LG LMX28988 Series, LMX25988 Series, LMX28988ST, LMX28988SB, LMX28988SW Service Manual

...

REFRIGERATOR

SERVICE MANUAL

CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

MODEL : LMX28988**

LMX25988**

COLOR : STAINLESS(ST)

SMOOTH BLACK(SB) SUPER WHITE(SW)

CONTENTS

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

1. SPECIFICATIONS .......................................................................................................................................................... 3-4

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

3. DISASSEMBLY ............................................................................................................................................................ 6-16

REMOVING AND REPLACING REFRIGERATOR DOORS ............................................................................................. 6

DOOR ................................................................................................................................................................................ 7

DOOR ALIGNMENT .......................................................................................................................................................... 8

FAN AND FAN MOTOR(EVAPORATOR) ......................................................................................................................... 8

DEFROST CONTROL ASSEMBLY ................................................................................................................................... 8

LAMP ................................................................................................................................................................................. 9

MULTI DUCT ..................................................................................................................................................................... 9

MAIN PWB ....................................................................................................................................................................... 10

DISPENSER .................................................................................................................................................................... 10

DISPLAY PCB ................................................................................................................................................................. 10

ICE BUTTON ASSEMBLY ............................................................................................................................................... 10

WATER BUTTON ASSMEBLY ........................................................................................................................................ 11

ICE CORNER DOOR REPLACEMENT ........................................................................................................................... 11

ICEMAKER REPLACEMENT ..................................................................................................................................... 11-12

SUB PWB FOR WORKING DISPENSER ....................................................................................................................... 12

CAP DUCT MOTOR REPLACEMENT ............................................................................................................................ 12

HOW TO REMOVE A ICE BIN ........................................................................................................................................ 13

HOW TO INSERT A ICE BIN ........................................................................................................................................... 13

HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER ............................................................................. 14-15

WATER VALVE DISASSEMBLY METHOD .................................................................................................................... 16

FAN AND FAN MOTOR DISASSEMBLY METHOD ........................................................................................................ 16

TOP DRAWER ................................................................................................................................................................. 17

BOTTOM DRAWER ......................................................................................................................................................... 17

4. ADJUSTMENT ........................................................................................................................................................... 18-19

COMPRESSOR ................................................................................................................................................................ 18

INTRODUCTION OF E-LINEAR COMPRESSOR ...................................................................................................... 18-20

5. CIRCUIT DIAGRAM ................................................................................................................................................... 21-22

6. TROUBLESHOOTING .................................................................................................................................................... 23

7. PCB PICTURE ........................................................................................................................................................... 24-26

8. Troubleshooting With Error Display ....................................................................................................................... 27-35

9. Troubleshooting Without Error Display ................................................................................................................. 36-44

10. Reference .................................................................................................................................................................. 45-48

11. COMPONENT TESTING INFORMATION ................................................................................................................. 48-56

12. TROUBLESHOOTING .............................................................................................................................................. 57-63

13. ICEMAKER OPEARTING AND TROUBLE SHOOTING METHOD ......................................................................... 64-67

14. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM ........................................................................................... 68-71

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

1-1 LMX28988**

●

28 cu.ft.

ITEMS

DOOR DESIGN

DIMENSIONS (inches)

NET WEIGHT (pounds)

COOLING SYSTEM

TEMPERATURE CONTROL

DEFROSTING SYSTEM

DOOR FINISH

HANDLE TYPE

INNER CASE

INSULATION

DIMENSIONS

SPECIFICATIONS

Side Rounded

/4 X 35 3/8 X 69 3/4 (WXDXH) 28cu.ft.

165 kg. (364 lb)

Fan Cooling

Micom Control

Full Automatic

Heater Defrost

PCM, VCM, Stainless

Bar

ABS Resin

Polyurethane Foam

ITEMS

VEGETABLE TRAY

COMPRESSOR

EVAPORATOR

CONDENSER

REFRIGERANT

LUBRICATING OIL

DEFROSTING DEVICE

LAMP

REFRIGERATOR

FREEZER

SPECIFICATIONS

Clear Drawer Type

Linear

Fin Tube Type

Spiral Condenser

R-134a (145 g)

ISO10 (280 ml)

SHEATH HEATER

LED Module(24)

Depth w/ Handles

Depth w/o Handles

Depth w/o Door

Depth (Total with Door Open)

Height to Top of Case

Height to Top of Door Hinge

Width

Width (door open 90 deg. w/o handle)

Width (door open 90 deg. w/ handle)

Description LMX28988**

35 3/8 in

32 7/8 in

29 in

47 5/8 in

68 3/8 in

69 3/4 in

35 3/4 in

39 1/4 in

44 1/4 in

- 3 -

1-2 LMX25988**

●

25 cu.ft.

ITEMS

DOOR DESIGN

DIMENSIONS (inches)

NET WEIGHT (pounds)

COOLING SYSTEM

TEMPERATURE CONTROL

DEFROSTING SYSTEM

DOOR FINISH

HANDLE TYPE

INNER CASE

INSULATION

DIMENSIONS

SPECIFICATIONS

Side Rounded

/32 X 35 3/8 X 69 3/4 (WXDXH) 25cu.ft.

153kg (337lb)

Fan Cooling

Micom Control

Full Automatic

Heater Defrost

PCM, VCM, Stainless

Bar

ABS Resin

Polyurethane Foam

ITEMS

VEGETABLE TRAY

COMPRESSOR

EVAPORATOR

CONDENSER

REFRIGERANT

LUBRICATING OIL

DEFROSTING DEVICE

LAMP

REFRIGERATOR

FREEZER

SPECIFICATIONS

Clear Drawer Type

Linear

Fin Tube Type

Spiral Condenser

R-134a (130 g)

ISO10 (280 ml)

SHEATH HEATER

LED Module(18)

LED Module(12)

Depth w/ Handles

Depth w/o Handles

Depth w/o Door

Depth (Total with Door Open)

Height to Top of Case

Height to Top of Door Hinge

Width

Width (door open 90 deg. w/o handle)

Width (door open 90 deg. w/ handle)

Description LMX25988**

35 3/8 in

32 7/8 in

29 in

46 3/64 in

68 3/8 in

69 3/4 in

32 23/32 in

36 7/32 in

41 7/32 in

- 4 -

2. PARTS IDENTIFICATION

ADJUSTABLE REFRIGERATOR SHELVING

The refrigerator compartment shelves are adjustable to allow flexibility for storage needs.

GALLON STORAGE BINS

Three interchangeable bins can be arranged to suit your storage needs.

REMOVABLE ICE STORAGE BIN

The ice storage bin can be removed to fill ice buckets, coolers, or pitchers.

LED INTERIOR LAMPS

Two separate LED arrays light the freezer and refrigerator interiors.

CAN STORAGE BIN

FIXED DOOR BINS

- 5 -

3. DISASSEMBLY

Correct

Incorrect

3-1 REMOVING AND REPLACING REFRIGERATOR DOORS

●

Removing Refrigerator Door

CAUTION: Before you begin, unplug the refrigerator. Remove food and bins from doors.

▶

Left Door -FIG. 2

1. Disconnect water supply tube by pushing back on the disconnect ring (3).-FIG. 1

2. Open door. Loosen top hinge cover screw (1). Use flat tip screwdriver to pry back hooks on front underside of cover (2). Lift up cover.

3. Disconnect door switch wire harness and remove the cover.

4. Pull out the tube.

5. Disconnect all 3 wiring harnesses (4). Remove the grounding screw (5).

6. Rotate hinge lever (6) counterclockwise. Lift top hinge (7) free of hinge lever latch (8).

CAUTION: When lifting hinge free from the latch, be careful that door does not fall forward.

7. Lift door from middle hinge pin and remove door.

8. Place the door with the insides facing up, on a not scratch surface.

▶

Right Door -FIG. 3

1. Open the door, remove 1 screw on the top of the hinge cover. Loosen top hinge cover screw (1). Lift up cover (2).

2. Disconnect door switch wire harness and remove the cover.

3. Rotate hinge lever (3) clockwise. Lift top hinge (4) free of hinge lever latch (5).

4. Lift door from middle hinge pin and remove door.

CAUTION: When lifting hinge free from the latch, be careful that the door does not fall forward.

5. Place the door with the insides facing up, on a not scratch surface.

Figure 2 Figure 3

Figure 1

1) Insert the tube until you can see only one of the lines printed on the tube.

2) After inserting, pull the tube to ascertain that it is secure.

3) Assemble clip.

- 6 -

3-2 DOOR

●

Mullion Removal

1. Remove 2 screws.

2. Lift Mullion up carefully.

●

Door Gasket Replacement

1. Insert gasket into channel

Press gasket into channels on the four remaining sides of door.

●

Mullion Replacement

1. Connect wire harness.

3. Disconnect wire harness.

●

Door Gasket Removal

1. Remove gasket

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

2. Insert mullion into the channel.

Insert the cover assembly into bracket, door.

3. Assemble 2 screws.

- 7 -

3-3 Door Alignment

If the space between the door are uneven, follow the instructions to align them. Remove the Base Grillie. Turn the leveling legs counter clock wise to raise or clock wise to lower the height of the front of the refrigerator by using flat blade screw driver or 11/32" wrench. Use the wrench (Included with the User Manual) to adjust the bolt in the door hinge to adjust the height. (CCW to raise or CW to lower the height.)

* Ice Fan Scroll Assembly Replacement

1) Remove the plastic guide on the left side, using a phillips screwdriver to remove the screws.

2) Pull off the sensor cover.

3) Remove the grill cover.

4) Gently pull on the grill assembly to remove.

5) Disconnect the wiring harness.

6) Remove all screws on the scroll assembly.

(1) (2)

(3) (4)

3-4 FAN AND FAN MOTOR(EVAPORATOR)

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

2. Remove the plastic guide for slides on left side by unscrewing phillips head screws.

3. Remove the grille by removing 4 screws and pulling the grille forward.

4. Remove the Fan Motor assembly by loosening 3 screws and disassembling the shroud.

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

FAN MOTOR

Shroud

(5) (6)

3-5 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. At 46F(8°C), it turns the Defrost Heater off. Fuse-M is a safety device for preventing over-heating of the Heater when defrosting.

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

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

GRILLE ASSEMBLY

DEFROST-CONTROL ASSEMBLY

BRACKET

MOTOR

- 8 -

Figure 1

Figure 2

3-6 LAMP

Unplug, or disconnect power at the circuit breaker. If necessary, remove top shelf or shelves.

3-6-1 Refrigerator Compartment Lamp

1) Release 2 screws.

2) Hold both ends and pull down to remove.

3) To remove the lamp case and cover, release 2 screws as shown.

4) Use a flat tool as shown below to remove the lamp cover.

3-6-2 Freezer Compartment Lamp

1. Unplug refrigerator power cord form outlet.

2. Remove screw with driver.

3. Grasp the cover Lamp, pull the cover downward.

3-7 MULTI DUCT

1. Romove the upper and lower caps with a flat screwdriver and remove 2 screws. (Figure 3)

2. Disconnect the lead wire on the bottom position.

5) To remove the LED assembly, pull apart the cover.

Case, lamp

Cover, lamp

LED, Assembly

Figure 3

- 9 -

3-8 MAIN PWB

1) Loosen 3 screws on the PWB cover.

2) Remove the PWB cover

3) Disconnect wire harness and replace the main PWB in the reverse order of removal.

4) Holding the inner side of the dispenser pull forward to remove.

CAUTION: When replacing the dispenser cover make sure the lead wire does NOT come off and the water line is not pinched by the dispenser.

5) Remove the lead wire.

3-10 DISPLAY PCB

As shown below, remove 1 screw on the PCB fixing screw. Remove the display PCB fixing screw.

3-9 DISPENSER

1) Pull out the drain 2) Use these 2 holes to pull out the bottom

3) If nozzle is interfered with button, push and pull out the bottom of button and then pull out the right side.

Case, PCB Display PCB

3-11 ICE BUTTON ASSEMBLY

1) Remove the 1 screw holding the lever.

2) Remove the spring from the hook.

3) Push and pull on the tab to remove.

Button Lever

- 10 -

3-12 WATER BUTTON ASSMEBLY

1) Remove screws.

2) Grasp the Button assembly and lift.

Button Lever

3-13 ICE CORNER DOOR REPLACEMENT

1) Loosen the front screw as shown in the picture.

2) Lift up the hinge with one hand.

3) Pull out the Ice Corner Door with the other hand.

3-14 ICEMAKER REPLACEMENT

1) Remove 4 screws as shown.

2) Grasp the bottom of motor cover assembly and pull slowly.

hinge

3) Disconnect wire harness from wall of compartment.

In-door motor

- 11 -- 11 -

CAUTION: Make sure that the motor housing is taped to

the mold, if not positioned correctly the cover will not fit properly.

3-16 CAP DUCT MOTOR REPLACEMENT

1) Separate the Housing of the Cap Duct Motor.

2) Unscrew 3 screws to disassemble the motor.

3-15 SUB PWB FOR WORKING DISPENSER

1) Disconnect the wire harness.

2) Remove 1 screw from PWB and replace with new PWB.

3) When replacing the motor, check the position of the door duct and the link for proper fit.

Duct Door

Link

Cap Duct Motor

NG Position

4) Insert 2 screws.

5) Push housing aside.

- 12 -

3-17 HOW TO REMOVE A ICE BIN



1) Grip the handles, as shown.

2) Tilt and lift slightly as shown.

3-18 HOW TO INSERT A ICE BIN

1) Insert the Ice Bin, slightly tilting to avoid touching the Icemaker. (Especially, Ice-Detecting Sensor)

3) Remove ice bin slowly.

- 13 -

3-19 HOW TO REMOVE AND REINSTALL THE PULLOUT DRAWER

3-19-1 Follow Steps to Remove

Step 1) Open the freezer door. Step 2) Remove the lower basket.

Step 3) Remove the two screws from the guide rails

(one from each side).

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.

Step 4) Lift the freezer door up to unhook it from the rail

support and remove. Pull both rails to full extension.

NOTE: THIS TAB MUST BE PUSHED IN TO RELEASE THE GEAR.

Pull the Tab from the Motor.

- 14 -

3-19-2 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.

- 15 -

3-20 WATER VALVE DISASSEMBLY METHOD

1) Turn off the water to unit. Remove the waterline from the valve.

3-21 FAN AND FAN MOTOR DISASSEMBLY

METHOD

1) Remove screws for the Drain Pipe Assembly and the 1 connected to the Motor Cover.

MOTOR COVER

Figure 59

2) Remove cover and 1 screw from the valve.

Mechanical Cover

Figure 60

3) Separate the housing and remove the valve.

Housing

Figure 61

4) Remove the clip, and press the collet to separate the tube from the connector. Note: there maybe some water in the line.

Figure 63

2) Separate the Fan Assembly and Motor, turn counter clockwise to remove from the motor shaft.

FAN ASSEMBLY MOTOR

Figure 64

Assemble in reverse order. Taking care to avoid.

1. Do not to bend the tube during assembly.

2. Press the Water Dispenser button letting water pour out, this checks for any leaks in the tube connection, this may vary depending on the water pressure ( about 2 minutes.).

Figure 62

- 16 -

3-22 TOP DRAWER

To remove the freezer drawer, pull the drawer open to full extension. Remove the drawer and Ice Bin lifting the basket from

To remove the freezer drawer, pull the drawer open to full extension. Remove the drawer and Ice Bin lifting the basket from the rail system.

the rail system.

3-23 BOTTOM DRAWER

To remove the freezer drawer, pull the drawer open to full extension. Remove the lower DuraBase ®basket by lifting the basket from the rail system.

- 17 -

4. ADJUSTMENT

❸

❶

❷

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 Note for Usage

(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 Cover PTC Compressor may fail due to breakdown of their insulating capabilities.

(4) Always use the Parts 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. Use only approved substitute parts.

4-1-3 Remove the cover PTC

4-2 INTRODUCTION OF E-LINEAR COMRESSOR

E-Linear compressor is run by mechanical part design through automatically varying the cooling power. The main parts consist of compressor and Sub PCB which controls the compressor. PCB authorizes constant voltage and constant frequency to the compressor and protects it.

4-2-1 Control of Compressor Block Diagram

PWM

Compressor Controller Inverter

Main

Micom

Control Block Diagram of Compressor

Signal

Frequ

-ency

Counter elec-

tromotive force

DC link Voltage

Calculate counter

electromotive force

Linear Comp

Vcap Voltage

(1) Remove the Cover Back M/C

(2) Loosen two screws on comp base

(3) Use a L-shaped flap tooll to pry off the cover (4) Assembly in reverse order of disassembly

4-2-2 Compressor operating pattern

Drive half stroke after turning on initial power for 30 seconds. Then, slowly increase stroke and reach target input. Once reaching the target input, input naturally changes according to refrigerator load without any special control.

Comp. input

Interval 1) Half stroke interval - after initial running, stay at

the initial value for 30 seconds

Interval 2) Running interval - Increase at every 0.8 till it

reaches the target input; it takes about 3’ 45”

Interval 3) CVCF interval - Run by target voltage and main

operating frequency and the input naturally changes according to refrigerator load

- 18 -

4-2-3 Compressor protection logic

Since linear Comp conducts linear reciprocating motion, we have protection logic for compressor, motor and PCB as the below.

- Stroke Trip During the operation, if stroke is above the target value, decrease the target volt by 3V.

- Current Trip Current trip is set in order to protect compressor mechanical part and drive from the overcurrent that might arise during the operation. Check the current for every 416.7us and if the Trip exceeds 1.86Arms more than three times at Comp ON, forcibly stop and restart six minutes later.

4-2-4 Compressor problems diagnosis

When there is a problem or failure with the `operation, you are kindly recommended to check it as follows ;

1) Check to normality by measurement of resistance

Measure the resistance between poles of the hermetic terminal (as shown picture) with a multi-tester. (measurement several minutes after power off)

P : Power Line C : Common Line

Multi-tester

- Lock Piston Trip If stroke is under 5mm even if the current is more than 14Arms, Take it as ‘piston lock’ and restart after 2’30” of Comp OFF. Check the current and stroke for every

416.7us and if the condition fits more than three times at Comp ON, the Trip occurs.

- IPM fault Trip It occurs if FO signal received from IPM is LOW. For every 416.7us, check whether FO signal is LOW. The trip occurs if it is found three times during the five periods(83ms).

Case 1-1 If the measured values lie in the normal resistance range as in the table below,

Compressor is normal.

Case 1-2 If the measured values are above several M

Wire is disconnected in the shell.

Case 1-3 If the measured values are excessively of small number,

There is short somewhere in the shell.

Normal resistance range (measured at ambient temperature 23℃)

Resistance

FC75LANE

According to ambient temperature or operation situation, the values could show a little deviation.

6~8

Ω

or a infinity,

- 19 -

2) Check to normality by measurement of Voltage

3) Check problems by LED On & Off Count _ (Sub PCB)

Measure the resistance between pin of the connector (as shown picture) with a multi-tester.

<Fig. 1> <Fig. 2>

Standard for normality

- In order to decide whether compressor operating is normal or not, check the output transfer during the refrigerator operation.

- After input the initial power and compressor operates, wait for 10 minutes to estimate.

- Compressor operation may be diagnosed as normal if the voltage falls between 145V and 180V.

Warning

1. Please be cautious of electric shock and short (it is

estimated after turning on initial power).

2. If the voltage is estimated less than 80V, it is diagnosed

as bad.

If compressor protection logic is running, LED Lamp’s blinking frequency of sub PCB, which takes in charge of control, can help estimate the protection logic’s symptoms and the cause of its problems.

Trip name

Stroke Trip

Current Trip

Lock Piston Trip

IPM fault trip

- Current Trip PCB defects or Cycle clogging maybe the causes. After estimating winding resistance, estimate compressor operation voltage to check if there is any problem and take actions to repair cycle at replacement of compressor.

- Stroke Trip temperature is high, C-Fan, F-Fan and so on are constrained, or when cycle problems, such as moisture blocking or compressor defect, are related.

- Lock Piston Trip potential cause of a defect, estimate the compressor resistance value according to #1’s compressor winding value estimation method and estimate the #2’s compressor operation voltage to decide whether it is defective or not (Before replacement of compressor, replace PCB and conduct the replacement of compressor during compressor replacement)

can occur when the surrounding

Led Times

Since compressor itself can be a

Comp Off Time

1min

6min

2min 30sec

20sec

- IPM fault Trip chance that it is caused by sub PCB’s part defect.

Replace sub PCB since there is high

- 20 -

5. CIRCUIT DIAGRAM

5-1 LMX28988**

- 21 -

5-2 LMX25988**

- 22 -

6. TROUBLESHOOTING

6-1 Error Code Summary

WARNING: When checking Resistance values, make sure to

turn off the power, and wait for the voltage to discharge.

NOTE) Within 3 hours after the error : Press the Ice Plus button and Freezer button simultaneously

3 hours after the error : All errors, except for "Er rt", "Er SS", "Er IS(except for Icing sensor)", "Er gF", "Er It" error, are displayed. "Er IS" which is displayed without input of user is the error of Icing Sensor.

Error Display

Error Detection

LG LMX28988 Series, LMX25988 Series, LMX28988ST, LMX28988SB, LMX28988SW Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual