LG LSC27990TT Service Manual
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LG LSC27990TT Service Manual

LG LSC27990TT Service Manual

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REFRIGERATOR
SERVICE MANUAL
CAUTION
PLEASE READ CAREFULLY THE SAFETY PRECAUTIONS OF THIS MANUAL
BEFORE CHECKING OR OPERATING THE REFRIGERATOR.
MODEL : LSC27990TT
COLOR : TITANIUM

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Summary of Contents for LG LSC27990TT

  • Page 1 REFRIGERATOR SERVICE MANUAL CAUTION PLEASE READ CAREFULLY THE SAFETY PRECAUTIONS OF THIS MANUAL BEFORE CHECKING OR OPERATING THE REFRIGERATOR. MODEL : LSC27990TT COLOR : TITANIUM...

  • Page 2: Table Of Contents

    CONTENTS WARNINGS AND PRECAUTIONS FOR SAFETY ........................ 3 SPECIFICATIONS................................... 4 PARTS IDENTIFICATION ................................5 HOW TO INSTALL THE REFRIGERATOR ..........................6 HOW TO ADJUST DOOR HEIGHT............................6 FILTER ....................................7 HOW TO CONTROL THE ICEMAKER WATER SUPPLY....................8 MICOM FUNCTION ................................9 EXPLANATION OF MICOM CIRCUIT ...........................22 EXPLANATION OF PWB CIRCUIT .............................22 PWB PARTS DIAGRAM AND LIST.............................37...

  • Page 3: Warnings And Precautions For Safety

    WARNINGS AND PRECAUTIONS FOR SAFETY 8. Do not fray, damage, run over, kink, bend, pull out, or Please observe the following safety precautions to use the refrigerator safely and correctly and to prevent accident or twist the power cord. injury when servicing. 9.

  • Page 4: Specifications

    SPECIFICATIONS 1. Ref No. : GR-G277STSA(LSC27990TT) ITEMS SPECIFICATIONS ITEMS SPECIFICATIONS DIMENSIONS 1771 mm DRIER MOLECULAR SIEVE XH-7 in.) CAPILLARY TUBE ID Ø0.83 NET WEIGHT 145 kg (319.7 lbs.) FIRST DEFROST 4 - 5 Hours COOLING SYSTEM Fan Cooling DEFROST CYCLE...

  • Page 5: Parts Identification

    PARTS IDENTIFICATION 1. Ref No. : GR-G277STSA(LSC27990TT) PWB Cover Frame Display Water Tubes Dispenser Lamp Ice & Water Dispenser Button Freezer Refrigerator Compartment Compartment Dairy Product Corner Water Filter Lamp Automatic Icemaker Shelf Shelf Lamp Snack Drawer Shelf Door Rack...

  • Page 6: How To Install The Refrigerator

    HOW TO INSTALL REFRIGERATOR 1. How to Adjust Door Height of Refrigerator I Make the refrigerator level first. (If the refrigerator is not installed on a flat floor, the height of freezer and refrigerator door may not be the same.) 1) If the freezer door is lower than the refrigerator 2) If the freezer door is higher than the refrigerator door:...

  • Page 7: Filter

    NOTE: - To purchase replacement water filter cartridges, visit your local appliance dealer or part distributor. - You can also visit our website : www.lgappliances.com or call 1-877-714-7481. LG MDL PART NO MAKER NOTE: There will be some water (25cc) in the filter...

  • Page 8: How To Control The Icemaker Water Supply

    HOW TO INSTALL REFRIGERATOR 3. How to Control the Amount of Water Supplied to Icemaker. 3-1. Confirm the amount of water supplied to the icemaker. 1) Confirm the amount of water supplied to the icemaker (1) Press the button (Figure 1) to selsct the level of water (Optimum level Large Small.) 2) Icemaker Operation Test (Test mode)

  • Page 9: Micom Function

    MICOM FUNCTION 1. Monitor Panel 1-1. GR-G277STSA(LSC27990TT) Temperature Adjust Button Calendar & Anniversary Reminder MENU Selection Button Dispenser Selection Button Lock Button Door Alarm Button Dispenser Light Button - 9 -...
  • Page 10 MICOM FUNCTION 1-2. Display Second Function LCD Check Mode Demo Mode Door Alarm Buzzer Communication Data Check Mode Mute Mode 1. Door Alarm Buzzer Mute Mode Press button to the buzzer on or off. 2. Demo Mode Demo mode is available for displaying the refrigerator in a sales setting or similar condition. It allows the display, dispenser, lights, and fan to operate without running the compressor.
  • Page 11 MICOM FUNCTION 2. Description of Function 2-1-1. Function of Temperature Selection Division Power Initially On 1st Press 2st Press 3th Press 4th Press Setting Temperature Temperature COLD COLDER COLDEST COOL COOLER Control Freezer Control -2 °F -5 °F -8 °F 7 °F 1 °F Refrigeration...
  • Page 12 MICOM FUNCTION 2-1-3. Lock function 1. If desiring to lock the dislay the dispenser and control panel, push on button more than 3 seconds. Lock icon is appeared at the right of display with lock status. 2. The buzzer sound and control panel and dispenser function is not performed even if pressing display button other than lock key in the lock status.
  • Page 13 MICOM FUNCTION 2-2. Dispenser use selection You can select water or ice. ❉ Select WATER, CRUSHED ICE, or CUBED ICE by pressing the DISPENSER button as you desire. ❉ Use your cup to press lightly on the actuator. • Each graphic is indicated for the selected function. •...
  • Page 14 MICOM FUNCTION 2-5. ICE PLUS freezing 1. ICE PLUS freezing is a function to increase the cooling speed of the freezer compartment by running both the compressor and the fan simultaneously. 2. ICE PLUS is cancelled and the refrigerator returns to its default setting in the event of a power interruption. 3.
  • Page 15 MICOM FUNCTION 2-7. Control of variable type freezing fan 1. To increase cooling speed and response to load, the MICOM will vary the speed of the freezer fan between low and high. 2. The MICOM runs the fan at high speed only at power-up and for ICE PLUS cycles, and runs at low speed for all other settings.
  • Page 16 MICOM FUNCTION 2-11. Ringing of manual operation, manual frost defrost buzzer 1. The buzzer sounds briefly when the test button on the main PCB is pressed. 2. If you select manual operation, the buzzer sounds three times for second each, then it sounds three times for second each every thirty seconds until the door is closed.
  • Page 17 MICOM FUNCTION 2-14. Sequential operation of components Component products such as compressor, frost removal heater, freezing room fan, cooling fan, and step motor damper are sequentially operated as follows for preventing noise and part damage occurred due to simultaneous operation of many parts in applying initial power and completing test.
  • Page 18 3. If a failure code is released, the MICOM resets and normal operation continues. 4. The failure code is displayed on the display screen. All display graphics that are not part of the failure code are turned off (1) GR-G277STSA(LSC27990TT) - 18 -...
  • Page 19 MICOM FUNCTION ✻ LCD check function: If simultaneously pressing TEMPERATURE and button for a second in the lock status, a back light is turned on and all display LCD graphics on. If releasing the button, the LCD graphic displays the previous status. - 19 -...
  • Page 20 MICOM FUNCTION 2-16. Test Function 1. The test function assists in diagnosing the PWB and determining the exact mode of failure. 2. The test button is on the main PCB. When test mode is engaged, it will complete its test cycle and default to normal operation within 2 hours.
  • Page 21 MICOM FUNCTION 2-17. Dispenser Function 1. The dispenser allows serving ice and water without opening the door. 2. Pressing the dispenser switch dispenses crushed or cubed ice or water. If ice is selected, the switch operates the door solenoid also. The door will close 5 seconds after the ice is dispensed. 3.

  • Page 22: Explanation Of Micom Circuit

    Caution : Since high voltage (160 Vdc) is maintained at the power terminal, wait at least 3 minutes after unplugging the appliance to check the voltages to allow the current to dissipate. Voltage of every part is as follows: Part Voltage 120 Vac 160 Vdc 14 Vdc 12 Vdc 15.5 Vdc 5 Vdc (1) GR-G277STSA(LSC27990TT) - 22 -...
  • Page 23 MICOM (IC1). The oscillator (OSC1) must always be replaced with an exact replacement part. If this specification is changed, the change will affect the time calculations of the MICOM and it might not work at all. (1) GR-G277STSA(LSC27990TT) 1-3. Reset circuit The RESET circuit allows various parts of the MICOM, such as RAM, defrosting, etc., to be restarted from the initial state...
  • Page 24 ✽ In the TEST mode, the fan will stop if any door is opened. It will resume operation when the door is closed. Defrost AC Converting Refrigerator Dispenser Type of Load Compressor Heater Relay LAMP Heater Measuring part (IC6) IC6-16 IC6-13 IC6-12 IC6-15 IC6-14 Within 1 V Status 12 V (1) GR-G277STSA(LSC27990TT) - 24 -...
  • Page 25 EXPLANATION FOR MICOM CIRCUIT 1-5. Dispenser operation circuit (1) GR-G277STSA(LSC27990TT) 1) Check load driving status WATER VALVE PILOT GEARED SOLENOID SOLENOID Type of Load MOTOR CUBE DISPENSER VALVE WATER Measuring part IC7-15 IC7-14 IC7-13 IC7-12 IC7-11 Within 1 V Status...
  • Page 26 EXPLANATION FOR MICOM CIRCUIT 1-6. Door opening sensing circuit (1) GR-G277STSA(LSC27990TT) Measuring part IC1 (MICOM) No. (44, 45) / (45, 46) / (47, 48) Pin Door of Freezer and Refrigerator Closing 5 V ( A - B , C - D . Switch at both ends are at Off status) Opening 0 V ( A - B , C - D .
  • Page 27 EXPLANATION FOR MICOM CIRCUIT 1-7. Temperature sensing circuit (1) GR-G277STSA(LSC27990TT) The circuits involving the freezer and refrigerator sensors control the temperature in both the freezer and the refrigerator. The icemaker sensor detects when ice is made. The defrost sensor determines both the need for defrosting and the efficiency of the defrost operation.
  • Page 28 EXPLANATION FOR MICOM CIRCUIT 1-8. Switch entry circuit The following circuits are sensing signal form the damper motor reed switch for testing and diagnosing the refrigerator. (1) GR-G277STSA(LSC27990TT) 1-9. Option designation circuit (model separation function) (1) GR-G277STSA(LSC27990TT) The circuits shown above vary according to which features are included on your particular model.
  • Page 29 EXPLANATION FOR MICOM CIRCUIT 1-10. Stepping motor operation circuit (1) GR-G277STSA(LSC27990TT) The motor is driven by magnetism formed in the areas of the coils and the stator. Rotation begins when a HIGH signal is applied to MICOM Pin 33 of IC10 (TA7774F). This causes an output of HIGH and LOW signals on MICOM pins 34 and 35.
  • Page 30 3. This circuit stops the fan motor by cutting off power to the fan when it senses a lock-up condition. a , d part b part e part Motor OFF 2V or less 2V or less Motor ON 2 ~ 3V 12 ~ 14V 8 ~ 16V (1) GR-G277STSA(LSC27990TT) - 30 -...
  • Page 31 EXPLANATION FOR MICOM CIRCUIT 1-12. Temperature compensation and temperature compensation circuit 1. Temperature compensation in freezer and refrigerator (1) GR-G277STSA(LSC27990TT) Temperature compensation at refrigerator Temperature compensation at freezer Temperature compensation at refrigerator Temperature compensation at freezer Freezer Refrigerator Resistance value...
  • Page 32 EXPLANATION FOR MICOM CIRCUIT u Temperature compensation table at the refrigerator is as follows: Modification resistance 470 Ω 2 kΩ 3.3 kΩ 5.6 kΩ 8.2 kΩ 10 kΩ 12 kΩ 18 kΩ 33 kΩ 56 kΩ 180 kΩ Current resistance 0.5 °C 1 °C 1.5 °C...
  • Page 33 EXPLANATION FOR MICOM CIRCUIT 2. Compensation circuit for temperature at freezer (1) GR-G277STSA(LSC27990TT) Temperature compensation in CUT JCR1 +1 °C [+1.8 °F] +2 °C [+3.6 °F] JCR2 +1 °C [+1.8 °F] JCR3 -1 °C [-1.8 °F] -2 °C [-3.6 °F] JCR4 -1 °C [-1.8 °F]...
  • Page 34 Poor communication occurs if a continuous information exchange fail to continue for more than 2 minutes between main MICOM of main PCB and LCD dedicated MICOM for LCD control of display PCB. Main PCB L/Wire FD/H(4-wires) Display PCB DC 12V Main MICOM LCD(LED) dedicated MICOM Transmission (error status) Reception (notch status) (1) GR-G277STSA(LSC27990TT) - 34 -...
  • Page 35 EXPLANATION FOR MICOM CIRCUIT 2) Sensor resistance characteristics table Refrigerator sensor 1&2 Measuring Temperature (°C) Freezing Sensor Defrost sensor, Ambient sensor -20 °C 22.3 kΩ 77 kΩ -15 °C 16.9 kΩ 60 kΩ -15 °C 13.0 kΩ 47.3 kΩ -5 °C 10.1 kΩ...
  • Page 36 EXPLANATION FOR MICOM CIRCUIT 1-14. OptiFresh stepping MOTOR/Display (1) GR-G277STSA(LSC27990TT) - 36 -...

  • Page 37: Pwb Parts Diagram And List

    EXPLANATION FOR MICOM CIRCUIT 2. PWB parts diagram and list 2-1. PWB Assembly, main part diagram (1) GR-G277STSA(LSC27990TT) - 37 -...
  • Page 38 EXPLANATION FOR MICOM CIRCUIT 2-2. Parts list (1) GR-G277STSA(LSC27990TT) - 38 -...
  • Page 39 EXPLANATION FOR MICOM CIRCUIT - 39 -...
  • Page 40 EXPLANATION FOR MICOM CIRCUIT 2-3. DISPLAY ASSEMBLY part diagram (1) GR-G277STSA(LSC27990TT) - 40 -...
  • Page 41 EXPLANATION FOR MICOM CIRCUIT - 41 -...
  • Page 42 EXPLANATION FOR MICOM CIRCUIT 2-4. DISPLAY circuit diagram (1) GR-G277STSA(LSC27990TT) ARM920T Instruction Instruction External CACHE Coproc (16KB) Interface JTAG ARMSTDMI AMBA Processor core (Internal EMbedded ICE) Data WriteBack CACHE PA Tag Data (16KB) BUS CONT 4" TFT LCD CONT Arbitor/Decode USB HOST CONT.

  • Page 43: Pwb Circuit Diagram

    EXPLANATION FOR MICOM CIRCUIT 3. PWB Circuit Diagram may vary by model. (1) GR-G277STSA(LSC27990TT) - 43 -...
  • Page 44 EXPLANATION FOR MICOM CIRCUIT - 44 -...

  • Page 45: Icemaker And Dispenser Working Principles And Repair

    ICEMAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR 1. OPERATION PRINCIPLE 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 Mode icemaking operation. Harvest •...

  • Page 46: Function Of Icemaker

    ICEMAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR 2. ICEMAKER FUNCTIONS 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 47 ICEMAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR 2-5. Function TEST 1. This is a forced 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 48: Circuit

    CIRCUIT (1) GR-G277STSA(LSC27990TT) - 48 -...

  • Page 49: Trouble Diagnosis

    TROUBLE DIAGNOSIS 1. Troubleshooting CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK * Measuring instrument: 1) No power at outlet. 1. Faulty start Multi tester 2) No power on cord. I Check the voltage. Bad connection between plug and adapter (faulty plug). The distance between pins.
  • Page 50 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK I Heat a clogged evaporator to 2. No cooling. 2) Refrigeration system is clogged. check it. As soon as the Moisture Residual moisture Air Blowing. Not performed. cracking sound starts, the clogged.
  • Page 51 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 3. Poor Cooling 1) Refrigerant Partly leaked. Weld joint leak. Parts leak. 2) Poor defrosting capacity. I Check visually. Drain path (pipe) clogged. Inject adiabatics into drain Inject through the hose.
  • Page 52 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 3. Poor Cooling Residual Weak heat from heater. Sheath Heater - rated. frost. Too short defrosting time. Defrost Sensor. - Faulty characteristics. Seat-D (missing, location. thickness). Structural fault. Gasket gap. Air inflow through the fan motor.
  • Page 53 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 3. Poor Cooling 4) No cooling air circulation. Faulty fan motor. Fan is Fan shroud contact. - Clearance. constrained. Damping evaporator contact. Accumulated residual frost. Small cooling air Insufficient Fan overload. - Fan misuse. Bad low termperature RPM characteristics.
  • Page 54 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 4. Warm 1) Clogged cooling path. refrigerator Adiabatics liquid leak ?. compartment Foreign materials. –– Adiabatics dump liquid temperature. 2) Food storage. Store hot food. Store too much at once. Door open.
  • Page 55 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 6. Condensation 4) Condensation on door. and ice Condensation on the duct door. - Duct door heater is cut. formation. Condensation on the Recess Heater is cut. dispense recess. Duct door is open. / Foreign material clogging. Condensation on the Not fully filled.
  • Page 56 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 7. Sounds 1) Compressor compartment operating sounds. Transformer sound. Bad connection. –– Correct screw connection. Drip tray vibration sound. Bad assembly. Distortion. Foreign materials inside. Back cover machine sound. Bad connection. Partly damaged.
  • Page 57 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 8. Faulty lamp 1) Lamp problem. Filament blows out. (freezer and Glass is broken. refrigerator 2) Bad lamp assembly. Not inserted. compartment). Loosened by vibration. 3) Bad lamp socket. Disconnection. Bad soldering.
  • Page 58 TROUBLE DIAGNOSIS CLAIMS. CAUSES AND CHECK POINTS. HOW TO CHECK 10. Structure, 1) Door foam. appearance, Sag. Hinge loose Bolt is loosened during and others. transportation. Not tightly fastened. Fastener worn or damaged. Weak gasket Gasket sealing surface defective. adhesion. Fixed tape.

  • Page 59: Faults

    2. Faults 2-1. Power Problems Causes Checks Measures Remarks No power on - Power cord cut. - Check the voltage with tester. -Replace the components. outlet. - Faulty connector insertion. - Check visually. -Reconnect the connecting parts. - Faulty connection between plug - Check visually.
  • Page 60 2-3. Temperature Problems Causes Checks Measures Remarks High Poor cool air circulation due to faulty - Lock –– Check resistance with a - Replace fan motor. temperature fan motor. tester. in the freezer 0Ω: short. ∞Ω: cut. compartment. - Reconnect and reinsert. - Rotate rotor manually and check rotation.
  • Page 61 2-4. Cooling Problems Causes Checks Measures Remarks High Refrigerant leak. Check sequence Weld the leaking part, recharge the Drier must be replaced. temperature 1. Check the welded parts of the refrigerant. in the freezer drier inlet and outlet and drier compartment.
  • Page 62 Problems Causes Checks Measures Remarks High Cycle pipe is clogged. Check sequence. - Maybe evacuate should be the first Direr must be replaced. temperature in 1. Check temperature of condenser step here. If the servicer puts a torch the freezer manually.
  • Page 63 2-5. Defrosting failure Problems Causes Checks Measures Remarks No defrosting. Heater does not generate heat as 1. Check the resistance of heater. Heating wire is short and wire is cut. Seal the lead wire with 0Ω: Short. ∞Ω: Cut. the heating wire is cut or the circuit •...
  • Page 64 Problems Causes Checks Measures Remarks No defrosting Melting fuse blows. - Check melting fuse with tester. - Faullty parts: parts replacement. 1) Lead wire is cut. If 0Ω: OK. - Check wire color when maeasuring If ∞Ω: wire is cut. 2) Bad soldering.
  • Page 65 2-6. Icing Problems Causes Checks Measures Remarks Icing in the 1) Bad circulation of cool air. - Check if food is stored properly - Be acquainted with how to use. - Check the defrost refrigerator - Clogged intake port in the (check if discharge and intake port - Sealing on connecting parts.
  • Page 66 Problems Causes Checks Measures Remarks Ice in the freezer 1) Bad cooling air circulation. - Check food storage conditions - Be acquainted with how to use. - Check the parts related compartment. - Intake port is clogged in the freezer visually.
  • Page 67 2-7. Sound Problems Causes Checks Measures Remarks Hiss sound 1. Loud sound of compressor 1.1 Check the level of the 1) Maintain horizontal level. operation. refrigerator. 2) Replace bushing and seat if they 1.2 Check the bushing seat are sagged and aged. conditions (sagging and aging).
  • Page 68 Problems Causes Checks Measures Remarks Vibration sound. 1. Vibration of shelves and foods in 1-1. Remove and replace the 1) Reassemble the vibrating parts Clack. the refrigerator. shelves in the refrigerator and insert foam or cushion where 2. Pipes interference and capillary 1-2.
  • Page 69 Problems Causes Checks Measures Remarks Sound Popping It happens when refrigerant expands - Check the sound of refrigerant at the - Check the restrainer attached on the at the end of capillary tube. initial installation. evaporator and capillary tube weld - Check the sound when the refrigerator joints and attach another restrainer.
  • Page 70 2-8. Odor Problems Causes Checks Measures Remarks Food Odor. Food (garlic, kimchi, etc) - Check the food is not wrapped. - Dry the deodorizer in a sunny place - Check the shelves or inner with adequate ventilation. wall are stained with food juice. - Store the food in the closed - Be sure food is securely covered container instead of vinyl wraps.
  • Page 71 2-9. MICOM Problems Symptom Causes Checks Measures Remarks Bad PCB All display Bad connection Bad connector Visual check on connector Reconnect electric power. LCD are off. between Main PCB connection from main connection. connector. and display circuit. PCB to display PCB. Defective PCB PCB transformer Check resistance of PCB...
  • Page 72 Problems Symptom Causes Checks Measures Remarks Bad cooling. Freezer Compressor does Compressor Lead Wire Check compressor Lead Wire Reconnect Lead temperature is not start. is cut. with a tester. Wire. high. Defective compressor Measure voltage at PCB CON2 Replace relay RY1 Refer to load driving relay.
  • Page 73 Problems Symptom Causes Checks Measures Remarks Bad cooling Wrong Defective Step Motor Check Step Motor Check if Step Motor damper Reconnect lead Refrigerator Damper. damper motor and motor and reed switch lead wire. temperature. reed switch and lead wire are cut with a tester. wire are cut.
  • Page 74 Problems Symptom Causes Checks Measures Remarks Bad defrost. Defrost is not Defrost lead wire is cut. Check if defrost lead wire is cut with a Reconnect Lead working. tester. Wire. Defective defrost driving relay. Check the voltage of CON2 (1 and 7) Replace relay (RY 7 Refer to load with a tester after pressing main and RY 3) or PCB.
  • Page 75 Problems Symptom Causes Checks Measures Remarks Defective Buzzer does Trouble mode indication. Check trouble diagnosis function. Repair troubles Refer to mode display button. not sound indication in and buttons function do not operate. explanations. Door Buzzer Buzzer Defective connecting lead wire from Check lead wire associated with door Repair lead wire.

  • Page 76: Cooling Cycle Heavy Repair

    TROUBLE DIAGNOSIS 3. Cooling Cycle Heavy Repair 3-1. The Heavy Repair Standards for Refrigerator with R134a Refrigerant Items Unit Standards Purposes Remarks Pipe and piping Min. Pipe: within 1 hour. To protect The opening time should be reduced to a system opening time.
  • Page 77 TROUBLE DIAGNOSIS 3-2. Summary Of Heavy Repair Process Contents Tools Trouble diagnosis Remove refrigerant - Cut charging pipe ends and discharge refrigerant from Filter, side cutters Residuals drier and compressor. - Use R134a oil and refrigerant for compressor and drier Pipe Cutter, Gas welder, N - Confirm N sealing and packing conditions before use.
  • Page 78 TROUBLE DIAGNOSIS 3-3. Precautions During Heavy Repair Items Precautions 1. Use of tools. 1) Use special parts and tools for R134a. 2. Recovery of refrigerant. 1) Continue to recover the refrigerant for more than 5 minutes after turning the refrigerator off. 2) Install a piercing type valve on the high pressure line (drier side).
  • Page 79 TROUBLE DIAGNOSIS 3-4. Practical Work For Heavy Repair Items Precautions Evaporator 1. Removal of residual Low pressure side refrigerant. KEY POINT Hot Line Compressor Observe the sequence for removal of refrigerant. Drier Suction (If not, compressor oil may leak.) High pressure side Release Condenser Refrigent...
  • Page 80 TROUBLE DIAGNOSIS Items Precautions Evaporator 4. Vacuum degassing. Suction pipe Hot Line Compressor Drier Condenser pressure High Blue pressure Yellow KEY POINT - If power is applied Vaccum Pump during vacuum degassing, vacuum degassing shall be more effective. Pipe Connection - Run the compressor Connect the red hose to the high pressure side and the blue hose to the while charging the...
  • Page 81 TROUBLE DIAGNOSIS Items Precautions Evaporator Hot Line Compressor Drier Condenser Charging Canister 4) Refrigerant Charging Charge refrigerant while operating a compressor as shown above. 5) Pinch the charging pipe with a pinch-off plier after completion of charging. 6) Braze the end of a pinched charging pipe with copper brazer and test for gas leakage at the brazed parts.
  • Page 82 TROUBLE DIAGNOSIS 3-6. Brazing Reference Drawings HOT LINE PIPE ASSEMBLY (Freezer) Copper Brazing Copper Brazing TUBE DRIER ASSEMBLY Copper Silver Brazing Brazing JOINT PIPE ASSEMBLY SUCTION PIPE ASSEMBLY Copper Brazing JOINT PIPE WIRE CONDENSER ASSEMBLY ASSEMBLY Copper Brazing Silver Brazing Copper Brazing Coppper Brazing - 82 -...

  • Page 83: How To Deal With Claims

    TROUBLE DIAGNOSIS 4. HOW TO DEAL WITH CLAIMS 4-1. Sound Problems Checks and Measures I Explain general principles of sounds. Hiss sounds • All refrigerators make noises when they run. The compressor and fan produce sounds. There is a fan in the freezer compartment which blows cool air to freezer and refrigerator compartments.
  • Page 84 TROUBLE DIAGNOSIS Problems Checks and Measures I Explain the flow of refrigerant. Sounds of water flowing • When the refrigerator stops, the water flowing sound happens. This sound happens when the liquid or vapor refrigerant flows from the evaporator to compressor. I Explain the characteristics of moving parts.
  • Page 85 TROUBLE DIAGNOSIS 4-2. Measures for Symptoms on Temperature Problems Checks and Measures I Check temperature set in the temperature control knob. Refrigeration is weak. • Refrigerator is generally delivered with the button set at normal use (MID). But customer can adjust the temperature set depending on their habit and taste. If you feel the refrigeration is weak, then set the temperature control button at strong position.
  • Page 86 ‘www. ambientdevices. com/ cat/ device/ coverage. html’ to know your coverage status. Even if you live in full coverage are, your refrigerator could not receive wireless weather forecast signal at some place in your home. Unfortunately, LG does not provide you with a service for coverage. - 86 -...
  • Page 87 TROUBLE DIAGNOSIS 4-5. Others Problems Checks and Measures I Explain the principles of radiator. The refrigerator case is hot. • The radiator pipes are installed in the refrigerator case and partition plate between the refrigerator and the freezer compartment in order to prevent condensation formation.

  • Page 88: Tv-Radio

    TV-RADIO 1. SAFETY PRECAUTIONS 2. FEATURE 1-1. Warning 2-1. Auto Program tuning 1. Be sure to make a safety check, if circuit is found, All stations that can be received are stored. components that appear to have overheated or are otherwise damaged should be replaced with new 2-2.

  • Page 89: Controls

    TV-RADIO 3. CONTROLS Antenna Jack Power Button TV/AV/RADIO MENU VOLUME CH/PR Remote Control Sensor POWER - 89 -...

  • Page 90: Remote Control Key Functions

    TV-RADIO 4. REMOTE CONTROL KEY FUNCTIONS - When using the remote control, aim it at the remote control sensor on the TV. TV/AV/RADIO POWER Selects : TV, AV Radio Selects MTS sound : Mono, Stereo, MUTE Switches the sound on or off. and SAP.

  • Page 91: Troubleshooting

    TV-RADIO S5. TROUBLESHOOTING 5-1. General Poor Symptoms Adjustment No Picture 1) No P401, P501 connector 1) Check P1 connector and switched on 2) Poor TV Main PCB 2) Change the TV Main PCB Poor Picture 1) Poor LCD Lamp 1) Change the LCD 2) LCD Connector 2) Check connector and switched on 5-2.

  • Page 92: Block Diagram

    TV-RADIO 6. BLOCK DIAGRAM - 92 -...

  • Page 93: Tv Part Disassemble

    TV-RADIO 7. TV PART DISASSEMBLE ❶ ❷ Place tape on the outer edge of the TV case to protect the soft plastic from damage (2 or 3 layers is Using a flat bladed screwdriver, carefully pry the trim recommended). loose from the frame. ❸...

  • Page 94: How To Disassemble And Assemble

    HOW TO DISASSEMBLE AND ASSEMBLE 1. DOOR (3) Disconnect upper hinge from the hinge supporter by grasping the front part of upper hinge and lifting up (Hinge Assembly, U) in arrow direction A and pull 1) Remove lower cover and then disconnect water forward in arrow B direction.

  • Page 95: Handle

    HOW TO DISASSEMBLE AND ASSEMBLE 2. HANDLE 3. FAN SHROUD GRILLE 1) Remove the caps and remove the two screws holding 1) Aluminum short handle Model the upper fan grille. (1) Grasp the handle by both hands and hold it upward. 2) Remove the upper fan grille by pressing in the hooks with a screwdriver blade.

  • Page 96: Water Valve Disassembly Method

    HOW TO DISASSEMBLE AND ASSEMBLE 4. WATER VALVE DISASSEMBLY 4). Separate the Mechanical Cover and Valve Screw. METHOD Mechanical Cover 1) Turn off the power of the refrigerator (pull out the plug). Open the FREEZER and REFRIGERATOR Door and disassemble the Lower Cover. 5) Separate the housing and pull out the valve.

  • Page 97: Dispenser

    HOW TO DISASSEMBLE AND ASSEMBLE 6. DISPENSER 4) Loosen four screws with a phillips screwdriver and pull the funnel assembly to disconnect. 1) Disconnect funnel and button assembly by pulling down and forward. Funnel Assembly Funnel Assembly Button 5) The duct cap assembly can be disconnected if the hold lever connecting screw is loosened with a phillips driver.
  • Page 98 HOW TO DISASSEMBLE AND ASSEMBLE 7) Dispenser Related Parts FRAME ASSEMBLY, DISPLAY COVER, DISPENSER DECO, FRAME DISPLAY PWB(PCB) ASSEMBLY, DISPLAY FUNNEL ASSEMBLY MICRO SWITCH FRAME, FUNNEL 10 LEVER(SWITCH) 11 FUNNEL 12 BUTTON LEVER 13 HOLLDER BUTTON 14 SOLENOID ASSEMBLY 15 SPRING 16 LEVER HOLDER 17 CAP ASSEMBLY, DUCT 18 CAP, DUCT...

  • Page 99: Exploded View

    EXPLODED VIEW FREEZER DOOR PART: GR-G277STSA(LSC27990TT) : Optional part 611B 200A 606A 600A 202A 610A 614A 210B 205A 210B 210C 201A 203A - 99 -...
  • Page 100 EXPLODED VIEW REFRIGERATOR DOOR PART: GR-G277STSA(LSC27990TT) : Optional part 241A 241C 230A 241B 232A 147C 147B 239A 147A 242B 242C 242A 238A 260B 242D 240B 243A 240A 205A 240C 233A 231A - 100 -...
  • Page 101 EXPLODED VIEW REFRIGERATOR COMPARTMENT: GR-G277STSA(LSC27990TT) : Optional part 270A 270C 402A 271B 271A 137A 136D 403A 136B 135A 136C 152A 329A 400A 302B 401A 128C 130A 128E 128D 128F 120D 120D 120B 120C 272A 103A 408A 135B 125A 105B 312A...
  • Page 102 EXPLODED VIEW REFRIGERATOR COMPARTMENT: GR-G277STSA(LSC27990TT) : Optional part 140A 270B 270D 402A 271B 271C 171A 141A 624D 140B 624B 624C 171B 624A 152A 116A 115A 170A 152A 142A 142C 408B 142D 401A 151A 177A 142B 150A 177B 142D 155A 166A...
  • Page 103 EXPLODED VIEW MACHINE COMPARTMENT: GR-G277STSA(LSC27990TT) : Optional part 502A 101B 406A 407A 303A 407B 500A 303B 304A 101A 303C 502B 313A 316A 300A 310B 307A 307A 328B 317A 328A 301A 327A 317B 104A 306A 308B 309A 309C 305A 403B 305B...
  • Page 104 EXPLODED VIEW DISPENSER PART: GR-G277STSA(LSC27990TT) : Optional part 278A 278C 402C 278B 276A 275A 278F 405A 276B 501A 401C 280A 279B 280D 280B 280C 281A 281A - 104 -...
  • Page 105 EXPLODED VIEW TV PART: GR-G277STSA(LSC27990TT) - 105 -...

  • Page 106: Replace Parts List

    P/No. 3828JD8985A JAN., 2006 Printed in Korea...

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