LG Gr P227 Ytqa Service Manual

							2-12. Function of Trouble Diagnosis(88-LED)
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 LED, which are placed at the display part of a refrigerator. All the LED 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
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							MICOM FUNCTION
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2-13. Function of Trouble Diagnosis(Bar-LED)
1. Function of trouble diagnosis is to make the repair  service easy when the refrigerator is out of order during service.
2. The function control button does not work but the recognition sound is heard when the refrigerator is out of order.
3. It returns to normal conditions when trouble code led is off. (reset)
4. Trouble code is indicated by the freezing temperature indicator led in the refrigerator display. All leds except trouble code
are off.
 
						

							Function of Trouble Diagnosis(88LED)
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.
MICOM FUNCTION
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							- 24 - Function of Trouble Diagnosis(BAR LED)
2-15. 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.
MICOM FUNCTION
 
						

							* LED check function- When freezer and refrigerator temperature control buttons are pressed for more than 1 second at the
same time, all LEDS on the display are on. And it returns to the normal conditions when the buttons are released. 
* Check of freezer fan rpm variation- Freezer fan speed changes from high speed to standard speed and vice versa for 30
seconds whenever freezer and refrigerator temperature control buttons are pressed at the same time for more than 1
second when freezer fan is in operation and returns to the previous rpm.
2-16. Functions of Ice Dispenser and Water Dispenser
1. Ice and cold water are available without opening refrigerator door. 
2. The desired ice (crushed or cube) or cold water are dispensed when dispenser press button (rubber button) is pressed
after selection of ice or cold water. When ice is selected, duct door opens by electric solenoid when dispenser press
switch is pressed. When dispenser press switch is released, duct door closes after it opens for 5 seconds.
3. Ice and water dispensing function stops when freezer door is open.
4. Geared motor and solenoid are automatically off if there is no signal after 3 minutes when ice (crushed and cube) or
water is selected and dispenser switch is pressed down. Solenoid (duct door) stops after 5 seconds when solenoid is off.
(in order to protect short circuit from solenoid heat generation)
5. Dispenser Lamp On/Off Function. The dispenser lamp shall be on or off whenever dispenser button is pressed or
released, respectively after selection of ice (crushed or cube) or water.
6. Water/Crushed Ice/Cube Ice Selection function
1) It is to select water/crushed ice/cube ice by user from the function control part and it will be indicated and selected by
pressing button.
2) Crushed ice is automatically selected when power is initially on.
3) When crushed ice is selected and its button is pressed, geared motor operates and crushed ice is dispensed.
4) When cube ice is selected and its button is pressed, geared motor and ice solenoid operate and cube ice is dispensed.
7. Function of Water Dispenser
1) When user selects water in the function control parts, it is indicated in the LED and water is selected.
2) Water dispenser is a direct tap water connection type. The water solenoid valve on the right of machine room opens
and water dispenses when user selects water and presses button.
MICOM FUNCTION
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							1. Explanation for PWB circuit
1-1. Power circuit
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:


Part VA1 CE1 CE2 CE3 CE4 CE5
Voltage 230 Vac inspection Vdc 13~16 Vdc 12 Vdc 15.5 Vdc 5 Vdc
EXPLATION FOR MICOM CIRCUIT 
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							EXPLATION FOR MICOM CIRCUIT 
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							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 
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							1-4. Load/dispenser operation, buzzer driving, door opening circuit
1. LOAD DRIVING CIRCUIT
✽InEven 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.
✽(A), (B), (C) and (D) of door switch for the freezing room or 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.
EXPLATION FOR MICOM CIRCUIT 
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Measuring part (IC6) No.16 No.12 No.11 No.15 No.13 No.14
StatusON Within 1 V
OFF 12 V

Type of Load COMPFrost
Removal
HeaterAC Converting
RelayR-room LAMPDispenser
HeaterPipe Heater
 
						

							EXPLATION FOR MICOM CIRCUIT 
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