DMT2420B DMT2420R DMT2420S SERVICE MANUAL S12M201DMT24E MICROWAVE OVEN MODELS DMT2420B DMT2420R DMT2420S In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used. WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with the following parts may result in a severe, possibly fatal, electrical shock.
DMT2420B DMT2420R DMT2420S PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY (a) Do not operate or allow the oven to be operated with the door open.
DMT2420B DMT2420R DMT2420S 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. (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. Don't Touch ! Danger High Voltage When the testing is completed, 1.
DMT2420B DMT2420R DMT2420S 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/cm2 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/cm2 at any point 5cm or more from the external surface of the oven.
DMT2420B DMT2420R DMT2420S SERVICE MANUAL dis tinctive appliances PRODUCT DESCRIPTION MICROWAVE OVEN DMT2420B/DMT2420R/DMT2420S GENERAL INFORMATION FOREWORD This Manual has been prepared to provide Dacor Service Personnel with Operation and Service Information for the DACOR MICROWAVE OVENS, DMT2420B, DMT2420R and DMT2420S. OPERATION 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.
DMT2420B DMT2420R DMT2420S SPECIFICATION ITEM DESCRIPTION Power Requirements 120 Volts / 14.3 Amperes 60 Hertz Single phase, 3 wire grounded Power Output 1200 watts (IEC 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" Height 10-1/2" Depth 18-5/8" 2.0 Cubic Feet Control Complement Touch Control System Clock ( 1:00 - 12:59 ) Timer (0 - 99 min.
DMT2420B DMT2420R DMT2420S Where a two-pronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to contact a qualified electrician and have it replaced with a properly grounded three-pronged wall receptacle or have a grounding adapter properly grounded and polarized. If the extension cord must be used, it should be a 3-wire, 15 amp. or higher rated cord.
DMT2420B DMT2420R DMT2420S OPERATION DESCRIPTION OF OPERATING SEQUENCE The following is a description of component functions during oven operation. 4. The microwave energy produced by the magnetron is channelled through the waveguide into the cavity feedbox, and then into the cavity where the food is placed to be cooked. 5. Upon completion of the cooking time, the power transformer, oven lamp, etc. are turned off, and the generation of microwave energy is stopped.
DMT2420B DMT2420R DMT2420S Note: Cooking Sequence. 1. Touch one of the SENSOR pads and then touch the Start pad. NOTE: The oven should not be operated on SENSOR immediately after plugging in the unit. Wait two minutes before cooking on SENSOR. 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 transformer is not turned on. 3. After about 16 seconds, the cook relay (RY-2) is energized.
DMT2420B DMT2420R DMT2420S SCHEMATIC NOTE: CONDITION OF OVEN 1. DOOR CLOSED. 2. CLOCK APPEARS ON DISPLAY. NOTE: Indicates components with potential above 250 V. C/T FUSE BLK RED COM N.O. HUMIDITY SENSOR F3 A2 (RY2) PRIMARY INTERLOCK RELAY (RY1) POWER TRANSFORMER F2 F1 H A1 RED RED DOOR SENSING SWITCH N.C. MONITOR SWITCH FAN MOTOR COM WHT BLU ORG TURN TABLE MOTOR WHT OVEN LAMP HIGH VOLTAGE CAPACITOR N.O.
DMT2420B DMT2420R DMT2420S DESCRIPTION AND FUNCTION OF COMPONENTS DOOR OPEN MECHANISM 3. If the door is opened, and the primary interlock relay (RY2) and secondary interlock switch contacts fail to open, the C/T fuse blows simultaneously with closing of the monitor switch contacts. CAUTION: BEFORE REPLACING A BLOWN C/T FUSE TEST THE DOOR SENSING SWITCH, PRIMARY INTERLOCK RELAY (RY2), RELAY (RY1), SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").
DMT2420B DMT2420R DMT2420S 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. These tests are given a procedure letter which will be found in the "Test Procedure "section.
DMT2420B DMT2420R DMT2420S CK = Check / RE = Replace POSSIBLE CAUSE AND DEFECTIVE PARTS CONDITION PROBLEM RE RE A B C D E E F F G H RE RE CK I CK CK CK J K L M N SHORT IN POWER CORD SHORT OR OPENED WIRING MAGNETRON POWER TRANSFORMER H.V.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 6. 7. 8. 9. Reconnect all leads removed from components during testing. Reinstall the outer case (cabinet). Reconnect the power supply cord after the outer case is installed. Run the oven and check all functions. MICROWAVE OUTPUT POWER The following test procedure should be carried out with the microwave oven in a fully assembled condition (outer case fitted).
TEST PROCEDURES PROCEDURE LETTER C DMT2420B DMT2420R DMT2420S COMPONENT TEST HIGH VOLTAGE RECTIFIER TEST 1. 2. 3. 4. Disconnect the power supply cord, and then remove outer case. Open the door and block it open. Discharge high voltage capacitor. 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.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST CAUTION: BEFORE REPLACING A BLOWN C/T FUSE, TEST THE PRIMARY INTERLOCK RELAY, SECONDARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH FOR PROPER OPERATION. If the C/T fuse is blown by improper switch operation, the C/T fuse and monitor switch must be replaced with "C/T fuse and monitor switch assembly" part number FFS-BA019/KIT, even if the monitor switch operates normally.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER G COMPONENT TEST MONITOR SWITCH TEST 1. 2. 3. 4. 5. 6. 7. 8. Disconnect the power supply cord, and then remove outer case. Open the door and block it open. Discharge high voltage capacitor. Before performing this test, make sure that the secondary interlock switch and the primary interlock relay are operating properly, according to the above Switch Test Procedure. Disconnect the wire lead from the monitor switch (COM) terminal.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER COMPONENT 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) 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.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 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.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST WEIGHT 0.5lb 1ST STAGE LEVEL TIME 70% 30sec. 2ND STAGE LEVEL TIME 40% 15sec. (5) If improper operation is indicated, the control unit is probably defective and should be checked. L 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. Foil pattern check and repairs.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 10) Discharge high voltage capacitor. 11) Reconnect all leads removed from components during testing. 12) Re-install the outer case (cabinet). 13) Reconnect the power supply cord after the outer case is installed. 14) Run the oven and check all functions. M AH SENSOR TEST Checking the initial sensor cooking condition WARNING : The oven should be fully assembled before following procedure.
DMT2420B DMT2420R DMT2420S TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 9-3. Close the door. 9-4. Touch the Timer/Clock pad once, the Power Level pad twice, the Start pad once and the number pad 1 once. 9-5. The control panel is in automatic Sensor operation. 9-6. And then the oven will turn off automatically, and the time for detecting moisture will be displayed. If new sensor dose not operate properly, the problem is with the control unit, and refer to explanation below.
DMT2420B DMT2420R DMT2420S TOUCH CONTROL PANEL ASSEMBLY OUTLINE OF TOUCH CONTROL PANEL unit from the AC line voltage. In addition, the synchronizing signal is available in order to compose a basic standard time in the clock circuit. The touch control section consists of the following units. (1) Key Unit (2) Control Unit (The Control Unit consists of Power Unit and LSI Unit). The principal functions of these units and the signals communicated among them are explained below.
DMT2420B DMT2420R DMT2420S LSI(IXA029DR) The I/O signal of the LSI(IXA029DR) is detailed in the following table. Pin No. Signal I/O Description 1 TIOCA2 OUT Terminal not used. 2 A20 OUT Terminal not used. 3 Vcc IN 4 TMO0 OUT 5 PB1 IN Signal coming from touch key. When either G11 line on key matrix is touched, a corresponding signal out of P93, P94, P95, P40, P41, P42, P43 and P44 will be input into PB1. When no key is touched, the signal is held at "H" level.
DMT2420B DMT2420R DMT2420S Pin No. 24 Signal Vss I/O IN 25 P44 OUT 26 P45 OUT Description Power source voltage : GND(0V). The power source voltage to drive LSI is input to VSS terminal. Key strobe signal. Signal applied to touch screen section. A pulse signal is input to PB1-PB5 terminal while one of G10 line keys on key matrix is touched. Oven lamp, fan motor and turntable motor driving signal 16.7 msec. To turn on and off shut off relay (RY1).
DMT2420B DMT2420R DMT2420S Pin No. 75-76 Signal MD0-MD1 I/O IN Description Connected to VCC. 77 MD2 IN Connected to GND. 78 Avcc IN A/D converter power source voltage : +5V. The power source voltage to drive the A/D converter. Connected to VCC. 79 Vref IN A/D converter power source voltage : +5V. The power source voltage to drive the A/D converter. Connected to VCC. 80 AN0 IN Terminal to judge whether the model has the sensor cooking function or not.
DMT2420B DMT2420R DMT2420S ABSOLUTE HUMIDITY SENSOR CIRCUIT With this voltage given, the switches SW1 to SW5 in the LSI are turned on in such a way as to change the resistance values in parallel with R98 ~ R102. Changing the resistance values results in that there is the same potential at both F-3 terminal of the absolute humidity sensor and AIN4 terminal of the LSI. The voltage of AIN5 terminal will indicate about -2.5V.
DMT2420B DMT2420R DMT2420S TOUCH CONTROL PANEL SERVICING 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 control panel and the oven itself is so short that the two can’t be separated. For those models, check and repair all the controls (sensor-related ones included) of the touch control panel while keeping it connected to the oven. B.
DMT2420B DMT2420R DMT2420S 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.. WARNING: Avoid possible exposure to microwave energy.
DMT2420B DMT2420R DMT2420S CAUTION: 1. DISCONNECT OVEN FROM POWER SUP PLY BEFORE REMOVING OUTER CASE. 2. DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING. NOTE: When replacing the outer case, the 2 special Torx screws must be reinstalled in the same locations. Special screw Screw Driver (Type: TORX T20 H or GTXH20-100) POWER TRANSFORMER REMOVAL 1. Disconnect the power supply cord and then remove outer case. 2. Open the oven door and block it open. 3.
DMT2420B DMT2420R DMT2420S OVEN LAMP AND LAMP SOCKET REMOVAL 1. 2. 3. 4. 5. Disconnect the power supply cord and remove outer case. Open the door and block it open. Discharge high voltage capacitor. Remove the oven lamp from the oven lamp socket. 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. 6. Remove the oven lamp socket from the magnetron duct by turning the socket counterclockwise. 7.
DMT2420B DMT2420R DMT2420S COOLING FAN MOTOR REMOVAL CAUTION: * Do not reuse the removed fan blade because the hole (for shaft) may be larger than normal. 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.
DMT2420B DMT2420R DMT2420S 3. Secure latch hook (with two (2) mounting screws) to oven flange. 4. Make sure that the monitor switch is operating properly and check continuity of the monitor circuit. Refer to chapter "Test Procedure" and Adjustment procedure. DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT 1. Disconnect the power supply cord, and then remove outer case. 2. Open the door and block it open. 3. Discharge high voltage capacitor.
DMT2420B DMT2420R DMT2420S Note: 13.Now, door panel is free. 14.Slide latch head upward and remove it from door frame by releasing latch spring from door frame and latch head. 15.Now, latch head and latch spring are free. 16.Remove one (1) screw holding the door glass stopper to the door frame. 17.Remove door glass stopper from door frame. 18.Slide the door glass rightwards and then slide upwards to release the door glass from the tabs holding it. 19.Remove the door glass from the door frame. 20.
CN-G CN-C 1 11 1 WHT WHT 1 IC1 15 AH SENSOR A 1 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. CAVITY TEMP. FUSE CN-F 1 BLK 2 RED 3 WHT B C D E F G H CONTROL UNIT H N RED GRY 3 DOOR SENSING SWITCH CN-F (CPU UNIT) N.O. PNK COM.
DMT2420B DMT2420R DMT2420S 2 1 4 3 6 5 A A R2 91 1w A2 C6 VA C4 GND C11 BZ/EN C10 BUZZR C9 OVEN LAMP FAN MOTOR TURNTABLE MOTOR B b AC120V 60Hz – R1 + ZD1 HZ-16-1 a D1 S1NB10 2.4k 1/4w d GND C (J1) C VR Q1 KTC1027 D1 C2 1000µ/35v A1 VRS1 CN-A R3 91 1w INT C5 T1 10G471K AC C1 B C3 c SP30 D OVEN LAMP FAN MOTOR TURNTABLE MOTOR RY1 NO D COM AC RY2 E E NO MICRO COM C7 MICRO C8 N.C C2 N.
A R10 470 1/2w IC3 D81 R69 15k C1 G2 G3 G5 SETUP DEFROST MICROWAVE RECIPES & INSTRUCTIONS G6 PASTA GRAINS BEVERAGES G13 G12 G11 R72 15k POULTRY G8 G9 G10 COM3 COM2 COM1 R90 43kF R99 15k C98 0.01µ /25v R100 4.7k SEG3 SEG2 SEG1 COM50 COM49 IC4 SDA SCL WP VCC 5 8 4 GND A2 A1 1 A0 C110 0.01µ/25v G14 COM51 SEG160 SEG159 SEG158 LIQUID CRYSTAL DISPLAY 100 x 160 Dots C19 0.1µ/25v R111 4.7k R112 47k R60 15k R61 15k R62 15k R64 15k R63 15k G7 COM100 COM99 COM98 C112 0.
DMT2420B DMT2420R DMT2420S 2 1 4 3 6 5 A A VH CN - B B 1 B CN - C Q1 B ZD1 SP30 R1 R2 DIP C SH-B E 1 2 R3 SH-A (GREEN) 11 C C2 C1 D1 D D20 D OM DU 1 7 D21 5 OM DU T1 3 XA 2 1 F E S P RY2 RY1 E F VRS1 2 (J1) 1 CN - A VH QKITPB033MREO G G H H Figure S-4.
