MICROWAVE OVEN M759 (WHITE) / M759C (RED) / M759B (BROWN) / M759GR (GREEN) SERVICE Manual MICROWAVE OVEN CONTENTS 1. Precaution 2. Specifications 3. Operating Instructions 4. Disassembly and Reassembly 1. 2. 3. 1. 2. 3. 1 Min + Auto Start 1. Auto Auto 2. 10s./ 5. Alignment and Adjustments 3. 6. Troubleshooting 1min /g 10min/kg 7. Exploded Views and Parts List 8. PCB Diagrams 9.
1. Precaution Follow these special safety precautions. Although the microwave oven is completely safe during ordinary use, repair work can be extremely hazardous due to possible exposure to microwave radiation, as well as potentially lethal high voltages and currents. 1-1 Safety precautions ( ) 1. All repairs should be done in accordance with the procedures described in this manual. This product complies with Federal Performance Standard 21 CFR Subchapter J (DHHS). 2.
Pretaution 1-2 Special Servicing Precautions (Continued) 17. When checking the continuity of the witches or transformer, always make sure that the power is OFF, and one of the lead wires is disconnected. 18. Components that are critical for safety are indicated in the circuit diagram by shading, or . 19. Use replacement components that have the same ratings, especially for flame resistance and dielectric strength specifications.
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3. Operating Instructions 3-1 Control Panel 1. 2. 3. 1. 2. 3. Auto Reheat Selection Auto Auto Cook Selection Auto Power Level Button Start Button 1 Min + Auto Start 1. 2. Auto Defrost Selection 3. 10s./ Time Setting and Weight Selection 1min /g 10min/kg Cancel Button Deodorization Button 3-2 Features & External Views Door Light Ventilation Holes Safety Interlock Holes 1. 2. 3. 1. 2. 3. 1 Min + Start Auto Auto Auto 1. 2. 3. Control Panel 10s.
4. Disassembly and Reassembly 4-1 Replacement of Magnetron, Motor Assembly and Lamp Remove the magnetron including the shield case, permanent magnet, choke coils and capacitors (all of which are contained in one assembly). Cover Air Thermo S/W Lamp 1. Disconnect all lead wires from the magnetron and lamp. 2. Remove a screw securing the magnetron supporter. 3. Remove the magnetron supporter. 4. Remove the air cover. 5. Remove screws securing the magnetron to the wave guide. 6.
Disassembly and Reassembly 4-3 Replacement of Door Assembly 4-3-1 Removal of Door Assembly Remove hex bolts securing the upper hinge and lower hinge. Then remove the door assembly. Upper Hinge Screws Lower Hinge Screws 4-3-2 Removal of Door "C" Insert flat screwdriver into the gap between Door "E" and Door "C" to remove Door "C". Be careful when handling Door "C" because it is fragile.
Disassembly and Reassembly 4-3-5 Reassembly Test After replacement of the defective component parts of the door, reassemble it and follow the instructions below for proper installation and adjustment so as to prevent an excessive microwave leakage. 1. When mounting the door to the oven, be sure to adjust the door parallel to the bottom line of the oven face plate by moving the upper hinge and lower hinge in the direction necessary for proper alignment. 2.
Disassembly and Reassembly 4-6 Replacement of Control Circuit Board 4-6-1 Removal of Ass'y Control Box 1. Be sure to ground any static electric charge in your body and never touch the touch control circuitry. 2. Disconnect the connectors from the control circuit board. SCREW 3. Remove screws securing the control box assembly. 4. Remove the screw securing the ground tail of the keyboard. CONTROL BOX 4-6-2 Remonal of Ass'y P.C.B 1.
5. Alignment and Adjustments PRECAUTION 1. High voltage is present at the high voltage terminals during any cook cycle. 2. It is neither necessary nor advisable to attempt measurement of the high voltage. 3. Before touching any oven components or wiring, always unplug the oven from its power source and discharge the high voltage capacitor. 5-1 High Voltage Transformer 1. Remove connectors from the transformer terminals and check continuity. 2.
Alignment and Adjustments 5-4 High Voltage Capacitor 1. Check continuity of the capacitor with the meter set at the highest resistance scale. 2. Once the capacitor is charged, a normal capacitor shows continuity for a short time, and then indicates 9MW. 3. A shorted capacitor will show continuous continuity. 4. An open capacitor will show constant 9MW. 5. Resistance between each terminal and chassis should read infinite. 5-5 High Voltage Diode 1.
Alignment and Adjustments 5-8 Output Power of Magnetron CAUTION MICROWAVE RADIATION PERSONNEL SHOULD NOT ALLOW EXPOSURE TO MICROWAVE RADIATION FROM MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY. The output power of the magnetron can be measured by performing a water temperature rise test. Equipment needed : * Two 1-liter cylindrical borosilicate glass vessel (Outside diameter 190 mm) * One glass thermometer with mercury column NOTE: Check line voltage under load.
Alignment and Adjustments 5-10 Procedure for Measurement of Microwave Energy Leakage 1) Pour 275¡ 15cc of 20¡ 5¡ ( 68¡ 9¢ ) water in a beaker which is graduated to 600cc, and place the beaker in the center of the oven. 2) Start to operate the oven and measure the leakage by using a microwave energy survey meter. 3) Set survey meter with dual ranges to 2,450MHz. 4) When measuring the leakage, always use the 2 inch spacer cone with the probe. Hold the probe perpendicular to the cabinet door.
6. Troubleshooting PRECAUTION 1. CHECK GROUNDING BEFORE CHECKING FOR TROUBLE. 2. BE CAREFUL OF THE HIGH VOLTAGE CIRCUIT. 3. DISCHARGE THE HIGH VOLTAGE CAPACITOR. 4. WHEN CHECKING THE CONTINUITY OF THE SWITCHES OR TRANSFORMER, DISCONNECT ONE LEAD WIRE FROM THESE PARTS AND THEN CHECK CONTINUITY WITHOUT THE POWER SOURCE ON. TO DO OTHERWISE MAY RESULT IN A FALSE READING OR DAMAGE TO YOUR METER. 5. DO NOT TOUCH ANY PART OF THE CIRCUIT OR THE CONTROL CIRCUIT BOARD, SINCE STATIC DISCHARGE MAY DAMAGE IT.
Troubleshooting 6-1 Electrical Maltunction(continved) SYMPTOM CAUSE CORRECTIONS Oven lamp and fan motor turn on 1. Misadjustment or loose wiring of primary latch switch 2. Defective primary latch switch Adjust door and latch switches. Oven can program but timer does not start. 1. Open or loose wiring of secondary interlock switch 2. Off-alignment of primary interlock 3. Defective secondary interlock S/W Adjust door and interlock switches. Microwave output is low;.
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Exploded Views and Parts List 7-2 Main Parts List Ref. No. Parts No. M 1 DE70-30116B PANEL-OUTER;SECC T0.6 W351.7 L1014.7 WHT-C 1 WHITE M 1 DE70-30116G PANEL-OUTER;SECC T0.6 W351.7 L1014.7 RED 1 RED M 1 DE70-30116H PANEL-OUTER;SECC T0.6 W351.7 L1014.7 BRN 1 BROWN M 1 DE70-30116F PANEL-OUTER;SECC T0.6 GREEN-SPRAY W351.
Exploded Views and Parts List 7-3 Door Parts List Ref. No. Parts No. Description / Specification Q'ty Remarks D 1 DE64-20116A HANDLE-DOOR;ABS BLK 10G RE-431 1 WHITE D 2 DE01-00099A FILM-DOOR;PET T0.13 W23 L177.
Exploded Views and Parts List 7-5 Control Parts List Ref. No. Parts No.
Exploded Views and Parts List 7-6 Standard Parts List Parts No.
8. P.C.B Diagrams 8-1 P.C.
P.C.B Diagrams 8-2 P.C.B Parts List Parts No. Description / Specification Q'ty 1003-001033 3501-001050 3501-001062 3710-000246 DE07-20126A DE09-30651A DE13-20016A DE26-20146A IC-SOURCE DRIVER;TD62781AP,DIP,18P,300MIL,OCTAL RELAY-MINIATURE;24VDC,200mW,5A,1FormA,10mS,5mS RELAY-POWER;24VDC,523.2mW,16A,1FormA,15mS CONNECTOR-SOCKET;9P,1R,2.5mm,STRAIGHT,SN LED DISPLAY;LTC-4638G,GRN,12,30,48.2X22.38 IC-MCU;KS57C0004-G7E,4,DIP,4,-,M759 IC-VOLT REGU;KA7805A,TO-220AB,1A,0/125C TRANS-L.
9. Schematic Diagrams 9-1 Schematic Diagrams ASSY NOISE FILTER LAMP (230V40W) L.V.TRANS 2200pF 500K BLK H.V.T L FM YEL YEL 0V H.V.D ORG 230V 21V DM H.V.FUSE MONITOR SWITCH 0V ORG H.V.C BLU E YEL MONITOR FUSE 2200pF BRN BLU MAIN RELAY C2 VOLTAGE FREG BLU 1mH PRIMARY SWITCH CAVITY TCO BRN BLK C1 MAIN FUSE E BRN BRN LIN-CAPACITORT 0.
