LG LFC20760 Series Service Manual
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LG LFC20760 Series Service Manual

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REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MODELS:
LFC20760**

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  • Page 1 https://appliancetechmanuals.com REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. MODELS: LFC20760**...

  • Page 2: Table Of Contents

    https://appliancetechmanuals.com CONTENTS SAFETY PRECAUTIONS ..................... 1. SPECIFICATIONS ......................2. PARTS IDENTIFICATION ....................3. DISASSEMBLY ......................... 3.1 Door ..........................3.2 Door alignment ......................3.3 Fan and fan motor ....................... 3.4 Defrost control assembly ..................... 3.5 Lamp ..........................3.6 Control box-refrigerator ....................3.7 Multi duct ........................
  • Page 3 https://appliancetechmanuals.com 1. SPECIFICATIONS LFC20760ST MODELS LFC20760SW LFC20760SB SPECIFICATIONS CAPACITY CUFT;(F/R/T) 6.39/13.21/19.6 DIMENSIONS in;(W*H*D) 29.88*68.43*32.17 WEIGHT lb; 270.28 HANDLE TYPE Vista-Handle REVERSIBLE DOOR DOOR FINISH STAINLESS/ VCM/ PCM REFRIGERANT/gr R134a 120±3 ICE TRAY Ice bank (1ea) SHELF BASKET DOOR LAMP YES (1) 40W/blue TRAY MEAT SHELF 4Fix...

  • Page 4: Specifications

    https://appliancetechmanuals.com DIMENSIONS Description LFC20760** Depth w/ Handles 34 ½ Depth w/o Handles Depth w/o Door 28 ¼ Depth (Total with Door Open) Height to Top of Case Height to Top of Door Hinge Width 29 ¾ Width (door open 90 deg. w/o handle) 32 ½...

  • Page 5: Parts Identification

    https://appliancetechmanuals.com 2. PARTS IDENTIFICATION Use this section to become more familiar with the parts and features. NOTE: This guide covers several different models. The refrigerator you have purchased may have some or all of the items listed below. The locations of the features shown below may not match your model. Filter (Inside)* Digital Sensor Control Dairy Bin...

  • Page 6: Disassembly

    https://appliancetechmanuals.com 3. DISASSEMBLY 2. Remove gasket bracket clips 3-1 DOOR There are two clips on each door. Start bracket removal near one of the middle clips. Left Door 1) Pull gasket back to expose gasket bracket clip and Loosen the cover screw (1). door frame.

  • Page 7: Door Alignment

    https://appliancetechmanuals.com 2. Insert gasket into channel 3-2 DOOR ALIGNMENT 1) Snap gasket assembly into the door bracket. If the space between your doors is uneven, follow the <Inserting the Gasket Assembly into the Bracket Door> instructions below to align the doors: 1.

  • Page 8: Fan And Fan Motor

    https://appliancetechmanuals.com 3-3 FAN AND FAN MOTOR 3-5-1 To change the refrigerator light (figure 14) 1. Remove the freezer shelf. (If your refrigerator has an 1. Unplug the power cord from the outlet. icemaker, remove the icemaker first) 2. Remove refrigerator shelves. 2.

  • Page 9: Adjustment

    https://appliancetechmanuals.com 4. ADJUSTMENT 4-1 COMPRESSOR 4-2-3 PTC-Applied Circuit Diagram • • Starting Method for the Motor 4-1-1 Role The compressor intakes low temperature and low pressure gas from the evaporator of the refrigerator and compresses OVERLOAD PROTECTOR this gas to high-temperature and high-pressure gas. It then delivers the gas to the condenser.

  • Page 10: Olp (Overload Protector)

    https://appliancetechmanuals.com 4-3 OLP (OVERLOAD PROTECTOR) 4-4 TO REMOVE THE COVER PTC 4-3-1 Definition of OLP (1) OLP (OVERLOAD PROTECTOR) is attached to the Compressor and protects the Motor by opening the circuit to the Motor if the temperature rises and activating the bimetal spring in the OLP.

  • Page 11: Circuit Diagram

    https://appliancetechmanuals.com 5. CIRCUIT DIAGRAM PWB(PCB) ASSEMBLY,DISPLAY CON101 STEPPING C-FAN F-FAN MOTOR PK WH BK YL CON5 CON6 CON4 CON8 RT-SENSOR PWB(PCB) ASSEMBLY, MAIN R-DOOR PERCEPTION S/W CON7 F-DOOR PERCEPTION S/W DEF-SENSOR R-SENSOR F-SENSOR POWER SUPPLY CON2 CON3 CON1 CORD GN/YL (GN) ICE MAKER PART GN/YL...

  • Page 12: Troubleshooting

    https://appliancetechmanuals.com 6. TROUBLESHOOTING 6-1 COMPRESSOR AND ELECTRIC COMPONENTS (Rated Voltage Remove PTC-Starter Power Source. ±10%)? from Compressor and measure voltage between Terminal C of Compressor and Terminal 5 or 6 of PTC. OLP disconnected? No Voltage. Replace OLP. Check connection condition.

  • Page 13: Ptc And Olp

    https://appliancetechmanuals.com 6-2 PTC AND OLP Normal operation of Separate PTC-Starter Observation value is Compressor is from Compressor and 115V/60Hz : 6.8? ±30% measure resistance impossible or poor. between No. 5 and 6 of PTC-Starter with a Tester. (Figure 19) Replace PTC- The resistance value Starter.

  • Page 14: Other Electrical Components

    https://appliancetechmanuals.com 6-3 OTHER ELECTRICAL COMPONENTS • Not cooling at all Check for open short or Compressor Cause incorrect resistance readings doesn't run. in the following components a. Starting devices Short, open, or broken. Poor contact b. OLP or shorted. Coil open or shorted. c.

  • Page 15: Service Diagnosis Chart

    https://appliancetechmanuals.com 6-4 SERVICE DIAGNOSIS CHART COMPLAINT POINTS TO BE CHECKED REMEDY No Cooling. • Is the power cord unplugged from the outlet? • Plug into the outlet. • Check if the power switch is set to OFF. • Set the switch to ON. •...

  • Page 16: Refrigeration Cycle

    https://appliancetechmanuals.com 6-5 REFRIGERATION CYCLE Troubleshooting Chart TEMPERATURE STATE OF STATE OF THE CAUSE REMARKS OF THE THE UNIT EVAPORATOR COMPRESSOR PARTIAL Freezer Low flowing sound of A little higher • Refrigerant level is low due LEAKAGE compartment and Refrigerant is heard and than ambient ¥to a leak.
  • Page 17 https://appliancetechmanuals.com 6-5-1 SEALED SYSTEM DIAGNOSIS “ Not Cooling” Complaint All components operating, No airflow problems, Not frosted up as a defrost problem problem has been isolated to sealed system area Frost None Partial Pattern? Equalization Equalization Test Test Very Fast Very Slow Very Slow Fast...

  • Page 18: Operation Principle And Repair Method Of Icemaker

    https://appliancetechmanuals.com 7. OPERATION PRINCIPLE AND REPAIR METHOD OF ICEMAKER 7-1 OPERATION PRINCIPLE 7-1-1 Operation Principle of Icemaker Power On Start Position •Adjusts Ejector to Start Position with power on. Icemaking • Waits until water becomes cold after starting the Mode Icemaking operation.

  • Page 19: Ice Maker Functions

    https://appliancetechmanuals.com 7-2 ICE MAKER FUNCTIONS 7-2-1 Ice Making Mode 1. Icemaking refers to the freezing of supplied water in the ice trays. Complete freezing is assured by measuring the temperature of the Tray with icemaking SENSOR. 2. Icemaking starts after completion of the water fill operation. 3.

  • Page 20: Defect Diagnosis Function

    https://appliancetechmanuals.com 7-2-5 Function TEST 1. This is a compulsory operation for test, service, cleaning, etc. It is operated by pressing and holding the Cube Size button for 3 seconds. 2. The test works only in the Icemaking Mode. It cannot be entered from the Harvest or Fill mode. (If there is an ERROR, it can only be checked in the TEST mode.) 3.

  • Page 21: Description Of Function & Circuit Of Micom

    https://appliancetechmanuals.com 8. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM 8-1 FUNCTION 8-1-1 Function 1. When the appliance is plugged in, it is set to "4" for Refrigerator and "4" for freezer. You can adjust the Refrigerator and the Freezer control temperature by pressing the ADJUST button. 2.
  • Page 22 https://appliancetechmanuals.com 8-1-5 Alarm for Open Door 1. This feature sounds a buzzer when the freezer or refrigerator door is not closed within 1 minute after it is opened. 2. One minute after the door is opened, the buzzer sounds three times each for 1/2 seconds. These tones repeat every 30 seconds.
  • Page 23 https://appliancetechmanuals.com 8-1-9 Defect Diagnosis Function 1. Automatic diagnosis makes servicing the refrigerator easy. 2. When a defect occurs, the buttons will not operate; but the tones. such as ding. will sound. 3.When defect is repaired the defect code is removed and refrigerator returns to normal operation (RESET) 4.
  • Page 24 https://appliancetechmanuals.com 8-1-10 TEST Mode 1. The Test mode allows checking the PCB and the function of the product as well as finding out the defective part in case of an error. 2. The test mode is operated by pressing two buttons at Display panel. 3.

  • Page 25: Pcb Function

    https://appliancetechmanuals.com 8-2 PCB FUNCTION 8-2-1 Power Circuit The secondary part of the TRANSFORMER is composed of the power supply for the display, the BLDC FAN Motor drive (15.5 V), the relay drive (12 Vdc) and the MICOM and IC (5 Vdc). The voltage for each part is as follows: PART VA 1...
  • Page 26 https://appliancetechmanuals.com 8-2-2 Oscillation Circuit This circuit generates the base clock for calculating time and the synchro clock for transmitting data from and to the inside logic elements of the IC1 (MICOM). Be sure to use specified replacement parts, since calculating time by the IC1 may be changed.
  • Page 27 https://appliancetechmanuals.com 8-2-4 Load / Buzzer Drive & Open Door Detection Circuit 1. Load Drive Condition Check FRENCH DOOR DEFROSTING LOAD TYPE COMP LAMP HEATER 1, 2 / HEATER DEW HEATER Measurement Location (IC6) NO.14 NO.12 NO.11 NO.13 1V or below Condition -26-...
  • Page 28 https://appliancetechmanuals.com 2. Motors driving circuit (freezing compartment fan) 1. The circuit makes the Motor Fan OFF by cutting Off the power supplied to driver inside the Fan Motor when the is necessary. 2. This is a circuit to perform a temporary change of speed for the fan motor and applies DC voltage up to 7.5V ~ 16V to motor . 3.
  • Page 29 https://appliancetechmanuals.com 3. Buzzer Drive Condition Check Condition Tone (Ding~Dong~) when the button on Alarm for open door Measure- the display is pushed. (beep-beep-beep) ment Location 0.05 s 0.2 s 0.1 s 0.5 s 0.5 s IC1 ( 2.63 kz (Ding~) 2.21 kz (Dong~) IC1 ( 2.63 kz(Beep~)
  • Page 30 https://appliancetechmanuals.com 8-2-5 Temperature Sensor Circuit The upper CIRCUIT reads REFRIGERA TOR temperature, FREEZER T emperature, and DEFROST-SENSOR temperature for defrosting and the indoor temperature for compensating for the surrounding temperature into MICOM. OPENING or SHORT state of each TEMPERA TURE SENSOR are as follows: 8-2-6 Refrigeration Compartment Stepping Motor Damper Circuit * The circuit shown below is the damper circuit to regulate the refrigerator temperature.
  • Page 31 https://appliancetechmanuals.com 8-2-7 Temperature compensation & overcooling/undercooling compensation circuit Table of temperature compensation by cutting JUMP WIRE to easy SVC temperature adjustments +1deg, +1deg, -1deg, -1deg. Four oprion are available for R Compensations by CUTTING JUMP WIRE. Example 1) CUTTING JCR1 and JCR2: R +2 deg compensation Example 2) CUTTING JCR1 and JCR3: no compensation in R compartment.

  • Page 32: Resistance Specification Of Sensor

    https://appliancetechmanuals.com 8-3 RESISTANCE SEPECIFICATION OF SENSOR TEMPERATURE DETECTED RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR & BY SENSOR SENSOR DEFROST SENSOR & ROOM SENSOR -20º C -15º C -10º C - 5º C 0º C + 5º C + 10º C + 15º...

  • Page 33: Troubleshooting

    https://appliancetechmanuals.com 8-4 TROUBLESHOOTING PROBLEM INDICATED BY CHECK CHECKING METHOD CAUSE SOLUTION POWER SOURCE 1. The whole DISPLAY 1. FREEZER/ Check if FREEZER/ POWER SOURCE is poor. Check outlet Voltage. is poor. LED/SEVEN SEGMENT REFRIGERATOR. REFRIGERATOR DOOR IS DISPLAYis off. OPEN and check display. 2.
  • Page 34 https://appliancetechmanuals.com PROBLEM INDICATED BY CHECK CHECKING METHOD CAUSE SOLUTION COOLING is poor. If REFRIGERATOR 1.If FREEZER TEMPERATURE Check is FREEZER Make sure the TEMPERATURE isn ormal. TEMPERATURE is t oo low. DOOR isattached. is too low. 2. If amount of cool air from Make sure that the amount FAN MOTOR is poor.

  • Page 35: Main Pwb Assembly And Parts List

    https://appliancetechmanuals.com 8-5 MAIN PWB ASSEMBLY AND PARTS LIST 8-5-1 Main PWB Assembly TOP VIEW BOTTOM VIEW - 34 -...
  • Page 36 https://appliancetechmanuals.com 8-5-2 Replacement Parts List - 35 -...
  • Page 37 https://appliancetechmanuals.com 8-5-3 PWB Assembly, Display and parts list - 36 -...

  • Page 38: Pwb Diagram

    https://appliancetechmanuals.com 8-6 PWB DIAGRAM 8-6-1 PWB Main Assembly - 37 -...
  • Page 39 https://appliancetechmanuals.com - 38-...

  • Page 40: Exploded View

    https://appliancetechmanuals.com #EV# 9.EXPLODED VIEW AND REPLACEMENT PARTS LIST CASE PARTS CAUTION: use the part number to order part, not the position number. 103B 281A 402A 271C 282E 103A 410A 402A 409D 501F 503G 503F 271A 903D 503D 610A 282F 503C 503E 501A 409B...
  • Page 41 https://appliancetechmanuals.com #EV# FREEZER PARTS CAUTION: Use the part number to order part, not the position number. 136B 131A 145C 248E 248F 237C 145F 136A - 40 -...
  • Page 42 https://appliancetechmanuals.com #EV# REFRIGERATOR PARTS CAUTION: Use the part number to order part, not the position number. 146A 143E 140D 140B 140E 143E 140D 143E 140D 140B 140E 140B 140E 143F 142D 140B 142E 103E 103E 128A 103E 170A 167B 128B 154A 103E 151A...
  • Page 43 https://appliancetechmanuals.com #EV# DOOR PARTS CAUTION: Use the part number to order part, not the position number. 241F 230A 230B 104E 231A 233A 233D 231B 233B 233C 212G 241C 233G 233H 237A 241C 237A 241C 233E 233F 244A 244A 212J 241C 212J 241C 241C...
  • Page 44 https://appliancetechmanuals.com #EV# WATER and ICE MAKER PARTS CAUTION: Use the part number to order part, not the position number. 602A 600C 600A 622B 618A 627A 619C 616E 623C 619A 262D - 43 -...
  • Page 45 https://appliancetechmanuals.com February, 2009 MFL49482901...

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