LG LFC21770ST - Panorama - 0.7 cu. ft Service Manual Download Page 1

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CAUTION

BEFORE SERVICING THE PRODUCT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

REFRIGERATOR

SERVICE MANUAL

COLORS: WESTERN BLACK(SB)

TITANIUM(TT)
SUPER WHITE(SW)
STAINLESS(ST)

LFC21770ST

LFC25770SW

LFC25770SB

LFC25770TT

LFC25770ST

MODELS:

Summary of Contents for LFC21770ST - Panorama - 0.7 cu. ft

Page 1: ...ERVICING THE PRODUCT READ THE SAFETY PRECAUTIONS IN THIS MANUAL REFRIGERATOR SERVICE MANUAL COLORS WESTERN BLACK SB TITANIUM TT SUPER WHITE SW STAINLESS ST LFC21770ST LFC25770SW LFC25770SB LFC25770TT LFC25770ST MODELS ...

Page 2: ...TS 15 SERVICE DIAGNOSIS CHART 16 REFRIGERATION CYCLE 17 18 OPERATION PRINCIPLE AND REPAIR METHOD OF ICEMAKER 19 22 DESCRIPTION OF FUNCTION AND CIRCUIT OF MICOM 23 36 EXPLODED VIEW AND REPLACEMENT PARTS LIST 37 CONTENTS 2 Please read the following instructions before servicing your refrigerator 1 Unplug the power before handling any elctrical componets 2 Check the rated current voltage and capacity...

Page 3: ...ENSER Wire Condenser REFRIGERANT R 134a 115 g LUBRICATING OIL ISO10 280 ml DEFROSTING DEVICE SHEATH HEATER LAMP REFRIGERATOR 60 W 2 EA FREEZER 60 W 1 EA Description LFC21770 LFC25770 Depth w Handles A 30 in 34 1 4 in Depth w o Handles B 27 1 2 in 31 3 4 in Depth w o Door C 23 5 8 in 27 7 8 in Depth Total with Door Open D 42 1 4 in 46 1 2 in Height to Top of Case E 68 3 8 in 68 3 8 in Height to Top...

Page 4: ...ator Light Shelves Optibin Crisper Keeps fruits and vegetable fresh and crisp Customcube Icemaker Glide N Serve Ice Bin Durabase Divider Pullout Drawer Tilt Out Door Basket Modular Door Bin Modular Door Bin Bottle Holder Dairy Bin Modular Door Bin Tilting 25770 Only ...

Page 5: ... back until clips snaps out 3 Continue prying back along seam until all clips snap out 3 Remove gasket Pull gasket free from gasket channel on the three remaining sides of door Door gasket replacement 1 Insert gasket bracket clips 1 Insert gasket bracket edge beneath door frame edge 2 Turn upper gasket bracket spring so that both spring ends are in the door channel 3 Push in clip until you hear it...

Page 6: ...er and working down snap the cover back into door 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 with the product 6 Figure 7 F...

Page 7: ...freezer door up to unhook it from the rail support and remove Pull both rails to full extension Step 5 First Remove 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 ...

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

Page 9: ...ently 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 2 3 1 Hook 9 ...

Page 10: ...th this configuration can maintain a residual voltage over the compressor when the thermostat is opened obstructing the proper functioning of the TSD It is vital f or the TSD circuit and compressor t o remain completely de energized after opening the thermostat Ð Use of the fixing clamp is essential as this prevents disconnection or bad TSD contact in relation to the compressor as well as to runni...

Page 11: ...he motor coil from being started in the compressor 2 For normal operation of the OLP do not turn the adjustment screw of the OLP in any way 11 Part Customer part number Lot code date code 330 FBYY S1 BOX98 12345678 Physical termination part number Electrical characteristics part number No Name Base phenolic UL 94 V 0 rated Movable arm support plated steel Stationary contact support plated steel He...

Page 12: ...BETTER MODEL 5 CIRCUIT DIAGRAM 12 ...

Page 13: ...cian Replace compressor Supply voltage rating with 10 Applied voltage isn t in acceptable range 115V 10 Remove TSD Starter from compressor and measure voltage between terminal C of compressor and terminal 5 or 6 of TSD Check resistance between M C S C and M S in motor compressor Check resistance of two terminals in TSD Starter Check resistance of two terminals in OLP Check the power supply under l...

Page 14: ...rate TSD Starter from compressor and measure resistance between No 5 and 6 of PTC Starter with a tester Figure 19 Separate OLP from compressor and check resistance value between two terminals of OLP with a tester Figure 20 Observation value is 115V 60Hz 6 8Ω 30 The resistance value is 0Ω short or open Check another electric component Replace OLP Replace TSD Starter Figure 19 Figure 20 ...

Page 15: ...city 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 evaproator Wire is open or shorted Coil is shorted or open Open Open Replace defrost heater Replace indicated ...

Page 16: ...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 behind of the unit Check if the drip tray is not firmly attached 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 refrigerator ...

Page 17: ...or 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 don t cool formed MOISTURE Cooling operation Flowing sound of refrigerant Lower than Cooling operation restarts CLOG stops periodically is not heard ...

Page 18: ...ial Very Fast Inefficient Compressor Partial Restriction Complete Restriction Equalization Test Condenser Temperature None Very Fast Very Slow Very Slow Hotter than Normal Air Low Side Leak Loss of Change Compressor Not Pumping Cap Tube Sound Room Temperature Trace of Oil Undercharge Leak Yes No Faint Fast None to Weak The equalization test is trying to restart a compressor using a start kit after...

Page 19: ...sition Icemaking Mode Harvest Mode 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 Performs Icemaking Mode after supplying water by operating the SOLENOID in ICE VALVE To operate LINE and SERVICE press and hold theFill Key for 3 seconds The icemaker will run through 3 stages Harvest Fill Icemak...

Page 20: ...uring the temperature of the Tray with icemaking SENSOR 2 Icemaking starts after completion of the water fill operation 3 The icemaking function is completed when the sensor reaches 7 C 60 minutes after starting 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 ices into the ice bin from t...

Page 21: ...usted by pressing the fill key repeatedly This changes the time allowed for fill as illustrated in the table below Water supply amount table 21 STAGE TIME TO SUPPLY INDICATIONS REMARKS 1 2 3 6 sec 7 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 22: ...ozen the ejector will pass through the water When the fill mode begins stage 4 unless the water supply has been shut off added water will overflow into the ice bin If the control doesn t operate normally in the test mode check and repair as needed 4 After water is supplied the normal cycle is followed icemaking harvest fill park position 5 Five seconds after stage 5 is completed the icemaker retur...

Page 23: ...ction will remain activated for 24 hours The first three hours the compressor and freezer fan will be ON The next 21 hours the freezer will be controlled at the lowest temperature After 24 hours or if the iICE PLUS key is pressed again the freezer will return to its previous temperature 5 During the first 3 hours 1 Compressor and freezer fan HIGH RPM run continuously 2 If a defrost cycle begins du...

Page 24: ...oduced 8 1 8 Defrosting removing frost 1 Defrosting starts each time the compressor running time reaches between 7 50 hours and 50 hours according to door open time 2 For initial power on or for restoring power defrosting starts when the compressor running time reaches 4 hours 3 Defrosting stops if the sensor temperature reaches 8 C or more If the sensor doesn t reach 8 C in 1 hours the defrost mo...

Page 25: ...d 25 OPERATING ORDERS Initial power on Power ON in 0 5 sec in 0 5 sec Total load OFF Compressor ON Freezer fan ON in 7 min in 0 5 sec Compressor ON Freezer fan ON Power ON Compressor ON Freezer fan ON Defrosting heater ON Defrost heater OFF in 0 5 sec in 0 5 sec in 0 5 sec in 10 sec Temperature of defrosting sensor is 45 C or more when unit is newly purchased or when moved Temperature of defrostin...

Page 26: ...s not indicated on the failure indicating part but indicated in checking display When pressing for more than the warmer key of refrigerator temp and the warmer kye of freezer temp for more than 1 second LED check function If press and hold the warmer key of refrigerator temp and the warmer key of freezer temp for a second all display LED graphics on When you release the buttons the LED graphics di...

Page 27: ... error code is displayed the test mode will not be activated Freezer Fan Variable RPM Check To check the variable rpm press and hold the WARMER keys of both the REF TEMP and FRE TEMP The fan speed will change low to high or high to low for 30 seconds before reverting to its original setting Demonstration Display MODE 1 To enter this mode raise either the Refrigerator or Freezer temperature to its ...

Page 28: ... 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 28 PART VA 1 CE 3 CE 4 CE 5 VOLTAGE 115 Vac 12 Vdc 15 5 Vdc 5 V ...

Page 29: ...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 30: ...erform 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 30 F FAN C FAN Pin number Pin 1 2 of con4 Pin 4 5 of con4 MOTOR OFF 2V or less 2V or less MOTOR ON 13V 15V 13V 15V Circuit Pin Numbe...

Page 31: ...j2 Open Door Detection Circuit Check 31 Pin 1 2 of con7 Pin 5 6 of con5 Closed 5 V Open 0 V Freezer Refrigerator Door Measurement Location ...

Page 32: ... Opening or short state of each temperature sensor are as follows 8 2 6 Refrigeration Compartment Stepping Motor Damper Circuit The circuit shown below is the damper circuit to regulate the refrigerator temperature 32 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 Room Tempe...

Page 33: ...speed Measure the F SENSOR SUPER FROST SENSOR R1 R2 SENSOR after disconnect CON5 of PWB ASSY MAIN TEMPERATURE RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR SENSOR DEFROST SENSOR ROOM SENSOR 20 C 22 3 KΩ 77 KΩ 15 C 16 9 KΩ 60 KΩ 10 C 13 0 KΩ 47 3 KΩ 5 C 10 1 KΩ 38 4 KΩ 0 C 7 8 KΩ 30 KΩ 5 C 6 2 KΩ 24 1 KΩ 10 C 4 9 KΩ 19 5 KΩ 15 C 3 9 KΩ 15 9 KΩ 20 C 3 1 KΩ 13 KΩ 25 C 2 5 KΩ 11 KΩ 30 C 2 0 KΩ 8 9 ...

Page 34: ...C or Replace OLP PTC after compressor shuts off compressor are failed Replace main PWB don t press the key and wait Connection wire is defective Check the connection of the black wire of the main PWB connector CON1 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 ...

Page 35: ...k door seal when Door liner damaged Replace door liner door is closed DEFROSTING is NO defrosting 1 If heater emits heat USE TEST MODE3 Heater disconnection Replace heater defective forced defrosting Temperature fuse Replace temperature is blown fuse Connection is poor Check evaporator connection and wire of main PWB connector Defrost sensor is defective Replace defrost sensor Heater relay is poor...

Page 36: ...8 5 MAIN PWB ASSEMBLY AND PARTS LIST 8 5 1 Main PWB Assembly 36 ...

Page 37: ...501F 318A 314A 300A 312A 317A 103A 105A 283B 283B 328A 103B 315B 315B 315C 315C 323B 329C 420A 319A 319C 503D 262B 410A 409D 503C 409B 158A 405F 404A 405C 332A 135D 405A 158B 503E 503G 145B 409B 106A 120B 145A 406D 249D 282G 282F 405B 329A 262H 103C 135C 410G 304A 207B 207A 271C 271B 271A 271B 402A 402A 400A 301A 408A 406B 152B 249C 313A 303B ...

Page 38: ...FREEZER PARTS CAUTION Use the part number to order part not the position number 38 145C 250C 250D 136B 145F 250D 136A 237C 131A 250E 250C ...

Page 39: ... CAUTION Use the part number to order part not the position number on some models 39 162B 145D 162A 147C 147A 145E 146E 151A 151B 161B 141D 161C 151A 151B 161A 141A 141C 141B 141A 141C 141B 141A 141C 141B 141A 141C 141B ...

Page 40: ...ome models Only for the service 40 233A 233D 231A 233B 233C 231B 241D 241E 241D 230B 241C 241A 241B 241D 241E 203A 201A 212D 244A 234D 234A 234C 212G 230A 243A 243B 243C 243A 243B 243C 262C 262C s s 244A 234B 249G 249J 249E 205C 205B 205A 249B 250B 250B 249A 249H 249F 249K 250A 200A ...

Page 41: ...WATER AND ICEMAKER PARTS CAUTION Use the part number to order part not the position number 41 619A 623B 627B 623A 616E 616K 600B 600A 602A S13 ...

Page 42: ...P No MFL47912301 FEB 2008 Printed in Korea ...

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LG LFC21770ST - Panorama - 0.7 cu. ft, Service Manual

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