Related Manuals for LG LMAB1240ST
Summary of Contents for LG LMAB1240ST
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Page 1: Microwave Oven
Website: http://us.lgservice.com MICROWAVE OVEN SERVICE MANUAL MODEL: LMAB1240ST CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. December, 2004 P/NO : 3828W5S5057 Printed in Korea... -
Page 2: Safety Precautions
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... -
Page 3: Table Of Contents
CONTENTS (Page) SAFETY PRECAUTIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Inside front cover SPECIFICATIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1-1 CAUTIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-1 INSTALLATION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3-1... -
Page 4: Specifications
SPECIFICATIONS ITEM DESCRIPTION MODEL LMAB1240ST Power Requiremen 120 Volts AC 60 Hz (13.3A) 1500 Watts Single phase, 3 wire grounded Power Output 1200 Watts full microwave power (IEC60705) Microwave Frequency 2450 MHz 2M246-050GF Magnetron 0 ~ 99 min. 99 sec. -
Page 5: Cautions
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. -
Page 6: Installation
INSTALLATION 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. -
Page 7: Operating Instructions
OPERATING INSTRUCTIONS FEATURES Oven Front Plate Window Door Screen Door Seal Display Window Control Panel Safety Door Lock System Turntable Roller Rest CONTROL PANEL 1. DISPLAY: The display includes a clock and indicators that tell you the time of day, cook time settings, and cooking functions selected. -
Page 8: Operating Sequence
OPERATING SEQUENCE 7. AUTO DEFROST COOKING The following is a description of component functions during oven operation. AUTO NUMBER OF STOP/CLEAR START DEFROST WEIGHT 1. SETTING THE CLOCK STOP/CLEAR CLOCK NUMBER CLOCK 8. CHILD LOCK ex.) To set 4:30, touch number key [4],[3], and [0]. This oven has a CHILD LOCK feature TO SET CHILD LOCK NOTE: 1) This is a 12 hour clock. -
Page 9: Schematic Diagram (I)
SCHEMATIC DIAGRAM (I) *Check the Rating Model No. -
Page 10: Schematic Diagram (Ii)
SCHEMATIC DIAGRAM (II) *Check the Rating Model No. (ADD Noise filter) -
Page 11: Circuit Description
CIRCUIT DESCRIPTION GENERAL DETAILS • A high voltage of approximately 2100 volts AC is generated in the secondary of the high voltage • The low voltage transformer supplies the necessary transformer which is increased by the action of the high voltage to the micom controller when power cord is voltage diode and charging of the high voltage plugged in. -
Page 12: Service Information
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 •... -
Page 13: Record Keeping And Notification After Measurement
MEASUREMENT WITH OUTER CASE NOTES WHEN MEASURING REMOVED • Do not exceed meter full scale deflection. • The test probe must be moved 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. -
Page 14: Measurement Of Microwave Power Output
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 a load of (1000 ±... - Page 15 D. PCB ASSEMBLY REMOVAL Remove choke cover 1) Remove the control panel assembly from the cavity. (Refer to control panel assembly removal on previous page.) 2) Remove screws which hold the PCB SUB ASSEMBLY to the control panel. 3) Disconnect the flat cable from the PCB SUB ASSEMBLY and take off the PCB SUB ASSEMBLY.
- Page 16 F. MAGNETRON REMOVAL G. REMOVING THE TURNTABLE MOTOR 1) Disconnect the lead wire from the magnetron. 1) Remove the turntable and rotating ring. 2) Carefully remove the mounting screws holding the 2) Lay the unit down on its back. magnetron and the waveguide. 3) Remove the turntable motor cover.
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Page 17: Diode Removal
H. HIGH VOLTAGE TRANSFORMER K. IINTERLOCK SYSTEM 1) INTERLOCK MECHANISM REMOVAL The door lock mechanism is a device which has 1) Discharge the high voltage capacitor. been specially designed to eliminate completely 2) Disconnect the lead wire from magnetron, high microwave activity when the door is opened during voltage transformer, and capacitor. -
Page 18: Interlock Continuity Test
INTERLOCK CONTINUITY TEST WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS. ALL THESE SWITCHES MUST BE REPLACED AT THE SAME TIME. TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF OR V-5230Q FOR PRIMARY SWITCH TYPE NO. SZM-V 16-FA-62, VP-532A-OF OR V-5220Q FOR MONITOR SWITCH TYPE NO. -
Page 19: Component Test Procedure
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. - Page 20 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...
- Page 21 COMPONENTS TEST PROCEDURE RESULTS POWER RELAY 2 Check for continuity of relay 2 with an LEVEL ohm-meter. (Remove wire leads from relay 2 and 4 sec 18 sec operate the unit.) 6 sec 16 sec 8 sec 14 sec 10 sec 12 sec 12 sec 10 sec...
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Page 22: Trouble Shooting
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. - Page 23 (PROBLEM 1) The following visual conditions indicate a probable defective control circuit. 1. Incomplete segments. • Segment missing. • Partial segment missing. • Digit flickering (NOTE: Slight flickering is normal.) 2. Colon does not turn on or blink. 3. A distinct change in the brightness of one or more numbers in display. 4.
- Page 24 (TROUBLE 2) Oven does not operate at all, Display window does not display any figures, and no input is accepted. CONDITION CHECK RESULT CAUSE REMEDY Malfunction of the Replace fuse, Check continuity 1. Fuse blows. Continuity. monitor switch. primary, monitor, of monitor secondary switch (with...
- Page 25 (PROBLEM 3) Display shows all figures set, but oven does not start cooking while desired program times are set and START pad is touched. CONDITION CHECK RESULT CAUSE REMEDY Defective Replace Check continuity 1.Setting time No continuity. secondary switch. secondary switch. of secondary does not count switch (with...
- Page 26 (TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run (Display operates properly) CONDITION CHECK RESULT CAUSE REMEDY Defective P.C.B No microwave Replace P.C.B Disconnect the No continuity. oscillation. assembly assembly wire leads from relay 2 and check continuity Continuity.
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Page 27: Exploded View
#EV# EXPLODED VIEW INTRODUCTION OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS... -
Page 28: Door Parts
#EV# DOOR PARTS 13581A 15006A 13552A 13536A 13213A 13551A 13352A 14026A 14970A... -
Page 29: Control Panel Parts
#EV# CONTROL PANEL PARTS 24781M 268711 24930D 23551A 23550D WTP018 24510L 24970A 23551B... -
Page 30: Oven Cavity Parts
#EV# OVEN CAVITY PARTS 33112U WSZ185 33052A WTT010 33390G 35889A 36549S WTP013... - Page 31 #EV# LARCH BOARD PARTS WSZ085 466001 43500A 466003 466001...
- Page 32 #EV# INTERIOT PARTS (I) Check the rating label of Model and order SVC parts according to the Model No. Model: LMAB1240ST * Check the * Check the Rating Model No. Rating Model No. WSZ002 56411A 568771 50FZZA * Check the 56930V Rating Model No.
- Page 33 INTERIOT PARTS (II) Check the rating label of Model and order SVC parts according to the Model No. Model: LMAB1240ST / 01 * Check the * Check the Rating Model No. Rating Model No. WSZ002 56411A 568771 50FZZA * Check the Rating Model No.
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Page 34: Base Plate Parts
#EV# BASE PLATE PARTS 56170D 63302A 63303A 948502 WTT021 647781 WTT028 WSZ002...