Technical description and composition of the LG 42LA644V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LA644V
Chassis / Version: LD33B
Panel: LC420EUN (SF) (F2) // (F3) // (F1)
LED backlight: 6020L-0001C; 6922L-0062A (cool)
T-CON: 6870C-0444A, LC470DUE-SFR1
LED driver (backlight): 3PHCC20006A-H PCLF-D202 A REV0.41 6917L-0119A
Power Supply (PSU): EAX64908001 (1.9) LGP3942-13P 3PCR00116A
PWM Power: FSD106LG, R2A20133DSP (PFC), L6544AD
MOSFET Power: MBR10U100CT, TK8P60V
MainBoard: EAX64797003 (1.2) EBR76823103
IC MainBoard: CPU: LGE2122, NAND: SAA36403538 VER. 3.20.33, H5TQ4G63AFR, SOUND: NTP7513
Tuner: EBL61240503 TDSQ-G601D (B)
Control: IR: EBR76405702 LA6400; Wi-Fi Module: EAT61813901 TWFM-B006D BEJTWFMB006D
Specifications 42LA644V
LG 42LA644V
General repair guidelines for TV LCD LED
In the case when the 42LA644V does not turn on, does not respond to the remote control and the front panel buttons, does not blink light bulbs and does not show any signs of operability, the EAX64908001 (1.9) LGP3942-13P 3PCR00116A power supply module is probably faulty in this case. In the general case, first of all, it is necessary to check the electrolytic capacitors of the secondary rectifier filters and the fuse at the input of the network. If it is broken, then you should check for breakdown of the PN junctions of the rectifier bridge diodes and the key transistor of the converter, which can either be on a separate radiator or integrated with a PWM controller in a common chip. Possible options.
It should be remembered that in the practice of repair, usually the power switches in switching power supplies (SMPS) do not fail due to their poor quality and, in such cases, it is necessary to look for the cause that led to a malfunction and provoked a breakdown of the key. Most often, the culprits of the accident are dried electrolytic capacitors or dangling resistors in the primary circuit, or the PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuits.
If the LG 42LA644V does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction in the backlight LED circuit of the LC420EUN (SF) (F2) // (F3) panel, or their power converter is an LED driver. Sometimes, when turned on, the image appears and immediately disappears. In such cases, it is necessary to check the electrolytic capacitors of the power filter of the backlight unit.
Often there is a need for disassembling the panel to check the health of the LEDs, as well as contact connections in the connectors and soldering.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check 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, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
Repair or diagnostics of the EAX64797003 (1.2) EBR76823103 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, you should update the software (software).
In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its CPU chips: LGE2122, NAND: SAA36403538 VER. 3.20.33, H5TQ4G63AFR, SOUND: NTP7513 and other possible defective components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
The malfunction of the tuner EBL61240503 TDSQ-G601D (B) is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Attention to the owners! Attempts to repair the LG 42LA644V TV independently are not recommended by the manufacturer and may lead to serious negative consequences!
Schematic diagram ------------> LG CHASSIS LD33B; MODEL 42LA64**, 42LA64**-Z*.
The appearance of the MainBoard EAX64797003 is shown in the figure below:
EAX64797003
EAX64797003 can be used in TVs:
LG 42LA620V (Panel LC420DUE (SF)(U1)), LG 32LN570V (Panel LC320DUE (SF)(R1)), LG 50LA644V (Panel LC500EUN (SF)(F1)), LG 47LA660V (Panel LC470EUG (PF)(F1)), LG 47LA621V (Panel LC470DUE (SF)(U1)), LG 42LA644V (Panel LC420EUN (SF)(F2)), LG 39LA620V ZA (Panel T390HVJ01.0), LG 42LA621V ZD (Panel LC420DUE (SF)(U1)), LG 32LA621V ZD (Panel LC320DUE (SF)(U1)), LG 32LN655V (Panel LC320EUB (PF)(M1)), LG 42LA667V (Panel LC420EUH (PF)(P1) ), LG 47LN613V (Panel LC470DUE (SF)(R4)), LG 32LA667V ZB (Panel LC320EUB (PF)(P1)), LG 55LA660V ZA (Panel LC550EUH (PF)(P1)), LG 47LA620V ZA (Panel LC470DUE (SF)(U1)), LG 32LN613V ZB (Panel LC320DUE (SF)(R4)), LG 42LN655V ZB.BRUZLJU (Panel LC420EUH (PF)(M1)), LG 32LA644V ZA (Panel LC320EUN (SF)(F1)), LG 42LN613V (Panel LC420DUE (SF)(R4)), LG 47LA690V ZB (Panel LC47EUH (PF)(P1)), LG 47LA662V (Panel LC470EUG (PF)(F1)), LG 42LA645V 42LA645V-ZC.BRUYLJU (Panel LC420EUN (SF)(F3)), LG 32LA660V (Panel LC320EUB (PF)(P1)), LG 47LA644V 47LA644V-ZA (Panel LC470EUN (SF)(F2)), LG 50LA667S (Panel T500HVD02.1), LG 47LA691V (Panel LC470EUH (PF)(P1)), LG 32LA662V (Panel LC320EUB (PF)(P1)).
PSU Advanced
The EAX64908001 power supply module is made using the Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced into the power supply by the device. The PFC node is a Step-Up Converter based on the R2A20133DSP PWM controller, which evenly distributes high-frequency impulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of an increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 42LA644V:
Installed matrix (LED-panel) LC420EUN (SF) (F2) or (F3) or (F1).
The matrix control uses the Timing Controller (T-CON) 6870C-0444A.
The LED driver 3PHCC20006A-H is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 42LA644V TV are generated by the EAX64908001 power module or its analogs using FSD106LG, R2A20133DSP (PFC), L6544AD microchips and power switches of the MBR10U100CT, TK8P60V type.
MainBoard - the main board (motherboard) is an EAX64797003 module using CPU chips: LGE2122, NAND: SAA36403538 VER. 3.20.33, H5TQ4G63AFR, SOUND: NTP7513 and others.
Tuner EBL61240503 TDSQ-G601D (B) provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUN-SFF2
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 927.94x521.96 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 350 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 10-bit), 51 pins
Voltage: 12.0V
