LG LRDN20724ST Service Manual

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Owner's manual (36 pages)

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LG LRDN20724ST

Owner's Manual

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Page 1 This Owner's Manual is provided and hosted by Appliance Factory Parts. LG LRDN20724ST Owner's Manual Shop genuine replacement parts for LG LRDN20724ST Find Your LG Refrigerator Parts - Select From 834 Models -------- Manual continues below --------...
Page 2 REFRIGERATOR SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, MODEL: READ THE SAFETY PRECAUTIONS IN THIS MANUAL. 12** 0724** C22744**...
Page 3: Table Of Contents
CONTENTS SAFETY PRECAUTIONS ............................... 2 SPECIFICATIONS................................... 3 PARTS IDENTIFICATION ..............................4-7 DISASSEMBLY..................................8-9 DOOR....................................8 DOOR SWITCH..................................8 FAN AND FAN MOTOR................................ 9 DEFROST CONTROL ASSEMBLY............................9 LAMP....................................9 CONTROL BOX-REFRIGERATOR ............................9 MULTI DUCT ..................................9 ADJUSTMENT.................................. 10-11 COMPRESSOR.................................. 10 PTC-STARTER..................................
Page 4: Specifications
1. SPECIFICATIONS 20 cu. ft. / 22 cu. ft. ITEMS SPECIFICATIONS ITEMS SPECIFICATIONS DOOR DESIGN Side Rounded VEGETABLE TRAY Opaque Drawer Type H) 20cu.ft COMPRESSOR PTC Starting Type DIMENSIONS (inches) H) 22cu.ft Dispenser EVAPORATOR Fin Tube Type H) 22cu.ft CONDENSER Wire Condenser 238.4 (20cu.ft) REFRIGERANT...
Page 5: Parts Identification
2. PARTS IDENTIFICATION PARTS AND FEATURES NOTE: This guide covers several different models.The refrigerator you have purchased may have some or all of the items listed below. The locations of the features shown below may not match your model. Digital Sensor Control Filter (inside)* Refrigerator Light Dairy Bin...
Page 6 PARTS AND FEATURES NOTE: This guide covers several different models.The refrigerator you have purchased may have some or all of the items listed below. The locations of the features shown below may not match your model. Digital Sensor Control Filter (inside)* Refrigerator Light Dairy Bin Shelves...
Page 7 PARTS AND FEATURES NOTE: This guide covers several different models.The refrigerator you have purchased may have some or all of the items listed below. The locations of the features shown below may not match your model. Digital Sensor Control Divider Refrigerator Light Dairy Bin Shelves...
Page 8 PARTS AND FEATURES NOTE: This guide covers several different models.The refrigerator you have purchased may have some or all of the items listed below. The locations of the features shown below may not match your model. Digital Sensor Control Dairy Bin Refrigerator Light Design-A-Door Shelves...
Page 9: Disassembly
3. DISASSEMBLY 3-1 DOOR Freezer Door 1. Loosen the hexagonal bolts attaching the lower hinge to Refrigerator Door the body to remove the refrigerator door only. 1. Remove the hinge cover by pulling it upwards. 2. Loosen the hexagonal bolts attaching the upper hinge to the body and lift the freezer door.
Page 10: Fan And Fan Motor
3-3 FAN AND FAN MOTOR 3-5-1 Refrigerator Compartment Lamp 1. Unplug the power cord from the outlet. 1. Remove the freezer shelf. (If your refrigerator has an icemaker, remove the icemaker first) 2. Remove refrigerator shelves. 2. Remove the grille by pulling it out and by loosening a 3.
Page 11: Adjustment
4. ADJUSTMENT 4-1 COMPRESSOR 4-2-3 PTC-Applied Circuit Diagram Starting Method for the Motor 4-1-1 Role The compressor intakes low temperature and low pressure gas from the evaporator of the refrigerator and compresses OVERLOAD PROTECTOR this gas to high-temperature and high-pressure gas. It then delivers the gas to the condenser.
Page 12: Olp (Overload Protector)
4-3 OLP (OVERLOAD PROTECTOR) 4-4 TO REMOVE THE COVER PTC 4-3-1 Definition of OLP (1) OLP (OVERLOAD PROTECTOR) is attached to the Compressor and protects the Motor by opening the circuit to the Motor if the temperature rises and activating the bimetal spring in the OLP. (2) When high current flows to the Compressor motor, the Bimetal works by heating the heater inside the OLP, and the OLP protects the Motor by cutting off the...
Page 13: Circuit Diagram
5. CIRCUIT DIAGRAM Best / Best dispenser GY: GRIS/GRAY - 12 -...
Page 14 Good / Better GY: GRIS/GRAY - 13 -...
Page 15: Troubleshooting
6. TROUBLESHOOTING 6-1 COMPRESSOR AND ELECTRIC COMPONENTS (Reated Voltage Remove PTC-Starter Power Source. ±10%)? from Compressor and measure voltage between Terminal C of Compressor and Terminals 5 or 6 of PTC. OLP disconnected? No Voltage. Replace OLP. Check connection condition. Reconnect.
Page 16: Ptc And Olp
6-2 PTC AND OLP Normal operation of Separate PTC-Starter Observation value is Compressor is from Compressor and 115V/60Hz : 6.8Ω±30% measure resistance impossible or poor. between No. 5 and 6 of PTC-Starter with a Tester. (Figure 14) Replace PTC- The resistance value Starter.
Page 17: Other Electrical Components
6-3 OTHER ELECTRICAL COMPONENTS M Not cooling at all Check for open short or Compressor Cause incorrect resistance readings doesn't run. in the following components a. Starting devices Short, open, or broken. Poor contact b. OLP or shorted. Coil open or shorted. c.
Page 18: Service Diagnosis Chart
6-4 SERVICE DIAGNOSIS CHART COMPLAINT POINTS TO BE CHECKED REMEDY No Cooling. • Is the power cord unplugged from the outlet? • Plug into the outlet. • Check if the power switch is set to OFF. • Set the switch to ON. •...
Page 19: Refrigeration Cycle
6-5 REFRIGERATION CYCLE M Troubleshooting Chart TEMPERATURE STATE OF STATE OF THE CAUSE REMARKS OF THE THE UNIT EVAPORATOR COMPRESSOR PARTIAL Freezer Low flowing sound of A little higher • Refrigerant level is low due LEAKAGE compartment and Refrigerant is heard and than ambient •...
Page 20 M General Control of Refrigerating Cycle ITEMS UNIT STANDARDS PURPOSES REMARKS Pipe and Min. Pipe: within 1 hour. To protect The opening time should be reduced piping system Comp: within 10 minutes. moisture to a half of the standards during rain opening time Drier: within 20 minutes.
Page 21: Operation Principle & Repair Method Of Icemaker
7. OPERATION PRINCIPLE AND REPAIR METHOD OF ICEMAKER 7-1 OPERATION PRINCIPLE 7-1-1 Operation Principle of IceMaker Power On Start Position • Adjusts EJECTOR to Start Position with power on. Ice Making • Waits until water becomes cold after starting the Mode ice making operation.
Page 22: Control Method According To Functions
7-2 CONTROL METHOD ACCORDING TO FUNCTIONS 7-2-1 Start Position 1. After POWER OFF or Power Outage, check the EJECTOR's position with MICOM initialization to restart. 2. How to check if it is in place: - Check HIGH/LOW signals from HALL SENSOR in MICOM PIN. 3.
Page 23 7-2-4 Fill / Park Position 1. When Ice-Removing control (Normal Ice-Removing control, Ice-Removing control for test) has completed, and the EJECTOR is in place, this control operates the ICE SOLENOID by time check in the compressor enclosure of the refrigerator. Then it supplies water to the ice making tray. 2.
Page 24: Defect Diagnosis Function
7-2-5 Function TEST 1. This is a compulsory operation for TEST, SVC, cleaning, etc. It is operated by pressing the water supply control KEY for 3 seconds. 2. It operates in the Ice Making mode, but not in the Ice-Removing mode or water supply process. (If there is an ERROR, it can only be checked in the TEST mode.) 3.
Page 25: Description Of Function & Circuit Of Micom (Best, Dispenser)
8. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM 8-1 FUNCTION 8-1-1 Function 1. When the appliance is plugged in, it is set to 37 °F for the Refrigerator and 0 °F for the Freezer. You can adjust the Refrigerator and the Freezer control temperature by pressing the COLDER button or the WARMER button.
Page 26: Express Freezing
8-1-4 CONTROL OF FREEZER FAN MOTOR 1. Freezer fan motor has high and standard speeds. 2. High speed is used at power-up, for express freezing, and when refrigerator is overloaded. Standard speeds is used for general purposes. 3. To improve cooling speed, the RPM of the freezer fan motor change from normal speed to high. 4.
Page 27 8-1-8 Buzzer Sound When the button on the front Display is pushed, a Ding~ Dong~ sound is produced. (Refer to the Buzzer Circuit 8-2-4 No. 3) 8-1-9 Defrosting (removing frost) 1. Defrosting starts each time the COMPRESSOR running time reaches 7 hours. 2.
Page 28: Error Code
8-1-13 Defect Diagnosis Function 1. Automatic diagnosis makes servicing the refrigerator easy. 2. When a defect occurs, the buttons will not operate; but the tones. such as ding. will sound. 3. When the defect CODE removes the sign, it returns to normal operation (RESET). 4.
Page 29 8-1-14 TEST Mode 1. The Test mode allows checking the PCB and the function of the product as well as finding out the defective part in case of an error. 2. The test mode is operated by pressing two buttons at Display panel. 3.
Page 30: Pcb Function
8-2 PCB FUNCTION 8-2-1 Power Circuit The secondary part of the TRANSFORMER is composed of the power supply for the display, the BLDC FAN Motor drive (15.5 V), the relay drive (12 Vdc) and the MICOM and IC (5 Vdc). The voltage for each part is as follows: PART VA 1...
Page 31 8-2-2 Oscillation Circuit This circuit generates the base clock for calculating time and the synchro clock for transmitting data from and to the inside logic elements of the IC1 (MICOM). Be sure to use specific replacement parts, since calculating time by the IC1 may be changed.
Page 32: Defrosting Heater
8-2-4 Load / Buzzer Drive & Open Door Detection Circuit 1. Load Drive Condition Check G5SB-14 FREEZER DOOR SWITCH REFRIGERATOR DOOR SWITCH VALVE DEFROSTING COMP LAMP LOAD TYPE POWER MODE (DISPENSER HEATER (OPTIONAL) MDL) Measurement Location (IC6) NO.13 NO.14 NO.16 NO.12 NO.15 1V or below...
Page 33 3. Buzzer Drive Condition Check Condition Tone (Ding~Dong~) when the button on Alarm for open door Measure- the display is pushed. (beep-beep-beep) ment Location 0.05 s 0.2 s 0.1 s 0.5 s 0.5 s IC1 ( 2.63 kz (Ding~) 2.21 kz (Dong~) IC1 ( 2.63 kz (Beep~) 4.
Page 34 8-2-5 Temperature Sensor Circuit FREEZER-SENSOR REFRIGERATOR-SENSOR DEFROST-SENSOR The upper CIRCUIT reads REFRIGERATOR temperature, FREEZER Temperature, and DEFROST-SENSOR temperature for defrosting and the indoor temperature for compensating for the surrounding temperature into MICOM. OPENING or SHORT state of each TEMPERATURE SENSOR are as follows: SENSOR CHECK POINT NORMAL (-30°C ~ 50°C)
Page 35 8-2-6 Refrigeration Compartment Stepping Motor Damper Circuit * The circuit shown below is the damper circuit to regulate the refrigerator temperature. 8-2-7 Dispenser Input/LED Output Circuit PUMP SWITCH - 34 -...
Page 36 8-2-8 Temperature Compensation & Overcooling/Undercooling Compensation Circuit 1. Refrigerator Temperature Compensation ➧ Table of Temperature Compensation by adjusting the Refrigerator resistance (difference from the current temperature) Resistance Temperature Remark e.g., If the refrigerator compensation resistance (RCR) Compensation (RCR) is changed from 10K (the current resistance) to 18K (the adjustment resistance), the temperature 180 KΩ...
Page 37 8-2-9 Key Button Input & Display Light-On Circuit ➧ The circuit shown above determines whether a function control key on the operation display is pushed. It also turns on the corresponding function indication LED (LED Module) SEVEN SEGMENT DISPLAY (SEVEN SEGMENT DISPLAY MODULE).
Page 38: Resistance Specification Of Sensor
8-3 RESISTANCE SPECIFICATION OF SENSOR TEMPERATURE DETECTED RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR & BY SENSOR SENSOR DEFROST SENSOR & ROOM SENSOR - 20 ˚C 22.3 KΩ 77 KΩ - 15 ˚C 16.9 KΩ 60 KΩ - 10 ˚C 13.0 KΩ 47.3 KΩ...
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Page 41: Main Pwb Assembly And Parts List
8-5 MAIN PWB ASSEMBLY AND PARTS LIST 8-5-1 Main PWB Assembly - 40 -...
Page 42 8-5-2 Replacement Parts List - 41 -...
Page 43 8-5-3 PWB Assembly, Display, And Parts List Dispenser Model Best Model SW106 - 42 -...
Page 44: Pwb Diagram
8-6 PWB DIAGRAM 8-6-1 PWB Main Assembly G5SB-14 FREEZER DOOR SWITCH REFRIGERATOR DOOR SWITCH PWB ASSEMBLY - 43 -...
Page 45 220 1/2W REFRIGERATOR DOOR SWITCH FREEZER SENSOR REFRIGERATOR SENSOR DEFROST SENSOR FREEZER DOOR SWITCH - 44 -...
Page 46: Description Of Function & Cicuit Of Micom (Good, Better)
9. DESCRIPTION OF FUNCTION & CIRCUIT OF MICOM 9-1 FUNCTION 9-1-1 Function 1. When the appliance is plugged in, it is set to "4" for Refrigerator and "4" for freezer. You can adjust the Refrigerator and the Freezer control temperature by pressing the ADJUST button. 2.
Page 47 9-1-5 Alarm for Open Door 1. This feature sounds a buzzer when the freezer or refrigerator door is not closed within 1 minute after it is opened. 2. One minute after the door is opened, the buzzer sounds three times each for 1/2 seconds. These tones repeat every 30 seconds.
Page 48 9-1-9 Defect Diagnosis Function 1. Automatic diagnosis makes servicing the refrigerator easy. 2. When a defect occurs, the buttons will not operate; but the tones. such as ding. will sound. 3. When the defect CODE removes the sign, it returns to normal operation (RESET). 4.
Page 49 9-1-10 TEST Mode 1. The Test mode allows checking the PCB and the function of the product as well as finding out the defective part in case of an error. 2. The test mode is operated by pressing two buttons at Display panel. 3.
Page 50 9-2 PCB FUNCTION 9-2-1 Power Circuit The secondary part of the TRANSFORMER is composed of the power supply for the display, the BLDC FAN Motor drive (15.5 V), the relay drive (12 Vdc) and the MICOM and IC (5 Vdc). The voltage for each part is as follows: CE 2 CE 1...
Page 51 9-2-2 Oscillation Circuit This circuit generates the base clock for calculating time and the synchro clock for transmitting data from and to the inside logic elements of the IC1 (MICOM). Be sure to use specific replacement parts, since calculating time by the IC1 may be changed.
Page 52 9-2-4 Load / Buzzer Drive & Open Door Detection Circuit 1. Load Drive Condition Check G5SB-14 FREEZER FREEZER DEFROSTING COMP LAMP LOAD TYPE FAN MOTOR FAN MOTOR HEATER (HIG RPM) (LOW RPM) Measurement Location (IC4) NO.11 NO.14 NO.15 NO.12 NO.13 1V or below Condition - 51 -...
Page 53 2. Buzzer Drive Condition Check Condition Tone (Ding~Dong~) when the button on Alarm for open door Measure- the display is pushed. (beep-beep-beep) ment Location 0.05 s 0.2 s 0.1 s 0.5 s 0.5 s IC1 ( 2.63 kz (Ding~) 2.21 kz (Dong~) IC1 ( 2.63 kz (Beep~) 3.
Page 54 9-2-5 Temperature Sensor Circuit The upper CIRCUIT reads REFRIGERATOR temperature, FREEZER Temperature, and DEFROST-SENSOR temperature for defrosting and the indoor temperature for compensating for the surrounding temperature into MICOM. OPENING or SHORT state of each TEMPERATURE SENSOR are as follows: SENSOR CHECK POINT NORMAL (-30°C ~ 50°C)
Page 55 9-2-6 Refrigeration Compartment Stepping Motor Damper Circuit * The circuit shown below is the damper circuit to regulate the refrigerator temperature. - 54 -...
Page 56 9-2-7 Temperature Compensation & Overcooling/Undercooling Compensation Circuit 1. Refrigerator Temperature Compensation ➧ Table of Temperature Compensation by adjusting the Refrigerator resistance (difference from the current temperature) Resistance Temperature Remark e.g., If the refrigerator compensation resistance (RCR) is changed from 10K (the current resistance) (RCR) Compensation to 18K (the adjustment resistance), the temperature...
Page 57 9-2-8 Key Button Input & Display Light-On Circuit ➧ The circuit shown above determines whether a function control key on the operation display is pushed. It also turns on the corresponding function indication LED DISPLAY. The drive type is the scan type. 150J - 56 -...
Page 58 9-3 RESISTANCE SPECIFICATION OF SENSOR TEMPERATURE DETECTED RESISTANCE OF FREEZER RESISTANCE OF REFRIGERATOR & BY SENSOR SENSOR DEFROST SENSOR & ROOM SENSOR - 20 ˚C 22.3 KΩ 77 KΩ - 15 ˚C 16.9 KΩ 60 KΩ - 10 ˚C 13.0 KΩ 47.3 KΩ...
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Page 61 9-5 MAIN PWB ASSEMBLY AND PARTS LIST 9-5-1 Main PWB Assembly - 60 -...
Page 62 9-5-2 Replacement Parts List - 61 -...
Page 63 9-5-3 PWB Assembly, Display, And Parts List - 62 -...
Page 64 9-6 PWB DIAGRAM 9-6-1 PWB Main Assembly G5S-1A - 63 -...
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Page 88 17 November, 2005 P/No. 3828JL8086C...

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