LG LRBN20512WW Service Manual
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LG LRBN20512WW Service Manual

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REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MODEL:
LRBN20512WW

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Summary of Contents for LG LRBN20512WW

  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. MODEL: LRBN20512WW...

  • Page 2: Table Of Contents

    CONTENTS SAFETY PRECAUTIONS ..................... 1. SPECIFICATIONS ......................2. PARTS IDENTIFICATION ....................3. DISASSEMBLY ........................ 3.1 Door ........................... 3.2 Door switch ......................... 3.3 Fan and fan motor ....................... 3.4 Defrost control assembly ..................... 3.5 Lamp ........................... 3.6 Refrigerator control box ....................3.7 Multi duct ........................

  • Page 3: Specifications

    1. SPECIFICATIONS MODELS LRBN20512WW SPECIFICATIONS CAPACITY litre(F/R/T)/cuft (176.72/382.33/559.05)/ 6.24*13.5*19.74 DIMENSIONS mm(W*H*D)/(in) (758.825/67.875/863.6) / 29 7/8*67 7/8* 34 WEIGHT kg/(lb) 110/ (242.5) HANDLE PL-SMOOTH/ WHITE REVERSIBLE DOOR DOOS FINISH EMBO REFRIGERANT R134a DOOR COOLING DEFROST SYSTEM AUTOMATIC ICE TRAY I/T(2EA)+I/B SHELF...

  • Page 4: Parts Identification

    2. PARTS IDENTIFICATION 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 Design-A-Door Shelves Wire Freezer Shelf...

  • Page 5: 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. Unplug the power cord from the outlet. 1. Remove the freezer shelf. (If your refrigerator has an icemaker, remove the icemaker first) 2. Remove refrigerator shelves. 2. Remove the grille by pulling it out and by loosening a 3.

  • Page 7: Adjustment

    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 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: Circuit Diagram

    5. CIRCUIT DIAGRAM LG Electronics LG Electronics CIRCUIT DIAGRAM CIRCUIT DIAGRAM *P.T.C START OPTION, WATER VALVE PART, *P.T.C START OPTION, WATER VALVE PART, HEATER AND FUSE CONFIGURATION, HEATER AND FUSE CONFIGURATION, PWB(PCB) ASSEMBLY,DISPLAY-R PWB(PCB) ASSEMBLY,DISPLAY-R CAPACITOR PART, ICE MAKER PART, ICE...

  • Page 10: Troubleshooting

    6. TROUBLESHOOTING 6-1 COMPRESSOR AND ELECTRIC COMPONENTS (Reated Voltage Remove PTC-Starter Power Source. ±10%)? from Compressor and measure voltage between T erminal C of Compressor and T erminals 5 or 6 of PTC. OLP disconnected? No Voltage. Replace OLP . Check connection condition.

  • Page 11: Ptc And Olp

    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 T ester. (Figure 14) 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 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 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 PARTIAL Freezer Low flowing sound of A little higher • Refrigerant level is low due LEAKAGE compartment and Refrigerant is heard and than ambient •...

  • Page 15: Description Of Function & Circuit Of Micom

    7. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM 7-1 FUNCTION 7-1-1 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 16 7-1-5 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 17 7-1-9 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 18 7-1-10 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 19: Pcb Function

    7-2 PCB FUNCTION 7-2-1 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 20 7-2-2 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 21 7-2-4 Load / Buzzer Drive & Open Door Detection Circuit 1. Load Drive Condition Check FRENCH DOOR DEFROSTING COMP LAMP LOAD TYPE HEATER 1, 2 / HEATER DEW HEATER Measurement Location (IC6) NO.14 NO.12 NO.11 NO.13 1V or below Condition - 21 -...
  • Page 22 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 23 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 24 7-2-5 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: - 24 -...
  • Page 25 7-2-6 Refrigeration Compartment Stepping Motor Damper Circuit * The circuit shown below is the damper circuit to regulate the refrigerator temperature. 7-2-7 Temperature compensation & overcooling/undercooling compensation circuit Table of temperature compensation by cutting JUMP WIRE to easy SVC temperature adjustments +1deg, +1deg, -1deg, -1deg.
  • Page 26 7-2-9 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 (LED Module) SEVEN SEGMENT DISPLAY (SEVEN SEGMENT DISPLA Y MODULE).

  • Page 27: Resistance Specification Of Sensor

    7-3 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 C + 20º...

  • Page 28: Troubleshooting

    - 28 -...
  • Page 29 - 29 -...

  • Page 30: Main Pwb Assembly And Parts List

    7-5 MAIN PWB ASSEMBLY AND PARTS LIST 7-5-1 Main PWB Assembly TOP VIEW BOTTOM VIEW - 30 -...
  • Page 31 7-5-2 Replacement Parts List - 31 -...
  • Page 32 7-5-3 PWB Assembly, Display and parts list - 32 -...

  • Page 33: Pwb Diagram

    7-6 PWB DIAGRAM 7-6-1 PWB Main Assembly - 33 -...
  • Page 34 - 34 -...

  • Page 35: Exploded View And Replacement Part List

    #EV# 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 282F 903D 503D 410G 145A 610A 503C 501A 409B 503E 623H 120B 411A 304A 125D 158A 282B...
  • Page 36 #EV# FREEZER PARTS CAUTION: Use the part number to order part, not the position number. 131A 125A 282X 149A 136C -36-...
  • Page 37 #EV# REFRIGERATOR PARTS CAUTION: Use the part number to order part, not the position number. 143A 140D 143E 143B 140E 140B 140D 140E 143F 142D 140B 142E 128A 170A 128B 103E 167B 154A 103E 151A 155B 151A 151C -37-...

  • Page 38: Door Parts

    #EV# DOOR PARTS CAUTION: Use the part number to order part, not the position number. 230A 241A 233A 286A 231A 241B 212G 281E 212F 241C 244E 241E 212J 244H 212F 286A 241D 212J 243A 700C 205D 286A 200A 203A 201A 282Z 281E 244P...
  • Page 39 #EV# LRBN20512WW Loc No. Part No. Description Loc No. Part No. Description 103A 3650JJ2003E Handle,Rear 282Z 5006JJ3010A Cap,Handle 103B 3650JJ2003A Handle,Rear 283B 4775JJ2007B Hinge Assembly,Lower 103C 3551JJ1015A Cover Assembly,Lower 283D 4774JJ2002A Hinge,Lower 103E 5218JJ3001A Rail,Slide 283F MJB36873201 Stopper,Door 105A 5251JA3003B Tube Assembly,Drain...
  • Page 40 P/No. 3828JL8089C Junio, 2008...

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