Instruction/ maintenance manual of the product MMD24B Sharp
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1 MMD24S MMD24B S38M289MMD24S MMD24S MICR O W A VE DRA WER MODELS SER VICE MANU AL MMD24B In the interest of user-safety the unit should be restored to its original condition and only par ts identical to those specified should be used.
2 MMD24S MMD24B PRECA UTIONS T O BE OBSER VED BEFORE AND DUR - ING SER VICING T O A V OID POSSIBLE EXPOSURE T O EXCESSIVE MICR O W A VE ENERGY (a) Do not operate or allo w the oven to be oper ated with the door open.
3 MMD24S MMD24B W ARNING T O SER VICE PERSONNEL Microw av e Oven units contain circuitry capable of producing v er y high v oltage and current, contact with f ollowing par ts ma y result in a sev ere, possib ly fatal, electrical shoc k.
4 MMD24S MMD24B MICR O W A VE MEASUREMENT PROCEDURE A. Requirements: 1) Microwa ve leakage limit (P ower density limit): The power density of microw av e radiation emitted by a microw av e ov en shoul.
5 MMD24S MMD24B PRODUCT DESCRIPTION SCHEMA TICS TEST PROCEDURE T OUCH CONTROL P ANEL MICRO W A VE DRA WER DISSASSEMBL Y AND ADJUSTMENT PROCEDURE WIRING DIA GRAM P AR TS LIST SER VICE MANU AL MICRO W A.
6 MMD24S MMD24B ITEM DESCRIPTION P ow er Requirements Canada - 117 V olts / 13.0 Amperes / 1500 Kw / 60 Hz (CUL) U .S.A. - 120 V olts / 13.6 Amperes / 1500 Kw / 60 Hz (UL) Single phase, 3 wire g rounded P ow er Output 950 watts (IEC TEST PR OCEDURE) Operating frequency of 2450MHz Cooking Cavity Dimensions Width 17-11/32 Height 5-7/8" 1.
7 MMD24S MMD24B GENERAL INFORMA TION GROUNDING INSTR UCTIONS This ov en is equipped with a three prong g rounding plug. It must be plugged into a wall receptacle that is properly installed and grounded in accordance with the National Electrical Code and local codes and ordinances.
8 MMD24S MMD24B OPERA TION DESCRIPTION OF OPERA TING SEQUENCE The f ollowing is a descr iption of component functions dur- ing ov en operation. OFF CONDITION Closing the drawer activates the door sensing switch and secondar y interlock switch. (In this condition, the monitor s witch contacts are opened.
9 MMD24S MMD24B SENSOR COOKING CONDITION Using the SENSOR function, food is cook ed without figur- ing time, power lev el or quantity . When the ov en senses enough steam from the food, it rela ys the inf or mation to its microprocessor which will calculate the remaining cooking time and power lev el needed for best results.
10 MMD24S MMD24B SCHEMA TIC (OFF CONDITION) 3. Only certain models use the absol ute humidity sensor . 2. T erminal that is located on the right side on lamp socket's back view 1. Circuits / Wire Colors subject to change without notice. NOTES: must be connected to neutral wire.
11 MMD24S MMD24B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST unlike conv entional microwa ve ovens , proper maintenance cannot be performed with only a voltmeter and ohmmeter .
12 MMD24S MMD24B C RELA Y TEST 4) Reconnect all leads remov ed from components dur ing testing. 5) Re-install the cov ers. 6) Reconnect the power supply cord after the co vers are installed. 7) Run the ov en and check all functions. TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST B KEY UNIT TEST 1.
13 MMD24S MMD24B W ARNING : The ov en should be fully assembled bef ore f ollowing procedure. (1) Place one cup of w ater in the center of the tray in the o ven ca vity . (2) Close the dra wer , touch the Defrost pad. Then select Steaks/Chops by touching the number pad 2.
14 MMD24S MMD24B W ARNING : The o ven should be fully assemb led before f ollowing procedure. (1) The ov en should be plugged in at least two minutes bef ore sensor cooking. (2) Room temperature should not e xceed 95 ο F (35 ο C). (3) The unit should not be installed in an y area where heat and steam are generated.
15 MMD24S MMD24B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST 9-2. Place the container on the center of tray in the o ven cavity . 9-3. Close the drawer . 9-4. T ouch the TIMER/CLOCK pad once, the PO WER LEVEL pad twice and the ST AR T pad once . And touch the number pads 1 once and the number pad 4 once .
16 MMD24S MMD24B 2. Open the dra wer and keep it open. 3. T o discharge high voltage capacitor , w ait for 60 seconds . 4. T o test f or 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.
17 MMD24S MMD24B I SECONDAR Y INTERLOCK SWITCH TEST ST OP SWITCH 1. Disconnect the pow er supply cord. 2. Open the dra wer and keep it open. 3. T o discharge high v oltage capacitor , wait for 60 seconds . 4. Isolate the s witch and connect the ohmmeter to the common (COM.
18 MMD24S MMD24B TEST PROCEDURES PROCEDURE LETTER COMPONENT TEST M PO WER TRANSFORMER TEST 1. Disconnect the pow er supply cord. 2. Open the dra wer and bloc k it open. 3. Discharge high voltage capacitor . 4. Disconnect the primar y input ter minals and measure the resistance of the transformer with an ohmmeter .
19 MMD24S MMD24B T OUCH CONTR OL P ANEL ASSEMBL Y OUTLINE OF T OUCH CONTROL P ANEL The touch control section consists of the f ollowing units. ( 1) K ey unit (2) Control Unit (3) P ower unit The pr incipal functions of these units and the signals com- municated among them are e xplained below .
20 MMD24S MMD24B 1 - 3 AN5- AN3 IN T erminal to change cooking input according to the Model. By using A/D con ver ter contained in the LSI, DC voltage in accordance with the Model in operation is applied to set up its cooking constant.
21 MMD24S MMD24B 27 COM0 OUT Common data signal. Connected to LCD signal C4. 28 VL3 IN Connected VC (+5V). 29 - 31 P27- P25 OUT T er minal not used. 32 SEG20 OUT Segment data signal. Connected to LCD segment S24. 33 P23 IN Signal coming from touc h key .
22 MMD24S MMD24B Pin No. Signal I/O Description 47 P05 OUT Magnetron high-v oltage circuit driving signal. T o tur n on and off the cook relay(R Y2). In 100% pow er operation, the signals holds “H” lev el during microw av e cooking and “L ” le vel while not cooking.
23 MMD24S MMD24B (1) Structure of Humidity Sensor The humidity sensor includes two ther mistors as shown in the illustr ation. One thermistor is housed in the closed vessel filled with dr y air while another in the open vessel. Each senso r is provided with the protectiv e cov er made of metal mesh to be protected from the e xter nal airflow .
24 MMD24S MMD24B 1. Precautions for Handling Electr onic Components This unit uses CMOS LSI in the int egral par t of the circu its. When handling these par ts, the following precautions should be str ictly follow ed. CMOS LSI hav e extremely high impedance at its input and output ter minals.
25 MMD24S MMD24B PRECA UTIONS FOR USING LEAD-FREE SOLDER 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 ser vice manual. The suffix letter indicates the alloy type of the solder .
26 MMD24S MMD24B ma y result in sev ere, possibly f atal, electric shock. (Example) High V oltage Capacitor , P ow er T ransf or mer , Magnetron, High V oltage Rectifier Assemb ly , High V oltage Har ness etc.. W ARNING: T o A void possib le exposure to micro wave energy , please f ollow the instructions below before operating the o ven.
27 MMD24S MMD24B Back cover Exhaust duct screws T op plate Right side panel Left side panel Air cover Cavity Fig. 1 1. Bef ore removing Micro wav e Dra wer , take measures to protect the Drawer louv er by either remo ving the louver or b y letting the louver ov er hang off flat protected surf ace (Fig 1) .
28 MMD24S MMD24B At this point, you will ha ve access to all par ts of the Micro wave Drawer . 7. T o remove the Control P anel F rame Assemb ly , remov e the 9 screws holding the C/P frame to the ca vity . (Fig 3) . With the C/P frame assemb ly now loose, y ou can unplug all wires.
29 MMD24S MMD24B 2. Open the dra wer and keep it open. 3. T o discharge the high voltage capacitor , wait for 60 seconds. 4. Remov e the screw holding the latch hook to the ov en flange. 5. Remov e the latch hook from the ov en flange. 6. Disconnect the wire leads of each s witch.
30 MMD24S MMD24B 1. F ollow the Microwa ve Draw er disassembly as previously stated 2. Open the dra wer and keep it open. 3. T o discharge the high voltage capacitor , wait for 60 seconds. 4. Remo ve the both right and left side panels. 5. Remov e (2) Dra wer Suppor t Covers from Choke Cov er as shown in (Fig.
31 MMD24S MMD24B (Locate either the right or left switch angle) 1. F ollow the Microw ave Dr awer disassemb ly as previously stated 2. Open the dra wer and keep it open. 3. T o discharge the high v oltage capacitor , wait for 60 seconds . 4. T o remov e switch, remo ve scre w (1) holding switch to s witch angle (Fig.
32 MMD24S MMD24B 1. Disengage any po wer going to the unit. 2. Open the dra wer and keep it open. 3. Remov e the top cov er and r ight side cabinet. 4. Unhook wiring to Auto Dr awer Gear . 5. Remov e bottom screw belo w Auto Dra wer Gear (Fig. G-1) . 6.
33 MMD24S MMD24B 6 4 5 1 2 3 6 4 5 1 2 3 A B C D E F G H A B C D E F G H HIGH VOL T AGE RECTIFIER HIGH V OL T AGE CAP ACIT OR HIGH V OL T AGE WIRE A HIGH VOL T AGE COMPONENTS POWER TRANSFORMER Po wer .
34 MMD24S MMD24B 6 4 5 1 2 3 6 4 5 1 2 3 A B C D E F G H A B C D E F G H Figure S-2. P ower Unit Circuit PA154DR VRS1 60Hz FUSE 2.5A C1 C2 1000uF/50V D1 -- D4 1N4002L x4 CN-A + D5 RY2 COM N.O. D7 RY1 COM N.O. D10 RY3 D11 RY4 D12 RY5 H-1 H-3 H-2 H-4 H-5 H-7 H-6 AC 120V MICRO COM (O.
35 MMD24S MMD24B 6 4 5 1 2 3 6 4 5 1 2 3 A B C D E F G H A B C D E F G H Figure S-3. Control Unit Cir cuit S21 S20 S19 S18 S17 S16 S15 S14 S13 S12 S11 S10 S9 S8 S7 S6 S5 S4 S3 S2 S1 S0 C2 C1 C0 P36 P3.
36 MMD24S MMD24B 6 4 5 1 2 3 6 4 5 1 2 3 A B C D E F G H A B C D E F G H Figure S-4. Printed Wiring Board of P ower Unit 2.5A 3 1 2 FUSE T1 4 8 D3 ZD 1 J1 0 RY1 D1 2 R Y5 DIP CN H Q1 R 1 D2 D1 1 1 1 D4 1 1 R1 0 C10 R Y2 1 3 P 3 D1 1 D10 7 CN A CNB C1 1 R1 1 R Y4 R Y3 CO M.
37 MMD24S MMD24B 6 4 5 1 2 3 6 4 5 1 2 3 A B C D E F G H A B C D E F G H Figure S-5. Printed Wiring Board of Control Unit 7 8 7 8 6 5 6 Q7 LCD CNE CNN R40 CF1 1 1 5 3 B C E 5 1 3 4 3 4 2 1 2 R6 R5 D2 .
44 MMD24S MMD24B COPYRIGHT © 2008 BY D ACOR, INC . ALL RIGHTS RESER VED . No part of this pub lica tion ma y be repr oduc ed, stored in retriev al systems, or transmitted in any form or by any means , electronic, mechanical, photocopying, recording, or otherwise, without pr ior wr itten per mission of the publisher .
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