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LG LB Series, Service Manual

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LG LB Series Service Manual Download Page 26

8-2-4 Load / Buzzer Drive & Open Door Detection Circuit

1. Load Drive Condition Check

2. Fan motor driving circuit (freezing compartment fan)

1. This circuit makes standby power 

0

by cutting off power supplied to ISs inside of the fan motor in the fan motor OFF.

2. This is a circuit to perform a temporary change of speed for the fan motor and applies DC voltage up to 7.5V ~ 16V to motor.

3. This circuit prevents over-driving the fan motor by cutting off power applied to the fan motor in the lock of fan motor by

sensing the operation RPM of the fan motor.

- 26 -

FREEZER DOOR

SWITCH

REFRIGERATOR

DOOR SWITCH

LOAD TYPE

COMP

NO.13

NO.14

NO.16

NO.12

NO.15

1V or below

12V

DEFROSTING

HEATER

LAMP

TCM

POWER MODE

(OPTIONAL)

VALVE

(DISPENSER

MDL)

Measurement Location (IC6)

Condition

ON

OFF

part

part

part

MOTOR OFF

2V or less

0V

5V

MOTOR ON

13V~15V

0V

2V~3V

a

b

c

G5SB-14

Summary of Contents for LB Series

Page 1: ...CAUTION BEFORE SERVICING THE PRODUCT READ THE SAFETY PRECAUTIONS IN THIS MANUAL REFRIGERATOR SERVICE MANUAL Models MODELS LB 22515 ...

Page 2: ... fins 9 Service on the refrigerator should be performed by a qualified technician Sealed system repair must be performed by a CFC certified technician SAFETY PRECAUTIONS Safety Precautions 2 1 Specifications 3 2 Parts Identifications 4 3 Disassembly 5 Door 5 Door Switch 5 Fan and Fan Motor 6 Defrost Control Asembly 6 Lamp 6 Refrigerator Control Box 6 Multi Duct 6 4 Ajustment 7 Compressor 7 PTC Sta...

Page 3: ...dle ABSResin PolyurethaneFoam Treansparent Drawer Type PTCStartingType FinTubeType WireCondenser R 134a 120g Freol 10G 310cc SHEATHHEATER REFRIGERATOR 60W FREEZER 60W LUBRICATINGOIL COMPRESSOR EVAPORATOR CONDENSER REFRIGERANT LAMP DEFROSTINGDEVICE ITEMS DOORDESING DIMENSIONS NETWEIGHT COOLINGSYSTEM TEMPEARTURECONTROL DEFROSTINGSYSTEM VEGETABLETRAY DOORFINISH HANDLETYPE INNERCASE INSULATION ...

Page 4: ... may not match your model PARTSANDFEATURES Digital Sensor Control Refrigerator Light Shelves Snack Pan Optibin Crisper Keeps fruits and vegetable fresh and crisp Ice Trays Ice Bin Wire Durabase Dairy Bin Design A Door Wire Freezer Shelf Refrigerator Door Rack Freezer Light Freezer Door Rack B C D A F E G H I J L M K N A B C D E F G H I J M N L K 4 2 PARTS IDENTIFICATIONS ...

Page 5: ...Door 1 Loosen the hexagonal bolts attaching the lower hinge to the body to remove the refrigerator door only 2 Pull out the door gasket to remove from the door foam assembly 3 2 DOOR SWITCH 1 T o remove the door switch pry it out with a slotted type driver as shown in Figure 4 2 Disconnect the lead wire from the switch 3 DISASSEMBLY 5 BOLT HINGE HINGE COVER Figure 1 GASKET Figure 2 LOWER HINGE BOL...

Page 6: ... power 2 Reach behind light shield to remove bulb 3 Replace bulb with a 60 watt appliance bulb 4 Plug in refrigerator or reconnect power 3 6 CONTROL BOX REFRIGERATOR 1 First remove all shelves in the refrigerator than remove the Refrigerator control Box by loosening 2 screws 2 Remove the Refrigerator Control Box by pulling it downward 3 Disconnect the lead wire on the right position and separate t...

Page 7: ...nt flow to both the start winding and main winding 4 2 3 PTC Applied Circuit Diagram Starting Method for the Motor 4 2 4 Motor Restarting and PTC Cooling 1 It requires approximately 5 minutes for the pressure to equalize before the compressor can restart 2 The PTC device generates heat during operation Therefore it must be allowed to cool before the compressor can restart 4 2 5 Relation of PTC Sta...

Page 8: ...over Back M C 2 Remove the screw on Cover PTC 3 Remove two Housings on upper part of Cover PTC 4 T ake out the cover PTC from upper to lower position like 1 5 Turn 45 in the direction of 2 and take it out 6 Assembly in reverse order of disassembly 8 Part Customer part number Lot code date code 330 FBYY S1 BOX98 12345678 Physical termination part number Electrical characteristics part number No Nam...

Page 9: ...5 CIRCUIT DIAGRAM 9 ...

Page 10: ...stomer that power supply needs to be checked by an electrician Replace Compressor Supply voltage rating with 10 Applied voltage isn t in range of Rating Voltage 10 Remove PTC Starter from Compressor and measure voltage between OLP terminal and T erminals 5 or 6 of PTC Check resistance between M C S C and M S in Motor Compressor Check resistance of two terminals in PTC Starter Check resistance of t...

Page 11: ...ure resistance between No 5 and 6 of PTC Starter with a T ester Figure 14 Separate OLP from Compressor and check resistance value between two terminals of OLP with a T ester Figure 15 Observation value is 115V 60Hz 6 8 30 The resistance value is 0 short or open Check another electric component Replace OLP Replace PTC Starter Figure 14 Figure 15 ...

Page 12: ...apacity Replace indicated component Advise customer that the Power supply needs to be checked by an electrician Replace indicated component Cause Check voltage at starting devices Check current flowing in sub coil of Compressor Check rating of OLP Fan motor doesn t run Heavy frost buildup on EVAPORATOR Wire is open or shorted Coil is shorted or open Open Open Replace Defrost Heater Replace indicat...

Page 13: ...e high Is there a gap in the door gasket Is the unit positioned in a firm and even place Are any unnecessary objects placed in the back side of the unit Check if the Tray Drip is not firmly fixed Check if the cover of the compressor enclosure in the front lower side is taken out Check if the door gasket is dirty with an item like juice Is the refrigerator level Is there too much food in the refrig...

Page 14: ...ng sound of refrigerant A little higher Normal discharging of the CLOG compartment and is heard and frost forms than ambient refrigerant Refrigerator don t in inlet only temperature The capillary tube is faulty cool normally WHOLE Freezer Flowing sound of refrigerant Equal to ambient Normal discharging of the CLOG compartment and is not heard and frost isn t temperature Refrigerant Refrigerator do...

Page 15: ...ixing Do not mix with R 12 refrigerant T o remove the moisture from pipe inside Defect in refrigerant leak area The opening time should be reduced to a half of the standards during rain and rainy seasons the penetration of water into the pipe is dangerous Refer to repair note in each part R 134a refrigerant is more susceptible to leaks than R 12 and requires more care during welding Do not apply f...

Page 16: ...with power on Start Position Ice Making Mode Harvest Mode Park Position Fill Test Mode Waits until water becomes cold after starting the ice making operation Runs MOTOR to drop ice from the tray into the ICE BIN 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 ice maker will run through 3...

Page 17: ...ice making function will be completed in 4 hours NOTE After Icemaker Power is ON the Icemaker heater will be on for test for 9 sec 7 2 3 Harvest Mode 1 Harvest Ice removing refers to the operation of dropping cubes into the ice bin from the tray when ice making has completed 2 Harvest mode 1 The Heater is ON for 30 seconds then the motor starts 2 After performing Step 1 the Heater is turned OFF th...

Page 18: ...essing the Fill Key repeatedly This changes the time allowed for fill as illustrated in the table below Water supply amount TABLE 19 ST AGE TIME TO SUPPL Y INDICA TIONS REMARKS 1 2 3 4 5 6 sec 6 5 sec 7 sec 7 5 sec 8 sec The water amount will vary depending on the water control Switch setting as well as the water pressure of the connected water line ...

Page 19: ...r supply control panel ERROR indicators in table can be checked only in TEST mode 20 STAGE ITEMS INDICATOR REMARKS 1 2 3 4 5 6 HEATER MOTOR HALL IC I detection of position VALVE HALL IC II detection of full filled Ice Reset Five seconds after heater starts heater will go off if temperature recorded by sensor is 10 C or lever is in up position Five seconds after heater starts you can confirm that m...

Page 20: ...4 hrs The first three hours the compressor and EXPRESS FREEZING will be ON The next 21hours the freezer will be controlled at the lowest temperature After 24 hours or if the EXPRESS FREEZING key is pressed again the freezer will return to its previous temperature 5 For the first three hours notice the following cases 1 Compressor and freezer fan HIGH RPM continuously operate for three hours 2 If d...

Page 21: ...Refer to the defect diagnosis function 7 1 9 4 Defrosting won t function if its sensor is defective wires are cut or short circuited 8 1 8 Electrical Parts Are Turned On Sequentially Electrical parts such as COMP defrosting heater freezer FAN etc are turned on in the following order to prevent noise and parts damage Several parts are started at the same time at initial power on and are turned off ...

Page 22: ...rost Cut or short circuit wire Cut or short circuit wire Cut or short circuit wire Inspect Connecting wires on each sensor Snapping of defrost heater or T emperature fuse pull out of Connector indicated minimum 2 Hours after failure occurs All off All off All off All off LED OFF LED ON 2 hours later after starting defrost If sensor doesn t be over 46ºF 8ºC 5 Failure of BLDC fan motor at freezing c...

Page 23: ...ormal speed to high speed for 30 seconds After 30 seconds it turns to its original RPM Demonstration MODE 1 When the EXPRESS FREEZING key and ADJUST key of refrigerator temperature control are pressed for more than 3 seconds at the same time temperature s it converts to demostration mode 2 In this status each LED is rotated with 1 second interval 3 In this status all Loads are off Compressor Fan D...

Page 24: ... and the MICOM and IC 5 Vdc The voltage for each part is as follows VA1 is a part for preventing over voltage and noise When 385V or higher power is applied the inside elements are short circuited and broken resulting in blowout of the fuse in order to protect the elements of the secondary part of the TRANSFORMER 24 PART VA 1 CE 3 CE 4 CE 5 VOLTAGE 115 Vac 12 Vdc 15 5 Vdc 5 V ...

Page 25: ...ot work 8 2 3 Reset Circuit The RESET circuit allows all the functions to start at the initial conditions by initializing various parts including the RAM inside the MICOM IC1 when the power is initially supplied or the power supply to the MICOM is restored after a momentary power failure For the initial 10ms of power supply LOW voltage is applied to the MICOM RESET terminal During a normal operati...

Page 26: ...n motor and applies DC voltage up to 7 5V 16V to motor 3 This circuit prevents over driving the fan motor by cutting off power applied to the fan motor in the lock of fan motor by sensing the operation RPM of the fan motor 26 FREEZER DOOR SWITCH REFRIGERATOR DOOR SWITCH LOAD TYPE COMP NO 13 NO 14 NO 16 NO 12 NO 15 1V or below 12V DEFROSTING HEATER LAMP TCM POWER MODE OPTIONAL VALVE DISPENSER MDL M...

Page 27: ...V 0 V 5 V 0 5 s 0 5 s 2 63 kz Beep OFF 0 05 s 0 1 s 0 2 s 2 s 0 V 5 V 0 V 5 V 2 63 kz Ding 2 21 kz Dong PIN NO 63 PIN NO 8 Closed 5 V Open 0 V Freezer Refrigerator Door Measurement Location FREEZER DOOR SWITCH REFRIGERATOR DOOR SWITCH A B Tone Ding Dong when the button on the display is pushed Alarm for open door beep beep beep ...

Page 28: ...emperature for compensating for the surrounding temperature into MICOM OPENING or SHORT state of each TEMPERATURE SENSOR are as follows 28 SENSOR CHECK POINT NORMAL 30 C 50 C SHORT CIRCUITED OPEN Freezer Sensor POINT Voltage Refrigerator Sensor POINT Voltage 0 5 V 4 5 V 0 V 5 V Defrosting Sensor POINT Voltage A B C FREEZER SENSOR REFRIGERATOR SENSOR DEFROST SENSOR ...

Page 29: ...8 2 6 Refrigeration Compartment Stepping Motor Damper Circuit The circuit shown below is the damper circuit to regulate the refrigerator temperature 29 1 2 3 ...

Page 30: ... Down Change Up Up Up Up Up Up Up Up 1 5 C 1 C 0 5 C No 0 5 C 1 C 1 5 C 2 C 2 5 C 3 C 3 5 C 5 6k Down Down Down 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 2k Down Down Down Down Change Up Up Up Up Up Up Refrigerator 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 RCR 10k Down Down Down Down Down Change Up Up Up Up Up 3 C 2 5 C 2 C 1 5 C 1 C 0 5 C No 0 5...

Page 31: ...uit shown above determines whether a function control key on the operation display is pushed It also turns on the corresponding function indication LED LED Module SEVEN SEGMENT DISPLAY SEVEN SEGMENT DISPLAY MODULE The drive type is the scan type 8 2 10 Power Failure Compensation Circuit DISPENSER MODEL 31 ...

Page 32: ...OR SUPER FROST SENSOR R1 R2 SENSOR after disconnect CON5 of PWB ASSY MAIN TEMPERATURE DETECTED RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR BY SENSOR SENSOR DEFROST SENSOR ROOM SENSOR 20º C 15º C 10º C 5º C 0º C 5º C 10º C 15º C 20º C 25º C 30º C 40º C 50º C 22 3 K Ω 16 9 K Ω 13 0 K Ω 10 1 K Ω 7 8 K Ω 6 2 K Ω 4 9 K Ω 3 9 K Ω 3 1 K Ω 2 5 K Ω 2 0 K Ω 1 4 K Ω 0 8 K Ω 77 K Ω 60 K Ω 47 3 K Ω 38 4 K...

Page 33: ...r compressor shuts off COMPRESSOR RELAY is Replace MAIN PWB donÕt press the KEY and poor wait THE CONNECTING WIRE Check the connection of the is poor black wire of the MAIN PWB CONNECTOR CON2 2 If refrigerant is leaking Measure the amount of frost Refrigerant leakage Replace the leaking part and sticking on EVAPORATOR replace any lost refrigerant and the surface temperature of the condenser pipe F...

Page 34: ...liner damaged Replace Door liner door is closed DEFROSTING is NO DEFROSTING 1 If HEATER emits heat USE TEST MODE2 HEATER disconnection Replace HEATER poor forced DEFROSTING TEMPERATURE FUSE Replace TEMPERATURE disconnection FUSE Connection is poor Check EVAPORATOR connection and wire of MAIN PWB CONNECTOR DEFROST SENSOR is poor Replace DEFROST SENSOR HEATER RELAY is poor Replace RY3 of MAIN PWB 2 ...

Page 35: ...9 5 MAIN PWB ASSEMBLY AND PARTS LIST 9 5 1 Main PWB Assembly 35 ...

Page 36: ...9 5 2 Replacement Parts List 36 ...

Page 37: ...10 5 3 PWB Assembly Display and Parts List 37 ...

Page 38: ... 38 9 6 PWB DIAGRAM 9 6 1 PWB Main Assembly FREEZER DOOR SWITCH REFRIGERATOR DOOR SWITCH PWB ASSEMBLY G5SB 14 RY4 RY5 ...

Page 39: ...Y PWB ASS Y DISPLAY TEMP TEMP FREEZER FREEZER TEMP TEMP REFRIGERATOR REFRIGERATOR 8 8 9 9 7 7 SW101 SW101 D101 D101 SW102 SW102 D102 D102 6 6 5 5 EXPRESS EXPRESS FREEZING FREEZING D103 D103 SW103 SW103 R6 R6 L101 L101 R7 R7 R2 R2 R3 R3 F5 F5 F6 F6 R5 R5 R4 R4 R1 R1 F7 F7 3 3 4 4 2 2 1 1 F1 F1 F2 F2 F4 F4 F3 F3 CON101 CON101 ...

Page 40: ...2A 317A 310A 103A 105A 301A 103B 328A 418A 281A 281B 305B 305B 305C 305C 105F 323B 329C 420A 319A 319C 503D 282B 282H 410A 409D 409B 158A 332A 135C 158E 145B 409B 503C 503E 120B 145A 406B 282E 903D 610A 903E 610A 282F 41 B01 503G 125D B01 106B S22 903A 903B 903B 103C 623H S04 S01 410G 405A 405C 405F 319E 329A 404A 405G 284D 106A 283D 282C 327A 619B 40 EV ...

Page 41: ...125A FREEZER PARTS CAUTION Use the part number to order part not the position number 131A 149A 136C 282X 41 EV ...

Page 42: ...se the part number to order part not the position number 154A 151A 155B 151A 151C 167B 140B 140E 140D 143E S24 S24 170A 128A 128B 143F 142E 142D S24 S24 140B 140B 140E 140D 143E 140B 140E 140D 143E S24 S24 S24 S24 103E 103E 42 EV ...

Page 43: ...art not the position number 233A 230A 231A 241A 241B 281E 241E 241C 241D 243A 203A 200A 201A 244H 244P 281E 244E 205D 700C 212G 212F 212F S02 282Z on some models S27 286A 286A 286A 212J 212J 244A 244J 212A 212G 244E 244J 281E 243A 283F S27 286A 43 EV ...

Page 44: ...405A 4811JJ2002A BRACKET ASSEMBLY MOTOR 158A 3550JJ1040A COVER LAMP 405C 5040JA2009B DAMPER MOTOR SUPPORT 158E 3550JJ1051A COVER LAMP 405F 5040JA2004B DAMPER MOTOR SUPPORT 167B 4890JL1002H SHELF GLASS 405G 4811JJ2002H BRACKET ASSEMBLY MOTOR 170A 3391JJ2004H TRAY ASSEMBLY MEAT 406B 6600JB1004A SWITCH PUSH BUTTON 200A 3581JJ8020A DOOR ASSEMBLY FREEZER 409B 6912JK2002C LAMP INCANDESCENT 201A 5433JJ00...

Page 45: ...C COVER TV 404A 4681JK1004A AC Motor 155B 4981JJ2001B SUPPORTER ASSEMBLY COVER TV 405A 4811JJ2002A BRACKET ASSEMBLY MOTOR 158A 3550JJ1040A COVER LAMP 405C 5040JA2009B DAMPER MOTOR SUPPORT 158E 3550JJ1051A COVER LAMP 405F 5040JA2004B DAMPER MOTOR SUPPORT 167B 4890JL1002H SHELF GLASS 405G 4811JJ2002H BRACKET ASSEMBLY MOTOR 170A 3391JJ2004H TRAY ASSEMBLY MEAT 406B 6600JB1004A SWITCH PUSH BUTTON 200A ...

Page 46: ...ER TV 404A 4681JK1004A AC Motor 155B 4981JJ2001B SUPPORTER ASSEMBLY COVER TV 405A 4811JJ2002A BRACKET ASSEMBLY MOTOR 158A 3550JJ1040A COVER LAMP 405C 5040JA2009B DAMPER MOTOR SUPPORT 158E 3550JJ1051A COVER LAMP 405F 5040JA2004B DAMPER MOTOR SUPPORT 167B 4890JL1002H SHELF GLASS 405G 4811JJ2002H BRACKET ASSEMBLY MOTOR 170A 3391JJ2004H TRAY ASSEMBLY MEAT 406B 6600JB1004A SWITCH PUSH BUTTON 200A 3581J...

Page 47: ... 3828JL 8799A MARCH 13TH 2006 ...

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