LG GR-A207CTBA, GR-A207NIS, GC-A207, GR-A207 Service Manual

CAUTION

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

REFRIGERATOR

SERVICE MANUAL

COLOR: TITANIUM

http://biz.lgservice.com

Ref. No. GR-A207NIS

MODEL : GR-A207CTBA

WARNINGS AND PRECAUTIONS FOR SAFETY ................................................................................................................ 3

SPECIFICATIONS................................................................................................................................................................... 4

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

HOW TO INSTALL THE REFRIGERATOR............................................................................................................................ 6

HOW TO ADJUST DOOR HEIGHT OF THE REFRIGERATOR.......................................................................................... 6

MICOM FUNCTION ................................................................................................................................................................ 7

EXPLATION FOR MICOM CIRCUIT..................................................................................................................................... 13

EXPLANATION FOR PWB CIRCUIT ..................................................................................................................................13

SENSOR RESISTANCE CHARACTERISTICS TABLE.......................................................................................................26

PWB PARTS DIAGRAM AND LIST.....................................................................................................................................27

PWB CIRCUIT DIAGRAM...................................................................................................................................................31

CIRCUIT................................................................................................................................................................................ 33

TROUBLE DIAGNOSIS........................................................................................................................................................ 34

TROUBLE SHOOTING ...................................................................................................................................................... 34

FAULTS .............................................................................................................................................................................. 44

COOLING CYCLE HEAVY REPAIR................................................................................................................................... 61

HOW TO DEAL WITH CLAIMS.......................................................................................................................................... 68

HOW TO DISASSEMBLE AND ASSEMBLE....................................................................................................................... 73

DOOR................................................................................................................................................................................. 73

HANDLE............................................................................................................................................................................. 74

SHROUD, GRILLE FAN..................................................................................................................................................... 74

EXPLODED VIEW ................................................................................................................................................................ 75

REPLACEMENT PARTS LIST............................................................................................................................................. 80

CONTENTS

- 2 -

Please observe the following safety precautions in order to use safely and correctly the refrigerator and to prevent accident and danger during repair.

1. Be care of an electric shock. Disconnect power cord from wall outlet and wait for more than three minutes before replacing PWB parts. Shut off the power whenever replacing and repairing electric components.

2. When connecting power cord, please wait for more than five minutes after power cord was disconnected from the wall outlet.

3. Please check if the power plug is pressed down by the refrigerator against the wall. If the power plug was damaged, it may cause fire or electric shock.

4. If the wall outlet is over loaded, it may cause fire. Please use its own individual electrical outlet for the refrigerator.

5. Please make sure the outlet is properly earthed, particularly in wet or damp area.

6. Use standard electrical components when replacing them.

7. Make sure the hook is correctly engaged. Remove dust and foreign materials from the housing and connecting parts.

8. Do not fray, damage, machine, heavily bend, pull out, or twist the power cord.

9. Please check the evidence of moisture intrusion in the electrical components. Replace the parts or mask it with insulation tapes if moisture intrusion was confirmed.

10. Do not let the customers repair, disassemble, and reconstruct the refrigerator for themselves. It may cause accident, electric shock, or fire.

11. Do not store flammable materials such as ether,

benzene, alcohol, chemicals, gas, or medicine in the refrigerator.

12. Do not put flower vase, cup, cosmetics, chemicals, etc., or container with full of water on the top of the refrigerator.

13. Do not put glass bottles with full of water into the freezer. The contents shall freeze and break the glass bottles.

14. When you scrap the refrigerator, please disconnect the door gasket first and scrap it where children are not accessible.

WARNINGS AND PRECAUTIONS FOR SAFETY

- 3 -

SPECIFICATIONS

- 4 -

ITEMS SPECIFICATIONS

DIMENSIONS (mm) 890(W)X725(D)X1750(H) NET WEIGHT (kg) 1 14 COOLING SYSTEM Fan Cooling TEMPERATURE CONTROL Micom Control DEFROSTING SYSTEM Full Automatic

Heater Defrost INSULATION Cyclo-Pentane COMPRESSOR P.T.C. Starting Type EVAPORATOR Fin Tube Type CONDENSER Wire Condenser REFRIGERANT R134a (180g) LUBRICATING OIL FREOL @15G (320 cc) DRIER MOLECULAR SIEVE XH-7

ITEMS SPECIFICATIONS

CAPILLARY TUBE 1Ø0.83 FIRST DEFROST 4 - 5 Hours DEFROST CYCLE 13 - 15 Hours DEFROSTING DEVICE Heater, Sheath ANTI-FREEZING HEATER Damper Heater FREEZER LAMP – REFRIGERATOR LAMP 40W (1 EA) / 30W (1 EA) DISPENSER LAMP –

1750

1720

1750

600

948 890

665

711

725

1133.5

1. Ref No. : GR-A207

PARTS IDENTIFICATION

- 5 -

Cover PWB

Cover Hinge

Frame Display

Cover Lower

Ice Tray

Freeze Room

Drawer

Lamp

Shelf

Vegetable Drawer

Shelf

Door Rack

Wine Holder (optional)

Dairy Product Corner

Door Rack

Freezer

Compartment

Refrigerator

Compartment

1. Ref No. : GR-A207

1. How to Adjust Door Height of Refrigerator

■ Make the refrigerator level first. (If the refrigerator is not installed on the flat floor, the height of freezer and refrigerator door may not be the same.)

1. If the height of freezer door is lower than that of refrigerator compartment :

2. If the height of freezer door is higher than that of refrigerator compartment :

Insert a driver  into the groove  of adjusting screw and rotate driver in arrow direction (clockwise) until the refrigerator becomes horizontal.

HOW TO INSTALL REFRIGERATOR

- 6 -

Adjusting Screw

Driver

Height

Difference

Height Difference

1. Monitor Panel

1-1. GR-A207

2. Description of Function

2-1-1. Funnction of Temperature Selection

* The temperature can vary ±3 °C depending on the load condition.

❉ Whenever pressing button, setting is repeated in the order of (Medium) ➝ (Medium Max) ➝ (Max) ➝ (Min) ➝

(Medium Min).

• The actual inner temperature varies depending on the food status, as the indicated setting temperature is a target temperature, not actual temperature within refrigerator.

• Refrigeration function is weak in the initial time. Please adjust temperature as above after using refrigerator for minimum 2~3 days.

MICOM FUNCTION

- 7 -

Temperature adjustment button for refrigerator compartment.

Temperature adjustment button for freezer compartment.

Super freezer.

Lock button.

FREEZER

REFRIGERATOR

LOCK

EXPRESS FRZ

FRZ TEMP

LOCK UNLOCK

ON OFF

3SECS

REF TEMP

Division Power Initially On 1st Press 2st Press 3th Press 4th Press

Temperature Control

Medium Medium Max Max Min Medium Min

Freezer Control

-19 °C -22 °C -23 °C -15 °C -17 °C

Refrigeration

3 °C2 °C0°C6 °C4 °C

Control

2-1-2. Lock function (display button lock)

1. In power application of refrigerator, the only “Release” text is turned on at the right side of lock graphic of LED with the lock release status.

2. If desiring to lock the display status and pressing the lock/release button once, “Release” text is turned off at the right side of lock graphic of LED and “Lock” text is turned on with lock status.

3. The only buzzer sound rings and function is not performed even if pressing display button other than lock/release key in the lock status.

4. If desiring to release the lock status and pressing the lock/release button once, “Lock” text is turned off at the right side of lock graphic of LED and “Release” text is turned on with lock release status.

2-2. When ice maker does not operate smoothly

Ice is lumped together

• When ice is lumped together, take the ice lumps out of the ice storage bin, break them into small pieces, and then place

them into the ice storage bin again.

• When the ice maker produces too small or lumped together ice, the amount of water supplied to the ice maker need to

adjusted. Contact the service center.

✻ If ice is not used frequently, it may lump together.

Power failure

• Ice may drop into the freezer compartment. Take the ice storage bin out and discard all the ice then dry it and place it

back. After the machine is powered again, crushed ice will be automatically selected.

The unit is newly installed

• It takes about 12 hours for a newly installed refrigerator to make ice in the freezer compartment.

2-3. Super freezer

Please select this function for prompt freezer.

• “On” or “Off” is repeated whenever pressing button.

• Super freezer function automatically turns off if a fixed time passes.

2-4. Lock

This button stops operation of different button.

• Locking or Release is repeated whenever pressing the .

• Pressing the other button when selecting ‘LOCK’, the button does not operate.

2-5. Special freezing

1. Special freezing is function to improve cooling speed of the freezing room by consecutively operating compressors and freezing room fan. If pressing the special freezing button, “OFF” text of the LED is turned off and “ON” is immediately turned on.

2. Special freezing is cycled in order of Selection/ Release (“On” / “Off”) whenever pressing the selection button.

3. Special freezing is released if power failure occurs and then returns to the original status.

4. Temperature setting is not changed even if selecting the special freezing.

5. The change of temperature setting at the freezing room or the cold storage room is allowed with special freezing selected and processed.

6. The cold storage room operates the status currently set with special freezing selected and processed.

7. If selecting the special freezing, the special freezing function is released after continuously operating compressor and freezing room fan.

8. If frost removal starting time is arrived during special freezing, special freezing operation is done only for the remaining time after completion of frost removal when the special freezing operation time passes 90 minutes. If passing 90 minutes, special freezing operation is done only for 2 hours after completion of frost removal.

9. If pressing special freezing button during frost removal, the special freezing LED is turned on but if pressing the special freezing, compressor operates after the remaining time has passed.

10. If selecting special freezing within 7 minutes (delay for 7 minutes of compressor) after the compressor stops,

compressor operates after the remaining time has passed.

11. The freezing room fan motor operates at the high speed of RPM during operation of special freezing.

MICOM FUNCTION

- 8 -

Ex) In selecting

"On"

Ex) In selecting

"Off"

Ex) In selecting

"LOCK"

Ex) In selecting

"LOCK" again

OFF

3SECS

OFF

3SECS

LOCK

SUPER FRZ

2-6. Control of variable type of freezing room fan

1. To increase cooling speed and load response speed, MICOM variably controls freezing room fan motor at the high speed of RPM and standard RPM.

2. MICOM only operates in the input of initial power or special freezing operation or load response operation for the high speed of RPM and operates in the standard RPM in other general operation.

3. If opening doors of freezing / cold storage room or home bar while fan motor in the freezing room operates, the freezing room fan motor normally operates (If being operated in the high speed of RPM, it converts operation to the standard RPM). However, if opening doors of freezing room or home bar, the freezing room fan motor stops.

4. As for monitoring of BLDC fan motor error in the freezing room, MICOM immediately stops the fan motor by determining that the BLDC fan motor is locked or poor if there would be position signal for more than 115 seconds at the BLDC motor. Then it displays failure (refer to failure diagnosis function table) at the display part of refrigerator, the BLDC motor doesn’t operate more. If you want to operate the BLDC motor, turn off and on power resource.

2-7. Control of M/C room fan motor

1. The M/C room fan motor performs ON/OFF control by linking with the COMP.

2. It controls at the single RPM without varying RPM.

3. Failure sensing method is same as in fan motor of freezing fan motor (refer to failure diagnosis function table for failure display).

2-8. Door opening alarm

1. Buzzer generates alarm sound if doors are not closed even when more than a minute consecutively has passed with doors of freezing / cold storage room or home bar opened.

2. Buzzer rings three times in the interval of 0.5 second after the first one-minute has passed after doors are opened and then repeats three times of On/Off alarm in the cycle of every 30 seconds.

3. If all the doors of freezing / cold storage room or home bar are closed during door open alarm, alarm is immediately released.

2-9. Ringing of button selection buzzer

1. If pressing the front display button, "Ding ~ " sound rings.

2-10. Ringing of compulsory operation, compulsory frost removal buzzer

1. If pressing the test button in the main PCB, "Phi ~ " sound rings.

2. In selecting compulsory operation, alarm sound is repeated and completed in the cycle of On for 0.2 second and Off for

1.8 second three times.

3. In selecting compulsory frost removal, alarm sound is repeated and completed in the cycle of On for 0.2 second , Off for

0.2 second, On for 0.2 second and Off for 1.4 second three times.

MICOM FUNCTION

- 9 -

Doors of freezing /

cold storage room

or home bar

BUZZER

Closing

Opening

Within

a minute

A minute

seconds30seconds30seconds

Opening

Closing Closing

3 Times 3 Times 3 Times 3 Times

2-11. Frost removal function

1. Frost removal is performed whenever total operation time of compressor becomes 7 ~ 7.5 hour.

2. In providing initial power (or returning power failure), frost removal starts whenever total operation time of compressor becomes 4 ~ 4.5 hour.

3. Frost removal is completed if temperature of a frost removal sensor becomes more than 5°C after starting frost removal. Poor frost removal is not displaced if it does not arrive at 5°C even if two hours have passed after starting frost removal.

4. No removal is done if frost removal sensor becomes poor (snapping or short-circuit).

2-12. Sequential operation of built-in product

Built-in products such as compressor, frost removal heater, freezing room fan, Cooling Fan and step motor damper are sequentially operated as follows for preventing noise and part damage occurred due to simultaneous operation of a lot of parts in applying initial power and completing test.

MICOM FUNCTION

- 10 -

Function Load Operation Sequence Remark

In applying Initial power TESTMODE

When temperature of a frost removal sensor becomes more than 45°C (In purchase, movement)

If error occurs during operation, initial operation is not done.

If pressing switch once more in the test mode 2 or temperature of a frost removal sensor is more than 5°C, it immediately returns to the test mode for initial operation (COMP operates after 7 minutes).

When temperature of a frost removal sensor becomes less than 45°C (In power failure, service)

Test mode 1 (Compulsory function)

Test mode 2 (Compulsory frost removal)

STEP

MOTOR

DAMPER

OPEN

STEP

MOTOR

DAMPER

TEST

S/W

(Press

Once)

COMP

TEST

S/W

(Press

2 times)

COMP

OFF

0.5

sec.

0.3

sec.

0.3

sec.

0.3

sec.

0.3

sec.

0.3

sec.

0.3

sec.

0.3

sec.

0.3

sec.

OTHER

LOAD

OFF

F-FAN

C-FAN

F-FAN

C-FAN

OFF

FROST

REMOVAL

HEATER

COMP

F-FAN

C-FAN

STEP

MOTOR

DAMPER

FROST

REMOVAL

HEATER

FROST

REMOVAL

HEATER

OFF

POWER

sec.

0.3

sec.

COMP

F-FAN

C-FAN

0.5

sec.

2-13. Failure Diagnosis Function

1. Failure diagnosis function is function to facilitate service when nonconforming matters affecting performance of product during use of product.

2. In occurrence of failure, pressing the function adjustment button does not perform function and only alarm sound (“Ding~”) rings.

3. If nonconforming matters occurred are released during display of failure code, MICOM returns to the original state (Reset).

4. Failure code is displayed on the display part of setting temperature for the freezing room and the display part of setting temperature for the cold storage room of LCD, which are placed at the display part of a refrigerator. All the LCD graphics other than a failure code are turned off.

✽ In display of the failure mode, all LEDs of setting temperature for freezing/ setting temperature for cold storage are turned

off (excluding Note1 and Note2).

MICOM FUNCTION

- 11 -

LOCK

EXPRESS FRZ

FRZ TEMP

LOCK UNLOCK

ON OFF

3SECS

REF TEMP

Failure Code display Part

Basic type

(GR-A207)

●● : Normal Operation

Er FS

Er RS

Setting temperature

display (Note 2)

Er DS

Er dH

Er FF

Er CF

Er CO

Setting temperature

display (Note 1)

Failure code display part

Setting

temperature

for freezing

Setting

temperature for

cold storage

No. Item

Contents of failure

Freezer

Fan

Compressor

Stepping

motor damper

Defrost

Heater

M/C room

Fan

Product operation status in failure

Failure of freezer sensor

Failure of refrigerator sensor 1

Failure of refrigerator sensor 2

Failure of frost removal sensor

Poor of frost removal

Failure of BLDC FAN at freezing room

Failure of BLDC FAN at machine room

Failure of Communication

Failure of Outside Sensor

Snapping or short-circuit of freezer sensor

Snapping or short-circuit of refrigerator sensor 1

Snapping or short-circuit of refrigerator sensor 2

Snapping or short-circuit of frost removal sensor

Snapping of frost removal heater or temperature fuse, pull-out of connector (indicated minimum 4 hours after failure occurs)

Poor motor, hooking of wires to fan. Contact of structures to Fan. Snapping or short-circuit of L/wire (if there is no fan motor signal for more than 60 seconds in operation of fan motor

Connection between main PCB and display PCB. Snapping or short-circuit of L/wire. Transmission between main PCB and display PCB. Poor TR and receiving part.

Snapping or short-circuit of outside temperature perceiving sensor

Standard

RPM

Standard

RPM

Standard

RPM

Standard

RPM

Standard

RPM

OFF (check every

30 minutes)

Standard

RPM

Standard

RPM

●●

OFF (check

every 30 minutes)

●●

ON for 15minutes

OFF for 15minutes

●●

No frost removal

●●

Open for 10munutes, closing for 15 minutes

●●

Note1) In error of outside sensor, setting temperature for freezing / cold storage is normally displayed and indicated “Er” on

the outside temperature display part (normally displayed except for the outside temperature display part).

Note2) Nonconforming contents of poor R2 sensor is displayed in LED check, not indicated on the failure display part (when

pressing freezing temperature adjustment button and special freezing button for a second or more).

Cold storage sensor 2 Normal : (C) Part LED graphic- ON (middle partition) Abnormal: Only (C) Part LED graphic-OFF

2-14. Test Function

1. The purpose of test function is to check function of the PWB and product and to search for the failure part at the failure status.

2. Test button is placed on the main PCB of refrigerator (test switch), and the test mode will be finished after maximum 2 hours irrespective of test mode and then is reset to the normal status.

3. Function adjustment button is not perceived during performance of test mode but only warning sounds ring.

4. In finishing test mode, always pull the power cord out and then plug-in it again for the normal state.

5. If nonconforming contents such as sensor failure are found during performance of test mode, release the test mode and display the failure code.

6. Even if pressing the test button during failure code display, test mode will not be performed.

✻ LED check function: If simultaneously pressing special freezing button and cold temperature adjustment button for a second,

a back light is turned on and all display LCD graphics on. If releasing the button, the LCD graphic displays the previous status, the back light is turned off (LCD graphic and back light ON/OFF check).

MICOM FUNCTION

- 12 -

Other LED graphics - ON

Test 1

Test 2

Normal

Status

Mode Manipulation Content Remarks

Press test button once (freezing force mode)

Press test button once at the test mode 1 status (compulsory frost removal mode)

Press test button once at the test mode 2 status (freezing force mode)

1. Continuous operation of compressor

2. Continuous operation of freezing room fan (high speed RPM) and M/C room fan

3. Frost removal heater OFF

4. Full opening status (baffle opened) status of electronic step motor damper

5. All display LED graphics - ON.

1. Compressor OFF

2. Freezing room fan and M/C room fan is turned off.

3. Frost removal heater ON

4. Full closing status (baffle closed) status of electronic step motor damper

5. FRZ, REF TEMP LED is displayed “22”

Return to the initial status.

Freezing room fan is turned off in door open.

Compressor is operated after 7 minutes.

FREEZER

REFRIGERATOR

LOCK

EXPRESS FRZ

FRZ TEMP

LOCK UNLOCK

ON OFF

3SECS

REF TEMP

FREEZER

REFRIGERATOR

LOCK

EXPRESS FRZ

FRZ TEMP

3SECS

REF TEMP

1. Explanation for PWB circuit

1-1. Power circuit

1. GR-A207

Power circuit consists of SMPS (SWITCHING MODE POWER SUPPLY) power. The SMPS consist of the rectifying part (BD1, CE1) converting AC voltage to DC voltage, the switching part (IC2) switching the converted DC voltage, transformer transferring energy of the primary side of the switching terminal to the secondary side and the feedback part (IC3, IC4) transferring it to the primary side.

Caution : Since high voltage (DC310V) is maintained at the power terminal, please take a measure after more than 3

minutes have passed after removing power cords in the abnormal operation of a circuit.

Voltage of every part is as follows:

EXPLATION FOR MICOM CIRCUIT

- 13 -

Part VA1 CE1 CE2 CE3 CE4 CE5

Voltage 230 Vac 310 Vdc 16 Vdc 12 Vdc 15.5 Vdc 5 Vdc

1-2. Oscillation circuit

Oscillation circuit is a circuit with the purpose of generating basic time for clock occurrence for synchronization and time calculation in relation with information transmission/reception of inside elements of IC1 (MICOM). The OSC1 must always use rated parts since if SPEC is changed, time calculated at the IC1 may be changed or no operation is done.

1-3. Reset circuit

The reset circuit is circuit allowing various parts such as RAM inside of MICOM (IC1) to initialize and the whole of function to start from the initial status, when initial power is input or when power is applied again to MICOM by a spontaneous power failure. ‘LOW’ voltage is applied to the reset terminal of MICOM in the beginning of power supply for a constant time (10ms). Reset terminal during general operation is 5V (No MICOM operates in failure of RESET IC).

EXPLATION FOR MICOM CIRCUIT

- 14 -

<GR-A207>

CC7

CC8

<GR-A207>

1-4. Load/dispenser operation, door opening circuit

1. LOAD DRIVING CIRCUIT

✽ In even if opening the door of freezing room or cold storage room during operation of fan motor at the freezing room, this

circuit does not stop and operates at the standard RPM. In addition, if doors of freezing room or cold storage room, the fan motor normally operates at the RPM previously operated.

✽ (C) and (D) of door switch cold storage room are connected to the door open sensing circuit in parallel toward both ends

of switch to determine door open at MICOM.

✽ Since a door switch of the home bar is connected to door switch (C), (D) of the cold storage room, it senses door opening

if even one of both is opened.

✽ The fan motor is immediately stop if opening doors of the freezing room or cold storage room at the TEST mode and it

immediately operates if closing them.

1) GR-A207

EXPLATION FOR MICOM CIRCUIT

- 15 -

Measuring part (IC6) No.16 No.11 No.10 No.15

Status

ON Within 1 V

OFF 12 V

Type of Load COMP

Frost Removal

Heater

AC Converting

Relay

R-room LAMP

2. Door opening sensing circuit

1) GR-A207

✽ Lamp does at the cold storage room not turn on if the door switch of the cold storage room fails to sense the door open

switch (C), (D) or the home bar switch.

EXPLATION FOR MICOM CIRCUIT

- 16 -

Closing 5 V ( C - D . S/W at both ends are at Off status)

Opening 5 V ( C - D . S/W at both ends are at On status)

Measuring part

IC1 (MICOM) No. 45 Pin

Door of Freezing/Cold Storage Room

1-5. Temperature sensing circuit

1) GR-A207

The above circuits are circuits attached to freezing room sensor or cold storage room sensor for adjusting setting temperature at the freezing room and cold storage room, ice-making sensor for sensing water temperature in ice-making, or an evaporator for sensing temperature of a frost removal sensor necessary for frost removal. Short or open status of every temperature sensor is as follows:

EXPLATION FOR MICOM CIRCUIT

- 17 -

SENSOR CHECK POINT

NORMAL(-30 °C ~ 50 °C) IN

SHORT IN OPEN

Freezing sensor POINT A Voltage

Frost removal sensor POINT B Voltage Cold storage sensor 1 POINT C Voltage 0.5 V~4.5 V 0 V 5 V Cold storage sensor 2 POINT D Voltage

Room temperature sensor POINT E Voltage

1-6. Switch entry circuit

The following circuits are entry circuits for sensing signal form test S/W, electronic single motor damper reed S/W for examining refrigerator.

1) GR-A207

1-7. Option designation circuit (model separation function)

1) GR-A207

The above circuits are used for designating separation by model as option and notifying it to MICOM. Designation of option by model and the application standards are as follows:

u These circuits are accurately pre-adjusted in shipment from factory and so you must not additionally add or remove

option.

EXPLATION FOR MICOM CIRCUIT

- 18 -

P46

R26

CC11

223

R21

4.7K

Separation Connection Status Application Standard

Connection MAGIC/ROOM

OP1

OUT NON-MAGIC/ROOM

1-8. Stepping motor operation circuit

For motor driving method, rotation magnetism is formed at coils wound on each phase of motor and stator and so motor becomes to rotate if applying “High” signal to the IC8 (TA7774P) at the MICOM PIN 33 and outputting “High”, “Low” signal by step numbers fixed through MICOM PIN 34 and 35,.

Explanation) For driving method of the stepping motor, send signals in the cycle of 3.33 mSEC using terminal of MICOM

PIN 33, 34 and 35 as shown in wave form of the following part. These signals are output to the output terminal (No.10, 11, 14, 15) via the input terminal (No. 3, 6, 8) of the IC10 (TA7774P) as IC for motor driving. Output signals allow motor coils wound on each phase of stator to form rotation magnetic field and the motor to rotate. Inputting as below figure to the input terminal (INA, INB) as IC (TA7774AP) for motor driving allows motor coils wound on each phase of stator to form rotation magnetic field and the stepping motor damper to rotate

EXPLATION FOR MICOM CIRCUIT

- 19 -

TA7774P

R49 R50 R51

CE11

IC8

CON6

INA

INB

CCW (Reverse rotation) (Positive rotation) CW

1-9. Fan motor driving circuit (freezing room)

1. This circuit performs function to make standby power ‘0’ by cutting off power supplied to ICs inside of the fan motor in the fan motor OFF.

2. This is a circuit to perform a temporary change of speed for the fan motor and applies DC voltage up to 7.5V ~ 16V to motor.

3. This circuit performs function not to drive the fan motor further by cutting off power applied to the fan motor in the lock of fan motor by sensing the operation RPM of the fan motor.

1) GR-A207

EXPLATION FOR MICOM CIRCUIT

- 20 -

Speed

R31

R32

R34

R35

1.5K

1mH

FR107

D10

CE7

CC15

R37

R36

FR107

R33

CC16

R41

R38

R39

R40

R42

D11 FR107

D12 FR107

CE8

CC17

R43

R44

CC18

1mH

1.5K

1-10. Temperature compensation and over-cool/weak-cool compensation circuit

1. Temperature compensation at freezing room, cold storage room

1) GR-A207

u Temperature compensation table by adjustment value (difference value against current temperature)

Ex) If changing compensation resistance at a cold storage room (RCR1) from 10 kΩ (current resistance) to 18 kΩ

(modified resistance), temperature at the cold storage will increase by +1°C.

Ex) Now (R)J1= , (R)J2=1.2kΩ, RCRI=5.6kΩ want to compensate -2°C for Freezing room temperature and

+2°C for Cold storage room temperature

(R)J1 = 12kΩ 1kΩ (R)J2 = 12kΩ RCRI = 5.6kΩ 18kΩ

EXPLATION FOR MICOM CIRCUIT

- 21 -

Freezing room Cold storage room

Resistance value

Temperature Resistance value Temperature Remarks

(R)J1 (R)J2

compensation (RCR1) compensation

+5 °C 180 kΩ +2.5 °C Warmly +4 °C 56 kΩ +2.0 °C compensate +3 °C 33 kΩ +1.5 °C +2 °C 18 kΩ +1.0 °C +1 °C 12 kΩ +0.5 °C

0 °C 10 kΩ 0 °C

Reference temperature

-1 °C 8.2 kΩ -0.5 °C

-2 °C 5.6 kΩ -1.0 °C

-3 °C 3.3 kΩ -1.5 °C

-4 °C2 kΩ -2.0 °C Coolly

-5 °C 470 Ω -2.5 °C compensate

6.2 kΩ

5.1 kΩ 3 kΩ

2.4 kΩ

1.2 kΩ

1 kΩ

1.8 kΩ

2.7 kΩ

3.9 kΩ

5.1 kΩ

: JUMP WIRE

u Temperature compensation table at the cold storage room is as follows:

u This circuit is a circuit to enter the necessary level of temperature compensation for adjusting different temperature every

model at the cold storage room into MICOM.

EXPLATION FOR MICOM CIRCUIT

- 22 -

470 Ω 2 kΩ 3.3 kΩ 5.6 kΩ 8.2 kΩ 10 kΩ 12 kΩ 18 kΩ 33 kΩ 56 kΩ 180 kΩ

No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C3 °C 3.5 °C4 °C 4.5 °C5 °C

470Ω

change

Up Up Up Up Up Up Up Up Up Up

0.5 °C No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C3 °C 3.5 °C4 °C 4.5 °C

2 kΩ

Down change

Up Up Up Up Up Up Up Up Up

1 °C 0.5 °C No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C3 °C 3.5 °C4 °C

3.3 kΩ

Down

change

Up Up Up Up Up Up Up Up

1.5 °C1 °C 0.5 °C No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C3 °C 3.5 °C

5.6 kΩ

Down Down Down

change

Up Up Up Up Up Up Up

2 °C 1.5 °C1 °C 0.5 ° No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C3 °C

Cold storage

8.2 kΩ

Down Down Down

Drop

change

Up Up Up Up Up Up

room

2.5 °C2 °C 1.5 °C1 °C 0.5 °C No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C

(RCR1) 10 kΩ

Down Down Down Down Down

change

Up Up Up Up Up

3 °C 2.5 °C2 °C 1.5 °C1 °C 0.5 °C No 0.5 °C1 °C 1.5 °C2 °C

12 kΩ

Down Down Down Down Down Down

change

Up Up Up Up

3.5 °C3 °C 2.5 °C2 °C 1.5 °C1 °C 0.5 °C No 0.5 °C1 °C 1.5 °C

18 kΩ

Down Down Down Down Down Down Down

change

Up Up Up

4 °C 3.5 °C3 °C 2.5 °C2 °C 1.5 °C1 °C 0.5 °C No 0.5 °C1 °C

33 kΩ

Down Down Down Down Down Down Down Down

change

Up Up

4.5 °C4 °C 3.5 °C3 °C 2.5 °C2 °C 1.5 °C1 °C 0.5 °C No 0.5 °C

56 kΩ

Down Down Down Down Down Down Down Down Down

change

5 °C 4.5 °C4 °C 3.5 °C3 °C 2.5 °C2 °C 1.5 °C1 °C 0.5 °CNo

180 kΩ

Down Down Down Down Down Down Down Down Down Down

change

Modification

resistance

Current resistance

u Temperature compensation table at the freezing room is as follows:

EXPLATION FOR MICOM CIRCUIT

- 23 -

J1: 5.1 kΩ J1: 3.9 kΩ J1: 2.7 kΩ J1: 1.8 kΩ J1: 910 Ω J1: . J1: . J1: . J1: . J1: . J1: .

J2: . J2: . J2: . J2: . J2: . J2: . J2: 1.2 kΩ J2: 2.4 kΩ J2: 3 kΩ J2: 5.1 kΩ J2: 6.2 kΩ

J1: 5.1 kΩ

Not

1 °C ↑ 2 °C ↑ 3 °C ↑ 4 °C ↑ 5 °C ↑ 6 °C ↑ 7 °C ↑ 8 °C ↑ 9 °C ↑ 10 °C ↑

J2:

compensate

J1: 3.9 kΩ

1 °C ↓

Not

1 °C ↑ 2 °C ↑ 3 °C ↑ 4 °C ↑ 5 °C ↑ 6 °C ↑ 7 °C ↑ 8 °C ↑ 9 °C ↑

J2:

compensate

J1: 2.7 kΩ

2 °C ↓ 1 °C ↓

Not

1 °C ↑ 2 °C ↑ 3 °C ↑ 4 °C ↑ 5 °C ↑ 6 °C ↑ 7 °C ↑ 8 °C ↑

J2:

compensate

J1: 1.8 kΩ

3 °C ↓ 2 °C ↓ 1 °C ↓

Not

1 °C ↑ 2 °C ↑ 3 °C ↑ 4 °C ↑ 5 °C ↑ 6 °C ↑ 7 °C ↑

J2:

compensate

J1: 910 Ω

4 °C ↓ 3 °C ↓ 2 °C ↓ 1 °C ↓

Not

1 °C ↑ 2 °C ↑ 3 °C ↑ 4 °C ↑ 5 °C ↑ 6 °C ↑

Freezing

J2:

compensate

room

J1:

5 °C ↓ 4 °C ↓ 3 °C ↓ 2 °C ↓ 1 °C ↓

Not

1 °C ↑ 2 °C ↑ 3 °C ↑ 4 °C ↑ 5 °C ↑

[(R)J1, (R)J2]

J2:

compensate

J1:

6 °C ↓ 5 °C ↓ 4 °C ↓ 3 °C ↓ 2 °C ↓ 1 °C ↓

Not

1 °C ↑ 2 °C ↑ 3 °C ↑ 4 °C ↑

J2: 1.2 kΩ

compensate

J1:

7 °C ↓ 6 °C ↓ 5 °C ↓ 4 °C ↓ 3 °C ↓ 2 °C ↓ 1 °C ↓

Not

1 °C ↑ 2 °C ↑ 3 °C ↑

J2: 2.4 kΩ

compensate

J1:

8 °C ↓ 7 °C ↓ 6 °C ↓ 5 °C ↓ 4 °C ↓ 3 °C ↓ 2 °C ↓ 1 °C ↓

Not

1 °C ↑ 2 °C ↑

J2: 3 kΩ

compensate

J1:

9 °C ↓ 8 °C ↓ 7 °C ↓ 6 °C ↓ 5 °C ↓ 4 °C ↓ 3 °C ↓ 2 °C ↓ 1 °C ↓

Not

1 °C ↑

J2: 5.1 kΩ

compensate

J1:

10 °C ↓ 9 °C ↓ 8 °C ↓ 7 °C ↓ 6 °C ↓ 5 °C ↓ 4 °C ↓ 3 °C ↓ 2 °C ↓ 1 °C ↓

Not

J2: 6.2 kΩ

compensate

Change

resistance

Now resistance

2. Compensation circuit for weak-cold, over-cold at freezing room

1) GR-A207

u The above option circuit is a circuit to compensate for temperature at the cold storage room by simply cutting in service.

EXPLATION FOR MICOM CIRCUIT

- 24 -

Compensation Compensation

for weak-cold for over-cold

Temperature compensation value

Remarks

JCR3 JCR4 JCR1 JCR2

at cold storage room

0 °C (In shipment from factory)

CUT -1 °C

CUT +1 °C

CUT CUT -2 °C

CUT CUT +2 °C CUT CUT 0 °C CUT CUT 0 °C

CUT CUT 0 °C CUT CUT 0 °C

CUT CUT CUT -1 °C

CUT CUT CUT +1 °C

CUT CUT CUT CUT 0 °C

Temperature compensation in CUT

JCR1 +1 °C

+2 °C

JCR2 +1 °C JCR3 -1 °C

-2 °C

JCR4 -1 °C

+ 56 hidden pages

LG GR-A207CTBA, GR-A207NIS, GC-A207, GR-A207 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual