LG GR-382R User manual

SERVICE MANUAL
REFRIGERATOR
ATTENTION
Before start servicing, carefully read the safety instructions
in this manual
MODEL(S): GR-382R
LRTP1231W

1
Contents
Safety Precautions ----------------------------------------------- -------------------------------------- 1
Service Precautions ----------------------------------------------------------------------------------- 2-3
Specifications ------------------------------------------------------------------------------------------- 4
Feature Chart ------------------------------------------------------------------------------------------- 5
Circuit Diagram ------------------------------------------------------------------------------------------ 6-7
Cooling Systems ---------------------------------------------------------------------------------------- 8
Product Disassembly ---------------------------------------------------------------------------------- 9-11
Doors ------------------------------------------------------------- ----------------------------------------- 9
Door Switch ---------------------------------------------------------------------------------------------- 9
Electronic Control Display PCB ----------------------------------------------------------------- --- 9
Freezer Fan ---------------------------------------------------------------------------------------------- 10
Defrost Control ------------------------------------------------------------------------------------------ 10
Lamp ------------------------------------------------------------------------------------------------------- 10
Refrigerator Control Box ------------------------------------------------------------------------------ 11
Reversible Door --------------------------------------- --------------------------------------------------- 12-13
Adjustments ----------------------------------------------------------------------------------------------- 14-15
Compressor ---------------------------------------------------------------------- ------------------------ 14
PTC Starter----------------------------------------------------------------------------------------------- 14
Overload Protector (OLP) ---------------------------------------------------------------------------- 15
Troubleshooting ----------------------------------------------------------------------------------------- 16-21
Compressor & Electrical Components ------------------------------------------------------------ 16
PTC & OLP ------------------------------------ ---------------------------------------------------------- 17
Other Electrical Components ----------------------------------------------------------------------- 18
Service Diagnosis Chart ------------------------------------------------------------- ----------------- 19
Refrigerant Cycle --------------------------------------------------------------------------------------- 20-21
MICOM circuit & operation --------------------------------------------------------------------------- 22-39
Refrigerator Exploded View-------------------------------------------------------------------------- 40-41
Service Parts list----------------------------------------------------------------------------------------- 42-43
Safety Precautions.
Read the following inst ructions before servicing your refrigerator.
1. Unplug the refrigerator before
servicing.
2. Visually inspect for gas leakage or
short circuit.
3. If testing with the refrigerator
plugged in, wear rubber gloves to
avoid electric shock.
4. Do not touch frozen metal parts;
your hands could freeze to the
surface. This may cause frostbite.
5. Be sure that no water is dripping
towards electrical or metal parts.
6. If you check the bottom part of the
refrigerator while the freezer
door is open, be careful standing
up. You could bump your head.
7. When you tilt your refrigerator be
sure to take out all metal, glass, or
other loose parts.
8. When servicing the evaporator,
wear cotton gloves to prevent cutting
by any of the evaporator fins.

Refrigerant Recharging
Test the compressor's operation before
recharging the refrigerant; this is very
important to detect failures and to
ensure the proper motor running, and
to identify failures immediately. If
failure has been detected, clean the
system from any other possible
R-134a residues by breaking the final
part of the compressor's service pipe
at it's thinnest part as shown in Fig. #1.
Replace the filter and any other part
that could be deteriorated. Unweld
and pull out the service pipe,
then place a new pipe extension with a
Hansen male connector and solder
the new pipe. See Fig. #2
Service Precautions
2
It is necessary to open the valve
when soldering to allow the gases to
escape without forcing the molten
solder out of the joint. The extension
with the male Hansen connector
should be connected to a female type
connector to the vacuum pump's pipe.
See Fig. #3
System air evacuation starts as soon
as the pump begins to run. The
system must be kept under vacuum
until the low pressure gauge shows
0(absolute or -1 atm, -760 mm Hg.) It
is not recommend to run the vacuum
pump for more than 30 minutes. See
Figure 3.
In case there is a large leak and the
vacuum operation must stop,
you must add a small amount of
refrigerant to the system and check
with an electronic leak detector. If a
soldering failure is detected, open the
valve before soldering to equalize the
pressure and keep solder from being
blown out of the joint or sucked into
the piping.
As soon as the repair is completed,
charge the correct amount of
refrigerant into the system.
Remember that each system requires
a specific amount of refrigerant with a
tolerance of ±5 grams. See Figure 4.
Before performing this operation (if
the vacuum pump and charging
cylinder are still attached to the
system) be sure the valve between
the pump and the cylinder is closed to

keep refrigerant out of the system.
See Figure 5.
For gas charging, check the
graduated scale on the cylinder to see
the amount of refrigerant that it
contains and the amount that will be
pumped into the system. For
example, if you have 750 grams of
refrigerant in the cylinder and we
have to pump 165 grams to the
system, this amount will be reached
when the indicator reaches 585
grams; remember that the indicator
shows a lower level of meniscus.
Do this after choosing the scale
corresponding to the gas pressure
indicated on the pressure indicator
located on the upper part of the
column. To let R-134a flow into the
system, open the valve at the
recharging cylinder's base. The total
amount of refrigerant should not be
Service Precautions
installed in one session, as it could
block the compressor. Install 20~30
grams at a time and close the valve.
The compressor will run and the
pressure will drop. Then open the
valve and install other 20~30 grams
of refrigerant. Repeat this procedure
until the entire amount has been
added to the system. Under operating
conditions, the system pressure
should stabilize between 0.3 and 0.6
atm.
3

5
Feature Chart
Temperature
Control
Ice Trays
Twist´n Serve
Shelf
Magic Crisper
(Vegetable Tray cover
that control humidity)
Refrigerator
Door Baskets
Freezer
Door Baskets
REFRIGERATOR
FREEZER
Temperature
Control
Fresh Meat
Tray
Lamp
Shelves
(Plastic or Glass)
Deodorizer
(Absorbs
Odors)*
Multi Air Flow
Air flow distributor
Vegetable Tray
(Keeps fruits and
vegetables fresh)
Leveling
Screws
MODEL(S): GR-382R
LRTP1231W
* This part is only included in model LRTP1231W

Graphic Circuit Diagram
White
White
Fan
Thermal Fuse
C
C
Evaporator
Defrost Resistance
(Heater Cord)
Sensor
Red
Blue
Orange
Orange
Brown
Red
c
Control
Brown
Red
Pink
Yellow
Blue
Violeta
Whitte
White
Defrost and Temperature Electronic Control
Orange
Orange
Sensor
Sensor
Red
Black
Black
Brown
Violet
Lamp
Switch Yellow
Blue
Defrost Resistance
Red
Brown
CON1
Yellow
Blue
Blue
Blue
Brown
Blue
Yellow
Black
M
Pink
OLP
Fan
Motor
Blue
Running Capacitor
Blue
Pink
COMPRESSOR
CON2
Black
AC Current
7

Cooling Systems
Direct System Indirect System
Important: Check that the air ducts are not
obstructed for a better cooling
performance.
Temperature variation during defrosting time, depending upon the cooling system .
Cold Air Warm Air
Temp.( ?) Refrigerator
Freezer
Indirect System
Direct System
Temp.( ?)
Tim
e
Tim
e
3
4
18
3
-18
-3
-18
-16
8

9
3. Product Disassemble.
Doors
Freezer Door
1. Remove hinge cover by pulling it
upwards.
2. Loosen the hexagonal bolts that
hold the upper hinge in place. See
Figure 1.
3. Remove door. See Figure 2.
Figure 2
Figure 1
Figure 4
Figure 3
4. Pull gasket to remove it. See
Figures 3 and 4.
Refrigerator Door.
1. Loosen the hexagonal bolts that
hold the central hinge in place.
See Figure 5.
2. Remove refrigerator door. See
Figure 6.
3. Pull out the gasket to remove it
from the door. See Figure 4 from
Freezer door.
Figure 6
Figure 5
Door Switch
1. Pull out the door switch out using
a flat head screwdriver. See
Figure 7
2. Disconnect all switche's cables.
See Figure 8
Figure 7 Figure 8
Control Circuit ( Display PWB)
1. Remove the lamp cover by
inserting a screwdriver in the lower
side's holes. See Figure 9.
2. Loosen and remove the 2 screws.
See Figure 10.
Figure 9 Figure 10
3. Pull out the Control Box. See
Figure 11.
4. Disconnect the connector from the
cable terminal. See Figure 12.
5. Remove the EPS Multi air duct
(insulation) from the control box.
6. Detach the electronic control
(Display, PWB). See Figure 13.
Figure 11 Figure 12

10
Figure 13
Fan and Fan Motor.
1. Remove freezer shelf.
3. Remove the ice bin assembly by
pulling it to the right side, until it
snaps out.
4. Remove Grill Fan screw cover.
See Figure 14.
5. Loosen the screw. See Figure 15.
6. Pull out the fan cover. Figure 16.
Figure 14 Figure 15
6. Unplug the connector.
7. Remove the fan holder shroud.
Figure 17.
8. Remove fan and loosen both
screws that hold the bracket.
9. Remove the motor bracket and the
rubber parts. Pull out the fan
motor. See Figure 17.
Figure 16 Figure 17
Defrost Control Assembly
1. The defrost control assembly
consists of one thermistor and a
fuse that melts with heat.
2. The termistor's function is to
sense the compartment's
temperature and automatically
stop the defrost. The termistor is
located beside of the evaporator
bracket.
3. The melting fuse is a safety device
to prevent an overheating of the
defrosting resistance when it
operates.
4. The fuse melts at 162° F and the
resistance heater stops.
5. To replace this components,
please follow the steps mentioned
at Figure 18.
Lamp.
Refrigerator Compartment Lamp
1. Remove the lamp cover with
a screwdriver or a similar tool.
See Figure 19.
2. Remove the lamp by unscrewing it
counterclockwise and replace it
with the same specifications
(125V,20W). Part Number
6912JB2002J.
1. Figure 18. Unplug the connector plugged to

11
Figure 13
Refrigerator Control Box.
Remove the lamp cover as mentioned
before.
1. Loosen the screws.
2. Remove the entire control box.
See Figure 20.
3. Disconnect the control box
connector. See Figure 21.
Figure 19
Figure 20 Figure 21

12
4. Reversible Door
PRECAUTION
1. Before reversing the doors, remove all foods and accesories,
like shelves or trays, which are not attached to the doors.
2. Use a Philips screwdriver, bolt driver, torque wrench, or spanner to
tighten and loosen the bolt.
3. Be careful not to drop the refrigerator or door when assembling or
disassembling lower hinge or the Adjustable Screw Assembly.
4. Don´t lay the refrigerator down to work on it. It will cause
malfunction.
5. The doors may be reversed to provide left or right opening, depending upon the customer´s
preference.
HOW TO REPLACE THE DOOR OPENING LEFT TO RIGHT
(when converting from left-opening to right opening)

13

14
5. Adjustments
1- COMPRESSOR
1-1 Function
The compressor sucks low pressure
evaporated gas from the evaporator
and compresses it into high
temperature/high pressure gas and
sends it to the condensor.
1-2 Composition
The compressor includes the
compressing system, a motor, and an
enclosure. The PTC (thermistor) and
OLP (Overload Protection Device) are
attached to its exterior. Handle and
repair the compressor with care. It
includes parts manufactured to 1
micron tolerance, and is hermetically
sealed to exclude dust or humidity
after fabrication. Dust, humidity, or
flux getting into the refrigeration cycle
could clog it or otherwise affect the
cooling.
1-3 Use notes.
(1) Protect your refrigerator from over
currents or overloads.
(2) Do not bump or jar the
compressor. If it is bumped or
forced (dropping or careless
handling,) it could damage the
compressor or cause noise or
undesirable operation.
(3) Use only exact replacement parts
when repairing the compressor. If
the terminals become corroded, it
could affect operation. If the
replacement parts are of incorrect
values, operation and safety will
be compromised.
2- PTC
2-1 PTC Composition
(1) The PTC (Thermistor) is a
semiconductive starting
component that is made with
BaTiO .
3
(2) The higher the temperature, the
higher the resistance value will be.
This characteristic is used for
starting the motor.
2-2 PTC Function
(1) The PTC is attached to the
hermetic compressor and its used
for its starting.
This household refrigerator uses a
single induction motor. During
normal operation, the motor starts
with current flowing through both
the main and the auxiliary
windings. After the motor starts,
current to the auxiliary winding is
cut off.
2-3 PTC- Electric Diagram
According to motor starting method.

15
2-4 Motor restarting and PTC cooling.
(1) To restart normal operation after a
power interruption, wait 5 minutes
to let the pressure equalize and
the PTC to cool.
(2) During normal operation, the PTC
generates heat. If it has not had
time to cool after a power
interruption, the motor will not
restart until the PTC cools.
2-5 PTC OLP Relation
(3) If power is cut off during
compressor operation and then
restored before the PTC has
cooled down, it's resistance value
increases. As a result, the current
cannot flow to the auxiliary
winding and the motor cannot start
and the OLP operates due to the
current overflow through the main
winding.
(3) While the OLP repeats the
ON/OFF operation 3~5 times, the
PTC cools and the compressor
operates normally. If the OLP
does not operate when the PTC is
hot, the compressor motor will
overheat, causing a short circuit or
possibly a fire. Therefore, use a
fail-safe OLP.
2-6 Note on using the starting PTC
(1) Be careful not to cause an
overvoltage or short circuit.
(2) Do not force or bump it.
(3) Keep the OLP dry. If water or oil
gets into the OLP, the electrical
insulation can degrade and fail.
(4) Do not replace the PTC at your
own convenience. Do not
disassemble the PTC. If the PTC's
exterior is damaged, the
resistance value changes and
may cause failure during the
stating of the compressor's motor.
Use a PTC in good condition.
3- OLP
3-1 OLP Definition
(5) The OLP is a bimetallic, heat-
sensitive switch attached to the
compressor. Its function is to
protect the motor in the event of
overheating.
(6) When an overvoltage flows to the
motor, the bimetal reacts by
heating and activating (opening)
the OLP.
3-2 OLP Function
(7) Prevents the starting to the motor
winding.
(8) Do not turn the adjustment screw
during normal OLP operation.
(OLP connection diagram)

6. Troubleshooting
6-1 COMPRESSOR AND ELECTRIC COMPONENTS
Power Source. Remove the PTC-Starter
from the Compressor
and measure the voltage
between Terminal C of
Compressor and
Terminals 5 or 6 of PTC.
(Rating Voltage
Go to Step 2
No Voltage. OLP disconnected?. Replace OLP.
Check connection
condition.
Reconnect.
Go to Step 5
Applied voltage isnÿ´tin
the range of Rating
Consult a qualified
electrician. Go to Step 5
NO
YES
2
Check the
resistance of
Motor
Compressor.
Check the resistance
among M-C, S-C and M-S
in Motor Compressor.
Replace
Compressor.
Go to Step 3
Go to Step 3
Go to Step 4 Go to Step 5
3
Check the
resistance of
PTC-Starter.
Check the resistance of
two terminals in PTC-
Starter.
Go to Step 4
Replacce
PTC-Starter. Go to Step 5
NO
NO
YES
4
Check OLP. Check if applying a
regular OLP.
OLP works within 30
seconds In forcible
OLP operation by
turning against power
on and off. Replace OLP.
Go to Step 5
NO
YES
Check
starting state.
Measure minimum starting
voltage after 5 min. for
balancing cycle pressure
and cooling the PTC.
5
Components start in
the voltage of Rating
O.K.
Go to Step 1
1
16
10%)
Voltage 10%.
Voltage 10% below.

6-2 PTC AND OLP
YES
NO
Normal operation of
Compressor is
impossible or poor.
Separates the PT
from Compressor and
measure the
resistance between
No. 5 and 6 (only
RSIR Type) or No. 4
and 5 of PTC with a
Tes ter or Wheatstone
Bridge (Figure 22).
Observation value is
220V/50Hz: 22 W±30%
115V/60Hz: 6.8 W±30%
240V/50Hz: 33 W±30%
127,220V/60Hz:22 W±30%
Check the other
electric components.
Separate the OLP
from Compressor and
check resistance value
between two terminals
of OLP with a Tester.
(Figure 23).
Replace PTC.
The Resistance value
is 0 or several
hundreds W
The value is ?
Check other electric
components.
Replace OLP
17

6-3 OTHER ELECTRIC COMPONENTS
No Cooling
Compressor
doesn´t run.
Cause
Check if current flows to
the following components.
a. Starting Devices Shorted or Broken
b. OLP Poor contact or shorted.
c. Compressor coil Coil Shorted.
d. Circuit Parts Poor contact or shorted. Replace each
component.
Running state of
Compressor is poor.
The items
described above
are normal.
Check capacity of
OLP.
Check current
flowing in sub-coil
of Compressor.
Check if current
flows to starting
devices.
Check starting
voltage.
Replace the
defective
component.
Raise the voltage.
Replace the
Compressor.
Compressor
Motor Coil.
Lack of Capacity
Shorted
Poor contacting
and broken.
Low Voltage
Fan Motor doesn´t
run.
Checker current
flow of the door
switch.
Check current
flowing in the fan
motor.
Poor contact
Coil is shorted
Replace the
defective
component.
Much frost is on the
evaporator.
Check current flow
of the following
components:
· Defrost Control
Check current flow
of the following
components:
· L-CORD, TE-PLATE
Shorted Replace PTC.
Replace PTC.
18

COMPLAINT POINTS TO BE CHECKED REMEDY
No Cooling
1. Is the power cord unplugged?
2. Check if the power switch is set to OFF.
3. Check if the fuse of power switch is
shorted.
4. Measure the voltage of power outlet.
· Plug it to the outlet.
· Set the switch to ON.
· Replace a regular fuse.
· If the voltage is low, check the wiring or
call an electrician.
Poor Cooling
1. Check if the refrigerator is placed close
to a wall.
2. Check if the refrigerator is placed close
to a stove, oven or in indirect sunlight.
3. Is the ambient temperature high or the
room door closed?
4. Check if putting in hot food.
5. Did you open the refrigerator door too
often?
· Place the set with the space of about 10
cm.
· Place the set apart from these heat
sources.
· Is the ambient temeperature within spec?
(above 10°C or 40°F )
· Put food in after it cools.
· Don´t open the door too often and close it
firmly.
Poor Freezing
1. Is the ambient temperature too low?
10°C (40°F).
2. To make the freezer colder, set the COLD
AIR CONTROL to 7and set the Rcontrol
button (PWB) to MAX.
Food in the refrigerator
is frozen
3. Is food buckling the cooling air outlet?
4. Check if the PWB is set to MAX.
5. Place food in high temperature section
(Front Part).
6. Set the button to MID.
Moisture or ice forms in
the chamber of the set.
7. Is watery food kept?
8. Check if putting in hot food.
9. Did you open the refrigerator door too
often?
10. Seal watery food with vinyl wrap.
11. Put food after it cools.
12. Don´t open the door too often and close it
firmly.
Moisture forms on the
outside
13. Check if ambient temperature and
humidity are high.
14. Is there a gap in the door gasket?
15. Wipe moisture with a dry cloth.
16. This does not occur if the temperature
and humidity are in the normal range.
17. Fix the gap.
Abnormal Noise
18. Is the refrigerator positioned in a firm
and even place?
19. Is something in the way behind the
refrigerator?
20. Check if the evaporating tray cover is
left off.
21. Check if the cover of mechanical room
in below and front sides is taken out.
22. Adjust the leveling screws. Position the
refrigerator properly.
23. Remove the objects.
24. Replace the tray.
25. Replace the cover.
Door doesn´t close well.
26. Check if the door gasket area has
become dirty or contaminated.
27. Is the refrigerator placed in a firm and
even place?
28. Is too much food put in the refrigerator?
29. Clean the door gasket.
30. Position the refrigerator in a firm place
and adjust the leveling screws.
31. Keep food from reaching to the door.
Ice and food smell
unpleasent.
32. Check if the inside of the refrigerator
becomes dirty.
33. Did you keep fragrant foods without
wrapping?
34. It smells plastic.
35. Clean the inside of the refrigerator.
36. Wrap fragrant food.
37. The new refrigerator smells of plastic, but
the odor will dissipate after a couple of
weeks.
In addition to the items described above, refer to the following to solve the complaint.
Check if frost forms
in the Freezer.
Check Refrigerating
Cycle.
Defrosting is poor.
The cycle is faulty.
Replace the
componets of the
defrosting circuit.
Repair the cycle.
6-4 SERVICE DIAGNOSIS CHART
19