Technical description and composition of the LG 39LB561V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 39LB561V
Chassis / Version: LC43B / LD43B / LB43T
Panel: NC390DUN VXBP1
T-CON: V390HJ4-CPE1
LED driver (backlight): integrated into PSU; 208V 250mA
PWM LED driver: BD9486F
MOSFET LED driver: MDD3752, 4NF20
Power Supply (PSU): EAX65423701 (1.9) REV 1.0 LGP3942-14PL1
PWM Power: MAP8800 (PFC), FA6A01N (PWM resonant)
MOSFET Power: TK7P60W
MainBoard: EAX65388003 (1.0)
IC MainBoard: CPU: LGE2132; NAND Flash: H27U1G8F2CTR BC 350F; SPI Flash: 25Q80; EEPROM: 24C256; SOUND: TAS5733;
Tuner: TDJM-G101D EBL61400501
Specifications 39LB561V
LG 39LB561V
General repair guidelines for TV LCD LED
Repair of the LG 39LB561V TV, it is advisable to start with an external examination. Visible damage to elements can sometimes indicate the direction of the search for a defect even before the necessary measurements are taken. Carbonized paint on the upper layer of resistors, electrolytic capacitors of rectifier filters swollen after boiling, cracked soldering at the terminals of heating elements or transformers can often suggest the cause of the defect and possible consequences.
In the case when the 39LB561V does not turn on, does not respond to the remote control and the front panel buttons, does not blink bulbs and does not show any signs of operability, the EAX65423701 (1.9) REV 1.0 LGP3942-14PL1 power supply module is probably faulty in this case. When diagnosing and repairing the power supply, first of all, replace the swollen capacitors of the filter of the secondary rectifiers and check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module — rectifier diodes and transistors in the primary circuit.
If the power keys of the pulse converter are not equal, you should pay attention to other elements in their bundling, which may be the result or cause of their breakdown.
If, when you turn on the TV, the image appears and immediately disappears, or is missing initially when you turn on, but the sound has other functions that work, there is a high probability of a malfunction of the display backlight LEDs or the LED driver (power converter for the NC390DUN VXBP1 panel backlight assembly).
In case of breaks or short circuits of the LEDs, it is necessary to completely disassemble the panel, check the LEDs, as well as the reliability of the connections in the connectors and rations of the terminals.
To identify a malfunction in the LED circuit, it is better to use a current source with a maximum voltage of 200-300V. We do not recommend using any voltage sources for this purpose. It is sometimes possible to test each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly.
In cases of attempts to repair the motherboard EAX65388003, it is necessary to check the operability of the linear stabilizers and power converters of its microcircuits and, if possible, update the software (software). BGA chips can sometimes be diagnosed with local heating.
In cases of complex MB repairs and with the necessary skills and equipment, sometimes it may be necessary to replace its CPU chips: LGE2132; NAND Flash: H27U1G8F2CTR BC 350F; SPI Flash: 25Q80; EEPROM: 24C256; SOUND: TAS5733; and other possible malfunctioning components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If you suspect a malfunction of the TDJM-G101D tuner, first of all, you need to make sure the software is correct, as well as the presence of the necessary voltage levels at the corresponding terminals of the tuner.
Remember! Attempts to self-repair by users of the LG 39LB561V TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
schematic diagram -------------> LG 39LB561V Chassis LC43B/LD43B/LB43T.
CHASSIS : LD43B/LD44B; MODEL : 39LB56** 39LB56**-Z*
In televisions with power supplies LGP3942-14PL1 (EAX65423701), the backlight current sensor - the resistor block R811-R818 consists of four pairs of 4.3 Ohm each. You can reduce the backlight current by 25% by removing one pair of resistors.
The appearance of the MainBoard EAX65388003 is shown in the figure below:EAX65388003
EAX65388003 can be used in TVs:
LG 42LB551V (Panel LC420DUE (FG)(A5)), LG 42LB620V ZD (Panel LC420DUE (FG)(P2)), LG 39LB561V (Panel NC390DUN VXBP1), LG 32LF580V (Panel NC320DUN).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the EAX65423701 module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the MAP8800 PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 39LB561V:
Installed matrix (LED-panel) NC390DUN VXBP1.
The matrix control uses the Timing Controller (T-CON) V390HJ4-CPE1.
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the BD9486F PWM controller. As power elements of the LED driver, keys of the MDD3752, 4NF20 type are used.
The necessary supply voltages for all nodes of the LG 39LB561V TV are generated by the EAX65423701 power module or its analogs using MAP8800 (PFC), FA6A01N (PWM resonant) microcircuits and TK7P60W power switches.
MainBoard - the main board (motherboard) is an EAX65388003 module, using CPU chips: LGE2132; NAND Flash: H27U1G8F2CTR BC 350F; SPI Flash: 25Q80; EEPROM: 24C256; SOUND: TAS5733; and others.
Tuner TDJM-G101D EBL61400501 provides the reception of television programs and tuning to channels.
