DCS MO-24SS Technical Service Manual
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DCS MO-24SS Technical Service Manual

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MICROWAVE
TECHNICAL SERVICE GUIDE
Models:
MO-24SS

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Summary of Contents for DCS MO-24SS

  • Page 1 MICROWAVE TECHNICAL SERVICE GUIDE Models: MO-24SS...

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

    Measurement Procedure outlined in this service manual. If microwave emissions level is in excess of the specified limit, contact DCS immediately at (888) 281-5698 If the unit operates with the door open, service person should 1) tell the user not to operate the oven...

  • Page 3: Warning To Service Personnel

    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

    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 purchaser, and thereafter (through the useful life of the oven), 5 mW/cm at any point 5cm or more from the external surface of the oven.

  • Page 5: Wiring Diagram

    PARTS LIST ............................37-41 DCS is a leading manufacturer of premium quality cooking and speciality appliances for both residential and professional use. We are proud of our reputation for quality and our commitment to customer satisfaction. We have set high standards for ourselves along with our network of independent Part Distributors and Service Agencies.

  • Page 6: Specification

    SPECIFICATION ITEM DESCRIPTION Power Requirements 120 Volts / 13.8 Amperes/1650Watts 60 Hertz Single phase, 3 wire grounded Power Output 1200 watts (IEC-705 TEST PROCEDURE) Operating frequency of 2450MHz Case Dimensions Width 24" Height 13-3/8" Depth 19-1/8" Cooking Cavity Dimensions Width 17-3/8" 2.0 Cubic Feet Height 10-1/2"...

  • Page 7: Oven Diagram

    adapter properly grounded and polarized. If the extension cord must be used, it should be 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.

  • Page 8: Description Of Operating Sequence

    OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions during the secondary interlock switch and primary interlock oven operation. relay and is mechanically associated with the door so that it will function in the following sequence. OFF CONDITION (1) When the door opens from the closed position, the primary interlock relay (RY2) and secondary interlock...

  • Page 9: Sensor Cooking Condition

    2. The coil of shut-off relay (RY-1) is energized, the turntable motor are turned on, but the power transformer SENSOR COOKING CONDITION is not turned on. 3. After about 16 seconds, the cook relay (RY-2) is Using the SENSOR function, food is cooked without figuring energized.
  • Page 10 SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED 2. CLOCK APPEARS ON DISPLAY MAGNETRON MONITOR TEMP. FUSE 20A FUSE COM. N.O. CAPACITOR 1.0µF AH SENSOR AC 2300V (RY-2) (RY-1) PRIMARY INTERLOCK RELAY CONTROL UNIT N.O. COM. 120V AC POWER 60 Hz TRANSFORMER N.C.

  • Page 11: Description And Function Of Components

    DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM open, the monitor fuse blows simultaneously with closing of the monitor switch contacts. The door is opened by pushing the open button on the control CAUTION: BEFORE REPLACING A BLOWN MONITOR panel, refer to the Figure D-1. When the open button is FUSE TEST THE DOOR SENSING SWITCH, pushed, the open button pushes up the switch lever, and PRIMARY INTERLOCK RELAY (RY2), RELAY...

  • Page 12: Troubleshooting Guide

    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 13: Test Procedures

    CK = Check / RE = Replace RE RE A B C D E E F F G H RE RE CK I CK CK CK J K L TEST PROCEDURE POSSIBLE CAUSE DEFECTIVE PARTS PROBLEM CONDITION Home fuse or circuit breaker blows when power cord is plugged into wall receptacle Monitor fuse blows when power...

  • Page 14: Power Transformer Test

    TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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. 5. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and chassis ground.
  • Page 15 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER HIGH VOLTAGE RECTIFIER 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. Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance across the terminals and observe, reverse the leads to the rectifier terminals and observe meter reading.
  • Page 16 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER CAUTION: IF THE TEMPERATURE FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERA- TURE, REPLACE TEMPERATURE FUSE. SECONDARY INTERLOCK SWITCH TEST 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3.

  • Page 17: Component Test

    TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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 Screw Driver functions.

  • Page 18: Key Unit Test

    TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST The following symptoms indicate a defective key unit. a) When touching the pads, a certain pad produces no signal at all. b) When touching a number pad, two figures or more are displayed. c) When touching the pads, sometimes a pad produces no signal. If the Key unit is defective.
  • Page 19 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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. MO24SS RELAY TEST 1. Disconnect the power supply cord, and then remove outer case. 2.
  • Page 20 TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER 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. 1.

  • Page 21: Ah Sensor Test

    TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER AH SENSOR TEST Checking the initial sensor cooking condition Warning: The oven should be fully assembled before following procedure. 1) The oven should be plugged in at least two minutes before sensor cooking. 2) Room temperature should not exceed 95 F(35 3) The unit should not be installed in any area where heat and steam are generated.

  • Page 22: Checking Control Unit

    TEST PROCEDURES PROCEDURE COMPONENT TEST LETTER CHECKING CONTROL UNIT (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 sensor connector that is mounted to control panel. (5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.

  • Page 23: Touch Control Panel Assembly

    TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL 4) Relay Circuit The touch control section consists of the following units. A circuit to drive the magnetron, fan motor, turntable motor and light the oven lamp. (1) Key Unit (2) Control Unit (The Control Unit consists of Power Unit 5) Buzzer Circuit and LSI Unit).
  • Page 24 LSI(IXA098DR) The I/O signal of the LSI(IXA098DR) is detailed in the following table. Pin No. Signal Description COM5 Common data signal : COM11. Connected to LCD signal COM11. COM4 Common data signal : COM12. Connected to LCD signal COM12. COM3 Common data signal : COM13.
  • Page 25 Pin No. Signal Description INT0 Signal synchronized with commercial power source frequency. This is the basic timing for time processing of LSI. H : GND L : -5V 16.7 msec. Key strobe signal. Signal applied to touch-key section. A pulse signal is input to AIN7, P14, P15, P16 and P17 terminal while one of G1 line keys on key matrix is touched.
  • Page 26 Pin No. Signal Description Terminal not used. XCOUT Terminal not used. XCIN Connected to VC. Terminal not used. Power source voltage: GND(0V). The power source voltage to drive LSI is input to VCC terminal. OSCSEL Connected to VC(-5V). XOUT Internal clock oscillation output. Output to control oscillation input of XIN.

  • Page 27: Absolute Humidity Sensor Circuit

    Pin No. Signal Description COM7 Common data signal : COM9. Connected to LCD signal COM9. COM6 Common data signal : COM10. Connected to LCD signal COM10. ABSOLUTE HUMIDITY SENSOR CIRCUIT (1) Structure of Absolute Humidity Sensor With this voltage given, the switches SW1 to SW5 in the The absolute humidity sensor includes two thermistors LSI are turned on in such a way as to change the as shown in the illustration.

  • Page 28: Touch Control Panel Servicing

    TOUCH CONTROL PANEL SERVICING 1. Precautions for Handling Electronic Components 5) Re-connect the power supply cord after the outer This unit uses CMOS LSI in the integral part of the case is installed. circuits. When handling these parts, the following 6) Run the oven and check all functions.

  • Page 29: Component Replacement And Adjustment Procedure

    COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING AGAINST HIGH VOLTAGE: Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in severe, possibly fatal, electric shock. (Example) High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. Avoid possible exposure to microwave energy.

  • Page 30: Power Transformer Removal

    CAUTION: 1. DISCONNECT OVEN FROM POWER SUP PLY BEFORE REMOVING OUTER CASE. 2. DISCHARGE THE HIGH VOLTAGE CA- PACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING. Special screw NOTE: When replacing the outer case, the 2 special Torx screws must be reinstalled in the same locations.

  • Page 31: Oven Lamp And Lamp Socket Removal

    OVEN LAMP AND LAMP SOCKET 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. Remove the oven lamp from the oven lamp socket. 5. Pull the wire leads from the oven lamp socket by pushing the terminal hole of the oven lamp socket with the small flat type screw driver.

  • Page 32: Cooling Fan Motor Removal

    COOLING FAN MOTOR REMOVAL REMOVAL CAUTION: 1. Disconnect the power supply cord and then remove outer * Do not reuse the removed fan blade because the hole case. (for shaft) may be larger than normal. 2. Open the door and block it open. 3.

  • Page 33: Door Sensing Switch/Secondary Interlock Switch And Monitor Switch Adjustment

    3. Secure latch hook (with two (2) mounting screws) to oven and check continuity of the monitor circuit. Refer to chapter flange. "Test Procedure" and Adjustment procedure. 4. Make sure that the monitor switch is operating properly DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT 1.

  • Page 34: Sealer Film

    SEALER FILM 6. Re-install choke cover to door panel by pushing. Installation Note: After any service to the door; 1. Put the adhesive tape on the backing film of the sealer (A) Make sure that door sensing switch and secondary film as shown in Fig.
  • Page 36 CN-C 12PIN LEAD WIRE HARNESS Q2 2SB1238 R4 27 R5 4.7k D1-D4 11ES1 CN-A 1SS270A 1SS270A – – R3 510 1/2w Q1 2SB1238 R2 680 1/2w SP1 PKM22EPT Q3 KRC243M BUZZER OVEN LAMP R6 3.3k TURNTABLE OVEN LAMP MOTOR TURNTABLE FAN MOTOR MOTOR –...
  • Page 38 (CN - C) CN - C CN - B CN - A (J1) (CN - D) (D10) Figure S-5 Printed Wiring Board of Power Unit...

  • Page 39: Oven And Cabinet Parts

    OVEN AND CABINET PARTS 7-10 1-10 1-15 7-10 4-10 1-14 1-11 1-12 1-13 7-10 4-11...

  • Page 40: Control Panel Parts

    CONTROL PANEL PARTS DOOR PARTS 5-1-1 MISCELLANEOUS 5-1-2 Actual wire harness may be different from illustration.

  • Page 41: Parts List

    PARTS LIST Note: The parts marked “∆ ∆ ∆ ∆ ∆ ” may cause undue microwave exposure. The parts marked “*” are used in voltage more than 250V. REF. NO. PART NO. DESCRIPTION Q'TY CODE ELECTRIC PARTS 1- 1 19133 High voltage capacitor 1- 2 19099...

  • Page 42: Screws,Nuts And Washers

    REF. NO. PART NO. DESCRIPTION Q'TY MISCELLANEOUS 6- 1 19103-01 Stop switch harness 6- 2 19103-02 Main wire harness 6- 3 19142 Cavity hole cover 6- 4 19101 Turntable support 6- 5 19117 Turntable tray 6- 6 19139 Monitor caution label 6- 7 19140 DHHS/Screw caution label...

  • Page 43: Packing And Accessories

    PACKING AND ACCESSORIES TOP PAD ASSEMBLY DOOR PROTECTION SHEET PLASTIC BAG TRAY HOLDER 6-5 TURNTABLE TRAY 6-8 OPERATION MANUAL BOTTOM PAD ASSEMBLY TRAY PACK PACKING CASE Non-replaceable items.
  • Page 44 As product improvement is an ongoing process at DCS, we reserve the right to change specifications or design without notice. 5800 Skylab Road, Huntington Beach, CA. 92647 Tel: (714) 372-7000 Part No. 17392 Rev. A Fax: (714) 372-7004 Parts/Customer Service (888) 281-5698 Litho in USA 01/2002 www.dcsappliances.com...

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