LG LSC 27950SB Service Manual Download Page 37

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1-11. Fan motor driving circuit (freezer, mechanical area)

1. The circuit cuts all power to the fan drive IC, resulting in a standby mode.

2. This circuit changes the speed of the fan motor by varying the DC voltage between 7.5 Vdc and 16 Vdc.

3. This circuit stops the fan motor by cutting off power to the fan when it senses a lock-up condition.

(1) GR-L277SV(S)VA, SSWA (LSC27950SW, LSC27950SB, LSC27950ST, LSC27960ST)

EXPLANATION FOR MICOM CIRCUIT

- 37 -

a , d part

b part

e part

Motor OFF

2V or less

Motor ON

2 ~ 3V

12 ~ 14V

8 ~ 16V

Summary of Contents for LSC 27950SB

Page 1: ...LY THE SAFETY PRECAUTIONS OF THIS MANUAL BEFORE CHECKING OR OPERATING THE REFRIGERATOR REFRIGERATOR SERVICE MANUAL MODEL LSC27950SW LSC27950SB LSC27950ST LSC27960ST COLOR SUPER WHITE WESTERN BLACK STAINLESS http aic lgservice com ...

Page 2: ...TS DIAGRAM AND LIST 45 PWB CIRCUIT DIAGRAM 50 ICEMAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR 52 WORKING PRINCIPLES 52 FUNCTION OF ICEMAKER 53 CIRCUIT 55 TROUBLE DIAGNOSIS 57 TROUBLESHOOTING 57 FAULTS 67 COOLING CYCLE HEAVY REPAIR 84 HOW TO DEAL WITH CLAIMS 91 HOW TO DISASSEMBLE AND ASSEMBLE 96 DOOR 96 HANDLE 97 FAN SHROUD GRILLE 97 WATER VALVE DISASSEMBLY METHOD 98 FAN and FAN MOTOR DISASSEM...

Page 3: ...ting parts 8 Do not fray damage run over kink bend pull out or twist the power cord 9 Check for evidence of moisture intrusion in the electrical components Replace the parts or mask with insulation tape if moisture intrusion was confirmed 10 Do not insert fingers or tools into the icemaker The geared motor drive could cause an injury or damage to tools or the icemaker 11 Do not suggest that custom...

Page 4: ...M Fan Cooling TEMPERATURE CONTROL Micom Control DEFROSTING SYSTEM Full Automatic Heater Defrost INSULATION Cyclo Pentane COMPRESSOR PTC Starting Type EVAPORATOR Fin Tube Type CONDENSER Wire Condenser REFRIGERANT R134a 185g 61 2 oz LUBRICATING OIL FREOL 10G 320 cc ITEMS SPECIFICATIONS DRIER MOLECULAR SIEVE XH 7 CAPILLARY TUBE ID Ø0 83 FIRST DEFROST 4 5 Hours DEFROST CYCLE 13 15 Hours DEFROSTING DEV...

Page 5: ...FREOL 10G 320 cc ITEMS SPECIFICATIONS DRIER MOLECULAR SIEVE XH 7 CAPILLARY TUBE ID Ø0 83 FIRST DEFROST 4 5 Hours DEFROST CYCLE 13 15 Hours DEFROSTING DEVICE Heater Sheath ANTI SWEAT HEATER Dispenser Duct Door Heater Dispenser Heater ANTI FREEZING HEATER Damper Heater FREEZER LAMP 40W 1 EA REFRIGERATOR LAMP 40W 4 EA DISPENSER LAMP 15W 1 EA 724 mm 28 1 2 in 1004 mm 391 2 in 908 mm 3911 16 in 779 mm ...

Page 6: ...ser Button PWB Cover Water Tubes Freezer Compartment Refrigerator Compartment Dairy Product Corner Water Filter Lamp Drawer Lamp Automatic Icemaker Shelf Door Rack Drawer Door Rack Lower Cover OptiFresh Display Humidity Switch Shelf Shelf Snack Drawer Can Server Lamp Bottle Guide Vegetable Drawer Door Rack Door Rack OptiFresh ...

Page 7: ...artment Refrigerator Compartment Dairy Product Corner Water Filter Lamp Drawer Lamp Automatic Icemaker Shelf Door Rack Drawer Door Rack Lower Cover OptiFresh Display Humidity Switch Shelf Shelf Snack Drawer Can Server Lamp Bottle Guide Vegetable Drawer Door Rack Door Rack OptiFresh 2 Ref No GR L277SSWA LSC27960ST ...

Page 8: ...or door is lower than the freezer door Adjust the level when the refrigerator door is lower than the freezer door during the use of the refrigerator 1 Using the wide side of the tool for adjustment turn the keeper nut clockwise to loosen the keeper nut 2 Using the narrow side of the tool for adjustment turn the adjustment hinge pin clockwise or counterclockwise to level the refrigerator and freeze...

Page 9: ...e knob in the vertical position push the new filter cartridge into the cover until it stops If you can t turn the filter from side to side it isn t fully inserted Push it in firmly and twist it into place You will hear the snap when it clicks into place Using the handle twist the cartridge clockwise about 1 4 turn 3 Flush the Water System After Replacing Filter Dispense water through the water dis...

Page 10: ...the operation of the operating part of the icemaker 3 If there is no problem with the operation water is supplied through the water tube up to the selected lebel of water 4 The test mode is completed after the water is supplied Note When using the test mode more than twice consecutively water can overflow When the water overflows wipe the ice storage bin It is acceptable if the adjusted level of w...

Page 11: ...tton Filter Status Display RESET Button Temperature Adjust Button For Refrigerator Compartment Temperature Adjust Button For Freezer Compartment Dispenser Selection Button Ice Plus Freezer Jet Freezer Function Selection Button Door Alarm Button Dispenser Lock Button Dispenser Light Auto On Off Button Filter Status Display RESET Button Temperature Adjust Button For Refrigerator Compartment Temperat...

Page 12: ...m Fahrenheit Mode To change temperature display from Fahrenheit to Celsius press and hold FREEZER and REFRIGERATOR buttons simultaneously for more than 5 seconds Do the same to convert back to Celsius 4 Exhibition 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 compress...

Page 13: ...with display Notch during Icemaking Control Mode and Icemaker Stop switch is selected with ON 2 1 2 Outside temperature display function 1 The ambient temperature sensor is located under the upper right hinge cover This sensor reads the temperature of the room and displays it in the upper right corner of the display 2 The ambient temperature is displayed between 16 F and 120 F Outside of that rang...

Page 14: ...s 4 If desiring to release the lock status and pressing the lock button more than 3 seconds LOCK text is turned off at the right side of lock graphic of display with the lock release status 2 1 4 Filter condition display function 1 There is a replacement indicator light for the water filter cartridge on the dispenser 2 Water filter needs replacement once six months 3 Water filter light and FILTER ...

Page 15: ...ress the button to cycle to toggle between the settings The arrow mark graphic remains at the ON status after flickering 4 times when selecting Special Refrigeration ICE PLUS FRZ or JET FRZ ICE PLUS freezer or JET freezer function automatically turns off after a set time Jet Freezing Not applicable to all models 2 4 Dispenser Light The dispenser light function is repeated following below whenever ...

Page 16: ...frost cycle is complete 9 If you press ICE PLUS within 7 minutes of compressor cut off the compressor will not operate until the 7 minute delay has passed 10 The freezer fan motor runs at high speed during the ICE PLUS cycle 2 6 JET FREEZING GR L277SSWA LSC27960ST 1 JET FREEZING is a function to increase the cooling speed of the JET FREEZING compartment within the freezer by running both the compr...

Page 17: ... a damper between OptiFresh and Freezer compartment and a temperature adjusting display at the top of it 3 When powered on the initial NOTCH of OptiFresh display will be on OptiFresh Crisper If only the refrigerator door is opened the OptiFresh LED will be ON 4 The OptiFresh sensor opens and closes the damper based on the temperature 5 The OptiFresh damper will cycle every hour to prevent icing up...

Page 18: ...lug it in again 2 9 Control of cooling fan motor 1 The cooling fan motor performs ON OFF control by linking with the COMPRESSOR 2 It controls at the single RPM without varying RPM 3 Failure sensing method is same as in fan motor of freezing fan motor refer to failure diagnosis function table for failure display 2 10 Door opening alarm 1 The buzzer sounds when any door is held open for more than on...

Page 19: ...ycled whenever the compressor s runtime reaches 7 7 hours 2 In providing initial power or returning power failure defrost starts whenever total operation time of compressor becomes 4 4 hour 3 Defrost is completed if temperature of a frost removal sensor becomes more than 5 C after starting frost removal Poor frost removal is not displaced if it does not arrive at 5 C even if two hours have passed ...

Page 20: ...y returns to the test mode for initial operation COMPRESSOR operates after 7 minutes When temperature of a frost removal sensor becomes less than 45 C In power failure service Test mode 1 Manual function Test mode 2 Manual frost removal POWER ON COMP ON F FAN C FAN ON R STEP MOTOR DAMPER ON OPTICHILL STEP DAMPER MOTOR ON FROST REMOVAL HEATER OFF FROST REMOVAL HEATER ON DAMPER DUCTDOOR OPTICHILL HE...

Page 21: ...n a failure is detected the buttons are deactivated 3 If a failure code is released the MICOM resets and normal operation continues 4 The failure code is displayed on the FRZ TEMP display All display graphics that are not part of the failure code are turned off 1 GR L277SV S VA LSC27950SW LSC27950SB LSC27950ST MICOM FUNCTION 21 ...

Page 22: ... 2 GR L277SSWA LSC27960ST MICOM FUNCTION 22 ...

Page 23: ...n abnormal ambient sensor and Er indicated on the amvient temperature display except for the ambient temperature display other LEDs or LCDs are indicated normally LCD LED check function If simultaneously pressing express freezer button and freezing temperature adjustment button for a second a back light is turned on and all display LCD LED graphics on If releasing the button the LCD LED graphic di...

Page 24: ...ode Press test button once at the test mode 1 status forced defrost mode Press test button once at the test mode 2 status 1 Continuous operation of compressor 2 Continuous operation of freezing BLDC motor high speed RPM and cooling BLDC motor 3 Defrost heater turns off 4 Stepping motor damper is completely opened baffle is closed 5 OptiFresh stepping motor damper is completely closed 6 All display...

Page 25: ...nds 5 The dispenser lamp turns on automatically if the crushed cubed water button is pressed or if the dispenser button is pressed It will turn off automatically shortly thereafter 6 Selection function of water crushed cube ice 1 Select crushed cubed water The display will show your selection 2 If you select cubed ice the auger is rotated to dispense cubes 3 If you select crushed ice the auger is ...

Page 26: ...feedback circuit IC3 and IC4 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 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 26 Part VA1 CE1 CE2 CE3 CE4 CE5 Voltage 120 Vac 160 Vdc 1...

Page 27: ...sion of data and calculations made by the 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 L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 27 ...

Page 28: ... when power is interrupted or restored A LOW signal applied to the reset terminal for 10 ms causes the MICOM to reset itself During normal operation the voltage at the reset terminal is 5 Vdc If the reset fails the MICOM will not operate 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 28 ...

Page 29: ... connected to the door open sensing circuit in parallel toward both ends of switch to determine door open at MICOM In the TEST mode the fan will stop if any door is opened It will resume operation when the door is closed 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 29 Measuring part IC6 IC6 16 IC6 13 IC6 12 IC6 15 IC6 14 Status ON Within 1 V OFF 1...

Page 30: ...driving status 2 Lever Switch sensing circuit EXPLANATION FOR MICOM CIRCUIT 30 Measuring part Lever S W IC1 Micom No 16 On OFF 5V 0 V 60 Hz 5 V Measuring part IC7 15 IC7 14 IC7 13 IC7 12 IC7 11 Status ON Within 1 V OFF 12 V Type of Load GEARED MOTOR SOLENOID CUBE PILOT VALVE WATER VALVE WATER SOLENOID DISPENSER ...

Page 31: ...nnected if either fails the other will not respond properly If either switch fails the light will not come on EXPLANATION FOR MICOM CIRCUIT 31 Closing 5 V A B C D Switch at both ends are at Off status Opening 0 V A B C D Switch at both ends are at On status Measuring part IC1 MICOM No 44 45 45 46 47 48 Pin Door of Freezer and Refrigerator ...

Page 32: ...n ice is made The defrost sensor determines both the need for defrosting and the efficiency of the defrost operation See the table below for voltages and checkpoints EXPLANATION FOR MICOM CIRCUIT 32 SENSOR CHECK POINT NORMAL 22 F 122 F IN SHORT IN OPEN Freezing sensor POINT A Voltage Defrost sensor POINT B Voltage Refrigerator sensor 1 POINT C Voltage 0 5 V 4 5 V 0 V 5 V Refrigerator sensor 2 POIN...

Page 33: ...uit The following circuits are sensing signal form the damper motor reed switch for testing and diagnosing the refrigerator 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 33 ...

Page 34: ...T LSC27960ST The circuits shown above vary according to which features are included on your particular model uThese circuits are preset at the factory and cannot be altered EXPLANATION FOR MICOM CIRCUIT 34 Separation Connection Status Application Standard Connection OptiFresh exist OP1 OUT OptiFresh don t exist ...

Page 35: ...1 10 Stepping motor operation circuit 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 35 ...

Page 36: ...ls of 3 33 mSEC via MICOM pins 33 34 and 35 as shown in the chart below These signals are output via terminals 10 11 14 and 15 via input terminals 3 6 and 8 of IC10 TA7774F the motor drive chip The output signals allow the coils wound on each phase of the stator to form a magnetic field which causes rotation Input to the terminals INA and INB of IC10 as shown in the chart below drives the motor EX...

Page 37: ...d of the fan motor by varying the DC voltage between 7 5 Vdc and 16 Vdc 3 This circuit stops the fan motor by cutting off power to the fan when it senses a lock up condition 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 37 a d part b part e part Motor OFF 5V 2V or less 2V or less Motor ON 2 3V 12 14V 8 16V b a d e ...

Page 38: ...ease by 1 C 1 8 F EXPLANATION FOR MICOM CIRCUIT 38 Temperature compensation at refrigerator Temperature compensation at freezer Freezer Refrigerator Resistance value Temperature Resistance value Temperature Remarks RCF1 compensation RCR1 compensation 180 kΩ 5 C 9 F 180 kΩ 2 5 C 4 5 F Warmer 56 kΩ 4 C 7 2 F 56 kΩ 2 0 C 3 6 F 33 kΩ 3 C 5 4 F 33 kΩ 1 5 C 2 7 F 18 kΩ 2 C 3 6 F 18 kΩ 1 0 C 1 8 F 12 kΩ ...

Page 39: ...own change Up Up Up Up Up Up Up 2 C 1 5 C 1 C 0 5 No 0 5 C 1 C 1 5 C 2 C 2 5 C 3 C 8 2 kΩ 3 6 F 2 7 F 1 8 F 0 9 F 0 9 F 1 8 F 2 7 F 3 6 F 4 5 F 5 4 F Refrigerator Down Down Down Drop change Up Up Up Up Up Up RCR1 2 5 C 2 C 1 5 C 1 C 0 5 C No 0 5 C 1 C 1 5 C 2 C 2 5 C 10 kΩ 4 5 F 3 6 F 2 7 F 1 8 F 0 9 F 0 9 F 1 8 F 2 7 F 3 6 F 4 5 F Down Down Down Down Down change Up Up Up Up Up 3 C 2 5 C 2 C 1 5 C...

Page 40: ... Compensation for too warm for too cold Temperature compensation value Remarks JCR3 JCR4 JCR1 JCR2 at refrigerator 0 C In shipment from factory CUT 1 C 1 8 F CUT 1 C 1 8 F CUT 1 C 1 8 F CUT 1 C 1 8 F CUT CUT 2 C 3 6 F CUT CUT 2 C 3 6 F CUT CUT 0 C 0 F CUT CUT 0 C 0 F CUT CUT 0 C 0 F CUT CUT 0 C 0 F CUT CUT CUT 1 C 1 8 F CUT CUT CUT 1 C 1 8 F CUT CUT CUT CUT 0 C 0 F Temperature compensation in CUT ...

Page 41: ...een the two boards is required for the display to function properly Poor communication occurs if a continuous information exchange fail to continue for more than 2 minutes between main MICOM of main PCB and LCD LED dedicated MICOM for LCD LED control of display PCB 1 GR L277SV S VA LSC27950SW LSC27950SB LSC27950ST EXPLANATION FOR MICOM CIRCUIT 41 Main MICOM LCD LED dedicated MICOM DC 12V GND Trans...

Page 42: ... 2 GR L277SSWA LSC27960ST EXPLANATION FOR MICOM CIRCUIT 42 ...

Page 43: ...ensor 1 and 2 shall be measured with a digital tester after separating CON8 of the PWB ASSEMBLY and the MAIN part u Resistance of the freezing sensor shall be measured with a digital tester after separating CON7 of the PWB ASSEMBLY and the MAIN part EXPLANATION FOR MICOM CIRCUIT 43 Measuring Temperature C Freezing Sensor Refrigerator sensor 1 2 Defrost sensor Ambient sensor 20 C 22 3 kΩ 77 kΩ 15 C...

Page 44: ...1 14 OptiFresh stepping MOTOR Display 1 GR L277SV S VA LSC27950SW LSC27950SB LSC27950ST 1 15 Jet freezing 1 GR L277SSWA LSC27960ST EXPLANATION FOR MICOM CIRCUIT 44 ...

Page 45: ...2 PWB parts diagram and list 2 1 PWB Assembly main part diagram 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 45 ...

Page 46: ...2 2 Parts list 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 46 ...

Page 47: ...EXPLANATION FOR MICOM CIRCUIT 47 ...

Page 48: ...2 3 DISPLAY ASSEMBLY part diagram 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 48 ...

Page 49: ...2 4 DISPLAY circuit diagram 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 49 ...

Page 50: ...3 PWB Circuit Diagram may vary by model 1 GR L277SV S VA SSWA LSC27950SW LSC27950SB LSC27950ST LSC27960ST EXPLANATION FOR MICOM CIRCUIT 50 ...

Page 51: ...EXPLANATION FOR MICOM CIRCUIT 51 ...

Page 52: ...Park Position Fill Test Mode Waits until water becomes cold after starting the icemaking operation Runs MOTOR to drop ice from the tray into the ICE BIN During harvest mode check if the ice bin is full Performs Ice Making Mode after supplying water by operating the SOLENOID in ICE VALVE To operate LINE and SERVICE press and hold the Fill Key for 3 seconds The icemaker will run through 3 stages Har...

Page 53: ... will be completed in 4 hours NOTE After Icemaker Power is ON the Icemaker heater will be on for test for 6 sec 2 3 Harvest Mode 1 Harvest Ice removing refers to the operation of dropping ices into the ice bin from the tray when icemaking has completed 2 Harvest mode 1 The Heater is ON for 30 seconds then the motor starts 2 The feeler arm senses the quantity of ice in the ice storage bin while rot...

Page 54: ...ts to the pre test setting Diagnosis TABLE 3 DEFECT DIAGNOSIS FUNCTION 3 1 ERROR CODES shown on Icemaker water supply control panel ERROR indicators in table can be checked only in TEST mode STAGE ITEMS INDICATOR REMARKS 1 2 3 4 5 6 HEATER MOTOR HALL IC I detection of position HALL IC II detection of position VALVE Reset Five seconds after heater starts a heater will go off if the temperature by s...

Page 55: ... 1 GR L277SV S VA LSC27950SW LSC27950SB LSC27950ST CIRCUIT 55 ...

Page 56: ... 56 2 GR L277SSWA LSC27960ST CIRCUIT ...

Page 57: ...uter diameter No power on power cord OLP is off No electric power on compressor Faulty compressor Faulty PTC Disconnectedcopperwire Internalelectricalshort Faultyterminalcontact Disconnected Capacity of OLP is small CharacteristicsofOLPisbad Badconnection Poweris disconnected InnerNi Crwireblowsout Bad internal connection Faultyterminalcaulking Cuwireiscut Badsoldering Weakconnection Shortinserted...

Page 58: ...n Leaveitintheair Moisturepenetration intotherefrigerationoil Capsaremissed Airblowing Duringtransportation During work Notperformed Performed Tooshorttime Lowairpressure Lessdryair AirBlowing Leaveitintheair Capsaremissed Shortpipeinsert Pipe gaps Toomuchsolder Toolarge Damagedpipes Notdriedinthecompressor Elapsedmorethan6monthsafterdrying Capsaremissed Nopressurewhenitisopen During rest time Aft...

Page 59: ...nnected Injectthroughthe hole Seal with drain Adiabatics lump input Damage by a screw or clamp Otherforeignmaterialsinput Parts disconnected Wire is cut Heatingwire Contactpoint betweenheating andelectricwire Dentbyfinevaporator Poorterminalcontacts Wire is cut Leadwire Heatingwire Contactpoint betweenheatingand electricwire Heatingwireiscorroded Waterpenetration Badterminalconnection Check visual...

Page 60: ...location thickness Structural fault Gasket gap Airinflowthroughthefanmotor Badinsulationofcasedoor SheathHeater rated Gap Badattachment Contraction Badadhesion Weakbindingforceathinge Fanmotor Door switch Self locked Wire is cut Badterminalcontact Contact distance Buttonpressure Meltedcontact Contact Poordoor attachment Door liner dimension Contractioninner liner Misalignment Badterminal connectio...

Page 61: ...ud Bent Iceandforeignmaterialsonrotatingparts Fanshroudcontact Clearance Dampingevaporatorcontact Accumulatedresidualfrost Fanmisuse Bad shape Looseconnection Nottightlyconnected Insertdepth Ratingmisuse Smallcapacity Lowvaltage Malfunction of charging cylinder Wrongsettingofrefrigerant Insufficient compressor Faulty compressor Fanoverload Fanmisuse BadlowtermperatureRPMcharacteristics Rated power...

Page 62: ...cs dump liquid Faulty contact Faulty temperature characteristics External air inflow Bushing installed incorrectly Door opens but not closes Gap around gasket Contraction distortion loose door twisted corner not fully inserted Food vapor Storing hot food Unsealed food Door opens but not closes Gasket gap Cool air leak and transmitted Highambienttemperature Insufficientspacearoundrefrigertor Differ...

Page 63: ...eaks holes Small Capacity Position of drain 1 Compressor compartment operating sounds Compressor sound Sound from machine itself inserted Sound from vibration Restrainer Bushing Too hard seat Distorted Aged Burnt Stopper Bad Stopper Not fit assembly inner diameter of stopper Tilted Not Compressor base not connected Bad welding compressor stand fallen Foreign materials in the compressor compartment...

Page 64: ... Bad connection Correct screw connection Bad assembly Distortion Foreignmaterialsinside Badconnection Partlydamaged Not connected Badpipecaulking Normaloperatingsound Vibrationsound Old dried orcrackedbushing Badtorqueforassemblingmotor bracket Fanguidecontact Shroudburrcontact Dampingevaporatorcontact Residualfrostcontact Unbalance Iceonthefan Airintake oppositetomotor bushingassembly Supporterdi...

Page 65: ...lel distance Bad connection Bad terminal contact Adiabatics liquid leak 1 Lead wire is damaged Wire damage when assembling PTC Cover Outlet burr in the bottom plate Pressed by cord heater lead wire evaporator pipe 2 Exposed terminal Compressor Compartment terminal Touching other components Freezer compartment terminal Touching evaporator pipe 3 Faulty parts Transformer Coil contacts cover Welded t...

Page 66: ...ator compartmentis openedwhenfreezer compartmentis closed faultystopper High Faultydampercontrol Button is set atweak Doorisopen somethinginthe way No deodorizer Poor capacity Seal condition Storageoffragrantfoods Longtermstorage Odorsfromcleanersoritemswhichshroudnot bestoredinarefrigerator Biggerdoorfoam Hinge Pintilted Poorflatness Nowasher No grease Stopperwornout Badfreezercompartmentdoor ass...

Page 67: ...oducts Replace with rated fuse Electricity leakage Check the resistance of power cord If fuse blowns out High voltage with tester if it is 0Ω it is shorted frequently confirm Short circuit of components the cause and repair tracking due to moisture and dust penetration Problems Causes Checks Measures Remarks Compressor Faulty PTC Check the resistance If resistance is infinite replace it does not V...

Page 68: ... faulty operation Confirm icing causes and repair switch operation Press button to check Replace door switch Faulty button pressure and contact Press button to check operation Door cannot press door switch Door sag fix door button Check visually Door liner bent replace door or attach sheets Poor heat exchange Check the clearance between the Keep clearance between The fan may be in compressor area ...

Page 69: ...pe low pressure side 3 Check silver soldered parts 4 Check bending area of wire condenser pipe in compressor compartment cracks can happen during bending 5 Check other parts compressor compartment and evaporators in freezer compartment Shortage of refrigerant Check frost formation on the surface Find out the leaking area repair Drier must be replaced of evaporator in the freezer evacuate and recha...

Page 70: ...t be clogged If it is not condenser outlet weld Discharge the system and recover the joints might be colgged refrigerant Then use a torch to disconnect unbraze the piping to repair the obstruction Repair evacuate the system and recharge it before testing Leak at loop pipe weld joint Check sequence Replace the compressor weld Drier must be replaced discharge in compressor 1 Manually check whether e...

Page 71: ...ut impurities by inserting 1 Impurities of ice insert the copper line copper wire Turn off more than 2 Ice through the hole to check 3 hours and pour in hot water if 2 Put hot water into the drain frost is severe check drains outside 2 Put in hot water to melt down frost 3 Check the water outlet 4 Push the heater plate to suction duct manually and assemble the disconnected parts Gap between Suctio...

Page 72: ...k by inserting soft copper 3 Reassemble the heater plate wire into the duct soft and thin copper not to impair heating wire Bad cool air inflow and discharge 1 Turn on power open or close the 1 Check the faulty connector of and bad defrosting due to faulty door check that motor fan housing and reassemble wrongly contact and insertion bad connector operates If it operates motor fan assembled parts ...

Page 73: ... compartment Check door assembly conditions conditions and replace it be done when it Faulty gasket Door assembly and replacement cannot be repaired Faulty assembly 3 Overcooling in the refrigerator Check if refrigerator compartment Replace faulty parts compartment is overcooled when button Faulty damper in the refrigerator pressed on weak compartment Check parts are faulty Faulty MICOM faulty sen...

Page 74: ...artment door Check gasket attachment Correct the gasket attachement Replace when it can not Icing in the Faulty gasket conditions conditions and replace it be repaired shute Faulty assembly Check door assembly conditions Door assembly and replacement 3 Over freezing in the freezer Refrigerator operates pull down Replace defective parts compartment Check if it is operated Faulty MICOM intermittentl...

Page 75: ...ng 5 Replace defective fan and fan conditions in pipes motor 2 3 Touch pipes with hands or screw 6 Adjust fan to be in the center of driver check the change of the fan guide sound 7 Leave a clearance between interfering parts and seal gaps in 3 Fan operation sound in the freezer 3 1 Check fan insertion depth and the structures compartment blade damage 8 Reassemble the parts which make 3 2 Check th...

Page 76: ...on with bushing 4 Moving wheel vibration 2 2 Check capillary tube touches and restrainer if it is severe 5 Other structure and parts cover back especially compressor and pipe vibration 3 1 Check compressor stopper 4 Replace compressor stopper if it vibration vibtates severely 4 1 Check vibration of front and rear moving wheels 5 1 Touch other structures and parts Irregular sound 1 It is caused by ...

Page 77: ...f freezing cycles Water boiling or It happens when refrigerant passes Check the sound when compressor is Explain the principles of freezing cycles flowing sound orifice in accumulator internal pipes by turned on and refrigerant flowing phenomenon by the pressure difference between Check the sound when compressor is internal pressure difference condenser and evaporator turned off If sound is server...

Page 78: ...plastic wrap Clean the refrigerator and set Chedk food cleanliness button at strong Plastic Odor Odors of mixed food and plastic Check wet food is wrapped with Clean the refrigerator odors plastic bowl and bag Persuade customers not to use It happens in the new refrigerator plastic bag or wraps with wet food or odorous foods Odor from the Odor from the old deodorizer Check the deodorizer odors Rin...

Page 79: ...tric circuit parts 7812 7805 terminals circuit in circuit explanation PCB electric terminal Check fuse in PCB electric Replace PCB fuse fuse is burned out terminal with a tester STR Parts are Check if STR No 2 and 3 pins Replace parts Applicable to damaged are cut when power is off model with dispenser Abnormal Bad connection Lead Wire connecting Check Lead Wire terminals Reconnect Lead display LC...

Page 80: ...it Refer to tables on pages 39 42 The wrong sensor Confirm the color of sensor in Repair main PCB explanation has been installed circuits main PCB sensor sensor housing Order by model number housing and part number Defective freezer fan Fan motor lead wire Check fan motor lead wire Reconnect lead motor is cut with a tester wire Defective door switch Measure the voltage between Replace door Refer t...

Page 81: ...xplanation Foreign materials in Step Check Step Motor damper Remove foreign Motor damper baffles baffle visually materials Ice formation on Check if Step Motor damper Replace Step Motor Step Motor damper Heater wire is cut with a damper or refrigerator baffles tester control Box Assembly Defective refrigerator Defective refrigerator Check the resistance of Replace refrigerator Refer to sensor sens...

Page 82: ... circuit explanation Defective Buzzer Defective connecting lead wire from Check lead wire related to door Repair lead wire buzzer continuously main PCB to door switch switch with a tester rings or door Defective door switch parts Refer to door switch in parts repair Replace door switch opening alarm guide does not work Defective Buzzer does Key input wire is cut or bad connector Check input wire w...

Page 83: ...ith lever Repair lead wire water ice are not Main PCB to lever switch switch with a tester dispenser dispensed Defective lever switch parts Refer to door switch in parts repair guide Replace lever switch Defective photo coupler IC parts Check voltage change at photo coupler Replace photo output terminals with lever switch coupler IC or PCB pressed It is OK if voltage change is between 0V 5V Defect...

Page 84: ...applicable to the model degree equipped with reverse flow protect plate Vacuum EA High and low Vaccum efficiency can be improved by Pressure sides are operating compressor during evacuation evacuated at the same time for models above 200 L Vacuum EA Use R134a To protect The bushing pipes for R12 refrigerant will piping exclusive mixing of be melted when they are used for R134a manifold mineral and...

Page 85: ...while compressor operates electronic scales pinch off Weld carefully after pinching off the inlet pipe plier gas welding machine Check leak at weld joints Electronic Leak Detector Minute leak Use electronic leak detector Driver Ruler Big leak Check visually Note Do not use soapy water for check Check cooling capacity Check radiator manually to see if warm Check hot line pipe manually to see if war...

Page 86: ... TO KEEP THE OIL FROM BEING FORCED OUT The use of piercing type valves will allow future servicing and eliminates the possibility of a defective pinch off 3 Replacement of drier 1 Be sure to replace drier with R134a only when repairing pipes and injecting refrigerant 4 Nitrogen blowing 1 Use pressurized nitrogen to prevent oxidation inside the piping welding Nitrogen pressure 0 1 0 2 kg cm2 5 Othe...

Page 87: ... assembling a drier When replacing a compressor Weld and parts by blowing nitrogen to the low pressure side Note For other parts nitrogen blowing is not necessary because it does not produce oxidized scales inside pipe because of its short welding time 3 Replacement of drier Inserting a capillary tube Measure distance with a ruler and put a mark 12 3 0 on the capillary tube Insert tube to the mark...

Page 88: ...ster and measure the weight Calculate the weight of refrigerant charged into the charging canister by subtracting the weight of an evacuated charging canister KEY POINT If power is applied during vacuum degassing vacuum degassing shall be more effective Run the compressor while charging the system It is easier and works better KEY POINT Be sure to charge the refrigerant at around 25 C 77 F Be sure...

Page 89: ... the mechanical area Compressor Condenser Drier Hot Line Evaporator Charging Canister Bushing 1 Observe the safety precautions for gas handling 2 Use JIG or a wet towel in order to prevent electric wires from burning during welding In order to prevent insulation break and accident 3 The inner case will melt and the insulation will burn 4 The copper piping will oxidize 5 Do not allow aluminum and c...

Page 90: ...E ASSEMBLY HOT LINE PIPE ASSEMBLY Freezer JOINT PIPE ASSEMBLY WIRE CONDENSER ASSEMBLY SUCTION PIPE ASSEMBLY DRIER ASSEMBLY TUBE Copper Brazing Copper Brazing Silver Brazing Copper Brazing Copper Brazing Copper Brazing Coppper Brazing Silver Brazing Copper Brazing ...

Page 91: ...vaporator in the refrigerator compartment expand and contract as the temperature changes during the refrigerator operation This sound also happens during defrosting twice a day when the ice on the evaporator melts Clunk sound Explain that it comes from the compressor when the refrigerator starts When the refrigerator operates the piston and motor in the compressor rotate at 3600 RPM This sound is ...

Page 92: ...nd water flowing also makes sound When water Noise from motor sounds Hiss freezes clicking sounds are heard When ice is being ejected sounds like Hiss produced by a motor to rotate an ice tray and ice dropping and hitting ice bin sounds are also heard Noise when supplying water Explain the principles of water supplied to dispenser When the water supply button in the dispenser is pressed the water ...

Page 93: ...ics of ice cream The freezing point of ice cream is below 15 C 5 F Therefore ice cream may melt if it is stored in the door rack Store ice cream in a cold place or set the temperature control button of a freezer at strong position Refrigeration is too strong Check the position of temperature control button Check if refrigeration is strong in whole area of the refrigerator or partly near the outlet...

Page 94: ...tton at strong Frost in the freezer compartment Explain the basic principles of frost formation The main causes for frosting Door was left open Air penetration through the gasket Too frequent door opening parties etc Hot foods are stored before they are cooled down The temperature of freezer is 19 C 2 2 F if temperature is set at MID If hot air comes into the refrigerator fine frost forms as cold ...

Page 95: ...d and wet foods are not stored in the air tight container or properly vegetable drawer wrapped Be sure to store wet foods in airtight containers or securely covered in plastic wrap When is the power connected When should the power be connected You can connect the power immediately after installation However if the refrigerator was laid flat before or during installation you must stand it upright f...

Page 96: ...ng refrigerator door turn hinge lever counterclockwise If the hinge or bracket are bent during assembly use two extra screws Tap Tite M6 Left Hinge attaching screw in the holes of the upper hinge 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 forward in arrow B direction Be careful because th...

Page 97: ...ctor A and remove the upper fan grille 4 Hold the upper part of the lower fan grille and pull it forward carefully 5 Loosen two screws 6 Disconnect electrical connector B on the back fan housing Use a screwdriver blade to remove the 2 rails and the fan housing 7 Pull the fan housing out from the top 8 Check the adhesive foam on the upper and lower fan grilles If it is damaged torn or loose replace...

Page 98: ... the housing and pull out the valve 5 FAN AND FAN MOTOR DISASSEMBLY METHOD 1 Using a short screwdriver loosen one SCREW in DRAIN PIPE ASSEMBLY and one connected to the MOTOR COVER 2 Pull and separate the FAN ASSEMBLY and MOTOR turning counterclockwise based on the MOTOR SHAFT The assembly is in the reverse order of the disassembly and take special care for the following details 1 Be careful not to...

Page 99: ...g 4 Loosen four screws with a phillips screwdriver and pull the funnel assembly to disconnect 5 The duct cap assembly can be disconnected if the hold lever connecting screw is loosened with a phillips driver 6 To install the duct cap assembly insert one end of the spring into the right hole of the dispenser lever and insert the other end into the right hole in the top part of the dispenser Then at...

Page 100: ...DISPENSER 3 DECO FRAME DISPLAY 4 PWB PCB ASSEMBLY DISPLAY 7 FUNNEL ASSEMBLY 8 MICRO SWITCH 9 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 19 DISPENSER LEVER 20 FOAM NEW 21 RUBBER CAP 22 DECO DRAIN NOTE Not every model includes every option ...

Page 101: ...FREEZER DOOR PART GR L277SV S VA LSC27950SW LSC27950SB LSC27950ST Optional part EXPLODED VIEW 101 611B 600A 614A 610A 202A 200A 203A 201A 210B 210C 210B 205A 611A EV ...

Page 102: ...REFRIGERATOR DOOR PART GR L277SV S VA LSC27950SW LSC27950SB LSC27950ST Optional part EXPLODED VIEW 103 240A 232A 240C 233A 230A 239A 231A 241B 241C 241A 243A 240A 147A 240A 243A 205A EV ...

Page 103: ... LSC27950SB LSC27950ST Optional part EXPLODED VIEW 105 271B 270C 271A 103A 400A 312A 152A 105B 272A 135B 137A 136D 329A 135A 136B 403A 136C 401A 408A 302B 130A 128E 128C 126A 125A 125A 270A 402A 128D 128C 128D 128F 120C 120B 120D 120D 623B 621B 621A EV ...

Page 104: ...0SB LSC27950ST Optional part EXPLODED VIEW 107 170A 271B 271C 103A 177A 166A 165A 272B 155A 177B 166B 150B 401A 116A 401A 115A 150A 120E 162A 162B 142D 142D 142A 270D 402A 270B 151A 142C 142B 624D 624B 624C 624A 504A 167A 141A 171B 171A 152A 152A 140A 140B EV ...

Page 105: ...C27950SB LSC27950ST Optional part EXPLODED VIEW 109 300A 310B 307A 304A 306A 310A 317B 317A 313A 301A 307A 104A 327A 328A 303C 303B 303A 500A 502B 406A 101B 101A 308A 308C 308B 309B 403B 309C 309A 502A 407B 407A 305C 305B 305C 305B 305A 328B 316A EV ...

Page 106: ...DISPENSER PART GR L277SV S VA LSC27950SW LSC27950SB LSC27950ST Optional part EXPLODED VIEW 111 278A 402C 405A 275A 276A 278B 278C 276B 279A 279B 281A 280C 280B 280A 501A 278D EV ...

Page 107: ...ICE WATER PART Optional part EXPLODED VIEW 117 EV 404A 625A 616G 619A 627A 616F ...

Page 108: ...P No 3828JD8970B JAN 2006 Printed in Korea ...

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LG LSC 27950SB, Service Manual

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