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REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MODELS:
LRFD22850ST
LRFD22850SW
LRFD22850TT

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Table of Contents

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   Summary of Contents for LG LRFD22850ST

  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. MODELS: LRFD22850ST LRFD22850SW LRFD22850TT...
  • Page 2: Table Of Contents

    CONTENTS SAFETY PRECAUTIONS ............................... 2 SPECIFICATIONS................................... 3 PARTS IDENTIFICATION ............................... 4 DISASSEMBLY..................................5-7 DOOR....................................5-6 TO REMOVE THE DISPENSER ............................6 FAN AND FAN MOTOR................................ 7 DEFROST CONTROL ASSEMBLY............................7 LAMP....................................7 CONTROL BOX-REFRIGERATOR ............................7 MULTI DUCT ..................................7 ADJUSTMENT..................................8-9 COMPRESSOR..................................
  • Page 3: Specifications

    1. SPECIFICATIONS 22 cu. Ft. (22.4 cu. Ft.) ITEMS SPECIFICATIONS ITEMS SPECIFICATIONS DOOR DESIGN Side Rounded VEGETABLE TRAY Opaque Drawer Type DIMENSIONS COMPRESSOR PTC Starting Type W(836)x D(870)x H(1764) mm W(32.91)x D(34.25)x H(69.45) in EVAPORATOR Fin Tube Type CONDENSER Wire Condenser 128.4 Kg NET WEIGHT 283.29 pounds...
  • Page 4: Parts Identification

    2. PARTS IDENTIFICATION Digital Sensor Control* Filter (inside)* Refrigerator Light Dairy Bin Shelves Egg Box Chef Fresh Design-A-Door Bins Can Dispenser Freezer Light Optibin Crisper Wire Basket Keeps fruits and vegetable fresh and crisper Customcube Icemaker Ice Bin Full Widht Wire Basket Wire Durabase *On some models - 4 -...
  • Page 5: Disassembly

    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 Disconnect water supply tube by pushing back door frame.
  • Page 6: To Remove The Dispenser

    2. Insert gasket into channel 3-2 TO REMOVE THE DISPENSER 1) Snap gasket assembly into the door bracket. 1. Use fiat tip screwdriver to pry back hooks on botton <Inserting the Gasket Assembly into the Bracket Door> underside of cover dispenser. Correct Figure 9 2.
  • Page 7: 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 plastic guide for slides on left side by 3.
  • Page 8: 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 9: 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 10: Circuit Diagram

    5. CIRCUIT DIAGRAM 5. CIRCUIT DIAGRAM - 10 - - 10 -...
  • Page 11: 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 12: 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 20) Replace PTC- The resistance value Starter.
  • Page 13: 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 14: 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 15: 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 16 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 Very Fast...
  • Page 17: Operation Principle & Repair Method Of Icemaker

    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. Ice Making • Waits until water becomes cold after starting the Mode ice making operation.
  • Page 18 7-2 ICE MAKER FUNCTIONS 7-2-1 Start Position 1. After POWER OFF or Power Outage, check the EJECTOR's position with MICOM initialization to restart. 2. How to check if it is in place: - Check HIGH/LOW signals from HALL SENSOR in MICOM PIN. 3.
  • Page 19 7-2-4 Fill / Park Position 1. Once a normal harvest mode has been completed, the water solenoid will be activated. 2. The amount of water is adjusted by pressing the Fill Key repeatedly. This changes the time allowed for fill as illustrated in the table below.
  • Page 20 7-2-5 Function TEST 1. This is a compulsory operation for TEST, SVC, cleaning, etc. It is operated by pressing and holding the Fill Key for 3 seconds. 2. The test works only in the Ice Making 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

    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 37°F for Refrigerator and 0°F for freezer. You can adjust the Refrigerator and the Freezer control temperature by pressing the ADJUST button. 2.
  • Page 22 8-1-6 CONTROL OF FREEZER FAN MOTOR 1. Freezer fan motor has high and standard speeds. 2. High speed is used at power-up, for express freezing, and when refrigerator is overloaded. Standard speeds is used for general purposes. 3. To improve cooling speed, the RPM of the freezer fan motor change from normal speed to high. 4.
  • Page 23 8-1-10 Buzzer Sound When the button on the front Display is pushed, a Ding~ Dong~ sound is produced. (Refer to the Buzzer Circuit 8-2-4 No. 3) 8-1-11 Defrosting (removing frost) 1. Defrosting starts each time the COMPRESSOR running time reaches 7 hours. 2.
  • Page 24: Defect Diagnosis Function

    8-1-14 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 25 8-1-15 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 26 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 27 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 28 8-2-4 Load / Buzzer Drive & Open Door Detection Circuit 1. Load Drive Condition Check 5mH/4A 470nF 275VAC CON1 POWER ICE MAKER RUNNING CAPACITOR CON2 COMP STARTING CAPACITOR ALZ21B12 KID65003AP PTC START 1N4004 COOLING-FAN G5NB-1A DEF-HEATER FUSE-M G5NB-1A LAMP-F DOOR S/W-F G5NB-1A LAMP-R I C 1...
  • Page 29 part part part MOTOR OFF 2V or less MOTOR ON 13V~15V 2V~3V 2.2 Cooling motor driving circuit (machine room) 1. This circuit makes standby power 0 by cutting off power supplied to ISs inside of the fan motor in the fan motor OFF . 2.
  • Page 30 3. Open Door Detection Circuit Check Measurement Location Freezer/ (PIN NO.30 & PIN NO.37) Refrigerator Door Closed Open 8-2-5 Temperature Sensor Circuit The upper CIRCUIT reads REFRIGERATOR 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 TEMPERATURE SENSOR are as follows: SENSOR CHECK POINT...
  • Page 31 8-2-6 Refrigeration Compartment Stepping Motor Damper Circuit * The circuit shown below is the damper circuit to regulate the refrigerator temperature. 8-2-7 Dispenser Input - 31 -...
  • Page 32 8-2-8 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) Compensation (RCR) is changed from 10K (the current resistance) to 18K (the adjustment resistance), the temperature 180 KΩ...
  • Page 33 8-2-9 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 Module SEVEN SEGMENT DISPLAY . The drive type is the scan type. CON 6 - 33 -...
  • Page 34 8-3 RESISTANCE SPECIFICATION OF SENSOR RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR & TEMPERATURE 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 - 5 ˚C 10.1 KΩ...
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  • Page 37 8-5 MAIN PWB ASSEMBLY AND PARTS LIST 8-5-1 Main PWB Assembly - 37 -...
  • Page 38 8-5-2 Replacement Parts List P/NO DESCRIPTION SPEC MAKER REMARK 6870JB8203A PWB(PCB) BEST BRAVO-PJT DOO SAN T=1.6 6170JB2012B TRANSFORMER,SMPS[COIL] DL-PJT 2.9MH/20W SAM IL TRANS 6170JB2012C TRANSFORMER,SMPS[COIL] TRANS 6630AQ9106D CONNECTOR (CIRC),WAFER YW396-09AV YEON HO CON1 6630AQ9106E CONNECTOR (CIRC),WAFER YW396-07AV YEON HO CON2 6630AQ9106B CONNECTOR (CIRC),WAFER YW396-05AV...
  • Page 39 8-5-3 PWB Assembly, Display, And Parts List - 39 -...
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  • Page 41 8-5-4 Circuit Diagram of Display - 41 -...
  • Page 42: Pwb Diagram

    8-6 PWB DIAGRAM TRANS D3SBA60 470nF 8-6-1 PWB Main Assembly 56KJ 275VAC 47uF +15.5V /630V /450V 560KJ 1.8KJ 1/2W RL1* FR107 9.1KF 32mH/0.5A FR107 103/100V 100J FUSE1 680uF 250V/2A 680uF 6.8KJ /25V 47uF /35V RL2* /50V 2.4KF KIA431 IC3-1 5mH/4A 680J 470nF 275VAC...
  • Page 43 330J CON4 KTB1151 FR107 4.7KJ 1.5KJ 1/2W 3.9KJ CE11 CC16* 220uF FR107 /25V (PDO/PWM) KTC3198 10KJ F-FAN 4.7KJ (INT4) CC17* 330J KTB1151 FR107 4.7KJ 1.5KJ 1/2W 3.9KJ CE12 CC19* 220uF FR107 (PPG) KTC3198 /25V R42* 10KJ C-FAN 4.7KJ (INT1) CC20* RJ1* CON5 R23*...
  • Page 44: Exploded View & Replacement Parts List

    9. EXPLODED VIEW & REPLACEMENT PARTS LIST CASE PARTS CAUTION: Use the part number to order part, not the position number. 103B 281A 402A 271C 611D 262A 282E 103A 410A 611B 402A 409D 501F 611C 271A 611A 903D 503D 610A 282F 501A 409B...
  • Page 45 FREEZER PARTS CAUTION: Use the part number to order part, not the position number. 285A 145C 136A 248F 136D 131C 136B 248A 136E 248F 131A 136G 128D 136C - 45 -...
  • Page 46 REFRIGERATOR PARTS CAUTION: Use the part number to order part, not the position number. 147C 147B 141D 147A 149C 141A 149E 141B 141E 140A 141C 140B 140F 103E 128A 142A 142D 142B 142E 128B 103E 103E 146A 128A 170A 103E 128M 128G 168A...
  • Page 47: Door Parts

    DOOR PARTS CAUTION: Use the part number to order part, not the position number. 230B 230A 104E 231B 233B 233C 231A 233D 233A 241A 241B 212G 241C 147D 244G 244G 241C 244B 244B 241C 700C 700C 241C 244E 244E 241C 241C 244C 244C...
  • Page 48 DISPENSER PARTS CAUTION: Use the part number to order part, not the position number. 616B 280F 280D 279B 279D 276A 113C 276B 279C 403A 616A 406C 279E - 48 -...
  • Page 49 ICE MAKER PARTS CAUTION: Use the part number to order part, not the position number. 602A 600A 628F 628B 615A 629B 262B 628D 629C 628E 629B 627B 628G 629A 628G 628C 262B 262D - 49 -...
  • Page 50 ICE & WATER PARTS CAUTION: Use the part number to order part, not the position number. 623C 262D 623B 623D 625A 616D 627A 623A 623C 616G 622A 616F 618A 619C 616E 627A 627A 619A 627B 627B 262D - 50 -...
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  • Page 55 May 20, 2005 P/No. 3828JL 8077A...

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