LG LMC25780 series Service Manual
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LG LMC25780 series Service Manual

LG LMC25780 series Service Manual

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See also: User Manual and Installation Instructions
REFRIGERATOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MODEL : LMC25780**
COLOR : WESTERN BLACK(SB)
ILLUMINA(AL)
SUPER WHITE(SW)

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  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. MODEL : LMC25780** COLOR : WESTERN BLACK(SB) ILLUMINA(AL) SUPER WHITE(SW)

  • Page 2: Table Of Contents

    CONTENTS SAFETY PRECAUTIONS ............................... 2 1. SPECIFICATIONS ................................3 2. PARTS IDENTIFICATION ..............................4 3. DISASSEMBLY ................................5-11 REMOVING AND REPLACING REFRIGERATOR DOORS ....................5 DOOR ....................................6-7 DOOR ALIGNMENT ................................7 LAMP ....................................8 MULTI DUCT ..................................8 MAIN PWB ................................... 8 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER ................

  • Page 3: Specifications

    1. SPECIFICATIONS 25 cu. ft ITEMS SPECIFICATIONS ITEMS SPECIFICATIONS DOOR DESIGN Side Rounded VEGETABLE TRAY Opaque Drawer Type DIMENSIONS (inches) X 34 X 69 (WXDXH) 25cu.ft COMPRESSOR Recipro NET WEIGHT (pounds) 324.18 (25cu.ft) EVAPORATOR Fin Tube Type COOLING SYSTEM Fan Cooling CONDENSER Wire Condenser TEMPERATURE CONTROL...

  • Page 4: Parts Identification

    2. PARTS IDENTIFICATION ADJUSTABLE REFRIGERATOR SHELVING The refrigerator compartment shelves are adjustable to allow flexibility for storage needs. MODULAR DOOR BINS Three interchangeable bins can be arranged to suit your storage needs. REMOVABLE ICE STORAGE BIN The ice storage bin can be removed to fill ice buckets,coolers,or pitchers.

  • Page 5: Disassembly

    3. DISASSEMBLY 3-1 REMOVING AND REPLACING REFRIGERATOR DOORS Removing Refrigerator Door CAUTION : Before you begin, unplug the refrigerator. Remove food and bins from doors. Left Door -FIG. 2 1. Open door. Loosen top hinge cover screw (1). Use flat tip screwdriver to pry back hooks on front underside of cover (2). Lift up cover. 2.

  • Page 6: Door

    3-2 DOOR Door Gasket Replacement 1. Insert gasket bracket clips Door Gasket Removal 1) Insert gasket bracket edge beneath door frame edge. 1. Remove door frame cover 2) Turn upper gasket bracket spring so that the spring Starting at top of cover and working down, snap cover ends are in the door channel.

  • Page 7: Door Alignment

    2) Press gasket into channels on the three remaining sides 3-3 DOOR ALIGNMENT of door. If the space between your doors is uneven, follow the instructions below to align the doors: 1. With one hand, lift the door you want to raise at middle hinge.

  • Page 8: Lamp

    3-4 LAMP 3-5 MULTI DUCT Unplug Refrigerator, or disconnect power at the circuit 1. Remove the upper and breaker. lower Caps by using a If necessary, remove top shelf or shelves. flat screwdriver, and remove 2 screws. (Figure 16) 3-4-1 Refrigerator Compartment Lamp 2.

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

    3-7 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER 3-7-1 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 10 3-7-2 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: Top Drawer

    3-8 TOP DRAWER To remove the freezer drawer, pull the drawer open to full extension. Remove the drawer and Ice Bin lifting the basket from the rail system. 3-9 BOTTOM DRAWER To remove the freezer drawer, pull the drawer open to full extension. Remove the lower DuraBase ®basket by lifting the basket from the rail system.

  • Page 12: Adjustment

    4. ADJUSTMENT 4-1 COMPRESSOR 4-2-3 PTC-Applied Circuit Diagram 4-1-1 Role Starting Method for the Motor 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 13: 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 current...

  • Page 14: Circuit Diagram

    5. CIRCUIT DIAGRAM - 14 -...

  • Page 15: Troubleshooting

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

  • Page 16: Other Electrical Components

    6-2 OTHER ELECTRICAL COMPONENTS Not cooling at all Compressor doesn't Check for open short or Cause run. incorrect resistance readings in the following components a. Starting devices Short, open, or broken. b. OLP Poor contact or shorted. c. Compressor coil Coil open or shorted.

  • Page 17: 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 18: Refrigeration Cycle

    6-5 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 19 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 Partial None Pattern? Equalization Equalization Test Test Very Fast Very Slow Very Slow Very Fast Fast...

  • Page 20: Operation Principle And Repair Method Of Icemaker

    7. ICE MAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR 7-1 Working Principles 7-1-1 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 21: Ice Maker Functions

    7-2 Function of Ice Maker 7-2-1 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 22 7-2-4 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 23 7-2-5 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 24: Description Of Function & Circuits Of Micom

    8. DESCRIPTION OF FUNCTION & CIRCUITS OF MICOM 8-1 FUNCTION 8-1-1 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 25 8-1-6 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 26 8-1-9 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 27 8-1-10 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 28 8-1-11 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 29: Pcb Picture

    9. PCB Picture 9-1 Main PCB CON8 CON7 CON6 CON5 Test S/W Water control Dip S/W CON1 CON2 CON3 CON4 * EBR523044 - 29 -...

  • Page 30: Display Pcb

    9-2 Display PCB CON101 CON101 * 6871JB1374 - 30 -...

  • Page 31: Troubleshooting With Error Display

    10. Troubleshooting With Error Display When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 10-1 Freezer Sensor Error Defect Symptom Check Point <Er FS> <CON5> Check for a loose connection. <CON5>...
  • Page 32 Using your Ohmmeter, Read the resistance of the sensor. The sensor is determined by the temperature. For example, 23 indicates -4°F. (1) To (2) Result -22°F / -30°C -13°F / -25°C -4°F / -20°C 5°F / -15°C 14°F / -10°C 23°F / -5°C 32°F / 0°C <Temperature table>...

  • Page 33: Refrigerator Sensor Error

    When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 10-2 Refrigerator Sensor Error Defect Symptom Check Point <Er rS> <CON5> Check for a loose connection. <CON5> Disconnect the wire connector. Set the meter to Check the White to White (1)WH(2)WH...
  • Page 34 Using your Ohmmeter, Read the resistance of the sensor. The sensor is determined by the temperature. For example, 30 indicates 32°F. (1) To (2) Result 23°F / -5°C 32°F / 0°C 41°F / 5°C 50°F / 10°C 19.5 59°F / 15°C <Temperature table>...

  • Page 35: Defrost Sensor Error

    When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 10-3 Defrost Sensor Error Defect Symptom Check Point <Er dS> <CON5> Check for a loose connection. <CON5> Disconnect the wire connector. Set the meter to Check the Orange to Orange.
  • Page 36 Remove the grill assembly in freezer room. Check the Orange to Orange. (1)BO (2)BO Using your Ohmmeter, Read the resistance of the sensor. The sensor is determined by the temperature. For example, 23 indicates -4°F. (1) To (2) Result -22°F / -30°C -13°F / -25°C -4°F / -20°C 5°F / -15°C...

  • Page 37: Ice Maker Sensor Error

    When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 10-4 Ice Maker Sensor Error Defect Symptom Check Point <Er IS> <CON7> Check for a loose connection. <CON7> Disconnect the wire connector. Set the meter to Check the Red to Orange.
  • Page 38 Using your Ohmmeter, Read the resistance of the sensor. The sensor is determined by the temperature. For example, 23 indicates -4°F. (1) To (2) Result -22°F / -30°C -13°F / -25°C -4°F / -20°C 5°F / -15°C 14°F / -10°C 23°F / -5°C 32°F / 0°C <Temperature table>...

  • Page 39: Defrost Heater Error

    When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 10-5 Defrost Heater Error Defect Symptom Check Point <Er dH> <Freezer> <CON4&CON5> Check the Freezer door gasket sealing. Remove the grille assembly in freezer. Unplug the defrost control assembly.
  • Page 40 Check the Orange to Orange. (1)B0 (2)B0 <Defrost control> (1) To (2) Result 23°F / -5°C 32°F / 0°C 41°F / 5°C 50°F / 10°C 19.5 59°F / 15°C Check the Black to Black. (1)BK (2)BK Test Point Result (1) To (2) 32~42 - 40 -...
  • Page 41 Check for a loose connection. <CON4> <CON5> Disconnect the wire connector. Set the meter to Check the Orange to Orange. (1)BO (2)BO <CON5> <Defrost sensor> (1) To (2) Result 23°F / -5°C 32°F / 0°C 41°F / 5°C 50°F / 10°C 19.5 59°F / 15°C - 41 -...
  • Page 42 Input the TEST 3 MODE. Push the button 3 times. Set the meter to V. Check the Blue to Brown. <CON3 & CON4> (1)BL (2)BN Test Point Result (1) To (2) 115V - 42 -...
  • Page 43 Release the TEST 3 MODE. Push the button 1 times. (Normal state) Check the Blue to Brown. <CON3 & CON4> (1)BL (2)BN Test Point Result (1) To (2) - 43 -...

  • Page 44: Freezer Fan Error

    When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 10-6 Freezer Fan Error Defect Symptom Check Point <Er FF> <Freezer> <CON8> Check for a loose connection. Reset and Push the TEST button. (TEST 1 MODE) Open the freezer door and check the air flow.
  • Page 45 If feel air come out, It’s OK. If not, Check the F-fan voltage. (1)WH (2)GY (3)PR <CON8> Test Point Result SVC Solution (1) To (2) Blew 12 V Change the PCB (2) To (3) 0 or 5 V Change the motor - 45 -...
  • Page 46 Although PCB make a voltage, the fan is not working, Check the Fan motor. Remove the gill assembly in freezer room. Check the connector status. (Frozen, short, ect.) Check the Fan blade. (Frozen, lock, ect.) Rotate fan using your hand. It feel sticky, change the motor.

  • Page 47: Condenser Fan Error

    When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 10-7 Condenser Fan Error Defect Symptom Check Point <Machine room> <Er CF> <CON8> Check for a loose connection. Reset and Push the TEST button. (TEST 1 MODE) Check the fan rotating.
  • Page 48 Check the C-fan voltage. (1)SB (2)BO (3)BN <CON8> Test Point Result SVC Solution (1) To (2) Blew 12 V Change the PCB (2) To (3) 0 or 5 V Change the motor Rotate fan using your hand. It feel sticky, change the motor. (cause of ice or rust inside of motor) - 48 -...

  • Page 49: Communication Error(Display Led Off)

    Because the signal of Tx and Rx is composed of the combination of digital code, you can’t measure the voltage exactly. 10-8 Communication Error(Display LED off) Defect Symptom Check Point <Lamp Cover> <CON101> Check for a loose connection. Check the Purple to Red. (1)RD (2)PR <CON101>...
  • Page 50 Check the Blue White to Red. (1)BL/WH (2)RD Test Point Result Solution (1) To (2) 0V or 5V Change the Display PCB Check the White Red to Red. (1)WH/RD (2)RD Test Point Result Solution (1) To (2) 0V or 5V Change the Main PCB - 50 -...

  • Page 51: Troubleshooting Without Error Display

    11. Troubleshooting Without Error Display When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 11-1 Freezer Room Lamp does not work. Defect Symptom Check Point <CON5 & CON4> <Freezer Lamp> Push the door s/w and check the s/w state.
  • Page 52 Check the Pink to Pink. (1)PK (2)PK <CON5> Part F/Door Test Point Result Closed (1) To (2) CON5 Open (1) To (2) Check the Blue to Red. (2)RD (1)BL <CON3&CON4> Part F/Door Test Point Result Closed (1) To (2) 0 ~ 2 V CON4 Open (1) To (2)

  • Page 53: Refrigerator Room Lamp Does Not Work

    When you check the resistance values, be sure to turn off the power WARNING and wait for the voltage-discharge sufficiently. 11-2 REFRIGERATOR Room LAMP does not work Defect Symptom Check Point <CON6 & CON4> <Refrigerator Lamp> Push the door s/w and check the s/w state. If feel sticky, Change the door s/w.
  • Page 54 Check the Gray to Gray. (1)GY (2)GY <CON6> Part F/Door Test Point Result Closed (1) To (2) CON6 Open (1) To (2) Check the Blue to Pink. (2)PK (1)BL <CON3&CON4> Part F/Door Test Point Result Closed (1) To (2) 0 ~ 2 V CON4 Open (1) To (2)

  • Page 55: Poor Cooling In The Refrigerator Compartment

    Because poor cooling is related to temperature, there can be many causes. Therefore, you must check every function of the PCB Board. 11-3 POOR COOLING in the refrigerator compartment Check for a loose connection. Reset and Push the TEST button. (TEST 1 MODE) Open the freezer door and check the air flow.
  • Page 56 If the air is not coming out, check the fan and damper. To judge the damper defect, check the resistance. (3)BL (1)RD (4)YL (2)WH Test Point Result (1) To (4) 373 ~ 456 (2) To (3) 373 ~ 456 To judge the fan defect, Reference Freezer fan error and Condenser fan error.

  • Page 57: Over-Cooling In The Refrigerator Compartment

    Because poor cooling is related to temperature, there can be many causes. Therefore, you must check every function of the PCB Board. 11-4 OVER-COOLING in the refrigerator compartment Check for a loose connection. Reset and Push the TEST button. (TEST 1 MODE) Open the freezer door and check the air flow.
  • Page 58 Pust the TEST button 1 more time. (TEST 2 MODE) If the air is not coming out of vent, It’s OK. If the air is coming out of vent, Check the damper. (3)BL (1)RD (4)YL (2)WH Test Point Result (1) To (4) 373 ~ 456 (2) To (3) 373 ~ 456...

  • Page 59: Reference

    12. Reference WARNING When you push the test button, be careful to avoid electrical shock. 12-1 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...

  • Page 60: Temperatrue Chart - Frz And Icing Sensor

    WARNING When you push the test button, be careful to avoid electrical shock. 12-2 TEMPERATRUE CHART - FRZ AND ICING SENSOR TEMP RESISTANCE VOLTAGE -39°F (-40°C) 73.29 4.09 V -30°F (-35°C) 53.63 3.84 V -21°F (-30°C) 39.66 3.55 V -13°F (-25°C) 29.62 3.23 V -4°F (-20°C)

  • Page 61: Temperatrue Chart - Ref And Def Sensor

    WARNING When you push the test button, be careful to avoid electrical shock. 12-3 TEMPERATRUE CHART - REF AND DEF SENSOR TEMP RESISTANCE VOLTAGE -39°F (-40°C) 225.1 4.48 V -30°F (-35°C) 169.8 4.33 V -21°F (-30°C) 129.3 4.16 V -13°F (-25°C) 99.30 3.95 V -4°F (-20°C)

  • Page 62: 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. 410A 207B 402A 409D 103B 271B 103A 503C 207A 402A 271B 406D 610D 503D 501F 610B 120A 503G 503E 282G 410G...
  • Page 63 FREEZER PARTS CAUTION: Use the part number to order part, not the position number. 131A 136B 250G 251A 251B 250G 237C 203D 203C 136A - 63 -...
  • Page 64 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 162B 145D 162A - 64 -...
  • Page 65 DOOR PARTS CAUTION: Use the part number to order part, not the position number. 230B 230A 241A 231B 233B 233C 233D 233A 231A 241C 234C 241B 234D 234B 234A 212G 241D 241D 241D 244A 244A 241D 241D 241E 241E 243C 243C 243A 243A...
  • Page 66 WATER AND ICEMAKER PARTS CAUTION: Use the part number to order part, not the position number. 600A 600B 616E 623A 623B 619A 619E - 66 -...
  • Page 67 P/No. MFL62188103 JUL., 2009 Printed in Korea...

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