LG LMVH1750SB Service Manual
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Also See for LMVH1750SB:
- Owner's manual & cooking manual (49 pages) ,
- Specifications (2 pages) ,
- Owner's manual (48 pages)
Table of Contents
Troubleshooting
Related Manuals for LG LMVH1750SB
Summary of Contents for LG LMVH1750SB
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Page 1: Microwave Oven
Website http://us.lgservice.com MICROWAVE OVEN SERVICE MANUAL MODEL: LMVH1750SB LMVH1750ST LMVH1750SW CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. August, 2005 P/NO : 3828W5S6189 Printed in Korea... -
Page 2: Warning To Service Technicians
CAUTION WARNING TO SERVICE TECHNICIANS PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY a. Do not operate or allow the oven to be operated with the door open. b. Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary;... -
Page 3: Table Of Contents
FOREWORD Read this Manual carefully. Failure to adhere to or observe the information in this Manual may result in exposing yourself to the Microwave Energy normally contained within the oven cavity. TABLE OF CONTENTS (Page) SAFETY PRECAUTIONS ........................Inside front page SPECIFICATIONS .............................. -
Page 4: Specifications
SPECIFICATIONS Rated Power Consumption ........Microwave 1600W Convection 1700W Microwave Output ..........Microwave 950W (IEC60705) Adjustable 95W through 950W, 10 steps Convection 1500W Frequency ............2450 MHz ±50 MHz Power Supply .............120 VAC, 60 Hz Rated Current ............Microwave 13.5A Convection 14.0A Magnetron Cooling ..........Forced Air Cooling Rectification ............Rectification Voltage Double Half-Wave Door Sealing ............Choke System Safety Devices ...........Magnetron Thermostat: Open at 150 °C ±... -
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: Installations
INSTALLATIONS BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY. PRECAUTIONS ON INSTALLATION A. Plug the power supply cord into a 120V AC, 60Hz, single-phase power source with a capacity of at least 20 amperes. B. Avoid placing the unit in a location where there is direct heat or splashing water. -
Page 7: Operating Instructions
OPERATING INSTRUCTIONS CONTROL PANEL... -
Page 8: Control Panel Instructions
CONTROL PANEL INSTRUCTIONS 1. DISPLAY: The Display includes a clock and indicators 14. COMBI.: Touch this pad when setting combination to tell you time of day, cooking time settings, and cooking or preheat. cooking functions selected. 15. NUMBER: Touch number pads to enter cooking time, 2. -
Page 9: Overall Circuit Diagram
OVERALL CIRCUIT DIAGRAM SCHEMATIC DIAGRAM... -
Page 10: Matrix Circuit For Touch Key Board
MATRIX CIRCUIT FOR TOUCH KEY BOARD KEY MATRIX CUSTOM MICRO. CONV. COMBI. COOK (VENT) (VENT) LIGHT AUTO SOFTEN MELT TIME SET 5-SPEED ON/OFF ON/OFF SPEED AUTO AUTO POPCORN COOK REHEAT EZ-ON DEFROST COMBI. AUTO CUSTOM TURNTABLE TIMER CLOCK MORE LESS COOK ON/OFF POWER... -
Page 11: General Information For Service
GENERAL INFORMATION FOR SERVICE GENERAL PRECAUTIONS IN USE FEATURES AND SPECIFICATIONS FEATURES A. Never operate the unit when it is empty. A. The safety systems incorporated in this model are: Operating the oven with no load may shorten the (1) Primary interlock switch life of the magnetron. -
Page 12: Service Information
SERVICE INFORMATION PRECAUTIONS AND REPAIR SERVICE TIPS PRELIMINARY (3) Do not operate the unit until it is completely repaired, if any of the following conditions exist. The unit must not be operated. A. SINCE NEARLY 4000 VOLTS EXISTS IN SOME (a) The door does not close firmly. -
Page 13: Microwave Leakage Test
MICROWAVE LEAKAGE TEST CAUTIONS EQUIPMENT- • Be sure to check microwave leakage prior to • TESTER ((VOLTS-DC, AC, Ohmmeter) servicing the oven if the oven is operative prior to • Microwave survey meter servicing. - Holaday HI-1500 • The service personnel should inform the HI-1501 manufacture importer, or assembler of any certified - Narda... -
Page 14: Power Output Measurement
MEASUREMENT WITH THE OUTSIDE CASE NOTE WHEN MEASURING REMOVED (1) Do not exceed meter full scale deflection. (2) The test probe must be removed no faster than (1) When you replace the magnetron, measure for 1 inch/sec (2.5cm/sec)along the shaded area, microwave energy leakage before the outer case otherwise a false reading may result. -
Page 15: Disassembly Instructions
DISASSEMBLY INSTRUCTIONS IMPORTANT NOTES: (4) Remove 4 screws securing the circuit board. UNIT MUST BE DISCONNECTED FROM ELEC- TRICAL OUTLET WHEN MAKING REPAIRS, RE- PLACEMENTS, ADJUSTMENTS AND CONTIN- UITY CHECKS. WAIT AT LEAST ONE MINUTE, UNTIL THE HIGH VOLTAGE CAPACITOR IN THE Circuit Board HIGH VOLTAGE POWER SUPPLY HAS FULLY DISCHARGED. - Page 16 HOW TO REMOVE THE F.P.C. CONNECTOR HOW TO INSERT THE F.P.C. CONNECTOR Follow the steps below as illustrated in Figures 4 Follow the steps below as illustrated in Figures 6 and 5 to remove the F.P.C. connector. and 7 to insert the F.P.C. connector. (1) Insert the F.P.C.
- Page 17 B. REMOVING THE OUTSIDE CASE (Figure 8) (1) Remove the vent grille by removing two screws securing it to the outside case. (2) Remove two screws securing it to the air duct. (3) Remove the mounting plate by turning the screws (1 or 2 screws)securing it to the out case.
- Page 18 C. REMOVING THE DOOR INTERLOCK SWITCHES (Figures 9, 10) (1) Disconnect the wire leads from the interlock switches. (2) Remove two screws securing the Latch Board. (3) Make necessary replacements and check microwave energy leakage according to “ADJUSTMENT PROCEDURES” on page 7-12. Latch Board Primary Latch Board...
- Page 19 D. REMOVING MAGNETRON NOTES: • When removing the magnetron, make sure that its (Figures 11 Through 13b) dome does not hit any adjacent parts, or it may be (1) Remove the vent grille by loosening two screws. damaged. (Figure 11) (2) Remove the outside case.
- Page 20 E. REMOVING STIRRER FAN F. REMOVING DOOR (Figure 16) (Figures 14 and 15) (1) Remove the vent grille by removing two screws (1) Remove two screws securing it to the oven securing it to the outside case loosening. upper plate by using drive screw. (2) Lift up and remove the door.
- Page 21 H. ASSEMBLING DOOR J. REPLACING THE HUMIDITY SENSOR (1) When mounting the door assembly to the oven (For sensor model only) assembly, be sure to adjust the door assembly (1) Remove the sensor by removing two screws parallel to the chassis. Also adjust so the door has no securing it to the air duct.
- Page 22 K. REMOVING THE TURNTABLE MOTOR L. REMOVING CONVECTION HEATER (1) Remove the turntable. AND THERMISTOR (Figure 23) (2) Remove the turntable shaft VERY CAREFULLY (1) Remove the out case. with a slotted screwdriver. (Figure 21) (2) Remove the air duct by removing six screws (3) Remove the base plate by removing 7 screws securing it to the oven front plate, guide air and securing it to the oven cavity.
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Page 23: Interlock System
INTERLOCK SYSTEM INTERLOCK MECHANISM The door lock mechanism is a device which has been specially designed to eliminate microwave activity when the door is opened during cooking and thus to prevent the danger resulting from the microwave leakage. ADJUSTMENT PROCEDURES CHECK THE DOOR LATCH AND SWITCH To avoid possible exposure to microwave energy CLOSING. - Page 24 TEST THE LATCH AND SWITCH SEQUENCE (7) When you achieve the proper sequence of switches in Steps 5 and 6, tighten the latch board screws at that point. (5) Open the oven door slowly. Watch the door latch, the Secondary Switch. Release Rod and Lever TEST THE MICROWAVE ENERGY LEAKAGE on the switches to make sure they are zero to the body of the switches in the following sequence:...
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Page 25: Interlock Continuity Test
INTERLOCK CONTINUITY TEST A. PRIMARY INTERLOCK SWITCH TEST B. SECONDARY INTERLOCK SWITCH TEST When the door is opened slowly, an audible click Disconnect the wire lead from the secondary should be heard at the same time or successively switch. at intervals and the latches should activate the Connect the ohmmeter leads to the common switches with an audible click (COM)and normally open (NO)terminals of the... -
Page 26: Test And Checkout Procedures And Troubleshooting
TEST AND CHECKOUT PRECEDURES AND TROUBLESHOOTING 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 LEAD WIRES FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER. 2. - Page 27 COMPONENTS TEST RESULTS CAPACITOR 1. Remove wire leads. 2. Measure resistance. (ohm meter scale: Rx1000) Normal: • Terminal to terminal Momently indicates several ohm, and then gradually returns to infinite • Terminal to case Normal: Infinite. DIODE Some inexpensive meters 1.
- Page 28 COMPONENTS TEST RESULTS VENTILATION MOTOR 1. Remove wire leads. Normal: 2. Measure resistance. Approximately (ohm meter scale: Rx1) 25 to 45 ohm DAMPER MOTOR (D.M) 1. Remove wire leads. Normal:Approximately TURNTABLE MOTOR (T.M) 2. Measure resistance. STIRRER MOTOR (S.M) (ohm meter scale: Rx1000) 2.3-3.5 2.6-3.5 100-170 Kohm...
- Page 29 COMPONENTS TEST RESULTS TOUCH KEY BOARD Measure the resistance between terminal When When not pins of KEY CONNECTOR. touched touched NOTE: Resistance When reconnecting the FPC connector, value More than Less than make sure that the holes on the FPC 1 mega ohm 400 ohms connector are properly engaged with hooks...
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Page 30: Checkout Procedures
B. CHECKOUT PROCEDURES (1) CHECKOUT PROCEDURES FOR FUSE BLOWING CAUTION: REPLACE BLOWN FUSE WITH 20 AMPERE FUSE. PROBLEMS CAUSES Fuse blows immediately after the door is closed. Improper operation of the primary interlock, secondary Fuse blows immediately after interlock switches and/or the interlock monitor switch. the door is opened. - Page 31 (2)CHECKOUT PROCEDURES FOR RELAY. -PROBLEM (A)- -PROBLEM (A)-- FAN motor turns on without touching START/ENTER Oven lamp turns on without touching START/ENTER key when the door is closed. key when the door is closed. Remove the mate connector of I/O Remove the mate connector of I/O GOOD GOOD...
- Page 32 (3) CHECKOUT PROCEDURES FOR CIRCUIT BOARD The following symptoms indicate a defective circuit 6) Wrong figures appear. board. 7) The figures of all digits. 1) The start function fails to operate but the high 8) Some of the indicators do no flicker light up. voltage Systems, the interlock switches, the door 9) The clock does not keep time properly.
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Page 33: Troubleshooting
C. 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 TOASTER AND MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL. CAUTIONS 1. - Page 34 (TROUBLE 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 35 (TROUBLE 2) Microwave 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 switches, and switch (with...
- Page 36 (TROUBLE 3) Display shows all figures set, but oven does not start cooking while desired program times are set and START/ENTER pad is touched. CONDITION CHECK RESULT CAUSE REMEDY Defective Replace Check continuity 1.Setting time does No continuity. secondary switch. secondary switch.
- Page 37 (TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run (Display operates properly) CONDITION CHECK RESULT CAUSE REMEDY No microwave Disconnect the Defective P.C.B Replace P.C.B No continuity. assembly oscillation. wire leads from assembly relay 8 and check continuity Continuity.
- Page 38 (TROUBLE 6) Convection oven does not operate at all or convection cook is bad. CONDITION CHECK RESULT CAUSE REMEDY Defective Relay Replace Relay Check the Relay Convection indicator Abnormal. 10 of P.C.B. light but oven does assembly. not go into cook cycle when START/ENTER Normal.
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Page 39: Exploded View
#EV# EXPLODED VIEW DOOR PARTS FOR MODEL: LMVH1750SB LMVH1750SW 13581A 13552A 13213A 14760A 14890A 13551B WTP004 14026A 14970A 14760A WTT028 13650A FOR MODEL: LMVH1750ST 13581A 13552A 13213A 14760A 14890A 13551A WTP004 14026A 14970A 14760A WMP027 WWS005 13650A 148901 148902 WTT028... -
Page 40: Controller Parts
#EV# CONTROLLER PARTS FOR MODEL: LMVH1750SB LMVH1750SW 24781M WTP015 23572A 23506A 268711 24810P FOR MODEL: LMVH1750ST 24781M 23551A WTP015 268711 24810P... -
Page 41: Oven Cavity Parts
#EV# OVEN CAVITY PARTS For Model LMVH1750SB WTT027 LMVH1750ST For Model 34960A WTT029 LMVH1750SW 33550P 33112U For Model WTP013 LMVH1750SB 33530A LMVH1750SW 34810Q For Model 33531A 36549S LMVH1750ST 33809A 63303A WMP004 34931A WNH001 63302A 36912H 33740A 330342 948501 WTT022 34890C... -
Page 42: Latch Board Parts
#EV# LATCH BOARD PARTS 43501A 43500A 466001 WSZ084 466003 466001 44510A... - Page 43 #EV# INTERIOR PARTS (I) WTT028 WSZ002 WTT037 55238A 35026C WTT028 54974S 56549F 33390M 55900A 54810C 50CZZH 33390G 34370T 56851D WSZ002 56930M 34930W 56324A WTT028 35889A 55893A 54810A 53300B 56170D WTT028 33052M WTT011 56549B 348101 WWS005 WTT022 349801 WNH003 WTP013 WWP008 348102 35300S WTT022...
- Page 44 #EV# INTERIOR PARTS (II) WTP005 WTP007 WTP007 WTT030 50FZZA 56501A 352641 53550L 54931A WTP018 WTT028 36912H 330341 56201A WTT028 352642 WTT028 50CZZM 55262A WTT028 56930V WTP005 WTT028 55231C 56411A 36549V 55012U 568771 WSZ002...
- Page 45 #EV# INSTALLATION PARTS 65862D 63300M 65862B 63861A VINYL COOKING *06-1 *06-2 UPPER WALL OWNERS SERVICE INSTALLATION GUIDE TEMPLATE TEMPLATE MANUAL MANUAL MANUAL LABEL...