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website: http://www.lgservice.com e-mail: http://www.lgeservice.com/techsup.html MICROWAVE OVEN SERVICE MANUAL MODEL: MA-6400W2 MA-6400B2 CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
SAFETY PRECAUTIONS This device is to be serviced only by properly qualified service personnel. Consult the service manual for proper service procedures to assure continued safety operation and for precautions to be taken to avoid possible exposure to excessive microwave energy. PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY...
SPECIFICATIONS ITEM DESCRIPTION MA-6400W2/MA-6400B2 MODEL 120 Volts AC 60 Hz Power Requirement 910 Watts (8.5A) Single phase, 3 wire grounded 600 Watts full microwave power (IEC60705) Power Output 2,450 MHz Microwave Frequency 2M213-09B Magnetron 0 ~ 30 min. Timer 19” (W) x 11” (H) x 12 ”...
CAUTIONS Unlike other appliances, the microwave oven is MICROWAVE RADIATION high-voltage and high-current equipment. Personnel should not be exposed to the Though it is free from danger in ordinary use, microwave energy which may radiate from the extreme care should be taken during repair. magnetron or other microwave generating device if it is improperly used or connection.
INSTALLATIONS BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY. INSTALLING GROUNDING INSTRUCTIONS 1. Empty the microwave oven and clean inside it with For personal safety, this appliance must be fully a soft, damp cloth. Check for damage such as grounded at all times.
OPERATING INSTRUCTIONS FEATURES Oven Front Plate Window Door Screen DEFROST Door Seal COOK Power Knob Timer Knob Door Open Button Safety Door Lock System Turntable Rotating Ring OPERATION CHECK After unpacking this appliance, examine the new 2. Place the glass tray inside the oven cavity. oven for evidence of shipping damage.
CIRCUIT DESCRIPTION • A high voltage of approximately 2100 volts AC is generated in the secondary of the high voltage GENERAL DETAILS transformer which is increased by the action of the high voltage diode and charging of the high voltage •...
SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS NECESSARY TOOLS NECESSARY MEASURING INSTRUMENTS Tools normally used for TV servicing are sufficient. • TESTER (VOLTS-DC, AC, Ohmmeter) Standard tools are listed below. • Microwave survey meter • Diagonal pliers - Holaday HI-1500 • Long nose pliers HI-1501 •...
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MEASUREMENT WITH OUTER CASE NOTES WHEN MEASURING REMOVED • Do not exceed meter full scale deflection. • The test probe must be removed no faster than • When you replace the magnetron, measure for 1 inch/sec (2.5 cm/sec) along the shaded area, microwave energy leakage before the outer case is otherwise a false reading may result.
MEASUREMENT OF MICROWAVE POWER OUTPUT • Microwave power output measurement is made with • The microwave power output P in watts is calculated the microwave oven supplied at its rated voltage and from the following formula : operated at its maximum microwave power setting with 4187 x (∆T) a load of (1000±5) g of potable water.
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D. TIMER MOTOR REMOVAL E. DOOR GROSS ASSEMBLY REMOVAL 1) Remove the control panel assembly from the 1) Open the door. cavity. (Refer to control panel assembly removal 2) Remove the choke cover very carefully with a on previous page.) flat-blade screwdriver.
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F MAGNETRON REMOVAL G. REMOVING THE TURNTABLE MOTOR 1) Remove the turntable and rotating ring. 1) Disconnect the leadwire from the magnetron. 2) Lay the unit down on its back. 2) Carefully remove the mounting screws holding the 3) Remove the turntable motor cover. magnetron and the waveguide.
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H. HIGH VOLTAGE TRANSFORMER K. INTERLOCK SYSTEM REMOVAL 1) INTERLOCK MECHANISM The door lock mechanism is a device which has 1) Discharge the high voltage capacitor. been specially designed to eliminate completely 2) Disconnect the leadwire from magnetron, and microwave activity when the door is opened during capacitor.
INTERLOCK CONTINUITY TEST WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS. TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR PRIMARY SWITCH TYPE NO. SZM-V 16-FA-62 OR VP-532A-OF FOR MONITOR SWITCH TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR SECONDARY SWITCH B.
COMPONENT TEST PROCEDURE CAUTIONS 1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUTER CASE FROM THE UNIT. PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER.
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COMPONENTS TEST PROCEDURE RESULTS Antenna Gasket Chassis Filament NOTE: When testing the magnetron, be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition. HIGH VOLTAGE Measure the resistance. Normal: Momentarily indicates CAPACITOR (Ohm-meter scale: Rx1000) several ohms, and...
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COMPONENTS TEST PROCEDURE RESULTS Check for continuity of relay 2 with an RELAY 2 POWER ohm-meter. LEVEL (Remove wire leads from relay 2 and operate the unit.) 4 sec 18 sec 6 sec 16 sec 8 sec 14 sec Relay 1 10 sec 12 sec 12 sec...
TROUBLE SHOOTING WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL. CAUTIONS 1. Check grounding before checking for trouble. 2.
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(TROUBLE 1) Oven does not operate at all and no input is accepted. CONDITION CHECK RESULT CAUSE REMEDY Malfunction of the Check continuity Replace fuse, 1. Fuse blows. Continuity. monitor switch. of monitor primary, monitor, switch (with secondary door closed). switches.
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(TROUBLE 2) Oven seems to be operating but little heat is produced in oven load. CONDITION CHECK RESULT CAUSE REMEDY Lower than 90% of Decrease in power Suggest customer Output is low Check the rating voltage. source voltage contact local power source with load.
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(TROUBLE 3) No microwave oscillation even though oven lamp and fan motor run. CONDITION CHECK RESULT CAUSE REMEDY No microwave Defective timer Replace timer Check the timer No continuity. oscillation. motor. motor. switch of timer motor.(cooking state) Continuity. Check high vol- Defective high Replace high Abnormal...