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LG LRBN20512WW, Service Manual

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LG LRBN20512WW Service Manual Download Page 24

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7-2-5  Temperature Sensor Circuit

The upper CIRCUIT reads REFRIGERA

TOR temperature, FREEZER Temperature, and DEFROST-SENSOR temperature

for defrosting and the indoor temperature for compensating for the surrounding temperature into MICOM.
OPENING or SHORT state of each TEMPERATURE SENSOR are as follows:

Summary of Contents for LRBN20512WW

Page 1: ...CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL REFRIGERATOR SERVICE MANUAL MODEL LRBN20512WW ...

Page 2: ...ins 10 Disassembly repair and servicing the sealed refrigeration system should be performed only by qualified and certified personnel Refrigerant should not be vented into the atmosphere proper recovery equipment should be used SAFETY PRECAUTIONS SAFETY PRECAUTIONS 1 SPECIFICATIONS 2 PARTS IDENTIFICATION 3 DISASSEMBLY 3 1 Door 3 2 Door switch 3 3 Fan and fan motor 3 4 Defrost control assembly 3 5 ...

Page 3: ...Fix Non S Proof LAMP YES 2 60W blue EGG BANK NO GUIDE BOTTLE NO MAGIC CRISPER NO WINE RACK NO BASKET 2 1 3 2 2 3 1Full SHELF CAPACITY litre F R T cuft DIMENSIONS mm W H D in 176 72 382 33 559 05 6 24 13 5 19 74 MODELS SPECIFICATIONS GENERAL FEATURES WEIGHT kg lb ICE TRAY WIRE I T 2EA I B REFRIGERATOR FREEZER DEFROST SYSTEM LRBN20512WW 758 825 67 875 863 6 29 7 8 67 7 8 34 110 242 5 AUTOMATIC ...

Page 4: ...own below may not match your model 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 IDENTIFICATION ...

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: ...cord from the outlet 2 Remove refrigerator shelves 3 Release the hooks on both ends of the lamp shield and pull the shield downward to remove it 4 Turn the lamp counterclockwise 5 Assemble in reverse order of disassembly Replacement bulb must be the same specification as the original Max 60 W 2EA 3 5 2 Freezer Compartment Lamp 1 Unplug refrigerator or disconnect power 2 Reach behind light shield 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: ...K HIGH HIGH LOW LOW CON2 CON2 SB SB BN BN SB SB 1 1 2 2 5 5 4 4 3 3 6 6 2 2 GY GY 9 9 8 8 7 7 3 3 PK PK 5 5 BL BL 4 4 PK PK RD RD 8 8 YL YL 7 7 6 6 BK BK CON5 CON5 WH WH WH WH 3 3 4 4 BO BO 5 5 1 1 GY GY BO BO 6 6 S W F S W F DOOR DOOR com com S W R S W R DOOR DOOR BO BO nc nc nc nc com com com com RD RD nc nc nc nc com com PERCEPTION S W PERCEPTION S W PERCEPTION S W PERCEPTION S W B B F DOOR F D...

Page 10: ...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 T erminal C of Compressor 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 resistanc...

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 Drip Tray is not firmly fixed Check if the cover of the compressor enclosure in the lower front 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: ... ICE PLUS ICE PLUS operates for the rest of time after defrost is completed when ICE PLUS operation time is less than 90 minutes If ICE PLUS operates for more than 90minutes the ICE PLUS will operate for two hours after defrost is completed 3 If ICE PLUS is pressed during defrost ICE PLUS LED is on but this function will start seven minutes after defrost is completed and it shall operate for three...

Page 16: ...ops if the sensor temperature reaches 46 4 F 8 C or more If the sensor doesn t reach 46 4 F 8 C in a hour the defrost mode is malfunctioning 4 Defrosting won t function if its sensor is defective wires are cut or short circuited OPERATING ORDERS Initial power on Temperature of Defrosting Sensor is 45 C or more when unit is newly purchased or when moved POWER ON In second COMP ON In second Freezer ...

Page 17: ... Connecting wires on each sensor Snapping of defrost heater or Temperature fuse pull out of Connector indicated minimum 1 Hours after failure occurs All off All off All off All off All off LED OFFLED ON 1 hours later after Open or short circuit Visible in LED CHECK MODE starting defrost If sensor doesn t be over 46ºF 8ºC 5 Failure of BLDC fan motor at freezing compartment DISPLAY CHECK MODE Press ...

Page 18: ...over 3 seconds Or press TEST S W one time in the Main PCB board Push ICEPLUS key and ADJUST key of Freezer temperature at the same time over 3 seconds being in TEST MODE1 Or press TEST S W one time being in TEST MODE 1 Push ICEPLUS key and ADJUST key of Freezer temperature at the same time over 3 seconds being in TEST MODE2 Or press TEST S W one time being in TEST MODE 2 1 Continuous operation of ...

Page 19: ... Vdc 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 high voltage 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 PART VA 1 CE 3 CE 4 CE 5 VOLTAGE 115 Vac 12 Vdc 15 5 Vdc 5 V 19 ...

Page 20: ...ll not work 7 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 ope...

Page 21: ...zer Drive Open Door Detection Circuit 1 Load Drive Condition Check LOAD TYPE COMP NO 14 NO 12 NO 11 NO 13 1V or below 12V DEFROSTING HEATER LAMP FRENCH DOOR HEATER 1 2 DEW HEATER Measurement Location IC6 Condition ON OFF ...

Page 22: ...riving 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 part part MOTOR OFF 2V or less 0V MOTOR ON 13V 15V 0V a b 3 Cooling motor driving circuit machine room 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 circuit prevents over driving the...

Page 23: ... 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 A B Tone Ding Dong when the button on the display is pushed Alarm for open door beep beep beep Pin No 14 Refrigerator Door Pin No 15 Freezer Door Closed 5 V Open 0 V Freezer Refrigerator Door Measurement Location REFRIGERATOR DOOR SWITCH FREEZER DOOR SWITCH ...

Page 24: ...IT reads REFRIGERA TOR temperature FREEZER T emperature and DEFROST SENSOR temperature for defrosting and the indoor temperature for compensating for the surrounding temperature into MICOM OPENING or SHORT state of each TEMPERA TURE SENSOR are as follows ...

Page 25: ...dercooling compensation circuit Table of temperature compensation by cutting JUMP WIRE to easy SVC temperature adjustments 1deg 1deg 1deg 1deg Four oprion are available for R Compensations by CUTTING JUMPWIRE Example 1 CUTTING JCR1 and JCR2 R 2 deg compensation Example 2 CUTTING JCR1 and JCR3 no compensation in R compartment Example 3 CUTTING JCR1 JCR2 and JCR3 compensation of temp 1deg 1deg 1deg ...

Page 26: ...circuit 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 DISPLA Y MODULE The drive type is the scan type 26 ...

Page 27: ...s in the measuring temperature This delay is necessary due to sensor response speed Measure the F SENSOR SUPER FROST SENSOR R1 R2 SENSOR after disconnect CON5 of PWB AS SY 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 27 ...

Page 28: ...C is poor Replace OLP PTC after compressor shuts off COMPRESSOR RELAY is Replace MAIN PWB don t 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 tempe...

Page 29: ...liner damaged Replace Door liner door is closed DEFROSTING is NO DEFROSTING 1 If HEATER emits heat USE TEST MODE3 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 RY2 of MAIN PWB 2 ...

Page 30: ...7 5 MAIN PWB ASSEMBLY AND PARTS LIST 7 5 1 Main PWB Assembly 30 TOP VIEW BOTTOM VIEW ...

Page 31: ... 31 7 5 2 Replacement Parts List ...

Page 32: ...7 5 3 PWB Assembly Display and parts list 32 ...

Page 33: ... 33 7 6 PWB DIAGRAM 7 6 1 PWB Main Assembly ...

Page 34: ... 34 ...

Page 35: ...105A 301A 283B 103B 328A 418A 281A 281B 284D 305B 305B 305C 305C 105F 323B 329C 420A 319A 319C 503D 282B 282H 410A 409D 409B 158A 405C 404A 405C 332A 135C 405A 158E 145B 409B 503C 503E 106A 120B 145A 406B 282E 903D 610A 282F 405B 329A 41 283D 284D B01 503G 503F 125D B01 106B 282C S22 903A 903B 903B 103C 623H S38 S01 EV 128E 128F 610A 903E 284E 284B 619B 327A 35 ...

Page 36: ...FREEZER PARTS CAUTION Use the part number to order part not the position number EV 282X 136C 149A 125A 131A 36 ...

Page 37: ...ARTS CAUTION Use the part number to order part not the position number EV 140D S24 143F 128B 128A 142E 140B 142D S24 S24 170A 103E 103E 167B 154A 151A 155B 151C 151A 143B 143A 143E 140D 140B 140E S24 S24 140E S24 37 ...

Page 38: ...86A S27 243A 286A 244E 700C 286A 200A 203A S02 201A 282Z 281E 205D 244P 212F 244H 212F 212J 212J 241D 241C 241A 241E 241B 230A 233A 231A 286A 212G DOOR PARTS CAUTION Use the part number to order part not the position number 38 ...

Page 39: ... Shutter 404A 4680JK1002B Motor AC Freezing 154A 3550JL1006D Cover TV 405A 4811JJ2002B Bracket Assembly Motor 155B 4981JJ2001B Supporter Assembly Cover TV 405B 4810JA3007A Bracket Motor 158A 3550JJ1040A Cover Lamp 405C J756 00008B Damper Motor Support 158E MCK30060901 Cover Lamp 406B 6600JB1010A Switch Push Button 167B 4890JL1002G Shelf Glass 409B 6912JB2004M Lamp Incandescent 170A 3391JJ2004G Tra...

Page 40: ...P No 3828JL8089C Junio 2008 ...

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