LG GR-389SQF Service Manual ▷ View online
3. SENSOR RESISTANCE CHARACTERISTICS TABLE
¥ The tolerance of sensor resistance is ±5%.
¥ Be sure to measure the sensor resistance after keeping the sensor more than 3 minutes at a measuring temperature.
(It needs delay due to sensor speed.)
¥ Measure the resistances of SENSORs with a digital tester after disconnecting CON 4 of MAIN PWB ASSY.
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MEASURED TEMPERATURE
RESISTANCE OF FREEZER SENSOR
RESISTANCE OF DEFROST SENSOR, ROOM TEMPERATURE SENSOR
-20¡C
22.3k½
77k½
-15¡C
16.9k½
60k½
-10¡C
13.0k½
47.3k½
-5¡C
10.1k½
38.4k½
0¡C
7.8k½
30k½
+5¡C
6.2k½
24.1k½
+10¡C
4.9k½
19.5k½
+15¡C
3.9k½
15.9k½
+20¡C
3.1k½
13k½
+25¡C
2.5k½
11k½
+30¡C
2.0k½
8.9k½
+40¡C
1.4k½
6.2k½
+50¡C
0.8k½
4.3k½
4. MAIN PWB ASS'Y AND PARTS LIST
1) MAIN PWB ASS'Y
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DIP
CE1
+
CM1
CM2
+
+
CE2
CE6
CE3
+
J06
J07
J01
+
IC3
CC1
CC2
CE4
+
CE5
D5
OP2
R21
OP1
R20
CC4
R6
CC10
R19
J05
J10
J11
J02 R7 J04
RF3
R10
R1
CC8
CC7
R16
R15
R17
RF2
RF1
TEST
R13
R12
R11
IC4
J09
IC1
CC3
J08
6871JB1037
STICKER
J12
Q1
J13
Q2
J14
Q3
R14
CC6
CC5
OSC1
R8
R9
CC9
1
D
6
R-DOOR
F
CON3
RT-SENSOR
9
1
CON2
98 12
COMP
F-FAN
D-HEATER
CON1
VA1
RY2
RY3
RY1
D8
D7
J15
D6
R4 R18 R3
BUZZER
Q4
IC6
TRANS
D1
D3
D4
D2
IC2
Air Recharging in Compressor
Test the refrigeration by connecting it electrically before
refilling operation. It is necessary to ascertain the function
of the motor-compressor and identify the defects
immediately. If defects have been found, empty the old
system of possible R134a residue by breaking off the end
of the extension piece at its narrow point. (Figure 1)
Replace the filter and any damaged components. Unsolder
and pull off the piece remaining inside the service tube and
then attach an complete extension with male Hansen and
at last, solder it to the same tube again. (Figure 2)
refilling operation. It is necessary to ascertain the function
of the motor-compressor and identify the defects
immediately. If defects have been found, empty the old
system of possible R134a residue by breaking off the end
of the extension piece at its narrow point. (Figure 1)
Replace the filter and any damaged components. Unsolder
and pull off the piece remaining inside the service tube and
then attach an complete extension with male Hansen and
at last, solder it to the same tube again. (Figure 2)
It is necessary to execute the soldering operation with
valve open so that the fumes caused by oil residue can
come out freely without blowholes between two tubes
during the heating of the point to be soldered.
The extension fitted with the male Hansen is connected to
the female fitting of the vacuum pump tube. (Figure 3)
valve open so that the fumes caused by oil residue can
come out freely without blowholes between two tubes
during the heating of the point to be soldered.
The extension fitted with the male Hansen is connected to
the female fitting of the vacuum pump tube. (Figure 3)
Air evacuating from the system begins as soon as the
pump starts. The refrigeration system must be kept under
vacuum until the reading on the low-pressure gauge
indicates vacuum (0 absolute, -1 atm., -760 mm hg) in any
case it is advisable to keep the pump running for about 30
minutes. (Figure 3)
In case that a considerable leakage occurs it will be
necessary to stop the vaccum pump and to add a small
quantity of Freon to the system, if vacuum should not be
obtained (pressure gauge can't fall to 1 atmosphere), start
the refrigeration unit and find the leakage with the special
leak-finder. When the defective soldering point is visible,
re-do it after opening the extension tube valve and
reestablishing the normal outside pressure inside the
group.
Because the melted alloy is sucked into the tubes and
block them, the pressure must be rebalanced when
vacuum is in the system in soldering. As soon as the
pump starts. The refrigeration system must be kept under
vacuum until the reading on the low-pressure gauge
indicates vacuum (0 absolute, -1 atm., -760 mm hg) in any
case it is advisable to keep the pump running for about 30
minutes. (Figure 3)
In case that a considerable leakage occurs it will be
necessary to stop the vaccum pump and to add a small
quantity of Freon to the system, if vacuum should not be
obtained (pressure gauge can't fall to 1 atmosphere), start
the refrigeration unit and find the leakage with the special
leak-finder. When the defective soldering point is visible,
re-do it after opening the extension tube valve and
reestablishing the normal outside pressure inside the
group.
Because the melted alloy is sucked into the tubes and
block them, the pressure must be rebalanced when
vacuum is in the system in soldering. As soon as the
vacuum operation is over, add the quantity in grams of
R134a to the refrigeration system. Remember that every
system has an exact quantity of R134a with a tolerance of
±5 grams that can be added. (Figure 4)
R134a to the refrigeration system. Remember that every
system has an exact quantity of R134a with a tolerance of
±5 grams that can be added. (Figure 4)
Before performing this operation (if the vacuum pump and
refilling cylinder are connected), make sure that the valve
placed between the vacuum pump and the refilling tube are
closed in order to keep the Freon for addition to the system.
(Figure 5)
refilling cylinder are connected), make sure that the valve
placed between the vacuum pump and the refilling tube are
closed in order to keep the Freon for addition to the system.
(Figure 5)
In addition, check the graduated scale on the cylinder for
the quantity of R134a to be added, for example, if we have
750 grams of Freon in the cylinder and must add 165
grams to the group, this amount will be reached when R-
134a has dropped to 585 grams, remembering that the
indicator shows a lower limit of meniscus. Do this after
choosing the scale corresponding to the gas pressure
different scales reported as the same gas pressure
indicated by the pressure gauge on the top of the column.
To make R134a flow into the system, open the valve
placed at the base of the cylinder and connected to the
filling tube. The amount of Freon cannot be added to the
system all at once because it may cause a blocking of
the motor-compressor. Therefore, proceed by adding the
original quantity of about 20-30 grams and close the valve
immediately.
The pressure rises and the motor compressor must start
sucking the gas and lowering the pressure again.
Regulate the valve again, in the safe way until reaching the
quantity of R134a established for the system being
charged. When the system is running, the suction pressure
must be stabilized between 0.30 to 0.6 atmosphere.
the quantity of R134a to be added, for example, if we have
750 grams of Freon in the cylinder and must add 165
grams to the group, this amount will be reached when R-
134a has dropped to 585 grams, remembering that the
indicator shows a lower limit of meniscus. Do this after
choosing the scale corresponding to the gas pressure
different scales reported as the same gas pressure
indicated by the pressure gauge on the top of the column.
To make R134a flow into the system, open the valve
placed at the base of the cylinder and connected to the
filling tube. The amount of Freon cannot be added to the
system all at once because it may cause a blocking of
the motor-compressor. Therefore, proceed by adding the
original quantity of about 20-30 grams and close the valve
immediately.
The pressure rises and the motor compressor must start
sucking the gas and lowering the pressure again.
Regulate the valve again, in the safe way until reaching the
quantity of R134a established for the system being
charged. When the system is running, the suction pressure
must be stabilized between 0.30 to 0.6 atmosphere.
POINT TO BE
BROKEN
BROKEN
CHARGE TUBE
EXTENSION
EXTENSION
FEMALE
HANSEN
HANSEN
MALE HANSEN
SOLDERING POINT
SERVICE TUBE EXTENSION
Figure 1
Figure 2
TO THE VACUUM
PUMP
PUMP
PRESSURE
GAUGE
GAUGE
Figure 3
TO THE R134a CYLINDER
TO THE REFRIGERATION
SYSTEM
SYSTEM
Figure 4
FILLING OR
CHARGE TUBE
CHARGE TUBE
VALVE TO BE OPENED
WHEN REFILLING
WHEN REFILLING
VALVE TO BE CLOSED
AFTER VACUUM
AFTER VACUUM
TO THE VACUUM PUMP
TO THE REFRIGERATION
SYSTEM
SYSTEM
TO THE CHARGE
CYLINDER
CYLINDER
Figure 5
SERVICING PRECAUTIONS
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2) REPLACEMENT PARTS LIST
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