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Goldstar MA-2005ST 4-4. Microwave generation system_Magnetron (1/2)

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* The magnetron is the energy source for the microwave oven.

The magnetron is a vacuum tube of special construction.

It is basically a diode with addition of a magnetic field.

It consists of a small, coiled heating element (filament) made of tungsten

which readily emits electrons when heated.

This element serves as the cathode (negative element) within the tube.

The anode (positive element of the tube) consists of a thick walled copper

cylinder with vertical vanes extending inward which surround but do not

touch the cathode.

To complete the magnetron, and make it operate distinctly different from

other vacuum tubes, two permanent magnets are mounted over each end

of the tube.

CATHODE

ANTENNA

ELECTRONS

ANODE

ANTENNA (OUTPUT)

MAGNET (MAGNETIC CIRCUIT)

VANE

FILAMENT TERMINALS

FEED THROUGH CAPACITOR

FILTER

FILTER CASE

MAGNET (FERRITE)

ANODE

FILAMENT (CATHODE)

GASKET

4-4. Microwave generation system_Magnetron (1/2)

Contents

Main SAFETY PRECAUTIONS 2-1. Function & Type (1/2) 1. How a Microwave Oven Works 2. Type of Microwave Oven 2-1. Function & Type (2/2) 2-2. Installation & Utensils (1/2) 1. Installation 2.COOKING UTENSILS 2-2. Installation & Utensils (2/2) 3-1. Whats the microwave? (1/2) 1. History of dielectric heating 2. The principle of dielectric heating - 13 - 3. The safety of microwave oven 3-1. Whats the microwave? (2/2) : Wave Length Where c: The Velocity of Light f: Frequency c f 300000 Km 245000 KHz 0.122 m 12.2 cm The division from the sound frequency to the light frequency. 3-2. Conventional heating vs. dielectric heating It shall be heated by the sources of the electric heater, the gas, and the briquet.! HEAT! 1. Conventional heating 2. Dielectric heating 4-1. Construction of microwave oven Magnetron Cavity Door Controller Page 4-3. WARNING - High voltage circuit ( 4,000 volt ) 4-4. Microwave generation system_Magnetron (1/2) 4-4. Microwave generation system_Magnetron (2/2) TESTING MAGNETRON TUBE Page Whats the infrared sensor? 5-2. Infrared sensor Whats does move automatically? 5-3. Auto moving heater Conventional Heater LGs Auto Moving Heater SPECIFICATIONS 1-1 ITEM MODEL DESCRIPTION OPERATING INSTRUCTIONS 4-2 OPERATING SEQUENCE 1ST STAGE 1. SETTING THE CLOCK 2. CANCEL FUNCTION 3. EZ ON 4. ONE TOUCH COOKING SCHEMATIC DIAGRAM SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT. NOTICE: SINCE THIS IS BASIC SCHEMATIC DIAGRAM, THE VALUES OF COMPONENTS AND IMPORTANT FOR PROTECTION FROM MICROWAVE RADIATION, FIRE, ELECTRICAL SHOCK, AND IMPORTANT SAFETY NOTE: THE SHADED AREAS ON THIS SCHEMATIC DIAGRAM INCORPORATE SPECIAL FEATURES CIRCUIT DESCRIPTION GENERAL DETAILS N L N SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS MICROWAVE LEAKAGE TEST NECESSARY TOOLS NECESSARY MEASURING INSTRUMENTS SPECIAL TIP The microwave power output P in watts is calculated from the following formula : 4187 x (T) T A. OUTER CASE REMOVAL B. POWER SUPPLY CORD 5-3 MEASUREMENT OF MICROWAVE POWER OUTPUT P = DISASSEMBLY AND ADJUSTMENT D. PCB ASSEMBLY REMOVAL E. DOOR MAIN ASSEMBLY REMOVAL 5-4 5-5 F. AIR DUCT ASSEMBLY REMOVAL G. MAGNETRON REMOVAL H. REMOVING THE TURNTABLE MOTOR I. HIGH VOLTAGE TRANSFORMER REMOVAL J. FAN MOTOR ASSEMBLY REMOVAL K. HIGH VOLTAGE CAPACITOR AND DIODE REMOVAL L. INTERLOCK SYSTEM 5-6 INTERLOCK CONTINUITY TEST A. PRIMARY INTERLOCK SWITCH TEST B. SECONDARY INTERLOCK SWITCH TEST C. MONITOR SWITCH TEST 5-7 COMPONENT TEST PROCEDURE 5-8 5-9 5-10 Relay 2 A B TROUBLE SHOOTING CAUSE REMEDY 5-11 CONDITION (TROUBLE 1) 5-12 The following visual conditions indicate a probable defective control circuit. (TROUBLE 2) 5-13 NOTE : All these switches must be replaced at the same time. Refer to page 5-7, 5-8 (TROUBLE 3) 5-14 NOTE : (TROUBLE 4) Oven seems to be operating but little heat is produced in oven load. (TROUBLE 5) 5-15 Page DOOR PARTS 6-2 CONTROLLER PARTS OVEN CAVITY PARTS Page INTERIOR PARTS 6-6 BASE PLATE PARTS 6-7 8-1 SCHEMATIC DIAGRAM OF P.C.B. 7-2 LOC. PART NO. DESCRIPTION SVC NO. 9-1 P.C.B. PARTS LIST 8-2 PRINTED CIRCUIT BOARD LOC. PART NO. DESCRIPTION SPECIFICATION SVC NO.