LG LFC21776ST Service Manual
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LG LFC21776ST Service Manual

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See also: Owner's Manual
REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE PRODUCT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MODELS : LFC21776ST
COLORS : STAINLESS(ST)

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Summary of Contents for LG LFC21776ST

  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE PRODUCT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. MODELS : LFC21776ST COLORS : STAINLESS(ST)

  • Page 2: Table Of Contents

    CONTENTS SAFETY PRECAUTIONS ............................... 2 SPECIFICATIONS ................................... 3 PARTS IDENTIFICATION ............................... 4 DISASSEMBLY .................................. 5-10 DOOR ....................................5-6 DOOR ALIGNMENT ................................6 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER ................... 7-9 ADJUSTMENT ................................. 10-11 COMPRESSOR ................................. 10 PTC-STARTER .................................. 10 OLP (OVERLOAD PROTECTOR) .............................

  • Page 3: Specifications

    60 W (1 EA) FREEZER INNER CASE ABS Resin INSULATION Polyurethane Foam DIMENSIONS Description LFC21776ST Depth w/ Handles 30 in. Depth w/o Handles 27 1/2 in. Depth w/o Door 23 5/8 in. Depth (Total with Door Open) 42 1/4 in.

  • Page 4: Parts Identification

    2. PARTS IDENTIFICATION Digital Sensor Control Dairy Bin Refrigerator Light Shelves Modular Door Bin Modular Door Bin Bottle Holder Optibin Crisper Keeps fruits and vegetable fresh and crisp Modular Door Bin Glide'N'Serve AUTOMATIC ICEMAKER Pullout Drawer Ice Bin Durabase Divider - 4 -...

  • Page 5: Disassembly

    3. DISASSEMBLY 3-1 DOOR Refrigerator door 1. Remove the top hinge cover and disconnect the wire Gasket harness. Bracket Clip Door 2. Remove the ground screw. Frame 3. Rotate the lever hinge and lift off hinge. 4. Lift off the refrigerator door. Flat Tip 5.

  • Page 6: Door Alignment

    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 7: How To Remove And Reinstall The Pullout Drawer

    3-3 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER 3-3-1 FOLLOW STEPS TO REMOVE Step 1) Open the freezer door. Step 2) Remove the lower basket. Step 3) Remove the two screws from the guide rails (one Step 4) Lift the freezer door up to unhook it from the rail from each side).
  • Page 8 3-3-2 FOLLOW STEPS TO REINSTALL Step 1) Reinstall the right side gear into the clip. Step 2) Insert the rail into the right side gear. Gears do not Step 3) Insert the rail into the left side gear, and insert the need to be perpendicular to each other.
  • Page 9 3-3-3 PULL OUT DRAWER To separate the drawer, push the front left and right hooks in direction to pull up and remove. Then gently lift the gear part of rear left and right side of the drawer and pull it out in direction.

  • Page 10: Adjustment

    4. ADJUSTMENT 4-1 COMPRESSOR 4-2 Introduction of E-Linear Compressor 4-1-1 Role E-Linear compressor is run by mechanical part design The compressor intakes low temperature and low pressure through automatically varying the cooling power. The gas from the evaporator of the refrigerator and compresses main parts consist of compressor and Sub PCB which this gas to high-temperature and high-pressure gas.
  • Page 11 4-2-3 Compressor protection logic 4-2-4 Compressor problems diagnosis Since linear Comp conducts linear reciprocating motion, When there is a problem or failure with the `operation, we have protection logic for compressor, motor and PCB you are kindly recommended to check it as follows ; as the below.

  • Page 12: Compressor

    2) Check to normality by measurement of Voltage 3) Check problems by LED On & Off Count _ (Sub PCB) Measure the resistance between pin of the connector (as If compressor protection logic is running, LED Lamp’s shown picture) with a multi-tester. blinking frequency of sub PCB, which takes in charge of control, can help estimate the protection logic’s symptoms and the cause of its problems.

  • Page 13: Circuit Diagram

    5. CIRCUIT DIAGRAM - 13 -...

  • Page 14: Troubleshooting

    6. TROUBLESHOOTING 6-1 Error Code Summary WARNING: When you check the Resistance values, be sure to turn off the power. And wait for the voltage-discharge sufficiently. Error Display Error Detection Error Generation Factors Remark Freezer Ref. Category Temperature Temperature Normality None Normal operation of Display Freezer Sensor...

  • Page 15: Pcb Picture

    7. PCB Picture 7-1 Main PCB P/No & MFG Picture CON9 CON3 CON4 EBR67348002 CON2 CON5 (2010.03 ~) CON8 CON1 - 15 -...
  • Page 16 7-2 Display PCB & Sub PCB P/No Picture CON01 Display PCB EBR42479305 (2010.03~) - 16 -...
  • Page 17 8. Troubleshooting With Error Display 8-1 Freezer Sensor Error (Er FS) Checking flow Result & SVC Action Check for a loose connection. Check the Blue/White to Result SVC Action Blue/White. Short Change the sensor Open Replace the refrigerator Check the Temp and Normal resistance (Table-1) <Temperature table-1>...
  • Page 18 8-2 Refrigerator Sensor Error (Er rS) Checking flow Result & SVC Action Check for a loose connection. Check the White to White. Result SVC Action Short Change the sensor Open Replace the refrigerator Check the Temp and Normal resistance (Table-2) <Temperature table-2>...
  • Page 19 8-3 Icing Sensor Error (Er IS) Checking flow Result & SVC Action Check for a loose connection. Check the Red to Bright Orange. Result SVC Action Short Change the sensor Open Replace the refrigerator Check the Temp and Normal resistance (Table-1) <Temperature table-1>...
  • Page 20 8-4 Defrost Sensor Error (F dS) Checking flow Result & SVC Action Check for a loose connection. Check the Orange to Orange. Result SVC Action Short Change the sensor Open Replace the refrigerator Check the Temp and Normal resistance (Table-3) Check the Brown to Brown.
  • Page 21 8-5 Defrost Heater Error (Er dH) Checking flow Result & SVC Action Check the Door gasket. Part Result SVC Action Go to the 3 Check the Defrost control part. Fuse-M Change Fuse-M Go to the 3 34~42 Fuse Sensor Heater Change Fuse-M Go to the 3 Sensor...
  • Page 22 8-6 Freezer Fan Error (Er FF) Checking flow Result & SVC Action Reset the unit and Input Test 1 Mode. (Push the button 1 time) Open the freezer door and Check the Status SVC Action air flow. No windy Go to 3 While an error code is displayed, the fan is not working.
  • Page 23 8-7 Condenser Fan Error (Er CF) Checking flow Result & SVC Action Reset the unit and Input Test 1 Mode. (Push the button 1 time) Check the fan rotating. Status SVC Action While an error code is displayed, No windy Check motor the fan is not working.
  • Page 24 8-8 Communication Error (Er CO) Checking flow Result & SVC Action Check the loose connection. Check the Orange to White/Black. Result SVC Action 12 V Go to the 3 Check the Hinge CON01 Other (loose connection) Change the Main PCB <Display>...

  • Page 25: Troubleshooting Without Error Display

    9. Troubleshooting Without Error Display 9-1 Freezer room AC Bulb Lamp doesn’t work Checking flow Result & SVC Action Check the Freezer door switch. If feel sticky, Change the door s/w. Check the door S/W resistance. Status Result SVC Action Go to the 3 Normal Change door S/W...
  • Page 26 9-2 Refrigerator room lamp doesn’t work Checking flow Result & SVC Action Check the Refrigerator door switch. If feel sticky, Change the door s/w. Check the door S/W resistance. Status Result SVC Action Go to the 3 Normal Change door S/W Infinity Go to the 3 Infinity...
  • Page 27 9-3 Poor cooling in Fresh food section Checking flow Result & SVC Action Check the sensor resistance. (1) To (2) Result 23°F / -5°C 38.5 ~ 36.5 32°F / 0°C 30.5 ~ 29.5 41°F / 5°C 24.5 ~ 23.5 50°F / 10°C 20 ~ 19 <CON4>...
  • Page 28 Checking flow Result & SVC Action Damper checking method. Test Damper Inputting TEST Mode, SVC Action Mode State Check the damper and PCB. 1 Mode Open Damper is normal. (Explain to customer) 2 Mode Closed Change the damper mode working Test Point Result SVC Action...
  • Page 29 9-3 Poor cooling in Freezer compratment Checking flow Result & SVC Action Check the sensor resistance. (1) To (2) Result -22°F / -30°C 40.5 ~ 38.5 -13°F / -25°C 30.5 ~ 28.5 -4°F / -20°C 23 ~ 21.5 17.5 ~ 16.5 5°F / -15°C <CON4>...
  • Page 30 9-4 Over cooling in Fresh food compartment Checking flow Result & SVC Action Check the sensor resistance. (1) To (2) Result 23°F / -5°C 38.5 ~ 36.5 32°F / 0°C 30.5 ~ 29.5 41°F / 5°C 24.5 ~ 23.5 <CON4> 50°F / 10°C 20 ~ 19 The sensor is determined by...
  • Page 31 10. Reference 10-1 TEST MODE and Removing TPA 1. How to make TEST MODE If you push the test button on the Main PCB, the refrigerator will be enter the TEST MODE. * 1 time : Comp / Damper / All FAN on (All things displayed) * 2 times : Damper closed (22 22 displayed)
  • Page 32 10-2 TEMPERATRUE CHART - FRZ AND ICING SENSOR TEMP RESISTANCE VOLTAGE -39°F (-40°C) 4.09 V 73.29 -30°F (-35°C) 3.84 V 53.63 -21°F (-30°C) 3.55 V 39.66 -13°F (-25°C) 3.23 V 29.62 -4°F (-20°C) 2.89 V 22.33 5°F (-15°C) 2.56 V 16.99 14°F (-10°C) 2.23 V...
  • Page 33 10-3 TEMPERATRUE CHART - REF AND DEF SENSOR TEMP RESISTANCE VOLTAGE -39°F (-40°C) 4.48 V 225.1 -30°F (-35°C) 4.33 V 169.8 -21°F (-30°C) 4.16 V 129.3 -13°F (-25°C) 3.95 V 99.30 -4°F (-20°C) 3.734 V 76.96 5°F (-15°C) 3.487 V 60.13 14°F (-10°C) 3.22 V...
  • Page 34 10-4 How to check the Fan-Error (1) EBR673480 After sending a signal to the fan, the MICOM checks the BLDC fan motor s lock status. If there is no feedback signal from the BLDC fan, the fan motor stops for 10 seconds and then is powered again for 15 seconds.
  • Page 35 Compressor Troubleshooting Step 1) Open PWB cover Step 2) Check for blinking frequency of LED, PWB If compressor is normal, it does not blink : Refer to the next page to find out what actions to take according to how many times LED blink - 35 -...
  • Page 36 Actions to take according to Led blinking frequency LED operating condition Cause Service guideline 1.After resetting LED two - time repetiton power, check if it is PCB part defect running normal 2.If the same (piston overrun) symptom arises after - off - - off - - off repeating...

  • Page 37: Component Testing Information

    11. COMPONENT TESTING INFORMATION 11-1 Defrost Controller Assembly Function - Controller assembly is consist of 2 kinds of part those are fuse-m and sensor. we can decide part is defect or not when we check the resistance. - Fuse-m can cut off the source when defrost heater operate the unusual high temperature. - Sensor give temperature information to Micom How to Set a ohmmeter to the 2 housing pin.
  • Page 38 11-2 Sheath Heater Function Sheath heater is a part for defrost. All heating wire is connected to only one line. So we can decide part is defect or not when we check the resistance. How to Measure (1) (2) Set a ohmmeter connect to The 2 housing pin. Measure the 2 pin connected to Sheath Heater.
  • Page 39 11-3 Door Heater Assembly Function The heater is designed to prevent the raising dew from door. How to Measure Standard Test Point Ressult (1) to (2) 2.3 ~ 2.9 - 39 -...
  • Page 40 11-4 Door Switch Function The switch sense if the door open or close. - When the door open, lamp on. - When the door open, the switch give information to Micom. When the door open, internal contact operate on and off moving plunger of door switch up and down.
  • Page 41 11-5 Dispenser DC Motor Function - Dispenser DC Motor : When customer push the dispenser button, Pull duct door and abstract from ice bank. How to Measure Dispensor DC Motor Standard Dispenser DC Motor Test Points Result (1) to (2) 9.9 ~ 12.1 - 41 -...
  • Page 42 11-6 AC Motor ASSEMBLY Function The In-door motor of AC motor assembly pushes ices to the dispenser. How to < In-door Motor > < In-door Motor > Measure Take out the male Take out the male housing from housing from female housing female housing Measure the...
  • Page 43 11-7 Damper Function The damper supplies the cold air at freezer room to chillroom by using the damper’s plate. Chillroom is colder than before when damper’s plate is open. When damper’s plate is close, chillroom’s temperature will rise. How to Measure <...
  • Page 44 11-8 Lamp Socket Function The lamp socket connect cover lamp assembly to lamp. The lamp socket fix lamp and unite lamp and cover lamp assembly. The lamp socket supply electric source to lamp also. How to Measure Check the resistance between connector of housing and connector of lamp socket. It means check whether or not applying an electric current.
  • Page 45 11-9 Flow Sensor Function Flow Sensor (in machine room) Count the water quantity from city water to water filter in refrigerator How to Measure Flow Sensor (in machine room) Standard Test Points Result Red wire to Black wire 4 ~ 30 - 45 -...
  • Page 46 12. TROUBLESHOOTING 12-1 INFORMATION OF LINEAR COMPRESSOR The information tag provides compressor model, refrigerant, serial number and safety approval Compressor Label 1. Compressor Model F C 9 0 L A N A Operating Type Series name A : A-Inverter DLF/FA/FB E : E-Inverter Displacement Rated Voltage...
  • Page 47 To reduce noise level, the piston stroke is slowly increased to full power during start up. Step 1) Start up - Half stroke interval for first 30 seconds. Step 2) Ramp up - Stroke increases every 0.8sec until maximum stroke length is reached (about 3 min, 15 sec) Step 3) CVCF interval - 180V / 60Hz Step 1) Start up - Half stroke interval for first 20...
  • Page 48 Bridge Diodes converts 115V AC (Alternating current) to 115V DC (Direct current) The Voltage Multiplying circuit then increases the 115V DC to 230V DC. Then the IPM (Intelligent Power Module) converts the 230V DC to 230V AC. The converted AC power can be regulated to any required voltage and frequency. E-Inverter FC75LANE A-Inverter...
  • Page 49 Compressor Winding Resistance Check Compressor Winding Resistance Check 6 ~ 8 Ω Between Po and Co 6 ~ 8 Ω Between Po and Co LG Linear Compressor NOTE : Any Terminal to Ground should read Inf ( ~ ) Inf (~) 6 ~ 8 Ω...

  • Page 50: Service Diagnosis Chart

    12-2 SERVICE DIAGNOSIS CHART COMPLAINT POINTS TO BE CHECKED REMEDY • Is the power cord unplugged from the outlet? • Plug into the outlet. No Cooling. • Check if the power switch is set to OFF. • Set the switch to ON. •...

  • Page 51: Refrigeration Cycle

    12-3 REFRIGERATION CYCLE Troubleshooting Chart TEMPERATURE STATE OF STATE OF THE OF THE CAUSE REMARKS THE UNIT EVAPORATOR COMPRESSOR PARTIAL Freezer Low flowing sound of A little higher than • Refrigerant level is low due LEAKAGE compartment and Refrigerant is heard ambient to a leak.
  • Page 52 12-3-2 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 53: Ice Maker And Dispenser Working Principles And Repair

    13. ICE MAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR 13-1 Working Principles 13-1-1 Ice Maker Working Principles Power Input Level Ice Maker Cube Mould for “Initial Control” Initial Control after power is input. Ice Making Wait until the water in the cube mould is frozen Control after ice maker starts operation.
  • Page 54 13-2 Function of Ice Maker 13-2-1 Initial Control Function 1. When power is initially applied or reapplied after power cut, it detects level of ice maker cube mould after completion of MICOM initialization. The detecting lever moves up and down. 2.
  • Page 55 13-2-4 Ice Ejection Control Function 1. This is to eject ice from ice maker cube mould after ice making is completed. 2. If Hall IC signal is on within 3.6 seconds after ice ejection motor rotates in normal direction, it does not proceed ice ejection but waits.
  • Page 56 13-2-5 Test Function 1. It is to force the operation during operation test, service, and cleaning. The test switch is mounted under the automatic ice maker. The test function starts when the test switch is pressed for more than 0.5 second. 2.

  • Page 57: Exploded View & Replacement Parts List

    14. EXPLODED VIEW & REPLACEMENT PARTS LIST CASE PARTS CAUTION : Use the part number to order part, not the position number. 207B 503C 402A 103B 103A 207A 271B 207C 402A 503G 503E 406D 501F 610D 120A 409D 282G 503D 271D 500A 610A...
  • Page 58 FREEZER PARTS CAUTION : Use the part number to order part, not the position number. 250C 250D 145C 250E 250D 250C 136B 145G 131A 145J 145K 145F 145M 145J 237C 145H 136A - 58 -...
  • Page 59 REFRIGERATOR PARTS CAUTION : Use the part number to order part, not the position number. 141A 141A 141B 141B 141C 141C 141A 141A 141B 141B 141C 141C 161B 161C 141D 154A 151A 151B 151C 146E 161A 145E 162B 145D 162A - 59 -...
  • Page 60 DOOR PARTS CAUTION : Use the part number to order part, not the position number. 230B 230A 241A 231B 233B 233C 231A 233D 233A 241C 241B 234C 234D 234B 234A 212G 241D 241D 241D 244A 244A 241D 241E 241D 241E 243C 243C 243A...
  • Page 61 WATER AND ICEMAKER PARTS CAUTION : Use the part number to order part, not the position number. 600A 600B 616E 623A 623B 627B 619A 619E - 61 -...
  • Page 62 P/No. MFL47912326...

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