Technical description and composition of the LG 42LV3551 TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LV3551
Chassis / Version: LD01U
Panel: LC420EUN (SD) (V3)
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX63729001 / 1 Rev1.0 EAY62171601
PWM Power: FAN7930B (PFC), 3BR4765JZ (Standby DIP-7), L6599AD (PWM Resonant)
MOSFET Power: K10A60D
MainBoard: EAX64290501 (0)
IC MainBoard: CPU: LGE107DC-RP, DDR: H5TQ1G63DFR-PBC, NAND: 01GW3B2CN6E, SPI FLASH: 25Q80BVSIG
Tuner: TDTJ-S001D
Specifications 42LV3551
LG 42LV3551
General repair guidelines for TV LCD LED
LG 42LV3551, like other televisions, it is advisable to start repairing with a careful examination of the external and internal elements and modules. It often happens that visible damage to elements or connections helps determine the direction of the troubleshooting. 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.
If LG 42LV3551 does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a malfunction of the EAX63729001_1 Rev1.0 power supply module. In some cases, only the processor power regulator may be faulty. 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.
Power switches in pulsed power supplies (SMPS) fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The cause may be a malfunction of the PWM controller chip, which can only be checked by replacing it with a new or obviously working one.
In cases where the LG 42LV3551 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 immediately. It must be borne in mind that with such manifestations the LEDs themselves also fail.
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 detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
Repair of the EAX64290501 (0) motherboard should begin with the diagnosis and verification of all linear stabilizers or power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM.
In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - CPU: LGE107DC-RP, DDR: H5TQ1G63DFR-PBC, NAND: 01GW3B2CN6E, SPI FLASH: 25Q80BVSIG with new or obviously working ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
If you suspect a TDTJ-S001D tuner malfunction, first of all, you need to make sure that there is a supply voltage on the corresponding output of the tuner.
Owners and users of the LG 42LV3551 TV must remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!
SCHEMATIC DIAGRAM ----------> LG CHASSIS: LD01U, 42LV3500/3550/3551, 42LV355A/355C/355N/355U, 42LV3500-ZA 42LV3551-ZD, 42LV3550/355A/355C/355N/355U-ZB SERVICE MANUAL
The appearance of the MainBoard EAX64290501 is shown in the figure below:EAX64290501
EAX64290501 can be used in TVs:
LG 32LV2500-ZA (Panel T315XW06 V.3), LG 37LV3500-ZA (Panel T370HW05 V.1), LG 42LV3400-ZA (Panel T420HW08 V.1), LG 32LK530 (Panel LC320WUD (SC)(A3)), LG 37LK430 (Panel LC370WUE), LG 32LK451 ZA (Panel T315HW04 V.9), LG 42LV3551 (Panel LC420EUN (SD) (V3)), LG 47LW4500 (Panel LC470EUF (SD)(F2)), LG 32LK551 ZB (Panel LC320WUD (SC)(A2)), LG 42LV3500 (Panel LC420EUN (SD)(V3)), LG 42LK551 ZB (Panel V420H2-LH5), LG 42LK451 42LK451-ZG.BRUYLJU (Panel T420HW09 V0), LG 42LK530 (Panel LC420WUF (SC)(A2)), LG 47LK950 ZA (Panel LC470WUF (SD)(P1)), LG 32LW4500 ZB (Panel LC320EUD (SD)(P1)), LG 42LW4500 ZB (Panel LC420EUF (SD)(PX)), LG 42LV4500 DA (Panel LC420EUF (SD)(A1)), LG 32LV4500 (Panel LC320EUD (SD)(A4)), LG 42LV369C (Panel T420HW08 V.9).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the EAX63729001 / 1 Rev1.0 module provides for the use of the 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 42LV3551:
Installed matrix (LED-panel) LC420EUN (SD) (V3).
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the LG 42LV3551 TV are generated by the EAX63729001 power module or its analogs using FAN7930B (PFC), 3BR4765JZ (Standby DIP-7), L6599AD (PWM Resonant) microcircuits and K10A60D type power switches.
MainBoard - the main board (motherboard) is an EAX64290501 module, using CPU chips: LGE107DC-RP, DDR: H5TQ1G63DFR-PBC, NAND: 01GW3B2CN6E, SPI FLASH: 25Q80BVSIG and others.
The TDTJ-S001D tuner provides TV reception and channel tuning.
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