LG GA-B379U*QA Service Manual Download Page 28

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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 3 of

MAIN PCB ASSY.

MEASURED TEMPERATURE

RESISTANCE OF FREEZER SENSOR

RESISTANCE OF DEFROST SENSOR, ROOM TEMPERATURE SENSOR

Ω

77k

Ω

60k

Ω

47.3k

Ω

38.4k

Ω

30k

Ω

24.1k

Ω

19.5k

Ω

15.9k

Ω

13k

Ω

11k

Ω

8.9k

Ω

6.2k

Ω

4.3k

Ω

4. MAIN PCB ASS'Y AND PARTS LIST

1) MAIN PCB ASS'Y

CE1

CM1

CM2

CE2

CE3

IC3

C2C

C1C

CE5

CE7

J06

CC3

J08

CC9
CC5

STICKER

C6C

OSC1

RF2

R10

IC1

R-DOOR F

CON3

R19

CC4

CC10

R15

R16

CC8

CC7

CON2

COMP

FAN

HEATER

LAMP

CON1

VA1

RY2

RY3

RY1

J01

7R F

IC6

TRANS

D1 D2 D3 D4

IC2

TEST

R17
R20

J09

R21

OP1
OP2

.6MM

DS-1107A

Summary of Contents for GA-B379U*QA

Page 1: ...REFRIGERATOR SERVICE MANUAL MODEL GA B409U QA B379U QA CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL http biz lgservice com ...

Page 2: ......

Page 3: ... kind of appliance check regular current voltage and capacity 5 Don t touch metal products in the freezer with wet hands This may cause frostbite 6 Prevent water from following to electric elements in the mechanical parts 7 When standing up after having checked the lower section of the refrigerator with the upper door open move with care to avoid hitting the upper door 8 When tilting the set remov...

Page 4: ...HARGE CYLINDER TO THE VACUUM PUMP PRESSURE GAUGE Features of refrigerant R600a Achromatic and odor less gas Flammable gas and the ignition explosion at 494 C Upper lower explosion limit 1 8 8 4 Vol Features of the R600a refrigerator Charging of 60 refrigerant compared with a R134a model The suction pressure is below 1bar abs during the operation Because of its low suction pressure the external air...

Page 5: ...r 3 EA COMPARTMENT Ice Tray 1 EA COMPRESSOR PTC Starting Type EVAPORATOR Fin Tube Type CONDENSER Side Wire Condenser Optional Parts ITEMS SPECIFICATIONS DIMENSIONS mm 595 W X651 D X1726 H NET WEIGHT kg 69 COOLING SYSTEM Fan Cooling TEMPERATURE REFRIGERATOR Knob Dial CONTROL FREEZER Button DEFROSTING SYSTEM Full Automatic Heater Defrost DOOR FINISH Pre Coated Metal or Vinyl Coated Metal OUT CASE Pa...

Page 6: ...2 or 3 Lamp Multi air Flow Duct Tray Meat Optional Refrigerator Temperature Control Vegetable Drawer Used to keep fruits and vegetables etc fresh and crisp Ice Cube Tray Freezer Compartment Removable Plinth Rotatable Door Basket 3 or 5 Utility Corner movable Leveling Screw Egg Tray Handle Door Basket Bottle 2 Door Swich ...

Page 7: ... separating the screw then install the door stop on the corresponding position on the left Separate the screw then separate the hinge upper right Hinge Upper 15 16 17 18 19 22 23 24 15 23 12 5 7 6 11 8 10 9 14 13 16 24 2 1 4 3 2 3 2 20 17 18 22 21 19 19 27 28 29 24 25 34 23 26 18 10 9 17 5 6 11 33 3 2 3 2 23 23 23 24 25 26 4 Remove two small caps on the front of the cover front with a screw driver...

Page 8: ...p cover 1 Using the driver remove two small cap of the front 3 Disconnect Lead Wire from switch 4 Disengage hook behind the switch by pressing it with hands 4 DISPLAY 3 After removing the lamp you must check the O RING which is made by rubber and prevent electric spark in the socket 2 Pry the display s cover from the gap between the display and display cover by using a screw driver Then pull out t...

Page 9: ...heat from the Heater 1 Pull out the Shroud F after removing the Grille 2 Separate the connector connected with the Defrost Control Assy and replace new one 6 DAMPER CONTROL 1 Remove the Cover Lamp R and loosen 2 screw 2 Pull the Control Box R and separate the lead wire housing 3 Remove the Cover Lamp R 4 Separate the Insulation Multi Duct and Control Box R 5 Disassemble the Knob 7 HEATER SHEATH In...

Page 10: ...tion of the single phase induction motor in the starting operation current flows in both main coil and sub coil After the starting is over the current in subcoil is cut off The proper features of PTC play all the above roles So PTC is used as a motor starting device 3 PTC Applied Circuit Diagram According to Starting Method for the Motor 4 Motor Restarting and PTC Cooling 1 For restarting after po...

Page 11: ... protects Motor by cutting off current which flows to the Compressor Motor 2 Role of the OLP 1 The OLP is attached to the Hermetic Compressor used for the Refrigerator and Show Case and prevents the Motor Coil from being started in the Compressor 2 Do not turn the Adjust Screw of the OLP in any way for normal operation of the OLP Composition and connection Diagram of OLP CONTACTING POINT COVER BIM...

Page 12: ...use a regular Trans Replace Compressor OLP works within 30 sec in forcible OLP operation by turning instant power on and off Components start in the voltage of Rating Voltage Applied voltage isn t in the range of Rating Voltage Check the resistance among M C S C and M S in Motor Compressor Check the resistance of two terminals in PTC Starter Check if applying a regular OLP Measure minimum starting...

Page 13: ...ge Figure 21 Separate the Relay Assy from the Compressor and check the resistance value between two terminals of OLP with a Tester Observation value is 220V 50Hz 22 Ω 30 115V 60Hz 6 8 Ωｱ30 240V 50Hz 33 Ω 30 127 220V 60Hz 22Ω 30 The resistance value is 0 or serveral hundreds Ω The value is Check another electric components Replace Relay Assy Check another electric components Replace Relay Assy 2 2 ...

Page 14: ... of motor Compressor Replace the compressor Replace each component Raise the voltage Replace each component Cause Check if current flows to starting devices Check current flowing in sub coil of Compressor Check capacity of OLP The items described above are normal Much frost are sticked to the EVAPORATOR Shorted Replace the Heater Sheath Replace each component Check current flowing of the following...

Page 15: ...h as juice Is the set positioned in a firm and even place Is too much food putted in the set Check if the inside of the set is dirty Did you keep smelly foods without wrapping It smells of plastic Plug to the outlet Set the switch to ON Replace a regular fuse If voltage is low wire newly Place the set with the space of about 10cm Place the set apart from these heat appliances Make the ambient temp...

Page 16: ...le high more than ambient temperature Equal to ambient temperature Low than ambient temperature A little high than ambient temperature Equal to ambient temperature A little Refrigerant discharges Normal cooling is possible when injecting of Refrigerant the regular amount No discharging of Refrigerant Normal cooling is possible when injecting of Refrigerant the regular amount Normal discharging of ...

Page 17: ...s no vacuum leakage state 3 Vacuum degree of vacuum pump must be 0 05 Torr below after 5 min 4 Vacuum degree must be same to the value described item 2 above for more than 20 min 1 The pressure of dry air must be more han 12 16kg cm2 2 Temperature must be more than 20 70 C 3 Keep the pressure at 12 16kg cm2 also when substituting dry air for Nitrogen Gas 1 Check if gas leaks with soapy water 2 Rep...

Page 18: ... 18 Figure 23 LOKRING Figure 24 LOKRING TOOL ASSEMBLY JAWS BOLT TOOL TUBE LOKRING LOKRING JOINT ...

Page 19: ...ELECTION Division LED 88 Change of Indication Lamp Freezer Control Power Initially On 1st Press 2nd Press 3rd Press 18 C 19 C 20 C 21 C 4th Press 5th Press 22 C 23 C 5th Press 15 C 5th Press 16 C 5th Press 17 C Division LED BAR Change of Indication Lamp Temperature Control Freezer Control Power Initially On 1st Press 2nd Press 3rd Press 4th Press Middle Middle Strong Strong Weak Middle Weak 19 C 2...

Page 20: ...ut SUPER FREEZING operation starts seven minutes after defrost is complete and it shall operate for three hours 7 If SUPER FREZZING is selected within seven minutes after compressor has stopped the compressor compressor delays seven minutes shall start after the balance of the delay time 8 If VACATION button is pressed during the SUPER FREEZING the SUPER FREEZING function is immediately released 4...

Page 21: ... FAN MOTOR operate in order as follows 7 SELF TEST 1 Function to make service easy in case of occuring a trouble in the product 2 When occurring a trouble if the button is pushed but the function could not operate 3 If a trouble release during the representation of trouble a refrigerator performs the normal function RESET 4 To represent a ERROR CODE it use FREEZE TEMP LEDs in the door If ERROR occ...

Page 22: ...T button once Press TEST button once in the state of TEST MODE 1 Press TEST button once in the state of TEST MODE 2 1 COMP OPERATES SUCCESSIVELY 2 FAN OPERATES SUCCESSIVELY 3 DEFROSTING HEATER OFF 4 ALL DISPLAY LEDS ON 1 COMP OFF 2 FAN OFF 3 DEFROST HEATER ON 4 ALL THE DISPLAY LEDS OFF EXCEPT QUICK FREEZE AND VACATION LEDS Return to the initial condition RESET If DEFROST HEATER is over 7 C it retu...

Page 23: ...mation and BASIC TIME for calculating time Use a proper form for OSC 1 Because in case that SPECIFICATION is changed the calculated time in IC1 is changed or IC1 isn t able to operate 3 RESET CIRCUIT All the internal parts of MICOM IC1 return to the initial condition when the early power ON or apply power again in MICOM after temporary power failure As a result all the functions operate according ...

Page 24: ...se there is a similar type DOOR S W R of NOT MICOM MODEL it s logic of the A B of DOOR S W R is reversed Even though LAMP R is operated a normal ON OFF according to DOOR S W R but the MICOM couldn t detect a DOOR R opened or closed of lead wire of the A B is abnormal or S W of the A B of DOOR S W R is abnormal When DOOR R open isn t detected Even though DOOR R is opened FAN MOTOR couldn t stop che...

Page 25: ...HECK POINT NORMAL 30 C 50 C SHORT OPEN ROOM TEMPERATURE POINT Voltage SENSOR DEFROST SENSOR POINT Voltage 0 5V 4 5V 0V 5V FREEZER SENSOR POINT Voltage The above circuit reads the surrounding temperature DEFROSTING temperature and FREEZER ROOM temperature into MICOM IC1 OPEN or SHORT state of each SENSOR is as follows C 7 7 8 8 28 2KF 28 2KF 16 2KF ...

Page 26: ...is changed from 10K present resistance to 18K revised resistance the temp of freezer compartment goes up by 2 C FREEZER ROOM RESISTANCE VALUES R1 TEMPERATURE COMPENSATION REMARKS 180 k Ω Y L M R A W E T A S N E P M O C C 0 5 56 k Ω 4 0 C 33 k Ω 3 0 C 18 k Ω 2 0 C 12 k Ω 1 0 C 10 k Ω D R A D N A T S C 0 8 2 k Ω 1 0 C 5 6 k Ω 2 0 C 3 3 k Ω 3 0 C 2 kΩ 4 0 C 470 Ω Y L L O O C E T A S N E P M O C C 0 5...

Page 27: ... NOT 1 C 2 C 3 C 4 C 5 C 6 C 8 2kΩ COMPENSATE FREEZER 5 C 4 C 3 C 2 C 1 C NOT 1 C 2 C 3 C 4 C 5 C ROOM 10kΩ COMPENSATE R1 6 C 5 C 4 C 3 C 2 C 1 C NOT 1 C 2 C 3 C 4 C 12kΩ COMPENSATE 7 C 6 C 5 C 4 C 3 C 2 C 1 C NOT 1 C 2 C 3 C 18kΩ COMPENSATE 8 C 7 C 6 C 5 C 4 C 3 C 2 C 1 C NOT 1 C 2 C 33kΩ COMPENSATE 9 C 8 C 7 C 6 C 5 C 4 C 3 C 2 C 1 C NOT 1 C 56kΩ COMPENSATE 10 C 9 C 8 C 7 C 6 C 5 C 4 C 3 C 2 C 1...

Page 28: ...5 1 Ω 60kΩ k 0 3 1 C 0 1 Ω 47 3k Ω k 1 0 1 C 5 Ω 38 4k Ω k 8 7 C 0 Ω 30kΩ k 2 6 C 5 Ω 24 1k Ω k 9 4 C 0 1 Ω 19 5k Ω k 9 3 C 5 1 Ω 15 9k Ω k 1 3 C 0 2 Ω 13kΩ k 5 2 C 5 2 Ω 11kΩ k 0 2 C 0 3 Ω 8 9k Ω k 4 1 C 0 4 Ω 6 2k Ω k 8 0 C 0 5 Ω 4 3k Ω 4 MAIN PCB ASS Y AND PARTS LIST 1 MAIN PCB ASS Y DIP CE1 CM1 CM2 CE2 CE3 J01 IC3 R8 R9 C2 C C1 C CE5 CE7 J06 CC3 J08 CC9 CC5 EBR358383 STICKER Q3 3 F R C6 C 4 R1...

Page 29: ... R11 1 1 1 1 25 180 1 4W R12 1 1 1 1 26 180 1 4W R13 27 5 5 5 5 28 R FUSE XIA MENG NING LI FUSE DRAWING FUSE ASSEMBLY THERMAL FUSE HOLDER 15A 250V 15 16 19 6 7 29 30 1 1 1 1 31 20K 1 4W R 14 4 4 4 4 32 4 7K 1 4W R 9 17 20 21 2 2 2 2 33 10K 1 4W R 1 10 1 1 1 1 34 1M 1 4W R 8 1 1 35 16 7KF 1 4W R F1 1 1 36 16 2KF 1 4W R F1 1 1 1 1 37 26 1KF 1 4W R F2 1 1 1 1 38 29 2KF 1 4W R F3 39 1 1 1 1 40 KRA106M...

Page 30: ...1 1 17 LED HBLED BOE LED1 1 1 1 18 RT SENSOR PBN 43 CHANGZHOUHUICHANG YAGEO UNI OHM RT SENSOR 1 1 1 19 BUZZER PIEZO KPT G2240BP 4KHZ NINGBOKAIPU BUZ1 10 10 10 20 RESISTOR METAL FILM 2K 5 00 XIANZHENGDIANZI YAGEO UNI OHM R20 R29 1 21 TRANSISTOR KRA106M KEC Q1 1 22 RESISTOR METAL FILM 820 5 00 XIANZHENGDIANZI YAGEO UNI OHM R12 1 1 1 23 RESISTOR METAL FILM 1M 5 00 XIANZHENGDIANZI YAGEO UNI OHM RM 4 4...

Page 31: ... 25 24 23 OP1 OP2 17 KIA7042 XOUT Vcc RESET XIN TEST P76 P10 P11 P12 P13 P66 P65 AIN5 P64 AIN4 P63 AIN3 P62 AIN2 P61 AIN1 P60 AIN0 P77 P76 5 6 7 9 D SENSOR 1 2 3 4 5 CON3 6 10 11 12 13 16 2 8 223 RF2 26 1K 19 2 10 223 RF3 29 2K 6 2 4 223 R7 2K F SENSOR 20 21 22 P14 21 P15 20 3 P16 P17 P72 19 18 A A 1 TO DISP CON2 2 3 4 5 6 7 8 13 2 P72 17 12 2 P72 16 11 R14 20K 2 P72 GND 15 14 RT SENSOR 6 102 ...

Page 32: ... 4 3 2 1 P33 P34 P35 P36 P37 BZ VSS X1 X0 RST P61 P60 P07 P06 P05 P04 19 18 17 P32 P31 20 P30 P50 P40 P72 P71 P70 P43 P42 P41 24 23 22 21 27 26 25 P00 P01 P02 28 29 30 P03 Vcc 31 32 0 1uF 1 CE1 100uF 16V 2 3 4 COM1 A d c b a d b COM2 COM3 COM4 FIG 1 LED1 FIG 2 FIG 2 FIG 2 FIG 1 REMARK R11 COM1 A c b a d b COM2 COM3 R12 R13 R14 R15 R16 R17 8 RT SENSOR P60 7 6 CON1 5 4 3 2 1 R29 2K Vcc A Vss P31 P32...

Page 33: ...9C 327A 420A 329C 323B 314A 312A 317A 307A 318A 105A 304A 411A 281F 610E 108A 604F 310A 4860 6921 120D 120C 120A 404A 405A 329A 332A 409B 405C 330B RING 281E Ref No GA B409U QA B379U QA The parts of refrigerator and the shape of each part are subject to change in different localities 501A 102A 281B 281A 406B 407B 102B 102C 328A 6922 302A 303J ...

Page 34: ... 34 249C 210A 249B 203A 281D 151B 155A 136E 249A Ref No GA B409U QA 136E 249A 241A 235A 241A 207A 233A 210A 281H 125A 136A 136B 136C 136D 241A 282D 282E 103E ...

Page 35: ... 35 210A 203A 281D 136E Ref No GA B379U QA 207A 233A 210A 281H 155A 151B 136A 136B 136C 136D 136E 282D 282E 249B 241A 249C 249A 241A 241A 241C 103E ...

Page 36: ......

Page 37: ...P NO 3828JS8029F ...

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