LG GR-K192AF Service Manual

CAUTION

PLEASE READ CAREFULLY THE SAFETY PRECAUTIONS OF THIS MANUAL BEFORE CHECKING OR OPERATING THE REFRIGERATOR.

KIMCHI REFRIGERATOR

SERVICE MANUAL

http://biz.lgservice.com

MODEL : GR-K192AF

1. Safety warnings and cautions.......................................................................................................................3

2. Product specification .....................................................................................................................................6

3. Product installation method ..........................................................................................................................7

4. Circuit diagram ...............................................................................................................................................8

5. MICOM function and circuit description.......................................................................................................9

6. Freezing cycle and refrigerant.....................................................................................................................31

7. General details about the product ..............................................................................................................33

8. Major repair method for freezing cycle.......................................................................................................35

9. Characteristics of each part ........................................................................................................................44

10. Cautions for disassembling the product..................................................................................................52

11. Assembly diagram and service parts list.................................................................................................53

1. First check if there is any electric leakage in the refrigerator unit.

2. Always unplug the refrigerator before handling any electricity conducting parts.

3. When testing the refrigerator with the power on, use insulated gloves for safety.

4. When using measuring instruments, check the rated current, voltage and capacity.

5. Do not allow water or moisture to get into the mechanical or electrical parts of the refrigerator.

6. Remove all things on top of the refrigerator before tilting it during repairs to avoid spills. Be especially careful for thin objects (glass sheet, book).

7. When the refrigerating cycle is damaged, always request service to the major repair service agency. (This is to prevent the house from getting dirty from the gas within the cycle.)

8. Always double check for repairs related to safety to ensure customer safety.

Safety regulations

Contents

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Chapter 1. Safety warnings and cautions

u Always observe the ‘Safety Warnings’ and ‘Cautions’, which hare intended to ensure safety while repairing or operating

the product.

u Precautions are classified into ‘Warning’ and ‘Caution’, as explained below.

w Warning Warning means a dangerous condition which could result in significant damage, injury or death if

the instructions are not followed.

w Caution Caution means a condition which could result in damage or injury if instructions are not followed.

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Safety warnings and cautions

Use caution to prevent electric shock

The control panel (main PCB) uses 310V. When replacing PCB parts, wait at least 3 minutes after unplugging. Always unplug the refrigerator before repairing.

Make sure that the power plug is not pressed by the back of the refrigerator

Power plug may be damaged and cause a fire or electric shock.

Use a dedicated circuit.

Overloading circuits or outlets could cause a fire.

Do not allow the consumer to repair , disassemble or modify the refrigerator .

Damaged power plug can cause fire or electric shock.

w Warning

Safety warnings and cautions

- 4 -

This product should always be grounded, when needed.

If you think that there is a possibility of electricity leakage by water or moisture, always ground the unit.

Do not store flammable liquid or gas in the refrigerator such as ether , benzene, alcohol, medicine, LP gas etc.

It can cause an explosion or a fire.

Do not store medicine or academic material etc. in the refrigerator .

Store an object that requires precise temperature control can cause deterioration in quality or unexpected reaction to cause a dangerous situation.

Do not set items, particularly flower vase, cup, cosmetic or medicine on top of the refrigerator .

It can cause fire and electric shock or cause an injury from dropping.

Do not stack items or carelessly store food on the refrigerator .

Items stored on the refrigerator could fall and cause injury.

When disposing the refrigerator , remove the rubber packing on the door and do not leave it where children play.

A child can be dangerously entrapped in the refrigerator.

w Warning

Grounding screw

Grounding line

Copper plate

More than

Ben

Ether

zene

gas

Safety warnings and cautions

- 5 -

When using the refrigerator for low temperature in freezer or refrigerator , do not store bottles.

Bottles can freeze and cause the bottles to crack, which can cause an injury.

During repairs, be sure all connectors are tight and wires are properly routed.

Make sure the connectors of the housing part are properly connected.

During repairs, remove all dust and foreign material from the housing part, connector part and check part.

It can prevent problems such as tracking or short circuit.

Do not bend, modify , bend, pull or twist the power cord.

It can cause fire or electric shock.

Allow at least 5 minutes for resetting if you unplug the refrigerator .

If can cause an overload to the condenser operation and cause problems.

After 5 minutes

Always use exact replacement parts.

Make sure that the model name, voltage, current and temperature ratings are correct for the electric part.

w Caution

Product specification

Chapter 2. Product specification

2-1. GR-K192AF

Item

Usable volume

Volume

External

dimensions

Total weight

Motor power consumption

Cooling method

Store/Season

Insulation material

Fresh vegetable basket

Kimchi refrigerator container

Left compartment

Right compartment

Width

Depth

Height

GR-K192AF

SPEC

188.8Li

94.3Li

922mm

699mm

883mm

66kg

115W

Direct cooling

Electronic

CYCLO PENTANE

1 pc.

6 pcs. (6 large)

Low temperature catalytic deodorizing system

Compressor

Freeze cycle Electrical part rating

Evaporator

Refrigerant (amount)

Oil

PTC

OLP

Fan motor for compressor cooling

Left compartment seasoning heater

Right compartment seasoning heater

Capacitor (running)

Capacitor (starting)

2 pcs.

NR58LBQH

PIPE ON SHEET

R134a(145g)

FREOL@15G(210cc)

P6R8MB

4TM412TFBYY

ø110,3 blades attached

115V / 80W(Resistance:605Ω)

250VAC 10µF

200VAC 50µF

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Chapter 3. Product installation method

3-1. Method to adjust height of refrigerator

■ First adjust the level of the refrigerator.

(If the floor is uneven, the refrigerator may vibrate or cause noise.)

u Adjust the front to be leveled by turning the height adjustment screws under the front corners in the arrow direction.

3-2. Grounding method

Plug the cord into a 115V grounded outlet. If you are unsure of the voltage or grounding integrity, consult a qualified electrician.

Take care not to ground the circuit at one of the following places:

1. Water pipe: If there is a plastic piping within the system, the

ground may not be valid.

2. Gas pipe: There is a danger of fire or explosion.

3. Phone line or lightning rod: If lightning strikes, dangerous

voltage may be induced in the circuit.

Product installation method

- 7 -

Horizontal adjustment leg (lower handle part)

More than 75cm

Grounding line

Copper plate

Caution

Chapter 4. Circuit diagram

Circuit diagram

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Chapter 5. MICOM function and circuit description

5-1. Function description

5-1-1. Display part

1. When the power is connected for the first time, it is set to “Lock”, “Left compartment-Cabbage Kimchi-Mid” and “Right compartment-Cabbage Kimchi-Mid”.

2. During a power shut-down or when the power is reconnected, the refrigerator maintains the prior display. But in case of a power-shut down or power reconnection during rhythm fermenting, the temperature returns to “Mid” for the applicable food type.

3. In “Lock” status, you will not hear a buzzer even when you press the buttons and the functions will not work.

MICOM function and circuit description

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Notch

Temperature

Kimchi srore

Vegetable/Fruit Light freezing Freezing food Min Mid Max Min Mid Max Min Mid Max Min Mid Max 0°C -1.0°C -2.0°C 3.5°C 2.5°C 1.5°C -4.0°C -5.0°C -6.0°C -5°C -18°C -21°C

5-1-2. Food storage/seasoning function

(1) When selecting food type and storing temperature

1. Press the “Lock/Unlock” button for more than 2 seconds to switch to “Unlock” status.

2. Press the “Kimchi store” button to select “Mid” ’ “Max” ’ “Min” ’ “Mid”, “Vegetable / Fruit” button “Mid” ’ “Max” ’ “Min” ’ “Mid”, and “Feezing” button “Normal” ’ “Max” ’ “Ligth Freeaing” ’ “Normal” in sequence

3. Press the “Lock/Unlock” button to complete the selection of food type and storing temperature. At this time, if a minute passes without pressing the “Lock/Unlock” button, it will automatically switch to Lock status and end the food type and storing temperature selection mode.

(2) When selecting rhythm fermenting (seasoning)

1. Press the “Lock/Unlock” button for more than 2 seconds to switch to “Unlock” status.

2. At this condition, press “Fermentation” button to select “Normal ” ’ ”Normal ” ’ ”More ” ’ ”Underground Fermentation ” ’ ”Less ” ’ ” Less ” ’ ” Normal ” in sequence, and when the fermentation type is changed from “Less” to “Normal”, the food type is selected by the order of “Cabbage kimchi” ’ ”Radish kimchi” ’ ”Broth kimchi” in sequence. However, “Underground Fermentation ” is only for “Cabbage kimchi.”

3. Press the “Lock/Unlock” button to complete the rhythm fermenting (seasoning). At this time, if a minute passes without pressing the “Lock/Unlock” button, it will automatically switch to Lock status and end the rhythm ferment (seasoning) selection mode.

4. When “Rhythmic fermentation” is terminated, the remaining time is displayed, and when the fermentation is completed, “0 hour” is displayed as the remaining time and the storing temperature is automatically set to “Mid

(3) When selecting flavor keeping

1. Press the “Lock/Unlock” button for more than 2 seconds to switch to “Unlock” status.

2. Select “Kimchi store” as storing type. (Flavor keeping function is only limited to “Kimchi store”)

3. At this time, press the “Flavor keeping” button to select or cancel the flavor keeping function.

4. Press the “Lock/Unlock” button to end the flavor keeping selection mode. At this time, if a minute passes without pressing the “Lock/Unlock” button, it will automatically switch to Lock status and end the flavor keeping selection mode.

5. If you select flavor keeping during seasoning process, it will immediately end the seasoning and switch to flavor keeping. At this time the storing temperature will automatically be set to “Mid”.

6. If you select the flavor keeping function, the refrigerator will lower the temperature to maintain the current Kimchi flavor. (-1 degrees for “Min”, -0.5 degrees for “Mid” and -0 degrees for “Max”.)

7. During flavor keeping operation, a cold shock operation is done every 12 hours.

8. If you select rhythm fermenting during flavor keeping, the flavor keeping function will be canceled.

MICOM function and circuit description

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MICOM function and circuit description

Time

Seasoning complete

Kimchi sensor temperature

18 ℃

(Broth Kimchi:

10 ℃)

5 ℃

1.0 ℃

-0.5 ℃

-2.0 ℃

Storage

operation

When the Kimchi placed in

the refrigerator is cool

When the Kimchi

placed in the refrigerator

is at room temperature

1st

seasoning

2nd

seasoning

3rd

seasoning

4th

seasoning

5th

seasoning

Seasoning start

: Seasoning heater ON/OFF : Seasoning heater OFF

5-1-3. When selecting power on/off function

1. Press the "Lock/Unlock" button for more than 2 seconds to switch to "Unlock" status.

2. At this time, press the "Power" button for more than 2 seconds to turn the power off.

3. At this time, all the LEDs in the display will be turned off with the power off LED turning on.

4. If you press the "Power" button when the power is off, it will turn on the power and recover to "Cabbage Kimchi" and "Mid".

5. When the power is turned off, the heater of the applicable compartment is turned off and the valve will be closed.

5-1-4. Rhythm fermenting control pattern diagram

1. The fermenting control pattern varies, depending on the temperature of the Kimchi when it is placed into the storage, the type of Kimchi being made and the degree of the seasoning selected.

2. In the 1st seasoning cycle, if the Kimchi is at room temperature, the cold control operates.

3. During the seasoning cycle, if the Kimchi is cold, the seasoning heater is turned on and if the Kimchi is warm, the seasoning heater is turned off.(Only 1stseasoning and 2ndseasoning)

4. If a failure occurs, such as a sensor error during seasoning, the storage will default to Cabbage Kimchi storage status.

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5-1-5. Temperature contr ol method

1. The compressor runs or stops and the 3-way valve opens or closes depending on the temperature sensed in the left and right compartment.

2. If the temperature in either compartment is unsatisfactory, the compressor is turned on and the 3-way value is opened to the affected compartment.

3. If the temperature in both compartments is unsatisfactory, the compressor is turned on and runs until both compartments become satisfactory. The 3-way valve is opened and closed to each compartment alternatively until the temperature is satisfactory.

4. During the seasoning cycle, if the temperature is low, the heater is turned on and if the temperature is high, the compressor is turned on and the 3-way value is opened.

Note1) When the temperature is satisfactory in both compartments, the 3-way valve is open to whichever compartment that

has had a satisfactory temperature most recently.

■ Summary chart of COMP and 3-Way valve operation

5-1-6. Buzzer sound

When you press a button on the front display, you will hear a varying buzzer sound depending on the type and function. (Refer to Buzzer operating circuit in p21).

5-1-7 Power failure compensation function

1. When the power is restored after an outage, the refrigerator performs the setting originally programmed except for Error status and Test mode.

2. If the power fails during the seasoning process, there is not power outage compensation function and the storage defaults to previously set Kimchi type and temperature of "Mid". (to protect excessive seasoning)

MICOM function and circuit description

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Left compartment temperature Right compartment temperature 3-Way valve position COMP

Satisfactory Satisfactory Note 1)g

OFF

Satisfactory Unsatisfactory Right compartment

Unsatisfactory Satisfactory Left compartment

Unsatisfactory Unsatisfactory Left 20 min/Right 20 min

Left

compartment

sensor

Right

compartment

sensor

Left

compartment

3-way valve

Right

compartment

3-way valve

COMP

Temperature

unsatisfactory

Temperature

satisfactory

OPEN

OFF

5-1-8. Operation in response to ambient temperature

The storage senses the ambient temperature and adjusts the temperature in the compartments accordingly. This keeps the storage from being too cold or too warm because of seasonal variations and maintains exact temperatures in the compartments.

5-1-9. Sequential operation of components

Components (compressor, 3-way valve and left/right seasoning heater) are operated in a specific order to prevent damage and noise caused by simultaneous operation of all parts when the unit is started and after completing the self-test routine.

g Operation order may slightly vary depending on temperature setting.

MICOM function and circuit description

- 13 -

Storage temperature

of the left and right

compartments

Operation in response to the ambient temperature

In general operation

Season Spring Summer Autumn Winter

Operation status Operating order Remarks

Initial power-up

Temperature of

the left of right

sensor is >45°C

Temperature of

the left of right

sensor is <45°C

When returning to

normal status in test

mode

The 3-way valve is

opened to both

compartments for 3

minutes; then it is

opened to either

the left or the right

compartment,

depending on the

temperature in the

compartments.

Power

All

loads

off

Compressor

Left

seasoning

heater

Right

seasoning

heater

3-way

valve

open

3-way

valve

left open

3-way

valve

open

3-way

valve

left open

Left

seasoning

heater

off

Right

seasoning

heater

off

Compressor

3-way

valve open

3-way

valve

left

open

Compre

ssor on

Immediately 3 min 10 sec

Immediately 0.5 sec 5 sec 0.5 sec

3 sec 3 min 10 sec

7 min

3 sec 3 min

5-1-10. Error diagnosis function

1. The error diagnosis function is the function to support SVC in case of an error that can affect the performance of the product.

2. If an error occurs, the control panel button will not work.

3. If an error occurs and is resolved, the refrigerator will default to the normal status. (The unit is reset.)

4. The error codes are shown in segment for the remaining seasoning time display of the right compartment, and all LEDs, except for failure code, are turned off.

Note 1) The failure code is not displayed for the outside temperature sensor failure, but for ‘LED CHECK’ (by pressing and holding “Kimchi

store” button on the left chamber and “Kimchi store” button on the right chamber together for one second or longer). If the outside temperature sensor is normal, all LEDs are turned ON, but if abnormal, all LEDs are turned ON with the remaining time display on the right chamber OFF.

MICOM function and circuit description

- 14 -

NO Item Error code displayError code display

Error contents

Failure of left compartment sensor (R1).

Failure of right compartment sensor (R2).

Failure of ambient temperature sensor (RTS)

Communications error

Left compartment lid sensor disconnected or short circuited

When communication is not working continuously for 30 sec

Displays "E1" on the seasoning remaining time part

Displays "E2" on the seasoning remaining time part

Only LED for "E1" and "E2" was on

In case of an ambient temperature sensor error, the error code is not displayed and press the left and right compartment "Store" buttons for more than 1 second when checking the LED.

5-1-11. Test function

1. The test function checks the functions of the PCB and the refrigerator, searching for errors in parts.

2. The test switch on the PCB operates the test mode. The refrigerator reverts to the normal mode after 2 hours if you forget to end it manually.

3. When the test mode is active, the buttons on the control panel are disabled but the buzzer still sounds a ding if one is pressed.

4. When the test mode is completed, unplug the refrigerator briefly and plug it in again to reset it and allow normal operation.

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

6. During the display of the error code, test mode does not work even if you press the Test switch.

LED CHECK function

All LEDs are turned ON by pressing and holding “Kimchi store” button on the left chamber and “Kimchi store” button on the right chamber together for one second or longer. When these buttons are released, the LED returns to the previous state.

MICOM function and circuit description

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Mode Operation

COMP fan motor

VALVE

Left and Right

DIAPLAY LED Remarks

seasoning heater

TEST1

TEST2

TEST3

TEST4

Normal

recovery

Press the test switch once

Press the test switch once when Test 1 indicates it is completed.

Press the test switch once when Test 2 indicates it is completed.

Press the test switch once when Test 3 indicates it is completed.

Press the test switch once when Test 4 indicates it is completed.

Left compartment 20minute / Right compartment 20 minute

Right compartment valve OPEN

Left compartment valve OPEN

OFF

Error code display “11”

Error code display “22”

Error code display “33”

Error code display “44”

OFF

This test checks the refrigeration system for the left and right compartments.

This test checks the refrigeration system for the right compartment only.

This test checks the refrigeration system for the left compartment only.

This test checks the seasoning heaters.

After a maximum of 30 minutes or when the temperature of the compartments is higher than 40C

, the storage will default to its initial status.

The compressor operates after a delay of 7 minutes.

5-2. Circuit description

5-2-1. Power circuit

The power circuit consists of the noise attenuation part and the SMPS (Switch Mode Power Supply) part. The SMPS consists of the rectifier (BD1 & CE1) to convert AC voltage to DC voltage, switching part (IC3) to switch the converted DC voltage, transformer to transmit energy of the first side of the switching end to the second side, the secondary power to supply power to MICOM and IC, and the feedback part (IC4) to feedback the secondary voltage to the first side of the transformer in order to maintain the secondary voltage constant.

: High voltage (DC 310V) is maintained in this circuit. Wait at least 3 minutes after unplugging to allow the

current to dissipate. There is a danger of electric shock.

5-2-2. Oscillation circuit

The oscillation circuit provides the clock signal for synchronization and calculation of time in relation to the logic elements of microprocessor IC1 (MICOM). OSC1 must always use the original rated parts, because if the specification changes, the timing generated will not be correct, causing erratic functioning of the microprocessor.

5-2-3. Reset circuit

The reset circuit allows the entire process to be started from the initial status by resetting the various elements within the MICOM (IC1), such as RAM, whenever power is applied to the unit. Low voltage is applied to the reset terminal for 10ms at the beginning of the power input. The reset terminal has a voltage of 5 V during general operation. (If the reset operation fails, the microprocessor will not operate.)

MICOM function and circuit description

- 16 -

Caution

MICOM function and circuit description

P15 (INT1)

P14 (PWM3/TC3/PDO3)

45ms

1046.5Hz 1174.7Hz 1318.5Hz

45ms 45ms 45ms 70ms 750ms

45ms

1568.0Hz 1318.5Hz 1046.5Hz

45ms 45ms 45ms 70ms 750ms

5-2-4. Load/Buzzer driving circuit

(1) Load driving circuit

Type of load COMP. fan motor Left seasoning heater Right seasoning heater

Measuring point (IC7)

Status

OFF 12V

13 10 11

Within 1V

(2) Buzzer driving circuit (located on display PCB)

g Only the buzzer sound for the Lock/Unlock operation is shown in this SVC technical manual.

LED MODULE TYPE

Status

Measuring point

Ex) Lock: "Ding-D-Dong" sound Ex) Lock: "Ding-D-Dong" sound Off

IC101 (Pin 3/61)

IC101 (Pin 2/62)

- 17 -

5-2-5. Switch input circuit

The following circuit is the input circuit to detect the test switch signal to check the refrigerator.

5-2-6. Temperature sensor circuit

The following temperature sensor circuit consists of a sensor to detect the outside (ambient) temperature and sensors in the left and right compartments for storing and seasoning Kimchi. The status of each sensor, whether open or shorted, is shown below.

MICOM function and circuit description

- 18 -

Sensor Check point Normal

(-30°C~50°C)

Shorted Open

Left compartment sensor

POINT Voltage

Right compartment sensor

POINT Voltage 0.5V~4.5V 0V 5V

Outside sensor

POINT Voltage

A B C

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