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LG LFC25770ST/01 Service Manual
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LG LFC25770ST/01 Service Manual

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R E FR IG E R ATOR
S E R VIC E MANUAL
C A UT ION
B E F OR E S E R V IC ING T HE P R ODUC T,
R E A D T HE S A F E T Y P R E C A UT IONS IN T HIS MA NUA L .
MODE L S : L F C 25770S T / 01

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Summary of Contents for LG LFC25770ST/01

  • Page 1 R E FR IG E R ATOR S E R VIC E MANUAL C A UT ION B E F OR E S E R V IC ING T HE P R ODUC T, R E A D T HE S A F E T Y P R E C A UT IONS IN T HIS MA NUA L . MODE L S : L F C 25770S T / 01...
  • Page 2 E C N (E ngineering C hange Number) LFC25770 /01 Loc No. Part Name 404A DC Motor 249E Rail,Slide 249F Rail,Slide 317A Drier Assembly 249B Connector Assembly 249A Connector Assembly 200A Door Assembly,Freezer 249C Holder,Rail 249D Holder,Rail - 2 -...
  • Page 3 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 4 1. SPECIFICATIONS ITEMS SPECIFICATIONS ITEMS SPECIFICATIONS DOOR DESIGN Side Rounded VEGETABLE TRAY Opaque Drawer Type COOLING SYSTEM Fan Cooling COMPRESSOR PTC Starting Type TEMPERATURE CONTROL Micom Control EVAPORATOR Fin Tube Type Full Automatic CONDENSER Wire Condenser DEFROSTING SYSTEM Heater Defrost REFRIGERANT R-134a (115 g) DOOR FINISH...
  • Page 5 2. PARTS IDENTIFICATION Digital Sensor Control Dairy Bin Refrigerator Light Egg Box Shelves Modular Door Bin Modular Door Bin Bottle Holder Optibin Crisper Keeps fruits and vegetable fresh and crisp Modular Door Bin Glide'N'Serve Customcube Icemaker Pullout Drawer Ice Bin Durabase Tilt- Out Door Basket...
  • Page 6 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 7 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 8 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 9 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 10 3-3-3 PULL OUT DRAWER To separate the drawer, push the front left and right hooks in ① 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 ③ direction. To install, reposition the gear part of rear left and right side of the drawer after pulling out both rails as much as possible, and gently push down both left and right side while checking the hook on the front part.
  • Page 11 4. ADJUSTMENT 4-1 COMPRESSOR 4-1-1 Role 4-2-3 PTC-Applied circuit diagram The compressor intakes low temperature and low pressure Starting method for the motor ● gas from the evaporator of the refrigerator and compresses this gas to high-temperature and high-pressure gas. It then ELECTRICAL AND DIMENSION DIAGRAM delivers the gas to the condenser.
  • Page 12 4-3 OLP (OVERLOAD PROTECTOR) 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 13 5. CIRCUIT DIAGRAM BETTER MODEL - 13 -...
  • Page 14 6. TROUBLESHOOTING 6-1 COMPRESSOR AND ELECTRIC COMPONENTS Remove TSD-Starter (Rated Voltage Power Source. from compressor and ±10%)? measure voltage between terminal C of compressor and terminal 5 or 6 of TSD. Replace OLP. No Voltage. OLP disconnected? Check connection condition. Reconnect.
  • Page 15 6-2 TSD AND OLP Normal operation of Separate TSD-Starter Observation value is compressor is from compressor and 115V/60Hz : 6.8 Ω ±30% impossible or poor. measure resistance between No. 5 and 6 of PTC-Starter with a tester. (Figure 19) The resistance value Replace is 0 Ω...
  • Page 16 6-3 OTHER ELECTRICAL COMPONENTS ▼ Not cooling at all Compressor Check for open short or Cause doesn't run. incorrect resistance readings in the following components a. Starting devices Short, open, or broken. Poor contact or b. OLP shorted. c. Compressor coil Coil open or shorted.
  • Page 17 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 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 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. Icemaking • Waits until water becomes cold after starting the icemaking Mode operation.
  • Page 21 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 22 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 23 7-2-5 Function TEST 1. This is a compulsory operation for test, service, cleaning, etc. It is operated by pressing and holding the fill key for 3 seconds. 2. The test works only in the icemaking 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 24 8. DESCRIPTION OF FUNCTION & CIRCUIT 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. test button at main PCB conttroller. 2. The test mode is operated by pressing 3.
  • Page 29 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 30 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 31 8-2-4 Load / Fan Motor Drive & Open Door Detection Circuit 1. Load Drive Condition Check Circuit Pin Number Pin Number Output Voltage Compressor Con1 pin1 Con1 pin3 115 VAC Defrost heater Con2 pin1 Con1 pin3 115 VAC F,R-lamp Con2 pin,3.5 Con1 pin3 115 VAC Frech Door Heater...
  • Page 32 3. Open Door Detection Circuit Check Measurement (Pin 1 & 2 of con7) Freezer/ Location (Pin 5 & 6 of con5) Refrigerator Door Closed Open - 32 -...
  • Page 33 8-2-5 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 34 8-3 RESISTANCE SPECIFICATION OF SENSOR RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR & TEMPERATURE SENSOR DEFROST SENSOR & ROOM SENSOR - 20°C 22.3 ㏀ 77 ㏀ - 15°C 16.9 ㏀ 60 ㏀ - 10°C 13.0 ㏀ 47.3 ㏀ - 5°C 10.1 ㏀ 38.4 ㏀...
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  • Page 36 - 36 -...
  • Page 37 8-5 MAIN PWB ASSEMBLY AND PARTS LIST 8-5-1 Main PWB Assembly - 37 -...
  • Page 38 9. E XP L ODE D V IE W & R E P L A C E ME NT PA R T S L IS T C AS E PAR TS C AUT ION: Us e the part number to order part, not the pos ition number. 207B 402A 103B...
  • Page 39 FR E E ZE R PAR TS C AUT ION: Us e the part number to order part, not the pos ition number. 250C 250D 145C 250E 250D 250C 145G 136B 145J 131A 145K 145F 145M 145J 145H 237C 136A...
  • Page 40 REFRIGERATOR PARTS CAUTION: Use the part number to order part, not the position number. 147C 141A 147A 141A 141B 141B 141C 141C 141A 141A 141B 141B 141C 141C 161B 161C 141D 154A 151A 151B 151C 146E 161A 162B 145D 162A * : on some models...
  • Page 41 DOOR PAR TS C AUT ION: Us e the part number to order part, not the pos ition number. 230B 230A 241A 231B 233B 233C 233D 233A 231A 241C 234C 241B 234B 234D 234A 212G 241D 241D 244A 241D 244A 241E 241E 243C...
  • Page 42 WATE R AND IC E MAK E R PAR TS C AUT ION: Us e the part number to order part, not the pos ition number. S 13 602A 600B 600A 616E 616K 623A 623B 627B 619A...
  • Page 43 P/No. MFL47912301 FEB., 2008 Printed in Korea...