LG LSC27990TT User Manual

http://aic.lgservice.com

REFRIGERATOR

SERVICEMANUAL

CAUTION

PLEASEREADCAREFULLYTHE SAFETYPRECAUTIONSOF THIS MANUAL BEFORECHECKINGOR OPERATINGTHE REFRIGERATOR.

MODEL : LSC27990TT COLOR :TITANIUM

CONTENTS

WARNINGS AND PRECAUTIONS FOR SAFETY ................................................................................................................ 3

SPECIFICATIONS ................................................................................................................................................................... 4

PARTS IDENTIFICATION ........................................................................................................................................................ 5

HOW TO INSTALL THE REFRIGERATOR ............................................................................................................................ 6

HOW TO ADJUST DOOR HEIGHT ...................................................................................................................................... 6

FILTER ................................................................................................................................................................................. 7

HOW TO CONTROL THE ICEMAKER WATER SUPPLY .................................................................................................... 8

MICOM FUNCTION ................................................................................................................................................................ 9

EXPLANATION OF MICOM CIRCUIT ................................................................................................................................... 22

EXPLANATION OF PWB CIRCUIT ..................................................................................................................................... 22

PWB PARTS DIAGRAM AND LIST..................................................................................................................................... 37

PWB CIRCUIT DIAGRAM ................................................................................................................................................... 43

ICEMAKER AND DISPENSER WORKING PRINCIPLES AND REPAIR ............................................................................ 45

WORKING PRINCIPLES .................................................................................................................................................... 45

FUNCTION OF ICEMAKER ............................................................................................................................................... 46

CIRCUIT ................................................................................................................................................................................ 48

TROUBLE DIAGNOSIS ........................................................................................................................................................ 49

TROUBLESHOOTING ....................................................................................................................................................... 49

FAULTS .............................................................................................................................................................................. 59

COOLING CYCLE HEAVY REPAIR ................................................................................................................................... 76

HOW TO DEAL WITH CLAIMS .......................................................................................................................................... 83

TV-RADIO ............................................................................................................................................................................. 88

SAFETY PRECAUTIONS ................................................................................................................................................... 88

FEATURE ........................................................................................................................................................................... 88

CONTROLS ........................................................................................................................................................................ 89

REMOTE CONTROL KEY FUNCTIONS ........................................................................................................................... 90

TROUBLESHOOTING ....................................................................................................................................................... 91

BLOCK DIAGRAM .............................................................................................................................................................. 92

TV PART DISASSEMBLE .................................................................................................................................................. 93

HOW TO DISASSEMBLE AND ASSEMBLE ....................................................................................................................... 94

DOOR ................................................................................................................................................................................. 94

HANDLE ............................................................................................................................................................................. 95

FAN SHROUD GRILLE ...................................................................................................................................................... 95

WATER VALVE DISASSEMBLY METHOD ......................................................................................................................... 96

FAN and FAN MOTOR DISASSEMBLY METHOD .............................................................................................................. 96

DISPENSER ....................................................................................................................................................................... 97

EXPLODED VIEW ................................................................................................................................................................ 99

REPLACE PARTS LIST ....................................................................................................................................................... 106

-2-

WARNINGS AND PRECAUTIONS FOR SAFETY

Please observe the following safety precautions to use the refrigerator safely and correctly and to prevent accident or injury when servicing.

1. Be careful of an electric shock. Disconnect the power cord from wall outlet and wait for more than three

minutes before replacing PWB parts. Shut off the power

whenever replacing and repairing electric components.

2. When connecting the power cord, please wait for more than five minutes after the power cord was disconnected

from the wall outlet.

3. Check if the power cord is pinched between the

refrigerator and the wall. If the plug or cord is damaged, it could cause a fire or an electric shock

4. If the wall outlet is overloaded, it may cause a fire. Use a dedicated circuit for the refrigerator.

5. Make sure the outlet is properly grounded.

Particularly in a wet or damp area.

6. Use standard electrical components.

7.Remove dust and foreign materials from the housing and

connecting 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.

De not suggest that customers repair their refrigerator

themselves. This work requires special tools and knowledge. Non-professionals could cause fire, injury, or damage to the product.

12. Do not store flammable materials such as ether, benzene, alcohol, chemicals, or gas.

13. Do not put anything on top of the refrigerator, especially something containing water, like a vase.

14. Do not put glass bottles with full of water into the freezer. The contents will freeze and break the glass

bottles.

15. When you scrap or discard the refrigerator, remove the doors and dispose of it where children are not likely to play in or around it.

16. This is a consumer grade product. It is not intended for precise storage of medication.

-3-

SPECIFICATIONS

1. Ref No. : GR-G277STSA(LSC27990TT)

ITEMS

DIMENSIONS

WxDxH

NET WEIGHT

COOLING SYSTEM

TEMPERATURE CONTROL

DEFROSTING SYSTEM

INSULATION

COMPRESSOR

EVAPORATOR

CONDENSER

REFRIGERANT

LUBRICATING OIL

SPECIFICATIONS

908x 896 x 1771mm

(3511/16x355h6x69W16in.)

145kg (319.7 Ibs.)

Fan Cooling Micom Control

Full Automatic

Heater Defrost

Cyclo-Pentane

PTC Starting Type

Fin Tube Type

Wire Condenser

R134a (185g) (61/2oz.)

FREOL @10G(320 cc)

ITEMS

DRIER

CAPILLARY TUBE

FIRST DEFROST

DEFROST CYCLE

DEFROSTING DEVICE

ANTI-SWEAT HEATER

ANTI-FREEZING HEATER

FREEZER LAMP

REFRIGERATOR LAMP

DISPENSER LAMP

SPECIFICATIONS

MOLECULAR SIEVE XH-7

ID a0.83

4 - 5 Hours

13 - 15 Hours

Heater, Sheath

Dispenser Duct Door Heater

Dispenser Heater

Water Tank Heater

Damper Heater

40W (1 EA)

40W (4 EA)

15W (1 EA)

E E

F--

I,,.,.

Front View

t- t-

_o _o

E E E E

i.q i.q

•r- ,r-

1004 mm (391/2 in.) .

908 mm (3911/16 in.)

c c

LO CO

LO LO

o oJ

Lo Ob

CO CO

v v

E E

Ob Ob

I_ o4 I',--. (3o

E E

,r-

Top View

-4-

PARTS IDENTIFICATION

1. Ref No. : GR-G277STSA(LSC27990TT)

PWB Cover

\\\,_

Frame Display

Dis

Ice &

Dispenser Button

Automatic Icemaker

Freezer

Compartment

............. '}i!l]J!iili

c? _ ===

Refrigerator

Compartment

Water Tubes

/.- /

Dairy Product Corner Water Filter

Lamp Shelf

Lamp

Shelf

Drawer

Door Rack

Drawer

Door Rack

Lower Cover ...............................................................-// OptiFresh Display Humidity Switch

-5-

Shelf

Snack Drawer

-- Door Rack

Lamp Bottle Guide

Vegetable Drawer

OptiFresh

Door Rack

HOW TO INSTALL REFRIGERATOR

1. How to Adjust Door Height of Refrigerator

• Make the refrigerator level first. (If the refrigerator is not installed on a flat floor, the height of freezer and refrigerator door may not be the same.)

1) If the freezer door is lower than the refrigerator

door:

2) If the freezer door is higher than the refrigerator

door:

i I

I Screw

Insert a driver _ into the groove O of the adjusting

screw and turn in the direction of the arrow (clockwise)

until the refrigerator is level.

3) When the refrigerator 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 O, turn the

keeper nut O ('_'_) clockwise to loosen the keeper nut.

(2) Using the narrow side of the tool for adjustment, turn the

adjustment hinge pin _ (,_,_) clockwise or (_V') counterclockwise to level the refrigerator and freezer door.

(3) After setting the level of the door, turn the keeper nut (_v)

counterclockwise to tighten.

Caution : Do not force too hard to level the height. The hinge

pin can be pulled out (Adjustable range of height: Maximum of 2/10 " (5 mm)).

Driver

Insert a driver _ into the groove O if the adjusting screw and turn in the direction of the arrow (clockwise) until the refrigerator is level.

(2_Adjustment

,'a)Tool for

adjustment

i O Keeper nut

hi_ _ge pin

!>J

-6-

HOW TO INSTALL REFRIGERATOR

2. Filter

Replace the filter when the indicator light comes on or the performance of the icemker or water dispenser decreases noticeably.

After changing the water filter cartridge, reset the water filter status display and indicator light by pressing and

holding the FILTER Button for 3 seconds. (page 13)

1) Remove the old cartridge.

Twist the knob of the cartridge counterclockwise.

2) Replace with a new cartridge.

Take the new cartridge out of its packaging and remove protective cover from the o-rings.

With cartridge 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.

When the cartridge is removed, you will feel it click.

Pull out the cartridge.

NOTE: There will be some water (25cc) in the filter

cartridge. Some spilling may occur. Catch it in a bowl or towel.

3) Flush the Water System After Replacing Filter Dispense water through the water dispenser for 3 minutes to purge the system. There may be a little air in the line, causing noise or hissing. Run the water at the dispenser until the hissing stops to purge the air from the system.

NOTE: - To purchase replacement water filter cartridges,

visit your local appliance dealer or part distributor.

- You can also visit our website : www.lgappliances.com or call 1-877-714-7481.

LG MDL PART NO MAKER

GR-G277STSA

(LSC27990TT)

5231JA2006A CUNO

-7-

HOW TO INSTALL REFRIGERATOR

3. How to Control the Amount of Water Supplied to Icemaker.

3-1. Confirm the amount of water supplied to the icemaker.

1) Confirm the amount of water supplied to the icemaker

(1) Press the button (Figure 1)to selsct the level of water (Optimum level --* Large -=, Small.)

2) Icemaker Operation Test (Test mode) (1) Press the button (Figure 1)for more than 3 seconds and It will start the Test mode.

(2) Test the operation of the operating part of the icemaker. (3) Ifthere 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.

Check water level

Water Amount

Indicator Light

_po Feeler

1.........// Water Amount Switch

* It is acceptable if the adjusted level of water is a bit smaller than optimum level.

wer Arm

Selection Button

Figure 1.

-8-

MICOM FUNCTION

1. Monitor Panel

1-1. GR-G277STSA(LSC27990TT)

Temperature Adjust Button -

oe OSe,ect,oo u, ooJ/

Calendar &

Dispenser Selection Button

Lock Button Door Alarm Button

' I'

Dispenser Light Button

-9-

MICOM FUNCTION

1-2. Display Second Function

LCD Check Mode

Demo Mode

Communication Data Check Mode

1. Door Alarm Buzzer Mute Mode

Press _))) _ button to the buzzer on or off.

2. Demo 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 compressor.

To enter the DEMO mode, press and hold the TEMPERATURE and _ I_ button simultaneously for 5 seconds until the

Ding- sounds in the lock status.

To exit the DEMO mode and return to normal operation, press and hold the TEMPERATURE and _ I_1 button simultaneously for 5 seconds until the Ding- sounds again in the lock status.

The refrigerator will default to the NORMAL mode (DEMO mode OFF) if the power fails.

2. LCD Check Mode Press TEMPERATURE and I_)))_, button simultaneously for 1 second in the lock status.

4. Communication Data Check Mode Press MENU and -',0_ button simultaneously for 6 seconds in the lock status.

Door Alarm Buzzer Mute Mode

-10-

MICOM FUNCTION

2. Description of Function

2-1-1. Function of Temperature Selection

Division Power Initially On 1st Press 2st Press 3th Press 4th Press

Setting Temperature

Temperature COLD COLDER COLDEST COOL COOLER Control

Freezer Control -2 °F -5 °F -8 °F 7 °F 1 °F

Refrigeration 37 °F 34 °F 32 °F 46 °F 41 °F Control

*The telnperature can vary ±5'>F(±3°C) depending on the load condition.

Whenever pressing button, setting is repeated in the order of COLD _ COLDER -_ COLDEST -_ COOL -_ COLDER.

• The actual inner temperature varies depending on the food status, as the indicated setting temperature is a target temperature, not actual temperature within refrigerator.

• Refrigeration function is weak in the initial time. Please adjust temperature as above after using refrigerator for minimum 2-3 days.

• Freezer Notch is fixed COLDER unconcerned 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

2. The ambient temperature is displayed between 16 °F and 120 °F. Outside of that range, the display will

temperature of the room and displays it in the upper right corner of the display. show Er.

3. Since the ambient temperature sensor is located at the hinge, its reading may differ from other thermometers in the room.

-11 -

MICOM FUNCTION

2-1-3. Lock function

1. If desiring to lock the dislay the dispenser and control panel, push on _ _ button more than 3 seconds. Lock icon is appeared at the right of display with lock status.

2. The buzzer sound and control panel and dispenser function is not performed even if pressing display button other than lock key in the lock status.

3. If desiring to release the lock status and pressing the lock button more than 3 seconds. Lock icon is disappeared at the right 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. You will see a reminder pop-up window in the LCD screen 2 weeks before / 1 week before / due date to replace the filter

to notify you that the filter needs to be replaced.

4. If you want to reset the filter, use the Menu * Refrigerator _ Filter Reset menu.

-12-

MICOM FUNCTION

2-2. Dispenser use selection

You can select water or ice.

=_:Select WATER, CRUSHED ICE, or CUBED ICE by pressing the DISPENSER button as you desire. =_:Use your cup to press lightly on the actuator.

• Each graphic is indicated for the selected function.

• You'll hear a CLICK when the ice door closes 5 seconds after ice is dispensed.

Pressing [

Switch /

REFERENCE : Hold your cup in the dispenser for a few seconds after dispensing

ice or water to catch the last few drops or pieces of ice.

2-3. ICE PLUS Freezing

Select this function to expedite freezing.

• Turn on/off the IcePlus function using the IcePlus button within the Temperature function.

• H =l

The IcePlus icon remains at the ON status after animation when selecting Special Refrigeration IcePlus FRZ

• ICE PLUS freezer function automatically turns off after a set time.

2-4. Dispenser Light

• The dispenser light function is repeated following below whenever pressing

-13-

button.

MICOM FUNCTION

2-5. ICE PLUS freezing

1. ICE PLUS freezing is a function to increase the cooling speed of the freezer compartment by running both the compressor and the fan simultaneously.

2. ICE PLUS is cancelled and the refrigerator returns to its default setting in the event of a power interruption.

3. Selecting ICE PLUS changes only the speed of the cooling without affecting the set temperature.

4. The temperature can be adjusted even when ICE PLUS has been selected and is in progress.

5. The freezer operates at whatever temperature was set at the time ICE PLUS was selected.

6. If you select ICE PLUS, the compressor and fan will run until it is deselected or the cycle time has elapsed.

(3 hours : compressor and fan run / 3 - 24 hours : COLDEST operation)

7. If a defrost cycle occurs while an ICE PLUS is already running, ICE PLUS runs for its remaining cycle time after the defrost cycle is completed. If the defrost cycle takes longer than 30 minutes, ICE PLUS will run for only 2 hours at the end of the defrost cycle.

8. If you press ICE PLUS during a defrost cycle, the ICE PLUS indicator will illuminate but the compressor will not operate

until the defrost 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. OptiFresh Function

1. The OptiFresh bin is positioned at the bottom of the refrigerator compartment and has a separate temperature control to allow perfect storage of fruits and vegetables.

2. OptiFresh comprises of OptiFresh sensor at the rear of OptiFresh and 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.

• Press the button to toggle between ON and OFF.

Activate

-14-

MICOM FUNCTION

2-7. Control of variable type freezing fan

1. To increase cooling speed and response to load, the MICOM will vary the speed of the freezer fan between low and high.

2. The MICOM runs the fan at high speed only at power-up and for ICE PLUS cycles, and runs at low speed for all other settings.

3. If you open the freezer door, the refrigerator door, or the home bar door, and the freezer fan was running at high speed, it will reduce to low speed. If it was running at low speed when a door was opened, it will turn off.

4. If the MICOM determines the BLDC fan motor is locked up, (no signal for 115 seconds) it will show a failure code on the display and cut power to the fan. To power the fan again, unplug the refrigerator for a few seconds and plug it in again.

2-8. 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).

2-9. Door opening alarm

1. The buzzer sounds when any door is held open for more than one minute.

2. After any door has been open for one minute, the buzzer sounds three times for ½ second each, then it sounds three times for ½ second each every thirty seconds until the door is closed.

3. When all open doors have been closed, the buzzer stops.

Doors of freezer, I 1 Jrefrigerator, or Closing Opening Closing Opening home bar.

BUZZER

!Lessthan! One minute _ 30 _ 30 _ 30

one minute secondssecondsseconds

2-10. Ringing of button selection buzzer

1. If pressing the front display button, Ding - sound rings.

Closing

3Times3Times3Times3Times

-15-

MICOM FUNCTION

2-11. Ringing of manual operation, manual frost defrost buzzer

1. The buzzer sounds briefly when the test button on the main PCB is pressed.

2. If you select manual operation, the buzzer sounds three times for 2/lOsecond each, then it sounds three times for 2/10 second each every thirty seconds until the door is closed.

3. If you select manual defrost, the buzzer sounds three times for 2/lOsecond each, then it sounds three times for 2/lOsecond each every thirty seconds until the door is closed.

2-12. Defrost function

1. Defrost is cycled whenever the compressor's runtime reaches 7 - 7 ½ hours.

2. In providing initial power (or returning power failure), defrost starts whenever total operation time of compressor becomes 4 - 4 ½ 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 after starting frost removal.

4. No defrost cycle is run if the defrost sensor fails.

2-13. Refrigerator room lamp automatic off

• Refrigerator room lamp turn on and off by refrigerator door switch.

• If refrigerator room lamp continuously turns on more than 7 minutes, the refrigerator room lamp turns off automatically.

-16-

MICOM FUNCTION

2-14. Sequential operation of components

Component products such as compressor, frost removal heater, freezing room fan, cooling fan, and step motor damper are

sequentially operated as follows for preventing noise and part damage occurred due to simultaneous operation of many

parts in applying initial power and completing test.

Function Load Operation Sequence Remark

Whentemperature ofa frost removal

sensorbecomes more than45°C

(At purchase,

shipping)

When

_ temperature of a

frost removal sensor becomes

_=.: less than 45°C

(In power failure,

-a

service)

(1:)

Testmode 1 (Manualfunction)

.-I

03 '--I

0 Testmode2 m (Manual frost

removal)

POWER 0.3

sec.

COMP

0.3 F-FAN

sec. &

---*- C-FAN

0.3 FROST 0.3 FROST

POWER sec. REMOVAL sec. REMOVAL

HEATER_ HEATER

ON OFF

0.3 PIPE 0.3 PIPE 0.3 0.3 F-FAN O.3 O.30PTICHILL

•c & sec. & sec. COMP sec. sec. R-STEP sec. STEP

0.3 R-STEP

sec. MOTOR

DAMPER

6.0

sec.

DAMPER0.3 DAMPER

& sec. &

) DUCTDOOR-_ DUCTDOOR--

&OPTICHILL &OPTICHILL

HEATERON HEATEROFF

OPTICMILL

0.3 STEP

sec.

-_ DAMPER

MOTOR

-_ DISP' ---_ DISP' ---*- _ & -_ MOTOR ---_ DAMPER

HEATER HEATER ON C-FAN DAMPER MOTOR

ON OFF ON ON ON

TEST

SWITCH

(PRESS -_

Onc_

TEST COMP

SWITCH (PRESS -_ OFF

2Times)

OTHER 0.3 COMP 0.3 F-FAN 0.3 R-STEP 0.3 STEP

LOAD sec. sec. & sec. MOTOR sec. DAMPER

OFF ON ON ON CLOSE

---_ _ C-FAN ---_ DAMPER---_ MOTOR

0.3 F-FAN 0.3 FROST 0.3 R-STEP

sec. & sec. REMOVAL sec. MOTOR

--_ C-FAN --_ HEATER-_ DAMPER OFF ON CLOSE

OPTICHILL

Iferror occurs during operation,

initial operationis not done.

• Sequence of load operation

when closing

FREEZER and REFRIGER-

ATOR.

If you press the switch in the

againtest mode 2 or temperature of

afrost removal sensor is more than5°C, it immediately

returns tothe test mode for initial

operation (COMPRESSOR

operates after 7 minutes).

-17-

MICOM FUNCTION

2-15. Failure Diagnosis Function

1. Failure diagnosis facilitates service when a failure code shows during product operation.

2. When 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 display screen. All display graphics that are not part of the failure code are turned off

(1) GR-G277STSA(LSC27990TT)

FAILURE CODE

ITEM

1 ABNORMAL

FREEZER SENSOR

ABNORMAL£EFRIGERATOF SENSORI(RI/

2 UPPER PART IN THE

REFRIGERATOR COMPARTMENT_

ABNORMALREFRIGERATOR SENSOR2(R2)

3 LOWER PART IN THE

REFRIGERATOR COMPARTMENT)

4 ABNORMAL

DEFROST SENSOR

5 FAILEO BEFROSTING

6 ABNORMALFREEZING

BLOC MOTOR

7 ABNORMALCOOLING

BLBC MOTOR

ABNORMAL

8 COMMUNICATION C_

9 ABNORMAL AMBIENTSENSOR SHORT

AMBIENT SENSOR CIRCUIT ©

10 ABNORMAL WATER TANK SENSOR ©

WATER TANK SENSOR SHORT CIRCUIT

11 ABNORMAL OPTICHILLSENSOR 0

OPTICHILL SENSOR SHORT CIRCUIT

INDICATION PART

FREEZERROOM NOTCHREFRIGERATORROOM NOTC TEMPERATUREDISPLAY TEMPERAqJREDISPLAY

Er FS

Er rS

NORMAL DISPLAY (NOTE 2)(See Pace 19)

Er dS

Er dH

Er FF

Er CF

Er CO

NORMAL DISPLAY (NOTE 1) (See pac e 19)

NORMAL DISPLAY (NOTE 2) (See PaCe 19 )

NORMAL OlSFLAY (NOTE 2) (See Pace 19)

CONTENTSOF FAILURE

FREEZER SENSOR SHORTCIRCUIT

REFRIGERATOR SENSOR 1 SHORT CIRCUIT

REFRIGERATOR SENSOR 2 SHORT CIRCUIT

ABNORMAL SHORT CIRCUIT

DEFROST HEATER, TEMPERATURE FUSE SHORT CIRCUIT, UNPLUGGED

CONNECTOR(INDICATED 4 HOURLATER AFTER TROUBLE)

MOTORDEFECT HOOKEDOF LEAS

WIRETOFAN,CONTACTOF

STRGCTRES WITHFAN SHORTOR

OPENOF LEADWIRE(THEREIS

NOSIGNALOF BLOCMOTORMORE

THAN115SECONDSINOPERATION

OFFANMOTOR}

SHORT OR OPENOF LEAS WIRE CONNECTINGBETWEEN MAIN PCE AND DISPLAYPCB,TRANSMISSION TB AND RECEIVINGPART

PRODUCT OPERATION STAUS IN FAILURE

COMPRESSOR

ONFOR15 MINUTES/ OFFFOR15 MINUTES

FREEZINGBLOC

MOTOR

STANDARD RPM

OFF

STANDARD RPM

COOLINGBLDC

MOTOR

OFF

O O

0 0

DEFROST

HEATER

NO DEFROST

STEPPING MOTOR

DAMPTER

FULLOPENINGFOR10 MINUTES/ FULLCLOSINGFOR1S MINUTES

-18-

MICOM FUNCTION

ALL DISPLAYPARTSTURN OFF OTHER THAN FREEZER ROOMNOTCHTEMPERATUREDISPLAYAND REFRIGERATORROOM NOTCH TEMPERATUREDISPLAY(FAILURECODE INDICATIONPART)

INCASEOF INDICATINGFAILUREMODES(EXCEPT FOR NOTE1,NOTE2)

NOTE1 ) FREEZERROOM NOTCHTEMPERATUREDISPLAYAND REFRIGERATORROOMNOTCH TEMPERATUREDISPLAY(FAILURECODE INDICATIONPART)ARE NORMALLY INDICATEDINABNORMAL

AMBIENTSENSOR, AND "Er" INDICATED ONTHE AMBIENTTEMPERATUREDISPLAY(EXCEPTFORTHE AMBIENTTEMPERATUREDISPLAY,OTHERDISPLAY PARTSARE INDICATED NORMALLY)

NOTE 2) R2-SENSOR, WATER-TANK SENSOR AND OPTICHILL SENSOR IS NOT INDICATED ON THE FAILURE INDICATING PART BUT INDICATED IN CHECKING ALL DISPLAY PARTS

(WHEN PRESSING THE TEMPERATRUE AND 4)) _ BUTTON INTHE LOCK STATUS FOR MORE THAN 1 SECOND).

R2-SENSOR(MIDDLE ROOM) [- N O R U A L : DISPLAY PART GRAPHIC ON THE ,_/C_PARTTURNS ON

WATER-TANKSENSOR [- N O R M A L : DISPLAYPARTGRAPHICONTHE_.)_ PARTTURNSON

OPTI-FRESH SENSOR [- N O R M A L : DISPLAYPARTGRAPHICONTHE(E_PARTTURNSON

(2)TEST FUNCTION

TESTKEYEXISTSONPWBASSY,MAINBOARD.

MODE OPERATION CONTENTS REMARKS

TEST1 <STRONG COLD MOOE> (HIGH-SPEED RPM) AND COOLING BLDC MOTOR 5. ALL DISPLAY GRAPHICS TURNS ON IN DOOR OPENING

TEST2 MODE 1 S-ATUS 2. FREEZING BLDC MOTOR AND COOLING BLDC MOTOR CLOSED (CLOSING OF BAFFLE) MODE WHEN THE

NORMAL PRESS TEST 8UTON ONCE AT THE TEST COMPERSSOR WILL OPERATE STATUS MODE 2 STATUS RETRUING TO INITIAL STATUS AFTER DELAY FOR 7 MINUTES

PRESS TEST BUTTON ONCE 2. CONTINUOUS OPERATION OF FREEZING BLDC MOTOR OPENED (OPEN OF BAFFLE) FREEZING FAN TURNS OFF

PRESS TEST BUTON ONCE AT THE TEST 1. COMPRESSOR OFF 4. MAIN STEPPING MOTOR DAMPER IS COMPLETELY RETURN TO THE NORMAL

<FORCED DEFROST MODE> TURN OFF 5. ALL DISPLAY GRAPHICS TURNS OFF (ONLY "FAILURE CODE DEFROST SENSOR IS

;_-"LCD check function: If simultaneously pressing TEMPERATURE and 4 ))_' button for a second in the lock status, a

back light is turned on and all display LCD graphics on. If releasing the button, the LCD graphic displays the previous status.

ABNORMAL DISPLAY PART GRAPHIC ON THE @ PART TURNS OFF THE OTHER DISPLAY GRAPHICS TURN ON ABNORMAL DISPLAY PART GRAPHIC ON THE _C)PART TURNS OFF

ABNORMAL DISPLAY PART GRAPHIC ON THE ,_F_PART TURNS OFF

1. CONTINUOUS OPERATION OF COMPRESSOR 4. MAIN STEPPING MOTOR DAMPER IS COMPLETELY

3. DEFROST HEATER TURNS OFF

3. DEFROST HEATER TURNS ON INDICATION PART"TURNS ON FOR '22"STATUS) ABOVE +S°C

-19-

MICOM FUNCTION

2-16. Test Function

1. The test function assists in diagnosing the PWB and determining the exact mode of failure.

2. The test button is on the main PCB. When test mode is engaged, it will complete its test cycle and default to normal operation within 2 hours.

3. The buttons are disabled while the test mode is in effect.

4. When you have finished running test mode, unplug the refrigerator to reset it to normal operation.

5. If a failure is detected during test mode, release the test mode to display the failure code.

6. If a failure code is displayed, the test mode cannot be started.

Mode

Test 1

Test 2

Normal Press test button once at Return to the initial status. Compressor will operate

Status the test mode 2 status after delay for 7 minutes

Press test button once (strong cold mode)

Press test button once at the test mode 1 status

(forced defrost mode)

Operation

Continuous operation of compressor

Continuous operation of freezing BLDC motor (high-speed RPM) and cooling BLDC motor

Defrost heater turns off

Stepping motor damper is completely opened (baffle is closed)

OptiFresh stepping motor damper is

completely closed.

All display LCD graphics turn on.

Compressor OFF

Freezing BLDC motor and cooling BLDC motor turn off

Defrost heater turns on

Stepping motor damper is completely closed (baffle is closed)

OptiFresh stepping motor damper is

completely closed.

Contents

Remarks

Freezer fan turns off when door is opened.

Return to the normal mode when the defrost sensor is

above +5°C (+41 °F)

- 20 -

MICOM FUNCTION

2-17. Dispenser Function

1. The dispenser allows serving ice and water without opening the door.

2. Pressing the dispenser switch dispenses crushed or cubed ice or water. If ice is selected, the switch operates the door solenoid also. The door will close 5 seconds after the ice is dispensed.

3. If the freezer door is opened, the dispenser is deactivated.

4. If there is no OFF signal 3 minutes after the ice dispenser is activated, the auger and door solenoid are turned off. The auger will stop immediately, but the door will not close for another 5 seconds.

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 rotated in the opposite direction to direct the cubes through the crusher.

7. Water dispenser function

1) If you select water, the display will indicate water.

2) The water dispenser uses a solenoid connected directly to the water pipe. Pressing the dispenser switch operates the solenoid, which is at the right side of the back plate.

-21 -

EXPLANATION FOR MICOM CIRCUIT

1. Explanation for PWB circuit

1-1. Power circuit

The power circuit includes a Switched Mode Power Supply (SMPS). It consists of a rectifier (BD1and CE1) convertingAC

to DC, a switch (IC2) switching the DC voltage, a transformer, and a 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 asfollows:

Part VA1

Voltage 120 Vac

(1) GR-G277STSA(LSC27990TT)

03::_A60 TRA_

2_4

CE1 CE2 CE3 CE4 CE5

160 Vdc 14Vdc 12 Vdc 15.5 Vdc 5 Vdc

TEST

15 2B 41 424748

CD C_

£J_ k-- <q2

[2Q

L!D 0

64 VD3

5_3 Vc_eP

CC2

POWER

-22 -

EXPLANATION FOR MICOM CIRCUIT

1-2. Oscillation circuit

The oscillation circuit generates a basic clock signal for synchronization and time calculation related to the transmission of data and calculations made by the MICOM (IC 1). 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-G277STSA(LSC27990TT)

XlN

CSTS4.0ObIG03! ¢I-_i I 30

F_0%1 EC]_ _ __

_t ½_T ] 3,

(MICOM

XOUT

1-3. Reset circuit

The RESET circuit allows various parts of the MICOM, such as RAM, defrosting, etc., to be restarted from the initial state

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-G277STSA(LSC27990TT)

ICE

(MICOM

RESET

- 23 -

EXPLANATION FOR MICOM CIRCUIT

1-4. Load/dispenser operation, door opening circuit

1. LOAD DRIVING CIRCUIT

=_The fan operates at the regular speed even if the door of the refrigerator or freezer is opened. When the doors are closed,

the fan reverts to its original speed.

=_(A), (B), (C), and (D) of door switch for the freezer or refrigerator are 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.

Defrost AC Converting Refrigerator Dispenser

Type of Load Compressor Heater Relay LAMP Heater

Measuring part (IC6) IC6-16 IC6-13 IC6-12 IC6-15 IC6-14

Status

(1) GR-G277STSA(LSC27990TT)

ON Within 1 V

OFF 12 V

F_J_N+K_CAPACkTO_

ST_TI_ C_IT C_ Ob°

s/w

PIF_ t_ATER

O_SP'_EATER

P.T.C ASSy

R-LA_ILO_RI

qJlFL

C0N2

--L_

RYI

(ALEIrzBI21

RY_

ALZI

RY: ALl

_)1_2

IALEISBIEI

RY_

ALZ_

IALEI

] IC6,

g K IDF_500:_"

15 2 3

_I 3 4

13 4 5

_Z 5 6

I_ 6

_72

[AINI21

_73

_74

IAtNI41 _

,75 _

_76 --

IA_N_71

(:;o (3

(20 It_

BWITC_

>_F.L F+DOOR

A_P

- 24 -

EXPLANATION FOR MICOM CIRCUIT

1-5. Dispenser operation circuit

(1) GR-G277STSA(LSC27990TT)

R¥7

EALEI_I21

, , 09 9 KID 5003_

IALEJEI_I21

ALOI_2

IWlO II

ALOI_2

RYIO E2

_DI_2

PaO

Pol

Po2 Z

Po3

Ps IE

---_ 0 , R-

< c@

£N

_ _ 15...... -_-Y4 ...............

P21

1_007 FN414B n_

1) Check load driving status

Type of Load

GEARED

MOTOR

SOLENOID

CUBE

WATER VALVE

WAT ER

PILOT

VALVE

Measuring part IC7-15 IC7-14 IC7-13 IC7-12 IC7-11

ON Within 1 V

Status

OFF 12 V

2) Lever Switch sensing circuit

............._leasuringpart

--.

LeverS/W................

ICl(Micom) (No. 16)

/ OHz,

OFF 5V

SOLENOID

DISPENSER

-25 -

EXPLANATION FOR MICOM CIRCUIT

1-6. Door opening sensing circuit

(1) GR-G277STSA(LSC27990TT)

40 C6_

F-_ _Jw

ICI

(MICOM)

CCZI*

....... Measuring part

Door of Freezer and Refrigerator

Since door switches (A) and (B) are interconnected, if either fails, the other will not respond properly.

If either switch fails, the light will not come on.

................ ............ ICl (MICOM) No. (44, 45) / (45, 46) / (47, 48) Pin

Closing 5 V ((_)- (_, (_- @. Switch at both ends are at Off status)

Opening 0 V ((_) - (_, (_)- (_). Switch at both ends are at On status)

R_030R S/_

- 26 -

EXPLANATION FOR MICOM CIRCUIT

1-7. Temperature sensing circuit

(1) GR-G277STSA(LSC27990TT)

-- IAI_]

-- P65

C05, i

F-SENSOR

D-SENSOR

RI-SENSOR

R2-SENSOR

Ii or)

IAINZ}

_AIN3J

P_4

IAIN4_

CC23']_

ccea,_ MA_/OPTI - FF_SH

/50V

R-

The circuits involving the freezer and refrigerator sensors control the temperature in both the freezer and the refrigerator. The icemaker sensor detects when 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.

; ]

SENSOR CHECK POINT NORMAL(-22 OF~ 122 OF) IN SHORT IN OPEN

Freezing sensor POINT _ Voltage

Defrost sensor POINT <B)Voltage

Refrigerator sensor 1 POINT _C_Voltage 0.5 V-4.5 V 0 V 5 V

..................................................................................................................................................i........................................................................................................................................

Refrigerator sensor 2 POINT _D_Voltage

Magic room/Opti Fresh Sensor POINT ,_E_Voltage

- 27 -

EXPLANATION FOR MICOM CIRCUIT

1-8. Switch entry circuit

The following circuits are sensing signal form the damper motor reed switch for testing and diagnosing the refrigerator.

(1) GR-G277STSA(LSC27990TT)

ICI

P40

_k CCIO*

(MIC©M)

_223

1-9. Option designation circuit (model separation function)

(1) GR-G277STSA(LSC27990TT)

4o7K_

T 28_4=7K

o 5Wlo

P28

P24

The circuits shown above vary according to which features are included on your particular model.

Separation Connection Status Application Standard

OP1

I_These circuits are preset at the factory and cannot be altered.

Connection OptiFresh exist

OUT OptiFresh don't exist

- 28 -

EXPLANATION FOR MICOM CIRCUIT

1-10. Stepping motor operation circuit

(1) GR-G277STSA(LSC27990TT)

The motor is driven by magnetism formed in the areas of the coils and the stator. Rotation begins when a HIGH signal is

[

] Jcl0 CON7

TA7774P

ICI

(MI00M)

P35 P36

P37

applied to MICOM Pin 33 of IC10 (TA7774F). This causes an output of HIGH and LOW signals on MICOM pins 34 and 35.

Explanation) The stepping motor is driven by sending signals 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.

ST/OPB 86

9,16

CEI3 1,2

/50V

luF

A 4_!

E4 I0 II II

10 12 B

CCW (Reverse rotation) 4-- --_ (Positive rotation) CW

I I I

INA

I I I I I I

INB J

j ,

I I I I

! I I

! I

! I ! ! ! ! ! !

! !

' I

I I I I I I I I

! I ! I

' I ' I

! I ! ! !

! ! ! !

I ' '

! !

! ! !

'i l

! ! ! !

! ! ! I I I I

! ! ! !

I ' I '

! !

I I I I

! I

' I ' I

! I

! ! I

! !

i'i

! !

! ! i

I I I I I I

I I I I

' I '

I I I !

! !

I I I

I I ! I !

! !

I '

I !

I I I I

' I '

I I I ! I

Ji-,,,

i ! i

-29 -

EXPLANATION FOR MICOM CIRCUIT

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.

®, ® part @part ® part

Motor OFF 5V 2V or less 2V or less

Motor ON 2 -3V 12 - 14V 8- 16V

(1) GR-G277STSA(LSC27990TT)

33O

- DI4

C-FAN PWM

P54

R38 4,7K

R40,' _ FRI07 223

IOK

TDI5

FRI07 L3

CEIO 220uF

/ZSV T

_ CCl7'

PSI 50

C-FAN LOCK

ICI

(MIOOM)

F-FAN PWM

F-FAN LOCK

P53 52

P50 49

R45

R45 3,9K

R47'

IOK

330

CCI8.

DI7 CEll

FRI07 220uF -CCI9'

/25V T 223

RSO _-F_51*

0C20_

2",<VV_ 4 4"7K

I02

- 30 -

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