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LG LFC21776ST, Service Manual

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LG LFC21776ST Service Manual Download Page 24

- 24 -

8-8 Communication Error (Er CO)

No

1

2

Checking flow

Check the loose connection.

Check the Orange to White/Black.

Result & SVC Action

Result

12 V

Other

SVC Action

Go to the 3

Check the Hinge 

(loose connection)

Change the Main PCB

5

Check the White/Red to Orange.

<CON5>

6

Check the White/Red to White/Black.

<CON5>

<CON101>

<Display>

3

Check the Orange to Brown.

Result

0 V or 5 V

Other

SVC Action

Change the Display PCB

Go to the 4

4

Check the Orange to Red.

Result

0 V or 5 V

Other

SVC Action

Change the Main PCB

Go to the 5

Result

0 V or 5 V

Other

SVC Action

Change the Display PCB

Go to the 6

Result

0 V or 5 V

Other

SVC Action

Change the Main PCB

Explain to customer

<CON101>

<Display>

<CON101>

<Display>

CON01

CON01

CON01

Summary of Contents for LFC21776ST

Page 1: ...REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE PRODUCT READ THE SAFETY PRECAUTIONS IN THIS MANUAL MODELS LFC21776ST COLORS STAINLESS ST ...

Page 2: ... 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 11 TO REMOVE THE COVER PTC 11 CIRCUIT DIAGRAM 12 TROUBLESHOOTING 13 17 COMPRESSOR AND ELECTRIC COMPONENTS 13 OTHER ELECTRICAL COMPONENTS 14 SERVICE DIAGNOSIS CHART 15 REFRIGER...

Page 3: ...atic Heater Defrost PCM VCM Stainless Bar ABS Resin Polyurethane Foam DOOR DESIGN DIMENSIONS inches NET WEIGHT pounds COOLING SYSTEM TEMPERATURE CONTROL DEFROSTING SYSTEM DOOR FINISH HANDLE TYPE INNER CASE INSULATION ITEMS 21 cu ft SPECIFICATIONS DIMENSIONS Description LFC21776ST Depth w Handles Depth w o Handles Depth w o Door Depth Total with Door Open Height to Top of Case Height to Top of Door...

Page 4: ...Control Refrigerator Light Shelves Modular Door Bin Glide N Serve Ice Bin Durabase Divider Dairy Bin Modular Door Bin Bottle Holder Modular Door Bin Pullout Drawer Optibin Crisper Keeps fruits and vegetable fresh and crisp AUTOMATIC ICEMAKER ...

Page 5: ...dge protrudes from beneath door frame edge 2 Remove gasket bracket clips There are two clips on each door Start bracket removal near one of the middle clips 1 Pull gasket back to expose gasket bracket clip and door frame 2 Insert a flat tip screwdriver into seam between gasket bracket and door frame and pry back until clips snaps out 3 Continue prying back along seam until all clips snap out 3 Rem...

Page 6: ...nto channels on the three remaining sides of door Figure 7 Figure 9 Figure 8 3 2 DOOR ALIGNMENT 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 2 With other hand use pliers to insert snap ring as shown 3 Insert additional snap rings until the doors are aligned Three snap rings are provided wi...

Page 7: ...ove the gear from the left side first by releasing the tab behind the gear place a screwdriver between the gear and the tab and pull up on the gear Second Remove the center rail Third Remove the gear from the right side by following the same steps for the left side NOTE THIS TAB MUST BE PUSHED IN TO RELEASE THE GEAR Step 4 Lift the freezer door up to unhook it from the rail support and remove Pull...

Page 8: ...ill align itself by pushing the rails all the way into the freezer section Pull the rails back out to full extension Step 5 Reinstall the freezer door by inserting the rail tabs into the guide rail Step 6 Reinstall the two screws into the guide rails one from each side Step 7 Reinstall the lower basket and close the freezer door Step 3 Insert the rail into the left side gear and insert the gear in...

Page 9: ...e Then gently lift the gear part of rear left and right side of the drawer and pull it out in 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 10: ...ressure gas from the evaporator of the refrigerator and compresses this gas to high temperature and high pressure gas It then delivers the gas to the condenser 4 1 2 Note for Usage 1 Be careful not to allow over voltage and over current 2 Do not drop or handle carelessly 3 Keep away from any liquid If liquid such as oil or water enters the Cover PTC Compressor may fail due to breakdown of their in...

Page 11: ...n logic Since linear Comp conducts linear reciprocating motion we have protection logic for compressor motor and PCB as the below Stroke Trip During the operation if stroke is above the target value decrease the target volt by 3V Current Trip Current trip is set in order to protect compressor mechanical part and drive from the overcurrent that might arise during the operation Check the current for...

Page 12: ...rent Trip Lock Piston Trip IPM fault trip Led Times 2 6 5 7 Comp Off Time 1min 6min 2min 30sec 20sec 3 Check problems by LED On Off Count _ Sub PCB Current Trip PCB defects or Cycle clogging maybe the causes After estimating winding resistance estimate compressor operation voltage to check if there is any problem and take actions to repair cycle at replacement of compressor Stroke Trip can occur w...

Page 13: ... 13 5 CIRCUIT DIAGRAM ...

Page 14: ...Sensor Error Er IS Short or Disconnection of Icing Sensor 6 Poor Defrosting Er dH Even though it is passed 1 hour since then Defrosting if Defrosting sensor is not over 8 C it is caused Temperature Fuse Disconnection Heater disconnection DRAIN Jam Poor Relay for Heater 7 Abnormality of BLDC FAN Motor for Freezer Er FF It is caused when feedback signal isn t over 65 seconds during BLDC FAN motor op...

Page 15: ... 15 7 PCB Picture 7 1 Main PCB P No MFG EBR67348002 2010 03 Picture CON4 CON5 CON8 CON3 CON2 CON9 CON1 ...

Page 16: ... 16 7 2 Display PCB Sub PCB P No Display PCB EBR42479305 2010 03 Picture CON01 ...

Page 17: ...eezer Sensor Error Er FS No 1 2 Checking flow Check for a loose connection Check the Blue White to Blue White Result SVC Action CON4 Temperature table 1 1 To 2 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 Result 40 5 38 5 30 5 28 5 23 21 5 17 5 16 5 13 5 12 5 10 5 9 5 8 7 5 The sensor is determined by the temperature For example 23 indicates 4 F ...

Page 18: ...Refrigerator Sensor Error Er rS No 1 2 Checking flow Check for a loose connection Check the White to White Result SVC Action Temperature table 2 1 To 2 23 F 5 C 32 F 0 C 41 F 5 C 50 F 10 C 59 F 15 C Result 38 5 36 5 30 5 29 5 24 5 23 5 20 19 16 15 5 The sensor is determined by the temperature For example 30 indicates 32 F CON4 ...

Page 19: ...Action No 1 2 Checking flow Check for a loose connection Check the Red to Bright Orange Result SVC Action Temperature table 1 1 To 2 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 Result 40 5 38 5 30 5 28 5 23 21 5 17 5 16 5 13 5 12 5 10 5 9 5 8 7 5 The sensor is determined by the temperature For example 23 indicates 4 F CON9 ...

Page 20: ...nsor Error F dS No 1 2 Checking flow Check for a loose connection Check the Orange to Orange Result SVC Action Check the Brown to Brown The sensor is determined by the temperature For example 23 indicates 4 F CON4 Temperature table 3 1 To 2 23 F 5 C 32 F 0 C 41 F 5 C 50 F 10 C 59 F 15 C Result 38 5 36 5 30 5 29 5 24 5 23 5 20 19 16 15 5 ...

Page 21: ...w Check the Door gasket Check the Defrost control part 3 Input Test 3 Mode Push the button 3 times 4 Check the Blue to Orange Result SVC Action Fuse M Def Heater Def Sensor 5 Release the test mode Push the button 1 times Normal CON3 CON3 Result 112 116 V 0 V SVC Action Go to the 5 Replace Main PCB 6 Check the Blue to Orange Result 0 V 112 116 V SVC Action Explain to customer Replace Main PCB ...

Page 22: ...ile an error code is displayed the fan is not working 3 Check the Fan motor Rotate fan using your hand It feel sticky change the motor Cause of ice or rust inside of motor 4 Check the Fan motor voltage Result SVC Action Below 9 V 0 or 5 V 1 2 2 3 Change the PCB Change the motor Point Result SVC Action CON4 Status No windy Windy SVC Action Go to 3 Go to 4 1 2 3 ...

Page 23: ...le an error code is displayed the fan is not working 3 Check the Fan motor and surrounding Rotate fan using your hand It feel sticky change the motor Result SVC Action 4 Check the Fan motor voltage Below 9 V 0 or 5 V 1 2 2 3 Change the PCB Change the motor Result SVC Action Status No windy Windy SVC Action Check motor Go to the 4 CON4 1 2 3 ...

Page 24: ...Orange CON5 6 Check the White Red to White Black CON5 CON101 Display 3 Check the Orange to Brown Result 0 V or 5 V Other SVC Action Change the Display PCB Go to the 4 4 Check the Orange to Red Result 0 V or 5 V Other SVC Action Change the Main PCB Go to the 5 Result 0 V or 5 V Other SVC Action Change the Display PCB Go to the 6 Result 0 V or 5 V Other SVC Action Change the Main PCB Explain to cust...

Page 25: ...to Sky blue 4 Check the Blue to Black Check the Blue to Black Closed Open 0 2 V Other 115 V Other Explain to customer Change the Main PCB Change the F Lampe Change the PCB Status Result SVC Action Closed Open 5 V Other 0 V Other Go to the 4 Change the Door S W Go to the 4 Change the Door S W Status Result SVC Action Normal Push S W 0 Infinity Infinity 0 Go to the 3 Change door S W Go to the 3 Chan...

Page 26: ...ck Closed Open 0 2 V Other 12 V Other Explain to customer Change the Door S W Explain to customer Change the LED Lamp Status Result SVC Action Normal Push S W 0 Infinity Infinity 0 Go to the 3 Change door S W Go to the 3 Change door S W Status Result SVC Action Normal 12 V Other Go to the 4 Change the PCB Status Result SVC Action Normal 12 V Other Go to the 5 Change the LED Lamp Status Result SVC ...

Page 27: ...s determined by the temperature For example 30 indicates 32 F Result SVC Action CON4 1 To 2 23 F 5 C 32 F 0 C 41 F 5 C 50 F 10 C 59 F 15 C Result 38 5 36 5 30 5 29 5 24 5 23 5 20 19 16 15 5 Status Windy No windy SVC Action Go to the 4 Check the R Fan motor Check the damper Go to the 6 4 Check the air temperature Cold or not Status Cold Not cold SVC Action Explain to customer Check the Compressor A...

Page 28: ...he F Fan motor voltage 1 3 2 4 Open Closed Not working 1 Mode 2 Mode 1 2 mode Damper is normal Explain to customer Change the damper Test Mode Damper State SVC Action 1 to 2 3 to 4 270 330 Other 270 330 Other It s normal Change damper It s normal Change damper Test Point Result SVC Action Below 12 V 0 or 5 V 1 2 2 3 Change the PCB Change the motor Point Result SVC Action Sticky Motor Change the mo...

Page 29: ...ermined by the temperature For example 23 indicates 4 F Result SVC Action Status Windy No windy SVC Action Go to the 4 Check the F Fan motor 4 Check the air temperature Cold or not Status Cold Not cold SVC Action Explain to customer Check the Compressor And sealed system 1 To 2 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 Result 40 5 38 5 30 5 28 5 23 21 5 17 5 16 5 13 5 12 5 ...

Page 30: ...efrigerator door and Check the air flow The sensor is determined by the temperature For example 30 indicates 32 F Result SVC Action 1 To 2 23 F 5 C 32 F 0 C 41 F 5 C 50 F 10 C 59 F 15 C Result 38 5 36 5 30 5 29 5 24 5 23 5 20 19 16 15 5 Status Windy No windy SVC Action Go to the 4 Check the R Fan Check the damper Go to the 5 4 Input Test 2 Mode and Check the air flow Push the button 1 time 5 Check...

Page 31: ...w to make TEST MODE If you push the test button on the Main PCB the refrigerator will be enter the TEST MODE 2 How to remove Terminal Position Assurance TPA 1 time Comp Damper All FAN on All things displayed 2 times Damper closed 22 22 displayed 3 times Forced defrost mode 33 33 displayed Main PWB AC TPA DC TPA ...

Page 32: ...F 5 C 32 F 0 C 41 F 5 C 50 F 10 C 59 F 15 C 68 F 20 C 77 F 25 C 86 F 30 C 95 F 35 C 104 F 40 C RESISTANCE 73 29 53 63 39 66 29 62 22 33 16 99 13 05 10 10 7 88 6 19 4 91 3 91 3 14 2 54 2 07 1 69 1 39 VOLTAGE 4 09 V 3 84 V 3 55 V 3 23 V 2 89 V 2 56 V 2 23 V 1 92 V 1 63 V 1 38 V 1 16 V 0 97 V 0 81 V 0 67 V 0 56 V 0 47 V 0 39 V ...

Page 33: ... C 32 F 0 C 41 F 5 C 50 F 10 C 59 F 15 C 68 F 20 C 77 F 25 C 86 F 30 C 95 F 35 C 104 F 40 C RESISTANCE 225 1 169 8 129 3 99 30 76 96 60 13 47 34 37 55 30 24 13 19 53 15 91 13 03 10 74 8 89 7 40 6 20 VOLTAGE 4 48 V 4 33 V 4 16 V 3 95 V 3 734 V 3 487 V 3 22 V 2 95 V 2 67 V 2 40 V 2 14 V 1 89 V 1 64 V 1 45 V 1 27 V 1 10 V 0 96 V ...

Page 34: ... there is a fan motor malfunction this process is repeated 3 times If the fan motor is determined to be defective the error code will be shown in the display for 30 minutes At this point the process will be repeated until the fan motor operates normally If normal operation is achieved the error display is erased and the MICOM is reset automatically No signal Error Display 15s 10s 15s 10s 15s Norma...

Page 35: ...oubleshooting Step 1 Open PWB cover Step 2 Check for blinking frequency of LED PWB If compressor is normal it does not blink Refer to the next page to find out what actions to take according to how many times LED blink ...

Page 36: ... on on off repeating piston constraint 1 After resetting power check if it is running normal 2 If the same symptom arises after the first action replace PCB 3 If the same symptom arises after the second action replace compressor 3 LED six time repetiton on on on on on on off on on on on on on off repeating circuit overcurrent error 1 After resetting power check if it is running normal If the same ...

Page 37: ...sure Fuse M Set a ohmmeter to the 2 housing pin Measure the 2 pin connected to Fuse M If the ohmmeter indicate below 0 1ohm fuse m is a good condition But infinitely great ohm Fuse M is disconnection How to Measure Sensor Set a ohmmeter to The 2housing pin Measure the 2 pin connected to Sensor If the ohmmeter indicate 11 at room temperature Sensor is not a defect When check the ohm at other temper...

Page 38: ...e resistance How to Measure Set a ohmmeter connect to The 2 housing pin Measure the 2 pin connected to Sheath Heater If the ohmmeter indicate V øV Watt R is good condition ex when watt 350w voltage 115v R 115 ø115 350 38 But the ohmmeter indicate infinitely great Sheath heater is disconnection Standard Sheath heater at all temperature Test Point 1 to 2 Ressult 34 42 1 2 ...

Page 39: ... 39 11 3 Door Heater Assembly Function The heater is designed to prevent the raising dew from door How to Measure Standard Test Point 1 to 2 Ressult 2 3 2 9 1 2 3 5 8 9 4 6 7 ...

Page 40: ...on and off moving plunger of door switch up and down How to Measure Switch Freezer Switch Refrigerator Check the resistance between connectors 1 2 and 3 4 It means check whether or not applying an electric current If there is resistance it means the switch not inferiority Standard Beep Beep Multimeter beep Switch F R Nomal Beep or 0 Push the button Plunger None Button Plunger 1 2 3 4 3 4 2 1 1 2 3...

Page 41: ... DC Motor Function Dispenser DC Motor When customer push the dispenser button Pull duct door and abstract from ice bank How to Measure Standard Dispensor DC Motor Dispenser DC Motor Test Points 1 to 2 Result 9 9 12 1 1 2 ...

Page 42: ...s 1 to 3 Result 31 1 42 09 Take out the male housing from female housing Measure the resistance between 1 and 2 Check the resistance between connectors In door motor 1 2 and In door motor 1 3 It means check whether or not applying an Electric current If there is resistance it means the geared motor or solenoid is not inferiority 1 2 3 1 1 2 Take out the male housing from female housing Measure the...

Page 43: ...temperature will rise How to Measure Damper Circuit extension Check the Standard Damper Test Points Red and Yellow Result 373 456 Test Points Blue and White Result 373 456 Check the resistance between connectors 1 3 and 2 4 It means check whether or not applying an electric current If there is resistance it means the damper not inferiority 1 Blue 1 Blue 2 Red 3 White 3 White 1 3 Check the 2 4 Chec...

Page 44: ... assembly The lamp socket supply electric source to lamp also How to Measure Standard Check the resistance between connector of housing and connector of lamp socket It means check whether or not applying an electric current If there is resistance it means the lamp socket is not inferiority Test Points 1 to 2 and 3 to 4 Result 0 1 2 3 4 ...

Page 45: ...Sensor Function Flow Sensor in machine room Count the water quantity from city water to water filter in refrigerator How to Measure Standard Flow Sensor in machine room Test Points Red wire to Black wire Result 4 30 ...

Page 46: ...al Number 4 Safety Approval Ex F C 9 0 L A N A 00 00 9 2003 5 13 0012 Series name DLF FA FB Operating Type A A Inverter E E Inverter Rated Voltage Frequency M 220V 50 60Hz N 115V 50 60Hz Efficiency version A 1st generation B 2nd generation Displacement ex 90 9 0 stroke Application Category L LBP with R134a H HBP with R134a N LBP with R600a Buyer Code Model Code Line Serial No Date Year VVVF Variab...

Page 47: ...e increases every 0 8sec until maximum stroke length is reached about 3 min 15 sec Step 3 CVCF interval 180V 60Hz Step 1 Start up Half stroke interval for first 20 seconds Step 2 Ramp up Stroke increases until maximum stroke length is reached about 1 min 40 sec Step 3 VVVF interval target voltage and frequency controlled by Control Board signals FCT0 Stroke Trip Locked Piston Trip Current Trip IPM...

Page 48: ...on the connector as shown picture with a multi tester There are two PCB located behind the PCB cover E Inverter FC75LANE A Inverter FC90LANA Multi Tester Multi Tester E Inverter A Inverter IPM Voltage Check To ensure proper diagnosis make sure that the unit has been plugged in for at least 10 min To determine if the compressor is receiving the proper voltage check the PCB output voltage during ope...

Page 49: ...citor Spec 450V 18uF 5 Po Power Co Common N C No Connecting Compressor Winding Resistance Check 6 8 Ω Between Po and Co FC75LANE Po N C Co Capacitor Spec 550V 10uF 5 Po Power Co Common N C No Connecting Compressor Winding Resistance Check 6 8 Ω Between Po and Co 6 8 Ω 6 8 Ω Inf Inf NOTE Any Terminal to Ground should read Inf GN GND ...

Page 50: ...rly Seal liquid foods with wrap Put in foods after they have cooled down Don t open the door too often and close it firmly Condensation forms in the Exterior Case Check if the ambient temperature and humidity of the surrounding air are high Is there a gap in the door gasket Wipe moisture with a dry cloth It will disappear in low temperature and humidity Fill up the gap There is abnormal noise Is t...

Page 51: ...ing of the Refrigerant MOISTURE CLOG Cooling operation stops periodically Flowing sound of refrigerant is not heard and frost melts Lower than ambient temperature Cooling operation restarts when heating the inlet of the capillary tube CLOGGED BY DUST COMP RESSION Freezer and Refrigerator don t cool Low flowing sound of refrigerant is heard and frost forms in inlet only A little higher than ambient...

Page 52: ...Test Very Slow None Equalization Test Very Fast Fast Very Fast Inefficient Compressor Partial Restriction Complete Restriction Condenser Temperature Cap Tube Sound Yes No Air Low Side Leak Loss of Change Very Slow Faint Hotter than Normal None to Weak Room Temperature Compressor Not Pumping Trace of Oil Undercharge The equalization test is trying to restart a compressor using a start kit after it ...

Page 53: ...y rotating ice ejection motor in normal and reverse direction and eject ice into the ice bucket if ice bucket is not full Conduct Ice Making Control after supplying water into the ice maker cube mould by operating water valve This is for refrigerator assembly line and service When ice making test switch is pressed it operates in the following steps initial ice ejection water supply control steps 1...

Page 54: ...jection control is completed and ice maker mould is even 2 The quantity of water supplied is determined by DIP switch and time 3 If water supply quantity setting is changed while power is on water supplies for the amended time If DIP switch is changed during water supply water shall be supplied for the previous setting time But it will supply for the amended time from the next supply 4 When water ...

Page 55: ...al direction If there is no change in Hall IC signals within 1 minute after ice ejection motor operates ice ejection motor stops as ice ejection motor or hall IC is out of order 5 If ice ejection motor or Hall IC is abnormal ice ejection motor rotates in normal direction to exercise initial operation It resets the ice maker if ice ejection motor or Hall IC is normal 6 The mould stops for 1 second ...

Page 56: ...mould conditions Water shall be splashed if test switch is pressed before the water in the mould freezes Water shall be supplied while the mould returns to the horizontal conditions after ice ejection Therefore the problems of ice ejection returning to the horizontal conditions and water supply can be checked by test switch When test function performs normally buzzer sounds and water supply shall ...

Page 57: ...62H 103C 207B 207A 402A 402A S03 B02 249C 312C B01 271B B01 271D 610A S03 S01 S01 S02 S12 S11 B02 B04 S17 302B 400A 316B 408A 323B 300A 314A 316A 105A 318A 317A 312A S20 329C 319A 319C 420A 309B 310B 610D 405F 404A 405C 405B 329A 407B S16 135C 610E 610C 332A 120B 120A 282G S08 145A 282F 250F 406B S10 207C 406D 158A 503D 503E S12 409D 504A 290A 500H 410G 413A 303A 304A B03 283B 106A 409B 158B B03 2...

Page 58: ... 58 FREEZER PARTS CAUTION Use the part number to order part not the position number 145C 250C 250D 136B 145F 250D 136A 237C 250E 250C 145M 145J 145H 145G 145J 145K 131A ...

Page 59: ...FRIGERATOR PARTS CAUTION Use the part number to order part not the position number 162B 145D 162A 145E 146E 151A 151C 161B 141D 161C 151B 154A 161A 141A 141C 141B 141A 141C 141B 141A 141C 141B 141A 141C 141B ...

Page 60: ...er 241D 241E 241D 234A 234C 212G 243A 243B 243C 262C 244A 203A 200A 201A 212D B06 B06 205C 205B 250B 250B 249F 250A B05 S25 B05 249G 249E 249J 230B 230A 241D 241D 241D 241E 244A 243A 243B 243C 262C 234B B05 S25 B05 234D 241C 241B 241A 249H 249K 250H 233C 231B 233D 231A 233B 233A ...

Page 61: ... 61 WATER AND ICEMAKER PARTS CAUTION Use the part number to order part not the position number 619A 623B 616E 600B 600A 619E 623A 627B ...

Page 62: ...P No MFL47912326 ...

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