LG LFC24770ST Service Manual
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LG LFC24770ST Service Manual

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REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
Models:
LFC22770**
LFC24770**
LFC24786**
Colors:
Stainless (ST)
Smooth Black (SB)
Super White (SW)

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Summary of Contents for LG LFC24770ST

  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. Models: LFC22770** LFC24770** LFC24786** Colors: Stainless (ST) Smooth Black (SB) Super White (SW)

  • Page 2: Table Of Contents

    CONTENTS SAFETY PRECAUTIONS ………………………………………………………………… …………… ….. 1. Specifications ………………………………………………………………………… ………………..2. Parts Identification ……………………………………………………………………......3. Disassembly …………………………………………………………………………....……..6-11 Removing and Replacing the refrigerator door …………………………........Door ………………………………………………………………………………………………….. Door Alignment ………………………………………………………………………..……….. Fan and Fan Motor (Evaporator) ………………………………………………....……… Defrost Control Assembly ………………………………………………………………....Lamp …………………………………………………………………………………………….……...

  • Page 3: Specifications

    1. SPECIFICATIONS SPECIFICATIONS Super Super Super Smooth Stainless Smooth Stainless Smooth Stainless White White White Color Black Steel Black Steel Black Steel (29 3/4 x 35 1/2 x 68 1/2) in (32 3/4 x 35 1/2 x 69 7/8) in Dimensions (W*D*H) Net Weight 237.4 Lb...
  • Page 4 Description 22cuft 24cuft Depth with Handles 35 1/2 35 1/2 Depth w/o Handles Depth w/o Doors Depth (Total with door open) 44 3/4 Height to Top of Door Hinge 68 1/2 69 7/8 Height to Top w/out Hinge 67 1/4 68 5/8 Width 29 3/4...

  • Page 5: Parts Identification

    2. PARTS IDENTIFICATION LED interior lamps Adjustable Refrigerator Shelf The interior lamps light up the The shelves in your refrigerator inside of the refrigerator. are adjustable to meet your individual storage needs. Dairy Product Bin Used to preserve dairy products. Modular Door Bins Interchangeable bins can be...

  • Page 6: Disassembly

    3. DISASSEMBLY 3-1 REMOVING AND REPLACING REFRIGERATOR 3-2 DOOR DOOR • Mullion Removal To remove and replace the refrigerator door: 1. Remove 2 screws. CAUTION: Before you begin, remove food and bins from the doors. 2. Lift mullion up carefully. •...

  • Page 7: Door Alignment

    • Mullion Replacement <22cu.ft> If the space between your doors is uneven, follow the 1. Connect wire harness. instructions below to align the doors With one hand, lift up the door that you would like to raise at the middle hinge. With your other hand, use pliers to insert snap ring as shown.

  • Page 8: Lamp

    3-6 LAMP 3-8 MAIN PWB 1) Loosen 3 screws on the PWB cover. Unplug Refrigerator, or disconnect power at the circuit breaker. If necessary, remove top shelf or shelves. 3-6-1 Refrigerator Compartment Lamp 1) Unplug refrigerator power cord from electric outlet. 2) Put flat screwdriver into service hole and remove cover of refrigerator light.

  • Page 9: How To Remove And Reinstall The Pullout Drawer

    3-9 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER 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 10 3-9-2 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 11: Pull Out Drawer

    3-10 PULL OUT DRAWER Top Drawer 1. To remove the Top drawer. Pull the drawer out to full extension. Lift the front of the drawer up, then pull it straight out. 2. To install, slightly tilt up the front and insert the drawer into the frame and push it back into push it back place. 3-11 COVER T/V ASSEMBLY 1) Refer to sections “How to remove the left refrigerator door”...

  • Page 12: Adjustment

    4. ADJUSTMENT 4-1 COMPRESSOR 4-2-3 Compressor protection logic 4-1-1 Role Since linear Comp conducts linear reciprocating motion, we The compressor intakes low temperature and low pressure have protection logic for compressor, motor and PCB as the gas from the evaporator of the refrigerator and compresses below.

  • Page 13: Circuit Diagram

    5. CIRCUIT DIAGRAM CIRCUIT DIAGRAM MEZ65042403...

  • Page 14: Pcb Picture

    6. PCB PICTURE 6-1 Main PCB P/No & MFG Picture CON8 Drawer CON7 CON201 EBR770425** (2013.05~) CON5 CON1 CON3 CON2 CON8 Swing CON7 EBR766714** . ~) 2013 05 CON9 CON4 CON5 CON3 CON1...
  • Page 15 6-2 Display PCB & Sub PCB P/No Picture CON01 EBR766839** (2013.05~)

  • Page 16: Troubleshooting With Error Display

    7. TROUBLESHOOTING WITH ERROR DISPLAY 7-1 Freezer Sensor Error (FS E) Checking flow Result & SVC Action Check for loose connection in CON7 1-. Unplug connector from CON7. Result SVC Action 2-. Check resistance between wires Blue/White to Blue/White Short Change the sensor 0 Ω...
  • Page 17 7-2 Refrigerator Sensor Error (rS E) Checking flow Result & SVC Action Check for loose connection in CON7 1-. Unplug connector from CON7. Result SVC Action 2-. Check resistance between wires White to White Short Change the sensor 0 Ω Open Replace the refrigerator <Drawer Model>...
  • Page 18 7-3 Icing Sensor Error (IS E) Checking flow Result & SVC Action Check for loose connection in CON8 <Drawer Model> Result SVC Action 1-. Unplug connector from CON8 Short Change the sensor 0 Ω 2-. Check resistance between wires Red to Orange Open Replace the refrigerator Check the Temp and...
  • Page 19 7-4 Defrost Sensor Error (dS E) Checking flow Result & SVC Action Check for a loose connection. 1. Check the wires Orange to Orange Result SVC Action Short Change the sensor 0 Ω Open Replace the refrigerator Check the Temp and Other Normal resistance (Table-3)
  • Page 20 7-5 Defrost Heater Error (dH E) Checking flow Result & SVC Action Check the Door gasket Part Result SVC Action Go to the 3 0 Ω Fuse-M 1.- Check for loose connection in defrost Change Fuse-M Other control part connector. 2-.
  • Page 21 7-5 Defrost Heater Error (dH E) Checking flow Result & SVC Action Check voltage between wires Blue to Red <Drawer Model> Result SVC Action Explain to customer 112 ~ 116 V Replace Main PCB <Swing Model>...
  • Page 22 7-6 Freezer Fan Error (FF E) 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. ※ While an error code is displayed, No windy Go to 3 the fan is not working.
  • Page 23 7-7 Condenser Fan Error (CF E) 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 7-8 Communication Error (CO E) Checking flow Result & SVC Action Check for loose connection in CON101 from PCB Display Check voltage between wires Red to Blue Result SVC Action 12 V Go to the 3 CON101 Check the Hinge <CON101>...
  • Page 25 7-8 Communication Error (CO E) Checking flow Result & SVC Action Check voltage between wires Blue to Purple Result SVC Action <Drawer Model> 0 V or 5 V Change the Main PCB Other Explain to customer <Swing Model>...

  • Page 26: Troubleshooting Without Error Display

    8. TROUBLESHOOTING WITHOUT ERROR DISPLAY 8-1 Freezer room LED 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 Go to the 3...
  • Page 27 8-2 Refrigerator room LED 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 Switch resistance. Status Result SVC Action Go to the 3 Normal Other Change door Switch Infinity Go to the 3...
  • Page 28 8-2 Refrigerator room lamp doesn’t work Checking flow Result & SVC Action 1.- Check for loose connection in Status Result SVC Action Refrigerator LED Lamp connector. 2-. Check voltage between wires White to 0 ~ 2 V Explain to customer Closed Gray Other...
  • Page 29 8-3 Poor cooling in Fresh food section Checking flow Result & SVC Action 1-. Unplug connector from CON7 Temperature Result 2-. Check resistance between wires White to White 23°F °C <Drawer Model> 32°F °C 41°F °C 50°F °C 19.5 59°F °C <Swing Model>...
  • Page 30 8-4 Poor cooling in Freezer compartment Checking flow Result & SVC Action 1-. Unplug connector from CON7 2-. Check resistance between wires Temperature Result Blue/White to Blue/White. -22°F °C <Drawer Model> -13°F °C -4°F °C 5°F °C 14°F °C 23°F °C <Swing Model>...
  • Page 31 Checking flow Result & SVC Action Check the Fan motor. Rotate fan using your hand. Point Result SVC Action It feel sticky, change the motor. Motor Sticky Change the motor (cause of ice or rust inside of motor). 1.- Check for loose connection in CON7 2-.

  • Page 32: Reference

    9. REFERENCE 9-1 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. <Drawer Model> * 1 time : Comp / Damper / All FAN on (All things displayed) * 2 times : Damper closed (22 22 displayed)
  • Page 33 9-2 TEMPERATURE 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) 16.99 ㏀...
  • Page 34 9-3 TEMPERATURE 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) 60.13 ㏀...
  • Page 35 9-4 HOW TO CHECK THE FAN-ERROR 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. To determine that there is a fan motor malfunction, this process is repeated 3 times.

  • Page 36: Component Testing Information

    10. COMPONENT TESTING INFORMATION 10-1 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 37 10-2 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 38 10-3 Damper The damper supplies the cold air from the freezer to the refrigerator Function section. How to Measure < Damper Circuit > Blue Blue White White Check the 3 Yellow < extension > Check the Check the Check the resistance between connectors 1,3 and 2,4 .It means check whether or not applying an electric current.
  • Page 39 10-4 Door Switch Function The switch sense if the door open or close. - When the door open, light 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 40: Troubleshooting

    11. COMPRESSOR TROUBLESHOOTING PCB Check (Simplify) Protection Logic TEST 1 Mode A-inverter Con201 Time>30sec Power Off Power On PCB OK Disconnect & V 200 ≒ Replace Driver PCB Test Button Check Voltage about 200V past 30second after turn on Test Mode Comp Ref.
  • Page 41 11-1 Check A - There is PC Board located in the PCB case. The control driver is PC board for the compressor. - This step shows the source voltage of the driver PC board. Step1. Open PCB Cover Step2. Check Driver PCB LED Lamp * Driver PCB located in back plate cover behind the refrigerator.
  • Page 42 11-2 Check B B1. LED blinks once, then repeats (FCT0 Fault) Protection Logic Blink OFF Blink OFF - Purpose: Detecting motor current and voltage error - Check voltage at point A (Motor Voltage), point B (Motor Current) andPoint C (Capacitor Voltage) when compressor is off.
  • Page 43 B3. LED blinks five times, then repeats (Locked Piston: A & E Inverters) Protection Logic Blink Blink Blink Blink Blink OFF - Purpose: To detect locked piston - Cause: Lack of oil to the cylinder, cylinder or piston damaged and or restricted discharge. A Locked Piston can also be caused by foreign materials inside the compressor.
  • Page 44 B5. LED blinks seven times, then repeats Protection Logic Blink Blink Blink Blink Blink Blink Blink OFF - Purpose: Prevent high current due to IPM Short - Cause: Damaged IPM (Dead Short) - Test for a dead short at Point A with a VOM. - Logic: Compressor is forced off and tries to restart in 20 seconds.
  • Page 45 11-3 Check C C1. Harness Connection Check Check Process C2. Capacitor Specifications C3. Compressor Check - Step 1. Power off. Step 2. Check capacitor spec. (table1). Step3. Check resistance of point A Step 4. Check wire harness (INF ohm). Step 5. Check resistance at point B. Step 6. Point D. Check Check Harness...
  • Page 46 11-4 Check D D1. Activate Protection logic Cycle check with protection logic - We have to check Condenser fan and Freezer fan before performing Check D - Locked Piston, Current trip and stroke trip can be activated by other problems then the driver or compressor. →...
  • Page 47 Compressor Troubleshooting WARNING HIGH VOLTAGE Step 1) Open PCB cover Step 2) Check for blinking frequency of LED and PCB LED Lamp When 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...
  • Page 48 LED operating condition Cause Service guideline 1. Please check, Whether connector of PCB Parts compressor is attached defect or rightly or not. after LED two - time repetiton (Stroke Trip) Compress power off 2. After the first action, Connector You check on normal miss operation of - off -...
  • Page 49 11-5 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 50 11-6 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 51 11-6-2 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 52: Ice Maker And Dispenser Working Principles And Repair

    12. ICE MAKER AND DISPENSER ICE MAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR 12-1 Operation Principle Power Input Initial Control • Adjust Ejector to Start Position with power on. Icemaking • Waits until water in the TRAY is frozen after Ice Maker starts Control operation.
  • Page 53 12-2 Icemaker functions 12-2-1 Start Position 1) When power is initially applied or reapplied after power is cut, it detects feeler arm of the TRAY after completion of MICOM initialization. The detecting feeler arm moves up and down. 2) The feeler arm of icemaker tray is judged by output signal, high and low signal, of HALL SENSOR. Make the tray to horizontal by rotating ice ejection motor in normal or reverse direction so that High/Low signal can be applied to MICOM Pin (P22).
  • Page 54 MAXIMUM TILTING POINT Bank is not full HALL Sensor Output Signals Bank is full HALL Sensor Output Signals Ice checking AXIS LEVEL 30° Ice checking AXIS -160° -170° -32° -41° -53° -58° -80° -8°-0° -10° Lock Lock Ice ejection Icemaking original point 2±1 sec Horizontal...
  • Page 55 12-2-4 Test Icemaker Mode Test function starts when test switch is pressed for more than 3 seconds . User shouldn’t force operation while doing test mode, service or cleaning. Test switch will work only when ice tray its in horizontal position, not during ice ejection or water supplying. When pressing the Test Switch, feeler arm will sense and then ice tray will start ice ejection, after twisting, ice tray returns to initial position.
  • Page 56 13. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM 13-1 FUNCTION 13-1-1 Function 1. When the appliance is plugged in, it defaults to 37°F for the refrigerator and 0°F for the freezer. You can adjust the refrigerator and the freezer control temperature by pressing the ADJUST button. 2.
  • Page 57 13-1-6 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 second. These tones repeat every 30 seconds.
  • Page 58 13-1-9 Electrical Parts Are Turned On Sequentially Electrical parts such as compressor, defrosting heater, freezer fan, etc. are turned on in the following order to prevent noise and parts damage. Several parts are started at the same time at initial power on and are turned off together when test is completed.
  • Page 59 13-1-10 Defect Diagnosis Function 1. Automatic diagnosis makes servicing the refrigerator easy. 2. When a defect occurs, the buttons will not operate. 3. When the defect CODE removes the sign, it returns to normal operation (RESET). 4. The defect CODE shows on the refrigerator and freezer display. Error Code ①...
  • Page 60 13-1-11 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 test button at main PCB conttroller. 3.
  • Page 61 #EV# 14. EXPLODED VIEW LFC24770** CASE PARTS Caution: Use the part number to order part, not the position number. 503F 903D 281A 402A 409A 280A 271B 103B 103A 282E 120A 104E 501F 282G 282F 410G 145A 271A 501A 282D 411A 304A 619B 282B...
  • Page 62 #EV# LLFC22770**&LFC24770**&LFC24786** FREEZER PARTS Caution: Use the part number to order part, not the position number. 133B 145C 136B 131A 133B 145F 133A 160C 133A 132P 132Q 237C 132P 136D...
  • Page 63 #EV# LLFC22770**&LFC24770**&LFC24786** REFRIGRATOR PARTS Caution: Use the part number to order part, not the position number. 141A 141C 141A 141C 167B 145J 151C 145G 154A 145H 151A 154B 151B 133C 155B 160B 128A 170A 128B...
  • Page 64 #EV# LFC24770** DOOR PARTS Caution: Use the part number to order part, not the position number. 230A 230B 241F 233A 231A 231B 233B 212G 241C 233J 212J 212J 241C 212K 241C 212K 241C 241C 244A 244A 241D 212J 241E 212J 212K 243D 212K...
  • Page 65 LLFC22770**&LFC24770** ICEMAKER PARTS Caution: Use the part number to order part, not the position number. 600A 627A 619A...
  • Page 66 P/No. MFL62526049 August, 2013 Printed in Mexico...

This manual is also suitable for:

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