 4-30 7-22 7-22 4-33 6-12 4-43 7-22 7-22 7-15 7-22 7-22 7-21 7-22 4-26 7-22 4-42 7-22 7-20 4-41 7-21 7-22 7-22 1-16 1-10 1-10 4-27 4-25 4-47...
  • Page 47 R-25JT-F CONTROL PANEL PARTS 3-2-3 6-15 3-2-2 DOOR PARTS 3-2-1 5-12 5-13 5-14 5-13 5-15 5-18 5-16 5-13 5-17 MISCELLANEOUS 5-10 5-13 5-20 5-19 5-11 5-10 To power transformer Actual wire harness may be different from illustration. To high voltage capacitor...
  • Page 48 R-25JT-F COPYRIGHT © 2005 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, me- chanical, photocopying, recording, or other- wise, without prior written permission of the...

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