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LG LRBN2251 Series Service Manual

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REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
Models : LRBN2251***

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Summary of Contents for LG LRBN2251 Series

  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. Models : LRBN2251***...

  • Page 2: Table Of Contents

    CONTENTS SAFETY PRECAUTIONS ............................... 2 SPECIFICATIONS................................... 3 PARTS IDENTIFICATION ............................... 4 DISASSEMBLY..................................5-6 DOOR....................................5 DOOR SWITCH..................................5 FAN AND FAN MOTOR................................ 6 DEFROST CONTROL ASSEMBLY............................6 LAMP....................................6 CONTROL BOX-REFRIGERATOR ............................6 MULTI DUCT ..................................6 ADJUSTMENT..................................7-8 COMPRESSOR..................................7 PTC-STARTER..................................

  • Page 3: Specifications

    1. SPECIFICATIONS 19 cu. ft. / 22 cu. ft. ITEMS SPECIFICATIONS ITEMS SPECIFICATIONS DOOR DESIGN Side Rounded VEGETABLE TRAY Opaque Drawer Type H) 20cu.ft COMPRESSOR PTC Starting Type DIMENSIONS (inches) H) 22cu.ft EVAPORATOR Fin Tube Type 238.4 (20cu.ft) CONDENSER Wire Condenser NET WEIGHT (pounds) 246.9 (22cu.ft) REFRIGERANT...

  • Page 4: Parts Identification

    2. PARTS IDENTIFICATION Digital Sensor Control Dairy Bin Refrigerator Light Shelves Adjustable Door Bin Egg Box Snack Pan Optibin Crisper Refrigerator Keeps fruits and Door Rack vegetable fresh and crisp Triple Twist Freezer Light Ice Tray Ice Bin Freezer Door Rack (Tilting) Durabase Basket Wire...

  • 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 BETTER / GOOD 3854JK1004D - 9 -...

  • 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 Terminal C of Compressor and Terminals 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 Normal operation of Separate PTC-Starter Observation value is Compressor is from Compressor and 115V/60Hz : 6.8Ω±30% measure resistance impossible or poor. between No. 5 and 6 of PTC-Starter with a Tester. (Figure 14) Replace PTC- The resistance value Starter.

  • Page 12: Other Electrical Components

    6-3 OTHER ELECTRICAL COMPONENTS M 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 M 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 M General Control of Refrigerating Cycle ITEMS UNIT STANDARDS PURPOSES REMARKS Pipe and Min. Pipe: within 1 hour. To protect The opening time should be reduced piping system Comp: within 10 minutes. moisture to a half of the standards during rain opening time Drier: within 20 minutes.

  • Page 16: Operation Principle & Repair Method Of Icemaker

    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 17 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 18 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 the defect CODE removes the sign, it returns to normal operation (RESET). 4.
  • Page 19 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 20 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 21 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 specific replacement parts, since calculating time by the IC1 may be changed.
  • Page 22 7-2-4 Load / Buzzer Drive & Open Door Detection Circuit 1. Load Drive Condition Check FREEZER FREEZER DEFROSTING COMP LAMP LOAD TYPE FAN MOTOR FAN MOTOR HEATER (HIG RPM) (LOW RPM) Measurement Location (IC4) NO.11 NO.14 NO.15 NO.12 NO.13 1V or below Condition - 22 -...
  • Page 23 2. 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~) 3.
  • Page 24 7-2-5 Temperature Sensor Circuit 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 25 7-2-6 Refrigeration Compartment Stepping Motor Damper Circuit * The circuit shown below is the damper circuit to regulate the refrigerator temperature. - 25 -...
  • Page 26 7-2-7 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 27 7-2-8 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. - 27 -...
  • Page 28 7-3 RESISTANCE SPECIFICATION OF SENSOR TEMPERATURE DETECTED RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR & BY SENSOR SENSOR DEFROST SENSOR & ROOM SENSOR - 20 ˚C 22.3 KΩ 77 KΩ - 15 ˚C 16.9 KΩ 60 KΩ - 10 ˚C 13.0 KΩ 47.3 KΩ...
  • Page 29 - 29 -...
  • Page 30 - 30 -...
  • Page 31 7-5 MAIN PWB ASSEMBLY AND PARTS LIST 7-5-1 Main PWB Assembly - 31 -...
  • Page 32 7-5-2 Replacement Parts List - 32 -...
  • Page 33 7-5-3 PWB Assembly, Display, And Parts List - 33 -...
  • Page 34 7-6 PWB DIAGRAM 7-6-1 PWB Main Assembly - 34 -...
  • Page 35 - 35 -...

  • Page 36: Exploded View & Replacement Parts List

    8. EXPLODED VIEW & REPLACEMENT PARTS LIST CASE PARTS CAUTION: Use the part number to order part, not the position number. 103B 281A 281B 103A 410A 409D 406B 501F 282E 282F 610B 503D 410G 145A 610A 503C 501A 282K 409C 503E 120B 411A...
  • Page 37 FREEZER PARTS(Swing) CAUTION: Use the part number to order part, not the position number. 125A 249E 136B 145E 248E 248F 131A 145D 249G 237D 237E 136C 249F : on some models - 37 -...
  • Page 38 REFRIGERATOR PARTS(Better) CAUTION: Use the part number to order part, not the position number. 141A 147A 141B 141D 141E 141A 141B 141D 141A 141E 141B 141D 142D 142A 141E 142B 142E 128A 170A 128B 167B 154A 160B 161A 151A 160B 155B 161A 151C...
  • Page 39 REFRIGERATOR PARTS(Good) CAUTION: Use the part number to order part, not the position number. 143A 143C 143B 143D 128A 170A 128B 143C 143A 143B 143D 160B 151A 155B 151A 151C - 39 -...
  • Page 40 DOOR PARTS(Swing) CAUTION: Use the part number to order part, not the position number. 230A 241A 233A 231A 241B 281E 244B 244B 607A 241C 244E 241E 237A 244A 212A 237A 241D 243A 244C 700C 205D 607A 244C 700A 205C 700C 200A 700A 203A...
  • Page 41 DESCRIPTION LRBN22514SB LRBN22514ST 103A HANDLE,BACK 3650JJ2003L 3650JJ2003L 103B HANDLE,BACK 3650JJ2003M 3650JJ2003M 103C COVER,LOWER 3550JJ0006C 3550JJ0006C 105A DRAIN ASSEMBLY ,PIPE-Z 5251JJ2003A 5251JJ2003A 105F SKIRT,LOWER 5070JJ3002A 5070JJ3002A 106A LEG ASSEMBLY ,ADJUST 4779JJ2001A 4779JJ2001A 106A LEG ASSEMBLY ,ADJUST 4779JJ2001A 4779JJ2001A 106B WASHER,DRAWING 4J00382C 4J00382C 120B DUCT ASSEMBLY ,MULTI...
  • Page 42 DESCRIPTION LRBN22514SB LRBN22514ST 281B HINGE ASSEMBLY,U 4775JJ2003B 4775JJ2003B 282B PIN,DRAWING 1PZZJJ3002F 1PZZJJ3002F 282B HINGE ASSEMBLY,C 4775JJ8002E 4775JJ8002E 282E CAP,HINGE 5006JJ2001F 5006JJ2001F 282F DECO,DUCT 3806JL2006E 3806JL2006E 282G CAP,DUCT 5006JJ3011A 5006JJ3011A 282H CAP,HINGE 5006JJ3004E 5006JJ3004E 282Z CAP,HANDLE 5006JJ3010C 5006JJ3010C 283D HINGE,L 4774JJ2002A 4774JJ2002A 283D HINGE,L...
  • Page 43 P/No. 3828JL8006B MAY,04 Printed in Mexico...

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