LG LFC25760SB, LFC25760SW, LFC25760TT, LFC21760ST, LFC25760ST User Manual

REFRIGERATOR

SERVICE MANUAL

CAUTION

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

MODELS:

LFC21760ST LFC25760SW
LFC25760SB LFC25760TT
LFC25760ST

COLORS: WESTERN BLACK(SB)

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

CONTENTS

SAFETY PRECAUTIONS ....................................................................................................................................................... 2

SPECIFICATIONS................................................................................................................................................................... 3

PARTS IDENTIFICATION ....................................................................................................................................................... 4

DISASSEMBLY.................................................................................................................................................................. 5-10

DOOR................................................................................................................................................................................ 5-6

DOOR ALIGNMENT..............................................................................................................................................................6

HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER.................................................................................... 7-9

ADJUSTMENT................................................................................................................................................................. 10-11

COMPRESSOR.................................................................................................................................................................. 10

PTC-STARTER ................................................................................................................................................................... 10

OLP (OVERLOAD PROTECTOR)...................................................................................................................................... 11

TO REMOVE THE COVER PTC .........................................................................................................................................11

CIRCUIT DIAGRAM.............................................................................................................................................................. 12

TROUBLESHOOTING..................................................................................................................................................... 13-18

COMPRESSOR AND ELECTRIC COMPONENTS ........................................................................................................... 13

PTC AND OLP.................................................................................................................................................................... 14

OTHER ELECTRICAL COMPONENTS ............................................................................................................................. 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 .......................................................................................... 23-40

EXPLODED VIEW AND REPLACEMENT PARTS LIST ................................................................................................... 41-

SAFETY PRECAUTIONS

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.

3. Take caution not to get water near any electrical components.

4. Use exact replacement parts.

5. Remove any objects from the top prior to tilting the product.

- 2 -

1. SPECIFICATIONS

ITEMS SPECIFICATIONS

DOOR DESIGN Side Rounded

COOLING SYSTEM Fan Cooling

TEMPERATURE CONTROL Micom Control

Full Automatic

DEFROSTING SYSTEM

Heater Defrost

DOOR FINISH PCM, VCM, Stainless

HANDLE TYPE Bar

INNER CASE ABS Resin

INSULATION Polyurethane Foam

DIMENSIONS

ITEMS SPECIFICATIONS

VEGETABLE TRAY Opaque Drawer Type

COMPRESSOR PTC Starting Type

EVAPORATOR Fin Tube Type

CONDENSER Wire Condenser

REFRIGERANT R-134a (115 g)

LUBRICATING OIL ISO10 (280 ml)

DEFROSTING DEVICE SHEATH HEATER

REFRIGERATOR 60 W (2 EA)

LAMP

FREEZER 60 W (1 EA)

Description LFC21760** LFC25760**
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 of Door Hinge F 69 3/4 in. 69 3/4 in.
Width G 35 3/4 in. 35 3/4 in.
Width (door open 90 deg. w/o handle) H 39 1/4 in. 39/1/4 in.
Width (door open 90 deg. w/ handle) I 44 1/4 in. 44 1/4 in.

- 3 -

2. PARTS IDENTIFICATION

Egg Box

Digital Sensor

Control

Refrigerator 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-LFC25760** Only)

- 4 -

3. DISASSEMBLY

HINGE

HINGE COVER

Frame Cover

Handle

Door

Frame

Gasket
Bracket Clip

Spring

IncorrectCorrect

3-1 DOOR

● Refrigerator door

1. Remove the top hinge cover and disconnect the wire
harness.

2. Remove the ground screw.

3. Rotate the lever hinge and lift off hinge.

4. Lift off the refrigerator door.

5. Replace in the reverse order.

Figure 1

Door

Frame

Flat Tip

Screwdriver

3. Remove gasket

Pull gasket free from gasket channel on the three
remaining sides of door.

Bracket Clip

Gasket

Gasket

Bracket

Figure 3

● Door gasket removal

1. Remove door frame cover

Starting at top of cover and working down, snap cover
out and away from door.

2. Remove gasket bracket clips

There are two clips on each door. Start bracket removal
near one of the middle clips.

1) Pull gasket back to expose gasket bracket clip and

door frame.

2) Insert a flat tip screwdriver into seam between gasket

bracket and door frame and pry back until clips snaps
out.

3) Continue prying back along seam until all clips snap

out.

Figure 4

● 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 snap securely into place.

Figure 2

Figure 5

4) Push in remaining two clips until you hear each snap
securely into place.

Note: Make sure that no part of gasket bracket edge

protrudes from beneath door frame edge.

- 5 -

2. Insert gasket into channel

1) Snap gasket assembly into the door bracket.

Inserting the gasket assembly into the bracket door

Correct

Incorrect

Figure 6

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.)

2) Press gasket into channels on the three remaining
sides of door.

Figure 7

3. Replace door frame cover

Starting at top of cover and working down, snap the
cover back into door.

Figure 9

Figure 8

- 6 -

3-3 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER

3-3-1 FOLLOW STEPS TO REMOVE

Step 1) Open the freezer door.

Step 3) Remove the two screws from the guide rails (one

from each side).

Step 2) Remove the lower basket.

Step 4) Lift the 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 PUSHED IN TO RELEASE THE GEAR.

- 7 -

3-3-2 FOLLOW STEPS TO REINSTALL

Step 1) Reinstall the right side gear into the clip.

Step 2) Insert the rail into the right side gear. Gears do not

need to be perpendicular to each other.

Step 4) The rail system will align itself by pushing the rails

all the way into the freezer section.
Pull the rails back out to full extension.

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 6) Reinstall the two screws into the guide rails

(one from each side).

Step 7) Reinstall the lower basket, and close the freezer

door.

- 8 -

3-3-3 PULL OUT DRAWER

1

To separate the drawer, push the front left and right hooks in

Then gently lift the gear part of rear left and right side of the drawer and pull it out in

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.

direction to pull up and remove.

direction.

3

2

Hook

- 9 -

4. ADJUSTMENT

PTC STARTER

SEALED
TERMINAL

COMPRESSOR
MOTOR

C

M

S

M

3

6

5

2

S

N

L1

OVERLOAD PROTECTOR

Resistance Starter Capacitor Running

PTC

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.
If the hermetic connector rusts out or fails, refrigerant
and oil will be expelled into the contact area, probably
resulting in smoke and fire.

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

humidity, and soldering flux don’t contaminate the inside
of the compressor. Contamination in the cylinder 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 BaTiO3.

(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

Figure 17

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 overcurrent

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.

- 10 -

4-3 OLP (OVERLOAD PROTECTOR)

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
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)

(OVERLOAD PROTECTOR cross section)

1

2 3

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

adjustment screw of the OLP in any way.

4-4 TO REMOVE THE COVER PTC

(1) Remove the back cover of the mechanical area..

(2) Disconnect the two connectors on the top of the

compressor..

(3) Loosen two screws on compressor base.

Figure 18

(4) Use a flat screwdriver to pry off the cover.

(5) Assembly is the reverse order of disassembly.

- 11 -

5. CIRCUIT DIAGRAM

BETTER MODEL

- 12 -

6. TROUBLESHOOTING

1

2

3

4

5

2

5

5

3

5

1

43

YES

NO

YES

The range of resistance is between 1~50½ (ok)

Open or short

YES

YES

NO

NO

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%)?

OLP disconnected?

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

Replace OLP.

Check connection
condition.

Reconnect.

Check
resistance of
motor
compressor.

Check
resistance of
PTC-Starter.

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

Check resistance of
two terminals in
PTC-Starter.

Replace
compressor.

Refer to page 12.

Check OLP.

Check resistance of two
terminals in OLP.

Refer to page 12.

Check
starting state.

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

Supply
voltage rating
with ±10%.

Did
compressor
start?

Compressor
is OK

Replace the
compressor

- 13 -

6-2 PTC AND OLP

65

Shows continuity

Open

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 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 PTC­Starter.

Figure 19

Figure 20

- 14 -

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
evaproator.

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
melting fuse

Check current flow in
the defrost heater.

Shorted.

Lack of capacity.

Wire is open or
shorted.

Coil is shorted
or open.

Open.

Open.

Replace
indicated component.

Replace
indicated component.

Replace
defrost heater.

- 15 -

6-4 SERVICE DIAGNOSIS CHART

COMPLAINT POINTS TO BE CHECKED REMEDY

No Cooling.

Cools poorly.

Food in the
Refrigerator
is frozen.

Condensation or ice
forms inside
the unit.

Condensation 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 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

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.

• 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 drip tray firmly in the original position.

• Place the cover in its original position.

Door does not
close well.

Ice and foods
smell unpleasant.

● Other possible problems:

Check if frost forms in
the freezer.

Check the
refrigeration system.

Check the
thermistor.

• Check if the door gasket is dirty with
an item like juice.

• Is the refrigerator level?

• Is there too much food in the refrigerator?

• Check if the inside of the unit is dirty.

• Are foods with a strong odor unwrapped?

• The unit smells of plastic.

Not
defrosting

The system
is faulty.

The operation of
the thermistor is
incorrect.

• Clean the door gasket.

• Position in a firm place and level the

leveling screw.

• Make sure food stored in shelves does not prevent
the door from closing.

• Clean the inside of the unit.

• Wrap foods that have a strong odor.

• New products smell of plastic, but this

will go away after 1-2 weeks.

Check components of
the defrosting circuit.

Perform sealed
system repair.

Replace the
thermistor.

- 16 -

6-5 REFRIGERATION CYCLE

▼ Troubleshooting Chart

CAUSE

PARTIAL Freezer Low flowing sound of A little higher • Refrigerant level is low due
LEAKAGE compartment and refrigerant is heard and than ambient • to a leak.

LEAKAGE

COMPLETE Freezer Flowing sound of refrigerant Equal to ambient • No discharging of refrigerant.
LEAKAGE compartment and is not heard and frost isn't temperature. • Normal cooling is possible by

CLOGGED BY DUST

PARTIAL Freezer Flowing sound of refrigerant A little higher • Normal discharging of the
CLOG compartment and is heard and frost forms than ambient • refrigerant.

WHOLE
CLOG

MOISTURE Cooling operation Flowing sound of refrigerant Lower than • Cooling operation restarts
CLOG stops periodically. is not heard and frost melts. ambient • when heating the inlet of the

COMPRESSION

COMP- Freezer and Low flowing sound of A little higher • Low pressure at high side

DEFECTIVE

RESSION refrigerator refrigerant is heard and than ambient • of compressor due to low

STATE OF

THE UNIT

refrigerator don't frost forms in inlet only. temperature. • Normal cooling is possible by
cool normally. • restoring the normal amount of

refrigerator don't formed. • restoring the normal amount of
cool normally. • refrigerant and repairing the leak.

refrigerator don't in inlet only. temperature. • The capillary tube is faulty.
cool normally.

Freezer
compartment and
refrigerator don't cool.

don't cool. frost forms in inlet only. temperature. • refrigerant level.

STATE OF THE

EVAPORATOR

Flowing sound of refrigerant Equal to ambient • Normal discharging of the
is not heard and frost isn't temperature. • refrigerant.
formed.

TEMPERATURE

OF THE

REMARKS

COMPRESSOR

• refrigerant and repairing the leak.

temperature. • capillary tube.

NO COMP- No compressing Flowing sound of refrigerant Equal to ambient • No pressure in the high
RESSION operation. is not heard and there is temperature. • pressure part of the

no frost. • compressor.

- 17 -

6-5-1 SEALED SYSTEM DIAGNOSIS

Not Cooling Complaint

All components operating, No airflow problems, Not frosted up as a defrost problem

problem has been isolated to sealed system area

Frost

Pattern?

Equalization

Test

Partial

Very Fast

Inefficient

Compressor

Partial

Restriction

Complete

Restriction

Equalization

Test

Condenser

Temperature

None

Very Fast

Very SlowVery 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 it has been operating.)

- 18 -

7. OPERATION PRINCIPLE AND REPAIR METHOD OF ICEMAKER

¥ Adjusts EJECTOR to

Start Position

with power on.

Power On

Start Position

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 the

Fill Key



for 3 seconds. The icemaker will run through 3 stages:

Harvest Fill Icemaking

.

¥ With the detect lever, checks if the ICE BIN is full.

7-1 OPERATION PRINCIPLE

7-1-1 Operation Principle of Icemaker

1. Turning the Icemaker stop switch off (O) stops the icemaking function.

2. Setting the Icemaker switch to OFF and then turning it back on will reset the icemaker control.

Icemaker

Cube Size
Indicator Light

Cube Size
Select Button

Power Switch

Automatic
Shut off Arm

- 19 -

7-2 ICE MAKER FUNCTIONS

7-2-1 Start Position

1. After POWER OFF or power outage, check the EJECTOR's position with MICOM initialization to restart.

2. How to check if it is in place:

- Check HIGH/LOW signals from HALL SENSOR in MICOM PIN.

3. Control method to check if it is in place:
(1) EJECTOR is in place,

- It is an initialized control, so the mode can be changed to ice making control.

(2) EJECTOR isn't in place:

A. If EJECTOR is back in place within 2 minutes with the motor on, it is being initialized. If not, go to step B.
B. If EJECTOR is back in place within 18 minutes after the heater turns from ON to OFF, it is being initialized. If not, it is

not functioning. Repeat step B with heater and motor off.

7-2-2 Ice Making Mode

1. Icemaking refers to the freezing of supplied water in the ice trays. Complete freezing is assured by measuring 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 to 240 minutes after starting.

4. If the temperature sensor is defective, the icemaking 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 ices into the ice bin from the tray when icemaking has
completed.

2. Harvest mode:
(1) The Heater is ON for 30 seconds, then the motor starts.
(2) Harvest mode is completed if it reaches start position again while Heater & Motor are on at the same time.

A. ice bin is full : The EJECTOR stops (heater off).
B. ice bin is not full : The EJECTOR rotates twice to open for ice.

NOTE : If the EJECTOR does not rotate once within 5 minutes in status (2), separate heater control mode starts

operating to prevent the EJECTOR from being constrained. (It is recommended that the user open for ice to
return to normal mode.)

- 20 -

7-2-4 Fill/Park Position

1. Once a normal harvest mode has been completed, the water solenoid will be activated.

2. The amount of water is adjusted by pressing the fill key repeatedly. This changes the time allowed for fill as illustrated in
the table below.

Water supply amount table

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.

- 21 -

7-2-5 Function TEST

1. This is a compulsory operation for test, service, cleaning, etc. It is operated by pressing and holding the fill key for 3 seconds.

2. The test works only in the icemaking mode. It cannot be entered from the harvest or fill mode. (If there is an ERROR, it
can only be checked in the test mode.)

3. Caution! If the test is performed before water in the icemaker is frozen, 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 returns to MICOM control. The time needed to supply water resets
to the pre-test setting.

7-3 DEFECT DIAGNOSIS FUNCTION

7-3-1 ERROR CODE on water supply control panel at Ice Maker

- 22 -

8. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM

Best Model

REFRIGERATOR TEMP

COLDER WARMER 37 °F IS RECOMMENDED 0 °F IS RECOMMENDED

FREEZER TEMP

COLDER WARMER

ICE PLUS

8-1 FUNCTION

8-1-1 Function

1. When the appliance is plugged in, it defaults to 37°F for the refrigerator and 0°F for the freezer.
You can adjust the refrigerator and the freezer control temperature by pressing the ADJUST button.

2. When the power is initially applied or restored after a power failure, it is automatically set to 37 & 0.

Control range : 32°F ~ 46°F

0°C ~ 8°C

8-1-2 How to Change the Temperature Mode to

1. The display temperature mode can be changed from °F to °C or °C to °F by pressing and holding the FRZ TEMP and the
COLDER key of REF TEMP keys at the same time for over five seconds

2. The initial setting is °F. Whenever the mode is changed, the LED lights are changed.

°F/°C

Control range : -6°F ~ 9°F

-21°C ~ -13°C

8-1-3 Control of freezer fan motor

1. Freezer fan motor runs at either regular or high speed.(2,400 or 2,700 rpm.)

2. High RPM is used when electricity is first on, for ICE PLUS, and when refrigerator is overloaded.
Standard RPM is used for normal usage.

3. The fan motor is stopped when any door is opened.

8-1-4 ICE PLUS

1. The purpose of this function is to intensify the cooling speed of freezer and to increase the amount of ice.

2. Whenever selection switch is pressed, selection/release, the icon will turn ON or OFF.

3. If there is a power outage and the refrigerator is powered on again, ICE PLUS will be canceled.

4.To activate this function you need to press the ICE PLUS key and the icon will turn ON. This function 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 during the first 90 minutes of ICE PLUS, the ICE PLUS cycle will complete its cycle after

defrosting has ended. If the defrost cycle begins when iICE PLUS has run for more than 90 minutes, ICE PLUS will run
for two hours after the defrost is completed.

(3) If ICE PLUS is pressed during defrost, ICE PLUS icon is on this function will start seven minutes after defrost is

completed and it shall operate for three hours.

(4) If ICE PLUS is selected within seven minutes after compressor has stopped, the compressor (compressor delays

seven minutes) will start after the balance of the delay time.

(5) The fan motor in the freezer compartment rotates at high speed during ICE PLUS.

6. For the rest of 21 hours, the freezer will be controlled at the lowest temperature.

8-1-5. REFRIGERATOR LAMP AUTO OFF

1. To protect the risk of lamp heat, when the refrigerator door is opened for 7 minutes, the refrigerator lamp will be turned off
automatically.

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8-1-6 Alarm for Open Door

Closed Open Closed Open

3 Times 3 Times 3 Times 3 Times

Closed

Within 1 min. 1 min.

30 sec 30 sec 30 sec

Freezer Door

or Refrigerator

Door

Buzzer

1. This feature sounds a buzzer when the freezer or refrigerator door is not closed within 1 minute after it is opened.

2. One minute after the door is opened, the buzzer sounds three times each for 1/2 second. These tones repeat every 30
seconds.

3. The alarm is cancelled when the freezer or the refrigerator is closed while the buzzer sounds.

8-1-7 Buzzer Sound

When the button on the front display is pushed, a Ding~ Dong~ sound is produced.

8-1-8 Defrosting (removing frost)

1. Defrosting starts each time the compressor running time reaches 7 hours.

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 2 hours, the defrost
mode is malfunctioning.

4. Defrosting won’t function if its sensor is defective (wires are cut or short circuited)

- 24 -

8-1-9 Electrical Parts Are Turned On Sequentially

Electrical parts such as compressor, 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 together when test is
completed.

OPERATING ORDERS

Temperature of defrosting
sensor is 45°C or more
(when unit is newly

Initial power on

purchased or when moved)

Power

ON

in 0.5 sec. in 0.5 sec.

Compressor

ON

Freezer fan

ON

Temperature of defrosting
sensor is lower than 45°C
(during power outages or
for service)

Reset to normal operation
from test mode

Power

in 0.5 sec.

ON

in 0.5 sec. in 0.5 sec.

Compressor

Defrosting

heater ON

ON

Total load

OFF

in 7 min. in 0.5 sec.

Compressor

ON

in 10 sec.

Freezer fan

ON

Defrost heater

OFF

Freezer fan

ON

- 25 -

8-1-10 Defect Diagnosis Function

햳 Defect code signs햲 Defect code signs

Best Model

REFRIGERATOR TEMP

COLDER WARMER 37 °F IS RECOMMENDED 0 °F IS RECOMMENDED

FREEZER TEMP

COLDER WARMER

ICE PLUS

1. Automatic diagnosis makes servicing the refrigerator easy.

2. When a defect occurs, the buttons will not operate; but the tones, such as ding, will sound.

3. When the defect CODE removes the sign, it returns to normal operation (RESET).

4. The defect CODE shows on the refrigerator and freezer display.

ERROR CODE on display panel

Note 1) Room temperature sensor is 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 displays the
previous status.

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8-1-11 TEST Mode

1. The test mode allows checking the PCB and the function of the product as well as finding out the defective part in case of
an error.

2. The test mode is operated by pressing two buttons on the display panel.

3. While in the test mode, the function control button is not recognized, but the recognition tone (beep~) sounds.

4. After exiting the test mode, be sure to reset by unplugging and then plugging in the appliance.

5. If an error, such as a sensor failure, is detected while in the test mode, the test mode is cleared and the error code is
displayed.

6. While an 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 FRX 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 highest setting. Then, press and hold
WARMER Key for 5 seconds.

2. The LED panels will display OFF, to indicate that the compressor, circulating fan, damper, and defrost heater are not
operating.

3. The open door alarm and the lamp auto-off feature will work normally and can be demonstrated.

4. To reset to normal operation, press and hold either WARMER key for about 5 seconds.

- 27 -

8-2 PCB FUNCTION

8-2-1 Power Circuit

The secondary part of the TRANSFORMER is composed of the power supply for the display, the BLDC FAN Motor drive
(15.5 V), the relay drive (12 Vdc) and the MICOM and IC (5 Vdc).

The voltage for each part is as follows:

PART VA 1 CE 3 CE 4 CE 5

VOLTAGE 115 Vac 12 Vdc 15.5 Vdc 5 V

VA1 is a part for preventing over voltage and noise. When 385V or higher power is applied, the inside elements are short­circuited and broken, resulting in blowout of the fuse in order to protect the elements of the secondary part of the
TRANSFORMER.

- 28 -

8-2-2 Oscillation Circuit

This circuit generates the base clock for calculating time and the synchro clock for transmitting data from and to the inside
logic elements of the IC1 (MICOM). Be sure to use specified replacement parts, since calculating time by the IC1 may be
changed. If changed, the OSC1 SPEC will not 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 operation, 5V is applied to the RESET terminal. (If a malfunction occurs in the RESET IC, the MICOM will
not operate.)

- 29 -

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

1. Load Drive Condition Check

LOAD TYPE

Measurement Location (IC6)

ON

Condition

OFF

2. Fan motor driving circuit (freezer 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.

MOTOR OFF 2V or less 0V 5V

MOTOR ON 13V~15V 0V 2V~3V

COMP

NO.16 NO.11 NO.12 NO.13 NO.14 NO.15

part part part

a b

DEFROSTING

HEATER

LAMP-F

1V or below

LAMP-R

12V

c

WATER

VALVE/VALVE2

FRENCH

DOOR

HEATER

- 30 -

2. Open Door Detection Circuit Check

Measurement
Freezer/
Refrigerator Door

Location

Closed 5 V

Open 0 V

(PIN NO.30 & PIN NO.27)

- 31 -

8-2-5 Temperature Sensor Circuit

The upper circuit reads refrigerator 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:

SENSOR CHECK POINT NORMAL (-30°C ~ 50°C)

Freezer sensor POINT Voltage

Refrigerator sensor POINT Voltage

A

B

0.5 V ~ 4.5 V 0 V 5 V

Defrosting sensor POINT Voltage

Room Temperature sensor

POINT Voltage

C

D

8-2-6 Refrigeration Compartment Stepping Motor Damper Circuit

* The circuit shown below is the damper circuit to regulate the refrigerator temperature.

SHORT-CIRCUITED

OPEN

- 32 -

8-3 RESISTANCE SPECIFICATION OF SENSOR

TEMPERATURE

- 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 KΩ

+ 40 ˚C 1.4 KΩ 6.2 KΩ

+ 50 ˚C 0.8 KΩ 4.3 KΩ

RESISTANCE OF FREEZER

SENSOR

RESISTANCE OF REFRIGERATOR &

DEFROST SENSOR & ROOM SENSOR

• The resistance of the SENSOR has a ±5% tolerance.

• Measure the resistance of the SENSOR after leaving it for over 3 minutes 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 ASSY, MAIN.

- 33 -

Power source 1.

Cooling is poor. No cooling. 1. If the compressor Use Test Mode1 Compressor locked or Replace compressor.

is poor.

PROBLEM INDICATED BY CHECK CHECKING METHOD CAUSE SOLUTION

8-4 TROUBLESHOOTING

is normal. of the refrigerator incorrect.

sensor.

3. If sensor Check the resistance Sensor resistance is Replace sensor.
is normal. sticking on the evaporator . is poor, page 34.

4. Gasket seal incorrect. Check the seal when Door liner damaged. Replace door liner.

the door is closed.

temperature is operates. (forced cooling).

incorrect Connection wire is defective. Refer to 8-2-4. 2 and check

2. If defrosting Check the amount of frost Defrosting is poor. See DEFROSTING

Freezer 1. If fan motor Use Test Mode 1 Fan motor is defective. Replace the fan motor.

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.

DISPLAY operates the main PWB connector. is poor.

abnormally connector. Transformer fuse is open. Replace transformer.

operates.

(forced cooling).

If less than 7 minutes pass OLP, PTC, 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

2.
DISPLAY is off.

The whole DISPLAY

LED/SEVEN SEGMENT

DISPLAY LED/

SEVEN SEGMENT

2. If lamp is dim. Check visually. Applied voltage error. Use boosting transformer.

3. The connection of Check connection of connector connection Reconnect connector.

1. FREEZER/ Check if freezer or Power source is poor. Check outlet voltage.

REFRIGERATOR. refrigerator door is open

and check display.

blocked.

black wire of the main PWB

connector (CON2).

- 34 -

DEFROSTING is NO defrosting. 1. If heater emits heat. USE TEST MODE3 Heater disconnection. Replace heater.

defective. (forced defrosting).

COOLING is defective. If refrigerator 1. If frezzer temperature Check is frezzer Make sure the

temperature is normal. temperature is too low. door is attached.

is too low. 2. If amount of cool air from Make sure that the amount FAN motor is defective. Replace fan motor.

PROBLEM INDICATED BY CHECK CHECKING METHOD CAUSE SOLUTION

3. If ice remains after Make sure that defrost Connection is poor. Reassemble the

defrosting. sensor is connected. defrost sensor.

Make sure that

refrigerator doors are

frezzer and Door does not close Reassemble door.

closed.

properly. Replace gasket.

blocked. Check heater plate

2. If drain pipe is Check drain pipe. Drain pipe is blocked. Remove ice and impurities.

Temperature fuse Replace temperature

is blown. fuse.

Defrost sensor is defective. Replace defrost sensor.

Heater relay is poor. Replace RY2 of main PWB.

Connection is poor. Check evaporator

3. Door gasket contact. Check door seal when Door liner damaged. Replace door liner.

check supplied on the Evaporator frozen. See defrosting is poor,

refrigerator. below.

door is closed.

fan motor is and speed of cool air are Passage of cool air Remove impurities.

sufficient. sufficient by touching the is blocked.

resistance.

connection and wire of main

PWB connector.

- 35 -

8-5 MAIN PWB ASSEMBLY AND PARTS LIST

8-5-1 Main PWB Assembly

- 36 -

8-5-2 Replacement Parts List

- 37 -

8-5-3 PWB Assembly, Display, And Parts List

- 38 -

8-6 PWB DIAGRAM

8-6-1 PWB Main Assembly

- 39 -

- 40 -

9. EXPLODED VIEW & REPLACEMENT PARTS LIST

S18

106A

315A

500A

411A

501F

303C

318A

303B

314A

300A

312A

317A

103A

105A

283B

283B

328A

103B

315B

315B

315C

315C

323B

329C

420A

319A

319C

262B

410A

409B

158A

405F

404A

405C

332A

135D

405A

158B

145B

409B

106A

120B

145A

406D

249D

406A

282F

405B

329A

262H

103C

135C

410G

304A

207B

207A

271C

271B

271A

271B

402A

402A

400A

301A

408A

406B

610A

249C

313A

503D

409D

503C

503E

CASE PARTS

CAUTION: Use the part number to order part, not the position number.

- 41 -

FREEZER PARTS

145C

250C

250D

136B

145F

250D

136A

237C

131A

250A

250C

CAUTION: Use the part number to order part, not the position number.

- 42 -

REFRIGERATOR PARTS

141B

141C

141A

141B

141C

141A

146A

161E

*

141B

141C

141A

141B

141C

141A

147C

147B

147A

167B

154A

161A

*

145E

161C

*

160B

161A

*

161D

*

151A

248H

162B

145D

160B

162A

160C

155J

146B

151C

161F

*

248A

141D

CAUTION: Use the part number to order part, not the position number.

: on some models

*

- 43 -

DOOR PARTS

233A233D

231A

233B 233C

231B

241C

237A

241C

241C

230B

241A

241B

241C

237A

241C

205C

203A

201A

205B

205A

*

212D

*

244E

212G

230A

281D

243A

243B

243A

*

243B

262C

262C

▲

▲

244E

249H

249F

249B

250B

250B

249G

249E

249A

250A

281D

200A

243B

234B

234A

CAUTION: Use the part number to order part, not the position number.

: on some models

*

▲ Only for the service

- 44 -

WATER AND ICEMAKER PARTS

602A

600A

619A

623B

627B

623A

616E

CAUTION: Use the part number to order part, not the position number.

- 45 -

P/No. 3828JD8990C MAR., 2006 Printed in Korea