LG LBC20514TT Service Manual

REFRIGERATOR

SERVICE MANUAL

CAUTION

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

MODELS:

LBC20514TT

CONTENTS

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 Assembly ……………………………………..................................6

Lamp……………………………………………………………..................................6

Refrigerator Control Box……………………………………….................................6

Multi Duct………………………………………………………..................................6

4- Ajustment……………………………………………………....................................7

Compressor……………………………………………………..................................7

PTC-Starter…………………………………………………….................................. 7

OLP (Overload Protector)…………………………………….................................. 8

To Remove the Cover PTC………………………………….................................. 8

5- Circuit Diagram……………………………………………..................................... 9

6- Troubleshooting……………………………………...................................……….10

Compressor and Electric Components…………………....................................…10

PTC and OLP …………………………………………....................................…….11

Other Electrical Components………………………….....................................……12

Service Diagnosis Chart……………………………....................................………13

Refrigeration Cycle…….………………………………....................................……14

7- Operation Principle and Repair Method of Ice Maker….................................16

8- Description of Function and Circuit of MICOM……….............................……19

11- Refrigerator Exploded View ….......................................................................38

SAFETY PRECAUTIONS

Pleasereadthefollowinginstructionsbeforeservicingyour refrigerator.

1.Checktherefrigeratorforcurrentleakage.

2.Topreventelectricshock,unplugbeforeservicing.

3.Alwayschecklinevoltageandamperage.

4.Usestandardelectricalcomponents.

5.Don'ttouchmetalproductsinthefreezerwithwet hands.Thismaycausefrostbite.

6.Preventwaterfromspilingontoelectricelementsorthe machineparts.

7.Beforetiltingtherefrigerator,removeallmaterialsfrom onorintherefrigerator .

8.Whenservicingtheevaporato,rwearglovestoprevent injuriesfromthesharpevaporatorfins.

9.Serviceontherefrigeratorshouldbeperformedbya qualifiedtechnician.Sealedsystemrepairmustbe performedbyaCFCcertifiedtechnician.

- 2 -

1. SPECIFICATIONS

Models

LBC20514TT

Color Capacity Dimensions (in) Refrigerant Climate Class Control Type Rating Case Material Door Material Reversible Door Lamp (F) Lamp ( R ) Basket (F) Basket ( R )

Specification

Shelf (F) Shelf ( R ) Cover, TV Drawer Vegetable Tray Meat

Multi Flow

Titanium

20cuft

29.8 (W) x 32.2 (D) x 67.9 (H) R134A (4.2oz)

Temperate(N)

F-control

115/60

EMBO(Normal)

VCM

Yes 1 (40W/Blue) 2 (40W/Blue)

1 (plastic)

2 (1/3) 2 (2/3)

1 full

1 Wire

4 fix

Humidity Control

Wire (lower)

Yes

- 3 -

2. PARTS IDENTIFICATIONS

PARTSANDFEATURES

L M

Use this section to become more familiar with the parts and features.

NOTE:This guide covers several different models.The refrigerator you have purchased may have some

or all of the items listed below.The locations of the features shown below may not match your model.

Digital Sensor Control

A B

Refrigerator Light

Shelves

Snack Pan

Optibin Crisper Keeps fruits and vegetable fresh and crisp

Ice Tray*

Ice Bin

Wire Durabase

Dairy Bin

Design-A-Door

Wire Freezer Shelf

Refrigerator Door Rack Freezer Light

Freezer Door Rack

*on some models

- 4 -

3. DISASSEMBLY

3-1 DOOR

Refrigerator Door

1. Remove the hinge cover by pulling it upwards.

2. Loosen the hexagonal bolts attaching the upper hinge to the body and lift the freezer door.

HINGE COVER BOLT

HINGE

Figure 1

3. Pull out the door gasket to remove from the door foam assembly.

GASKET

Freezer Door

1. Loosen the hexagonal bolts attaching the lower hinge to the body to remove the refrigerator door only.

LOWER HINGE

BOLT

Figure 3

2. Pull out the door gasket to remove from the door foam assembly.

3-2 DOOR SWITCH

1. To 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.

Figure 2

LEAD WIRE DOOR SWITCH

Figure 4

- 5 -

3-3 FAN AND FAN MOTOR

1. Remove the freezer shelf. (If your refrigerator has an icemaker, remove the icemaker first)

2. Remove the grille by pulling it out and by loosening a screw.

3. Remove the Fan Motor assembly by loosening 2 screws and disassemble the shroud.

4. Pull out the fan and separate the Fan Motor and Bracket.

5. Pull out the fan and separate the Fan Motor and Bracket.

FAN MOTOR

BRACKET

MOTOR

FAN

GRILLE

Figure 11

3-5-1 Refrigerator Compartment Lamp

1. Unplug the power 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).

Figure 9

3-5-2 Freezer Compartment Lamp

1. Unplug refrigerator or disconnect 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.

3-4 DEFROST CONTROL ASSEMBLY

Defrost Control assembly consists of Defrost Sensor and FUSE–M.

The Defrost Sensor works to defrost automatically. It is attached to the metal side of the Evaporator and senses its Temperature. Fuse-M is a safety device for preventing over-heating of the Heater when defrosting.

At 72°C, it turns the Defrost Heater off.

1. Pull out the grille assembly. (Figure 6)

2. Separate the connector with the Defrost Control assembly and replace the Defrost Control assembly after cutting the Tie Wrap. (Figure 7)

GRILLE ASSEMBLY

Figure 6

DEFROST-CONTROL ASSEMBLY

Figure 7

3-5 LAMP

3-6 CONTROL BOX-REFRIGERATOR

1. First, remove all shelves in the refrigerator, than remove the Refrigerator control Box by loosening 2 screws.

CONTROL BOX

COVER LAMP

Figure 10

2. Remove the Refrigerator Control Box by pulling it downward.

3. Disconnect the lead wire on the right position and separate the lamp sockets.

3-7 MULTI DUCT

1. Remove an upper and lower Cap by using a flat screwdriver, and loosen 3 screws. (Figure 11)

2. Disconnect the lead wire on the bottom position.

Figure 8

Figure 11

- 6 -

4. ADJUSTMENT

4-1 COMPRESSOR

4-1-1 Role

The compressor intakes low temperature and low pressure 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 Composition

The compressor includes overload protection. The PTC starter and OLP (overload protector) are attached to the outside of the compressor. Since the compressor is manufactured to tolerances of 1 micron and is hermetically sealed in a dust and moisture-free environment, use extreme caution when repairing it.

4-1-3 Note for Usage

(1) Be careful not to allow over-voltage and over-current. (2) If compressor is dropped or handled carelessly, poor

operation and noise may result.

(3) Use proper electric components appropriate to the

Particular Compressor in your product.

(4) Keep Compressor dry.

If the Compressor gets wet (in the rain or a damp environment) and rust forms in the pin of the Hermetic Terminal, poor operation and contact may result.

(5) When replacing the Compressor, be careful that dust,

humidity, and soldering flux don’t contaminate the inside of the compressor. Dust, humidity, and solder flux contaminate the cylinder and may cause noise, improper operation or even cause it to lock up.

4-2 PTC-STARTER

4-2-1 Composition of PTC-Starter

(1) PTC (Positive Temperature Coefficient) is a no-contact

semiconductor starting device which uses ceramic material consisting of BaTiO

(2) The higher the temperature is, the higher the resistance

value. These features are used as a starting device for the Motor.

4-2-2 Role of PTC-Starter

(1) The PTC is attached to the Sealed Compressor and is

used for starting the Motor.

(2) The compressor is a single-phase induction motor.

Durign the starting operation, the PTC allows current flow to both the start winding and main winding.

4-2-3 PTC-Applied Circuit Diagram

Starting Method for the Motor

OVERLOAD PROTECTOR

PTC

Resistance Starter Capacitor Running

PTC STARTER

COMPRESSOR MOTOR

SEALED TERMINAL

Figure 12

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-Starter and OLP

(1) If the compressor attempts to restart before the PTC

device is cooled, the PTC device will allow current to flow only to the main winding.

(2) The OLP will open because of the over current

condition. This same process will continue (3 to 5 times) when the compressor attempts to restart until the PTC device has cooled. The correct OLP must be properly attached to prevent damage to the compressor. Parts may appear physically identical but could have different electrical ratings. Replace parts by part number and model number. Using an incorrect part could result in damage to the product, fire, injury, or possibly death.

4-2-6 Note for Using the PTC-Starter

(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 PTC, PTC materials may fail due to breakdown of their insulating capabilities.

(4) If the exterior of the PTC is damaged, the resistance

value may be altered. This can cause damage to the compressor and result in a no-start or hard-to-start condition.

(5) Always use the PTC designed for the compressor and

make sure it is properly attached to the compressor. Parts may appear physically identical but could have different electrical ratings. Replace parts by part number and model number. Using an incorrect part could result in damage to the product, fire, injury, or possibly death.

- 7 -

4-3 OLP (OVERLOAD PROTECTOR)

4-3-1 Definition of OLP

(1) OLP (OVERLOAD PROTECTOR) is attached to the

Compressor and protects the Motor by opening the circuit to the Motor if the temperature rises and activating the bimetal spring in the OLP.

(2) When high current flows to the Compressor motor, the

Bimetal works by heating the heater inside the OLP, and the OLP protects the Motor by cutting off the current flowing to the Compressor Motor.

4-3-2 Role of the OLP

(1) The OLP is attached to the Sealed Compressor used

for the Refrigerator. It prevents the Motor Coil from being started in the Compressor.

(2) For normal operation of the OLP, do not turn the Adjust

Screw of the OLP in any way.

(OVERLOAD PROTECTOR cross section)

Part

No. Name

Base, phenolic (UL 94 V-0 rated) Movable arm support, plated steel Stationary contact support, plated steel Heater support, plated steel Heater, resistance alloy Disc, thermostatic alloy Movable arm, spring temper copper alloy Contact, movable, silver on copper Contact, stationary, silver on copper Slug, plated steel Cover, polyester (UL 94 V-0 rated) Pin connector, plated copper alloy (To engage 2.33/2.66 mm dia. pin) Quick-connect terminal, brass, conforms to UL 310, MEMA DC-2, DIN 46344

Figure 13

Electrical

characteristics

part number

12345678

330 FBYY -S1 BOX98

Customer part number

Lot code/ date code

Physical

termination part number

4-4 TO REMOVE THE COVER PTC

1) Remove the Cover Back M/C. (2) Remove the screw on Cover PTC.

(3) Remove two Housings on upper part of Cover PTC. (4) Take 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 -

5. CIRCUIT DIAGRAM

PWB(PCB) ASSEMBLY,DISPLAY

3SB52 8

CON101

/RD

/WH

STEPPING

F-FAN

MOTOR

/RD

8 11 13

/WH

CON4

BL3BK YLWH

5 6PR41

CON5

WHPR

2 64BK5

R-DOOR

PERCEPTION S/W

PKWH

GY GY

107

111

PWB(PCB) ASSEMBLY, MAIN

5 4

10BN9

POWER SUPPLY

CORD

CON1

N L

GN/YL

(GN)

ICE MAKER PART

GN/YL

(GN)

MOTOR

SHEATH

HEATER,

ICE SENSOR

WH 2

CON5

CON4

CON3

ICE MAKER

CON1

CON2

PWB (PCB) ASSEMBLY, ICE MAKER

*PLUG TYPE, ICE MAKER PART, CAPACITOR PART,

P.T.C START OPTION, COMP' EARTH PART AND COMP' ACCESSORIES ON CIRCUIT DIAGRAM ARE SUBJECT TO CHANGE IN DIFFERENT LOCALITIES AND MODEL TYPE.

BL BK

(98 C)

FUSE-M

S/W

POWER

I/MAKER

CON6

CAPACITOR PART

W/VALVE

BLBL

COMP' ACCESSORIES

CON2

PTC STARTER

* ALTERNATIVE COMP' ACCESSORIES

OLPBKOLP

COMP' EARTHCOMP' EARTH

PTC

PARTPART

CON6

2 3

132

F-DOOR

PERCEPTION S/W

DEF-SENSOR

R-SENSOR

F-SENSOR

(72 C)

FUSE-M

C-FAN

GNGN

/YL

(GN)(GN)

OLP

com

DOOR S/W-F

HEATER,SHEATH

BL BL

* P.T.C START OPTION

MC,MQ COMP'

com

F-LAMP

DOOR S/W-R

EG COMP'

com

R-LAMPS

BK:BLACK

COMBO KIT(PTC+OLP)

BN:BROWNWH:WHITE

PK:PINKYL:YELLOW

GN:GREEN

BO:BRIGHT ORANGE PR:PURPLE

GY:GREY

MEZ48108403

RD:REDSB:SKY BLUE BL:BLUE

- 9 -

6. TROUBLESHOOTING

6-1 COMPRESSOR AND ELECTRIC COMPONENTS

Power Source.

Remove PTC-Starter from compressor and measure voltage between Terminal C of compressor and

terminal 5 or 6 of PTC.

No voltage.

Applied voltage isn't in acceptable range. (115V ±10%)

(Rated voltage ±10%)?

YES

OLP disconnected?

Advise customer that power supply needs to be checked by an electrician.

YES

Replace OLP.

Check connection condition.

Reconnect.

Check

Check resistance

resistance of

of motor

motor

compressor.

Check resistance of PTC-Starter.

Check OLP.

Check starting state.

Check the resistance between M-C, S-C and M-S in motor compressor.

Check resistance of two terminals in

PTC-Starter.

Check resistance of two terminals in OLP.

Check the power supply under load. (Compressor attempting to re-start after being off for 5 minutes).

Open or short

Refer to Page 12.

Supply voltage rating with ±10%.

The range of resistance is between 1~50 ? (ok)

Replace compressor

YES

Did

compressor

start?

YES

Compressor is OK

Replace the compressor

- 10 -

6-2 PTC AND OLP

Normal operation of compressor is impossible or poor.

Separate PTC-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 whit a tester. (Figure 20)

Observation value is 115V/60Hz : 6.8 ?±30%

The resistance value is 0 ? (short) or 8(open).

Shows continuity

Open

Replace PTCStarter.

Check another electric component.

Replace OLP.

Figure 19

Figure 20

- 11 -

6-3 OTHER ELECTRICAL COMPONENTS

Not cooling at all

Compressor

doesn't run.

Poor cooling performance

Compressor runs poorly.

Check for open short or incorrect resistance readings in the following components

a. Starting devices b. OLP

c. Compressor coil d.Wiring harness

Check starting voltage.

Check voltage at starting devices.

Cause

Short, open, or broken. Poor contact

or shorted. Coil open or shorted.

Poor contact or shorted.

Low voltage.

Poor or broken or open contact.

Replace indicated component.

Advise customer that the power supply

needs to be checked

by an electrician.

Replace indicated component.

Fan motor doesn't run.

Heavy frost buildup on evaporator

Check current flowing in sub-coil of Compressor.

Check rating of OLP.

Check wiring circuit.

Check Fan Motor.

Check current flow in the following components: Sensor Fuse-M

Check current flow in the defrost heater.

Shorted.

Lack of capacity.

Wire is open or shorted.

Coil is shorted or open.

Open.

Replace indicated component.

Replace defrost heater.

- 12 -

6-4 SERVICE DIAGNOSIS CHART

COMPLAINT POINTS TO BE CHECKED REMEDY

No Cooling.

Cools poorly.

Foods in the Refrigerator are frozen.

Condensartion or ice forms inside the unit.

Condensartion forms in the Exterior Case.

There is abnormal noise.

• Is the power cord unplugged from the outlet?

• Check if the power switch is set to OFF.

• Check if the fuse of the power switch is shorted.

• Measure the voltage of the power outlet.

• Check if the unit is placed too close to the wall.

• Check if the unit is placed too close to the stove, gas cooker, or in direct sunlight.

• Is the ambient temperature too high or the room door closed?

• Check if food put in the refrigerator is hot.

• Did you open the door of the unit too often or check if the door is sealed properly?

• Check if the Control is set to Warm position.

• Is food placed in the cooling air outlet?

• Check if the control is set to colder position.

• Is the ambient temperature below 41°F(5°C)?

• Is liquid food sealed?

• Check if food put in the refrigerator is hot.

• Did you open the door of the unit too often or check if the door is sealed properly?

• Check if the ambient temperature and humidity of the surrounding air are 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.

• Plug into the outlet.

• Set the switch to ON.

• Replace the fuse.

• If the voltage is low, correct the wiring.

• Place the unit about 4 inches (10 cm) from the wall.

• Place the unit away from these heat sources.

• Lower the ambient temperature.

• Put in foods after they have cooled down.

• Don't open the door too often and close it firmly.

• Set the control to Recommended position.

• Place foods in the high-temperature section. (front part)

• Set the control to Recommended position.

• Set the control to Warm position.

• Seal liquid foods with wrap.

• Put in foods after they have cooled down.

• Don't open the door too often and close it firmly.

• Wipe moisture with a dry cloth. It will disappear in low temperature and humidity.

• Fill up the gap.

• Adjust the Leveling Screw, and position the refrigerator in a firm place.

• Remove the objects.

• Fix the Tray Drip firmly in the original position.

• Place the cover in its original position.

Door does not close well.

Ice and foods smell unpleasant.