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REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE PRODUCT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MODELS:
LBC20514TT

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Table of Contents
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Summary of Contents for LG LBC20514TT

  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE PRODUCT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. MODELS: LBC20514TT...
  • Page 2: Table Of Contents

    CONTENTS Safety Precautions………………………………………………........ 2 1- Specifications…………………………………………………........ 3 2- Parts Identifications …………………………………………........ 4 3- Disassembly……………………………………………………....... 5 Door……………………………………………………………........5 Door Switch……………………………………………………........5 Fan and Fan Motor……………………………………………........6 Defrost Control Assembly ……………………………………........6 Lamp……………………………………………………………........6 Refrigerator Control Box……………………………………….........6 Multi Duct………………………………………………………........6 4- Ajustment……………………………………………………........7 Compressor……………………………………………………........7 PTC-Starter……………………………………………………........7 OLP (Overload Protector)……………………………………........
  • Page 3: 1- Specifications

    1. SPECIFICATIONS Models LBC20514TT Titanium Color 20cuft Capacity 29.8 (W) x 32.2 (D) x 67.9 (H) Dimensions (in) R134A (4.2oz) Refrigerant Temperate(N) Climate Class F-control Control Type 115/60 Rating EMBO(Normal) Case Material Door Material Reversible Door 1 (40W/Blue) Lamp (F)
  • Page 4: 2- Parts Identifications

    2. PARTS IDENTIFICATIONS PARTSANDFEATURES 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. Digital Sensor Control Dairy Bin Refrigerator Light...
  • Page 5: 3- Disassembly

    3. DISASSEMBLY 3-1 DOOR Freezer Door 1. Loosen the hexagonal bolts attaching the lower hinge to Refrigerator Door the body to remove the refrigerator door only. 1. Remove the hinge cover by pulling it upwards. 2. Loosen the hexagonal bolts attaching the upper hinge to the body and lift the freezer door.
  • Page 6: Fan And Fan Motor

    3-3 FAN AND FAN MOTOR 3-5-1 Refrigerator Compartment Lamp 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. Remove the grille by pulling it out and by loosening a 3.
  • Page 7: 4- Ajustment

    4. ADJUSTMENT 4-1 COMPRESSOR 4-2-3 PTC-Applied Circuit Diagram 4-1-1 Role Starting Method for the Motor 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 8: Olp (Overload Protector)

    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 . (2) When high current flows to the Compressor motor, the Bimetal works by heating the heater inside the OLP , and the OLP protects the Motor by cutting off the...
  • Page 9: 5- Circuit Diagram

    5. CIRCUIT DIAGRAM PWB(PCB) ASSEMBLY,DISPLAY CON101 STEPPING F-FAN MOTOR BK YL GY GY PK WH CON4 CON5 PWB(PCB) ASSEMBLY, MAIN F-DOOR CON6 2 PK PERCEPTION S/W DEF-SENSOR R-SENSOR F-SENSOR POWER SUPPLY CON1 CON2 CORD GN/YL (GN) ICE MAKER PART GN/YL (GN) CAPACITOR PART (GN)
  • Page 10: 6- Troubleshooting

    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. Reconnect.
  • Page 11: Ptc And Olp

    6-2 PTC AND OLP Separate PTC-Starter Observation value is Normal operation of compressor is impossible from Compressor and ±30% 115V/60Hz : 6.8 or poor. measure resistance between No. 5 and 6 of PTC-Starter with a Tester. (Figure 19) Replace PTC- The resistance value Starter.
  • Page 12: Other Electrical Components

    6-3 OTHER ELECTRICAL COMPONENTS Not cooling at all Check for open short or Compressor Cause doesn't run. incorrect resistance readings in the following components a. Starting devices Short, open, or broken. Poor contact b. OLP or shorted. Coil open or shorted. c.
  • Page 13: Service Diagnosis Chart

    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 14: Refrigeration Cycle

    6-5 REFRIGERATION CYCLE * Troubleshooting Chart TEMPERATURE STATE OF STATE OF THE CAUSE REMARKS OF THE THE UNIT EVAPORATOR COMPRESSOR - Refrigerant level is low due to a Freezer Low flowing sound of A little higher than PARTIAL leak. ¥ compartment and refrigerant is heard and frost ambient...
  • Page 15 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 Partial None Pattern? Equalization Equalization Test Test Very Fast Very Slow Very Slow Very Fast Fast...
  • Page 16: 7- Operation Principle And Repair Method Of Ice Maker

    7. OPERATION PRINCIPLE AND REPAIR METHOD OF ICE MAKER 7-1 OPERATION PRINCIPLE 7-1-1 Operation Principle of Ice Maker 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 17: Ice Maker Functions

    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 18: Function Test

    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 19: 8- Description Of Function And Circuit Of Micom

    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 20 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 21 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 the defect CODE removes the sign, it returns to normal operation (RESET). 4.
  • Page 22 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 23 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 24 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 specific replacement parts, since calculating time by the IC1 may be changed.
  • Page 25 8-2-4 Load / Buzzer Drive & Open Door Detection Circuit 1. Load Drive Condition Check G5SB-14 FREEZER DOOR SWITCH REFRIGERATOR DOOR SWITCH VALVE DEFROSTING COMP LAMP LOAD TYPE POWER MODE (DISPENSER HEATER (OPTIONAL) MDL) Measurement Location (IC6) NO.13 NO.14 NO.16 NO.12 NO.15 1V or below...
  • Page 26 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~) 4.
  • Page 27 8-2-5 Temperature Sensor Circuit FREEZER-SENSOR REFRIGERATOR-SENSOR DEFROST-SENSOR The upper CIRCUIT reads REFRIGERATOR temperature, FREEZER Temperature, and DEFROST-SENSOR temperature for defrosting and the indoor temperature for compensating for the surrounding temperature into MICOM. OPENING or SHORT state of each TEMPERATURE SENSOR are as follows: SENSOR CHECK POINT NORMAL (-30°C ~ 50°C)
  • Page 28 8-2-7 Temperature Compensation & Overcooling/Undercooling Compensation Circuit 1. Refrigerator Temperature Compensation Table of Temperature Compensation by adjusting the Refrigerator resistance (difference from the current temperature) Resistance Temperature Remark e.g., If the refrigerator compensation resistance (RCR) is changed from 10K (the current resistance) (RCR) Compensation to 18K (the adjustment resistance), the temperature...
  • Page 29 8-2-8 Key Button Input & Display Light-On Circuit The circuit shown above determines whether a function control key on the operation display is pushed. It also turns on the corresponding function indication LED DISPLAY. The drive type is the scan type. 150J - 29 -...
  • Page 30 8-3 RESISTANCE SPECIFICATION OF SENSOR TEMPERATURE DETECTED RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR & BY SENSOR SENSOR DEFROST SENSOR & ROOM SENSOR - 20° C 22.3 K 77 K - 15° C 16.9 K 60 K - 10° C 13.0 K 47.3 K - 5°...
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  • Page 33 8-5 MAIN PWB ASSEMBLY AND PARTS LIST 8-5-1 Main PWB Assembly - 33 -...
  • Page 34 8-5-2 Replacement Parts List - 34 -...
  • Page 35 8-5-3 PWB Assembly, Dysplay and Parts List - 35 -...
  • Page 36 8-6 PWB DIAGRAM 8-6-1 PWB Main Assembly G5S-1A - 36 -...
  • Page 37 - 37 -...
  • Page 38: 11- Refrigerator Exploded View

    #EV# EXPPLODED VIEW CASE PARTS CAUTION: Use the part number to order part, not the position number. 103B 281A 281B 103A 410A 409D 406B 503G 501F 503F 282E 503D 282F 903D 503C 145A 610A 501A 503E 409B 619B 120B 411A 304A 125D 158A...
  • Page 39 #EV# FREEZER PARTS CAUTION: Use the part number to order part, not the position number. 131A 149A 136C - 39 -...
  • Page 40 #EV# REFRIGERATOR PARTS CAUTION: Use the part number to order part, not the position number. 143E 140D 140B 143E 140E 140D 140B 143E 140D 140B 140E 143F 140E 142D 140B 142E 128A 103E 103E 170A 128B 167B 154A 103E 151A 103E 155B 151A...
  • Page 41 #EV# DOOR PARTS CAUTION: Use the part number to order part, not the position number. 230A 241A 233A 231A 241B 286A 212G 281E 241C 244E 241E 244A 212J 286A 241D 243A 205D 200A 203A 201A 212J 281E 212A 286A 243A 283F - 41 -...
  • Page 42 #EV# WATER and ICE MAKER PARTS CAUTION: Use the part number to order part, not the position number. 602A 600C 600A 622B 618A 627A 616E 623C 619C 619A 262D - 42 -...
  • Page 43 MFL62526001 May, 2009...

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