website: http://www.lgservice.com MICROWAVE OVEN SERVICE MANUAL MODEL : LMV1625B LMV1625W CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
CAUTION SAFETY PRECAUTIONS 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.
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.................................................................................................................................
SPECIFICATIONS Rated Power Consumption .................................... 1,500W maximum (Microwave oven+Cook top lamp+Ventilation fan) Microwave Output .................................................. 1,000W (IEC 60705) Adjustable 100W through 1000W, 10 steps Frequency .............................................................. 2,450 MHz ± 50 MHz Power Supply ......................................................... 120 VAC, 60 Hz Rated Current .......................................................
CAUTIONS MICROWAVE RADIATION Unlike other appliances, the microwave oven is high-voltage and high-current equipment. Though it is free from danger in ordinary use, extreme care should be taken during repair. Personnel should not be exposed to the microwave energy which may radiate from the magnetron or other microwave generating device if it is improperly used or connection.
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 15A or 20A. B. Avoid placing the unit in a location where there is direct heat or splashing water. C. Install the unit on the mounting plate firmly. D. Place the unit as far away as possible from TV, radio, etc. to prevent interference.
OPERATING INSTRUCTIONS CONTROL PANEL 1 2 4 3 5 7 6 9 8 10 11 12 14 13 15 16 19 17 18 20 21 22 24 25 26 23 4-1
CONTROL PANEL INSTRUCTIONS 1. DISPLAY: The Display includes a clock and indicators to tell you time of day, cooking time settings and cooking functions selected. 14. CUSTOM SET: Touch this pad to change the oven’s default settings for sound, clock, display speed and defrost weight. 2. POPCORN: Touch this pad when popping popcorn in your microwave oven. 15. CLOCK: Touch this pad to enter the time of day. 16.
OVERALL CIRCUIT DIAGRAM SCHEMATIC DIAGRAM 5-1
MATRIX CIRCUIT FOR TOUCH KEY BOARD FAN HI/LO/OFF HELP LIGHT CUSTOM HI/LO/OFF SET COOK POPCORN REHEAT POTATO TIME COOK AUTO DEFROST LESS CLOCK Ez On BEVERAGE KITCHEN TIMER CUSTOM COOK LIGHT TIMER N.C PIZZA POWER LEVEL T/TABLE ON/OFF STOP CLEAR START N.C HOLD WARM MORE N.C N.C N.C N.C 5-2 N.C N.
GENERAL INFORMATION FOR SERVICE (1) Primary interlock switch (2) Secondary interlock switch (3) Interlock monitor switch (4) Choke system (5) Magnetron thermostat (6) Oven cavity thermostat (Note: This thermostat located on the oven cavity will open and stop the unit from operation only if a high temperature is reached, such as, a fire created by overcooking food.) B. Any one of 10 power output levels ranging 100W to 1000W can be selected by the touch control and electronic computer system.
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) The door does not close firmly. (b) The hinge is broken. (c) The door seal is damaged. (d) The door is bent or warped, or there is any other visible damage on the unit that may cause microwave energy leakage. NOTE: Always keep the seal clean.
MICROWAVE LEAKAGE TEST CAUTIONS MEASURING MICROWAVE ENERGY LEAKAGE • Be sure to check microwave leakage prior to servicing the oven if the oven is operative prior to servicing. • The service personnel should inform the manufacture importer, or assembler of any certified oven unit found to have a microwave emission level in excess of 5 mW/cm2 and should repair any unit found to have excessive emission levels at no cost to the owner and should ascertain the cause of the excessive leakage.
MEASUREMENT WITH THE OUTER CASE REMOVED NOTE WHEN MEASURING (1) Do not exceed meter full scale deflection. (2) The test probe must be removed no faster than 1 inch/sec (2.5cm/sec) along the shaded area, otherwise a false reading may result. (3) The test probe must be held with the grip portion of the handle. A false reading may result if the operator hand is between the handle and the probe.
DISASSEMBLY INSTRUCTIONS (4) Remove 2 screws securing the circuit board. IMPORTANT NOTES: UNIT MUST BE DISCONNECTED FROM ELECTRICAL OUTLET WHEN MAKING REPAIRS, RE-PLACEMENTS, ADJUSTMENTS AND CONTINUITY CHECKS. WAIT AT LEAST ONE MINUTE, UNTIL THE HIGH VOLTAGE CAPACITOR IN THE HIGH VOLTAGE POWER SUPPLY HAS FULLY DISCHARGED. THE CAPACITOR SHOULD BE DISCHARGED BY USING INSULATED WIRE - I.E. TEST PROBE CONNECTED TO 10K-OHM RESISTOR IN SERIES TO GROUND.
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 and 5 to remove the F.P.C. connector. Follow the steps below as illustrated in Figures 6 and 7 to insert the F.P.C. connector. (1) Insert the F.P.C. connector into the terminal socket securely with the fingers. (2) Hold the plastic fastener with thumb and forefinger of the other hand, and push it slowly into the terminal socket. (Figure 6) NOTE: When reconnecting the F.P.
B. REMOVING THE OUT CASE(Figure 8) (6) Remove the power cord cover from outcase by removing a screw. (7) Remove the power cord to the inner of the out case with turning power cord and remove the out case with pushing it back. (1) Remove the vent grille by removing two screws securing it to the out case. (2) Remove two screws securing it to the front bracket. (3) Remove two screws securing it to the air duct. (4) Remove the mounting plate by turning the two screws securing it to the out case.
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 PROCEDURE” on page 7-12. Latch Board Secondary Interlock Switch Latch Board Secondary Interlock Switch WH(from H.V.
D. REMOVING MAGNETRON NOTE: (Figures 11 Through 13) • When removing the magnetron, make sure that its dome does not hit any adjacent parts, or it may be damaged. (1) Remove vertgrille. (2) Remove mount all. (3) Remove outcase. (4) Discinnect the wireleads. (5) Remove the 3 screws and Magnetron very carefully. • When replacing the magnetron, be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition.
F. REMOVING DOOR (Figure 14) (1) Remove the vent grille by two screws securing it to the outcase loosening. (2) Lift up and draw the door. NOTES: • After replacing the door, be sure to check that the primary interlock switch, the secondary interlock switch and the interlock monitor switch is in good operating normally. • After replacing the door, check for microwave energy leakage with a survey meter. Microwave energy leakage must be below the limit of 5mW/cm2 (With a 275 ml water load) Figure 14 G.
H. ASSEMBLING DOOR (3) Carefully pull the ventilation motor ASS'Y out of the microwave oven. (See Figure 18) (1) When mounting the door assembly to the oven assembly, be sure to adjust the door assembly parallel to the chassis. Also adjust so the door has no play between the inner door surface and oven frame assembly. If the door assembly is not mounted properly, microwaves may leak from the clearance between the door and the oven. Space Figure 18 I.
K. REMOVING THE TURNTABLE MOTOR (1) Remove the turntable. (2) Remove the turntable shaft VERY CAREFULLY with a slotted screwdriver. (Figure 19) (3) Remove the base plate by removing 6 screws securing it to the oven cavity. (Figure 20) (4) Disconnect the leadwire from the turntable motor terminals. (5) Remove the 2 screws securing the turntable motor to the oven cavity ASS'Y. (Figure 21) NOTES: • Remove the leadwire from the turntable motor VERY CAREFULLY.
INTERLOCK SYSTEM INTERLOCK MECHANISM The door lock mechanism is a device which has been specially designed to eliminate completely microwave activity when the door is opened during cooking and thus to prevent the danger resulting from the microwave leakage. CHECK THE DOOR LATCH AND SWITCH CLOSING. ADJUSTMENT PROCEDURES To avoid possible exposure to microwave energy leakage, adjust the door latches and interlock switches, using the following procedure.
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.
INTERLOCK CONTINUITY TEST A. PRIMARY INTERLOCK SWITCH TEST B. SECONDARY INTERLOCK SWITCH TEST When the door is opened slowly, an audible click should be heard at the same time or successively at intervals and the latches should activate the switches with an audible click. If the latches do not activate the switches when the door is closed, the switches should be a adjusted in accordance with the adjustment procedure. Disconnect the wire lead from the primary switch.
TEST AND CHECKOUT PROCEDURES, AND TROUBLE SHOOTING - CAUTIONS -DISCONNECT THE POWER SUPPLY CORD FROM THE WALL OUTLET WHENEVER REMOVINGING THE CABINET FROM THE UNIT. PROCEED WITH THE TESTS ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER. (SEE FIGURE 24) Filament Winding Secondary Winding - ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER OF WATER IN CONTAINER) IN THE OVEN.
COMPONENTS TEST PROCEDURES Measure the resistance: (1) Terminal to terminal RESULTS Normal reading: Momentarily indicates several ohms, and then gradually returns to infinite ohms. Abnormal reading: Indicates continuity or infinite ohms from the beginning. Ohmmeter Figure 25-a HIGH-VOLTAGE CAPACITOR Normal readings: Infinite. (2) Terminal to case Abnormal reading: Indicates continuity. Ohmmeter Figure 25-b Normal readings: Infinite.
COMPONENTS TEST PROCEDURES RESULTS Measure the resistance between terminal pins of connector KEY CONNECTOR. NOTE: When reconnecting the FPC connector, make sure that the holes on the FPC connector are properly engaged with hooks on the plastic fastener. MATRIX CIRCUIT FOR TOUCH KEY BOARD CONNECTOR(KEY CON) (For detail matrix circuit of each model, refer to page 5-2.
COMPONENTS TEST PROCEDURES Check for continuity of relay 2 with an ohm-meter. (Remove wire leads from relay 2 and operate the unit.) Relay 7 RELAY2 Figure 30 wCAUTION : The relay connector 2(White) and 5(Red) must be correctly connected Relay 6. These two connectors are not Interchangeable.
(2) CHECKOUT PROCEDURES FOR RELAY. - PROBLEM (A) TT motor and oven lamp turn on without touching START key when the door is closed. NO GOOD YES Remove the mate connector of I/O CON from the circuit board. Does the unit still operate? NO Replace the circuit board YES Defective RELAY3 Replace RELAY3 - PROBLEM (B) TT motor and oven lamp turn on When the door is closed and START key is touched. NO YES GOOD Measure the voltage at pin NO.
(3) CHECKOUT PROCEDURES FOR CIRCUIT BOARD The following symptoms indicate a defective circuit board. 1) The start function fails to operate but the high voltage Systems, the interlock switches, the door sensing and the relay check good. 2) The unit with a normal relay continuously operates. 3) Proper temperature measurement is not obtained. 4) The buzzer does not sound or continues to sound.
7-21 Measure voltage between pin 1 and pin 3 of connector CN1. WH RD 1 Measure resistance of touch key board after removing connector S1. (See page 7-4 and 7-17) 120 Resistance incorrect Normal resistance Voltage incorrect 0 120 120V 0 Replace touch key board. Check contact of connector S1 Correct connections Replace circuit board Check: 1. POWER SUPPLY 2. FUSE (See “CHECKOUT PROCEDURES FOR FUSE BLOWING: on page 7-18) 3.
7-22 Measure resistance of H.V.Transformer (see page 7-15) 2 Normal resistance Resistance incorrect Contact OK NO continuity Replace H.V.T. Normal H.V.T. Normal circuit board Check the continuity of H.V.C. (see page 7-16) Check contact of connector S1 Replace circuit board Check: 1. PRIMARY AND SECONDARY INTERLOCK SWITCHES 2 .
7-23 1 Check normal operation circuit board PROBLEM - D : No buzzing when touching the key, between stages or at end of cooking Replace circuit board Normal circuit board Runs
7-24 1 Check the contact of oven thermostat Check: 1. POWER SUPPLY 2. FUSE Contact OK NO contact Check contact of connector S1 (see page 7-4) Replace oven thermostat PROBLEM - E : Ventilation fan does not operate when “FAN HIGH/LOW” key is touched.
EXPLODED VIEW DOOR PARTS 13552A 13581A 13536A 13213A 13720D WTT021 14890A 14026A 14970A 13650A 8-1
CONTROLLER PARTS 268711 24781M 24810P WTP018 23572A WTT029 *07 23506A 8-2
OVEN CAVITY PARTS WTT021 34960A WTT028 WTT029 33530A WTT029 34810Q *05 33112U *01 34930R *02 35026G 33052A *04 368771 33550L 63302A 36912C 34890C 34810T WTT022 WTT022 35230A 8-3 63303A
LATCH BOARD PARTS 43500A 466001 WSZ084 43501A 466003 466001 44510A 8-4
INTERIOR PARTS(I) WSZ002 33390G 34370T 56324A WTT021 35889A WTT028 56170D 33740A WTT021 36549S WSZ002 WTP013 533002 56851D WSZ002 54810C 50CZZH 533001 8-5
INTERIOR PARTS (II) 56912B 55231C 36549V 53550L 56804A WTT028 56411A 55262A 50FZZA 56930V 55006F 568771 WSZ002 55892A 54930F 53550F 340511 8-6
INSTALLATION PARTS 44360A WSZ098 WSZ133 WSZ204 WWZ068 WWZ068 63300M WSZ203 65862D WSZ136 65862B 63861A 8-7
8-12 HELP CLOCK LIGHT TIMER STOP CLEAR N.C LESS CUSTOM COOK T/TABLE ON/OFF MORE LIGHT CUSTOM HI/LO/OFF SET FAN HI/LO/OFF POPCORN N.C START N.C Ez On N.C N.C PIZZA BEVERAGE REHEAT POTATO COOK N.C HOLD WARM POWER LEVEL KITCHEN TIMER AUTO DEFROST TIME COOK N.C N.
PRINTED CIRCUIT BOARD 8-13
P/NO.
