Technical description and composition of the LG 42LV3700 TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LV3700
Chassis / Version: LD12B
Panel: LC420EUN (SD) (V3)
LED backlight: 3660L-0374A 201 42 V6 Edge FHD-3 Rev1.0 1 L-Type / R-Type
T-CON: 6870C-0368A, V6 32-42-47 FHD TM120HZ_TFTRA
LED driver (backlight): 3PEGC20008B-R PCLF-D002B Rev1.0 6917L-0061B
Power Supply (PSU): EAX63729001 / 8 EAY62171601 LGP4247-11SPL
PWM Power: FAN7930B (PFC), 3BR4765JZ (Standby), L6599AD (PWM Resonant)
MOSFET Power: K10A60D
MainBoard: EAX63557704 (0) EBR73063519
IC MainBoard: Cpu: LGE35230, Nand: TC58DVG3S0ETA, DDR: K4B2G1646C, Eeprom: 24C1024
Tuner: TDFR-G136D
Control: IR: 1BF-3001A
Appearance
LG 42LV3700
General repair guidelines for TV LCD LED
If the 42LV3700 TV does not turn on, does not make any sounds when it is turned on, and also no indicators on the front panel light or blink, there is a high probability of a malfunction in the power module. In some cases, there may be a malfunction only in standby power. When diagnosing and repairing the power supply, first of all, replace the swollen filter capacitors 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.
As a rule, the keys in switching power supplies (SMPS) are reliable enough and rarely fail for no reason to be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM chip is verified by replacing it with a known good one.
In cases where the LG 42LV3700 TV has lost its image, and the sound is there and all other functions are operational, there is a possibility of a malfunction of the LED driver (converter for powering the backlight LEDs of the LC420EUN (SD) panel (V3)). When you turn on the TV, the image may appear briefly and disappear. It must be borne in mind that with such manifestations the LEDs themselves also fail.
A malfunction in the backlight circuits often occurs due to an open in the power circuit of the LED lines. It requires disassembling the panel and checking the LEDs themselves, the rations of their terminals, as well as the reliability of the connections in the connectors and rations of the terminals.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
The EAX63557704 (0) EBR73063519 motherboard must be checked if there is no reaction to the remote control and function buttons, the standby indicator blinks or lights up continuously. In such cases, if the converters or power regulators of the microcircuit are working, a software update may be necessary.
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 pu chips: LGE35230, Nand: TC58DVG3S0ETA, DDR: K4B2G1646C, Eeprom: 24C1024 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If the TV works normally from external devices, but does not tune into television channels, the TDFR-G136D tuner may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Attention to users! Self-repair of the LG 42LV3700 TV without the appropriate qualifications and experience can lead to its complete non-repairability!
Led 3660L-0374A 201 42 V6 Edge FHD-3 Rev1.0 1 L-Type;
3660L-0374A 201 42 V6 Edge FHD-3 Rev1.0 1 R-Type.
SCHEMATIC DIAGRAM ----------> LG CHASSIS LD12B; MODEL 42LV3700, 42LV370S, 42LV3700/370S-ZC, 42LV375G/S/W 42LV375G/S/W-ZC.
The appearance of the MainBoard EAX63557704 is shown in the figure below:EAX63557704
EAX63557704 can be used in TVs:
LG 37LV370S (Panel T370HW05 V.1), LG 42LV370S (Panel LC420EUN (SD) (V5)), LG 32LV3700 (Panel T315HW07 V.8), LG 42LV3700 (Panel LC420EUN (SD)(V3)), LG 47LV370S ZB (Panel LC470EUE (SD)(V1)), LG 32LV370S (Panel T315HW07 V.8).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the EAX63729001 / 8 EAY62171601 LGP4247-11SPL module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the FAN7930B 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 42LV3700:
Installed matrix (LED-panel) LC420EUN (SD) (V3).
The matrix control uses the Timing Controller (T-CON) 6870C-0368A.
The LED driver 3PEGC20008B-R is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the LG 42LV3700 TV are generated by the EAX63729001 power module or its analogs using FAN7930B (PFC), 3BR4765JZ (Standby), L6599AD (PWM Resonant) microcircuits and K10A60D type power switches.
MainBoard - the main board (motherboard) is an EAX63557704 module using Cpu chips: LGE35230, Nand: TC58DVG3S0ETA, DDR: K4B2G1646C, Eeprom: 24C1024 and others.
The TDFR-G136D tuner provides TV reception and channel tuning.
Information from an alternative source:
LG 42LV3700-ZC.BRUYLJU Chassis LD12B
Panel Type (Matrix): LC420EUN (SD) (V5)
Motherboard: EAX63557704 (0), Tuner: TDFR-G136D EBL60740405
T-con: V6 32/42/47 FHD TMI20HZ_TETRA P / N: 6870C-0366A
LED Driver: 3PEGC20008B-R PCLF-D002 B Rev1.0 6917L-0061B
PSU: P / N: EAY62171601 EAX63729001 / 7
Remote control: AKB73275605
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUN-SDV3
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 360 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, 8-bit), 51 pins
Voltage: 12.0V