Technical description and composition of the LG 49LJ540V TV, panel type and modules used. The composition of the modules.
LG LED
Model: 49LJ540V ZA
Chassis / Version: LD75M / LD75H
Panel: SDL490FY (CD0-901) REV.R1
T-CON: TT4851B01-2-C-4
LED driver (backlight): integrated into PSU
Power Supply (PSU): 168P-L4R032-W1 5835-L4R032-W000
PWM Power: PFC, PWM
MOSFET Power: TO-220
MainBoard: EAX67129604 (1.0) EBU64581406
IC MainBoard: EEPROM: IC100 - 24C256
Tuner: TDJA-G501D
Control: WI-FI: LGSWFAC71
Specifications 49LJ540V
LG 49LJ540V
General recommendations for TV LCD LED repair
Possible manifestations of malfunctions
- LG 49LJ540V does not turn on, does not respond to buttons and the remote control, indicators on the front panel do not light or blink.
With similar manifestations, a malfunction is most likely found in the 168P-L4R032-W1 power module. Then you should measure its output voltages and, in case of their complete or partial absence, it is necessary to check the serviceability of the power switches (TO-220) and rectifier diodes of the converters for a possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and with a short circuit in the power elements of the primary circuit, the mains fuse or the current sensor in the source of the key is often cut off.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers PFC, PWM, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or known to be working properly.
- There is no picture, but there is sound and all other functions work. Sometimes when you turn it on, the image appears and disappears for a second.
In some of these cases, the malfunction is caused by the lack of display backlighting. The reason may be in the breakage of the LEDs, in the stabilization of their power supply, or in the violation of the contact connections of the strings connectors,
When diagnosing, it must be borne in mind that it is impossible to check for an open in the circuit of the LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally a current source. By opening the panel, you can check each LED separately. Typically, Chinese multimeters will lightly light one 3-volt LED if you connect the probes to it in the forward direction. For dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of LED health. In the event of a malfunction of the LED, its zener diode will either be cut off, or broken through in the K / Z.
- The TV does not go into operation, does not respond to the remote control. The indicator on the front panel is on or blinking.
Repair or diagnostics of the EAX67129604 motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - EEPROM: IC100 - 24C256 which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its pins with the board (detected by warming up).
If there is no reception of TV channels, but the TV is working properly from external devices, first of all, you need to check the supply voltage of the TDJA-G501D tuner and update the software. I2C communication pulses must be monitored with an oscilloscope.
If the LG 49LJ540V has no picture, but there is sound, often the display backlight SDL490FY (CD0-901) REV.R1 simply does not work. Moreover, in LED TVs, the LEDs inside the panel usually fail, less often the LED driver.
In such cases, you can see a barely noticeable image with a successful hit of external light on the screen.
Replacing the LEDs requires disassembling the SDL490FY LCD panel - a process that requires experience and qualifications from the master. We do not recommend doing such work on your own to the owners of TVs and craftsmen who do not have experience in repairing LCD panels
If there is no image, and the backlight is on, the screen becomes slightly lighter when turned on, and in an open TV you can see the light through the holes in the panel case.
In this case, the panel may also be faulty - damage to the strips, loops, for example, as a result of moisture ingress after unsuccessful washing of the screen, the T-CON (Timing Controller) board may be faulty. But the main board MainBoard EAX67129604 often turns out to be faulty, a software failure is also possible.
Then, first of all, it is necessary to check the panel supply voltage, the fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within the normal range, it is necessary to trace the passage of LVDS signals from the MainBoard EAX67129604 with an oscilloscope, as well as synchronization signals to the loops with the drivers.
Flooded or unsuccessfully washed screens of LED TVs can be restored, in about half of the cases, usually if significant damage has not formed in the loops and panel strips.
Users and owners of TVs should remember that attempts to self-repair the LG 49LJ540V TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
Additional MainBoard Repair
The appearance of the MainBoard EAX67129604 is shown in the figure below:
EAX67129604
External view of the power supply
Main features of the LG 49LJ540V device:
Installed matrix (LED-panel) SDL490FY (CD0-901) REV.R1.
Matrix control uses the Timing Controller (T-CON) TT4851B01-2-C-4.
A converter combined with a power supply is used to power the backlight LEDs.
The formation of the necessary supply voltages for all nodes of the LG 49LJ540V TV is carried out by the 168P-L4R032-W1 power module, or its analogs using PFC, PWM microcircuits and TO-220 power switches.
MainBoard - the main board (motherboard) is an EAX67129604 module, using EEPROM chips: IC100 - 24C256 and others.
Tuner TDJA-G501D provides reception of television programs and tuning to channels.
Instructions and updates
There are download files for the 49LJ540V from the manufacturer:
Update and instruction files:
File Description File Name Type Date Size
SW File (Version 05.80.40) . TV_Software_Update_Guide_v3.pdf PDF 26.08.2020 2014K update instructions
SW File (Version 05.80.40) . Firmware (USB) Software_File(Version_05.80.40).zip zip 26.08.2020 805359K
Compatible with 32LJ590U-ZA, 32LJ594U-ZA, 32LJ610V-ZD, 32LJ622V-ZB, 43LJ594V-ZA, 43LJ595V-ZD, 43LJ610V-ZA, 43LJ614V-ZA, 43LJ622V-ZC, 43LJ624V-ZC, 49LJ540V-ZA, 49LJ594V-ZA, 49LJ595V-ZD, 49LJ610V-ZA, 49LJ614V-ZA, 49LJ622V-ZC, 49LJ624V-ZC, 55LJ540V-ZA, 55LJ615V-ZA, 55LJ622V-ZB, 55LJ625V-ZB.
Manuals and User Manuals:
Document Language Date Size
Quick Start Guide English - English,Estonian,Latvian,Lettish,Lithuanian,Russian 10.31.2019 55 631K
Quick Start Guide English - English,Estonian,Latvian,Lettish,Lithuanian,Russian 10.31.2019 No data
Quick start guide English 09.13.2017 4888K
You can download the files from the manufacturer's website for the 49LJ540V model.
TV LG 49LJ540V with LCD SDL490FY, diagonal size 48.5 "(123 cm) 16: 9 format. The LCD panel implements the principle of direct backlight display with rear LEDs - Direct LED.
The SDL490FY sensor and the MainBoard EAX67129604 software provide viewing of broadcasts and movies in high quality HD at a resolution of 1920x1080 pixels in graphics resolution at 1080p (Full HD).
The 49LJ540V TV model has built-in SMART software and webOS operating system installed. The connection to the network can be carried out via Wi-Fi wireless connection. Supported media file formats: MP3, WMA, MPEG4, Xvid, MKV, JPEG.
Speaker power of 10 W (2x5 W) is provided by two speakers. The NICAM stereo audio processing system and the Sound Surround function are used.
Communication with other devices via an external interface is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x2, USB, Ethernet (RJ-45), Wi-Fi 802.11ac, WiDi, Miracast.
The digital tuner can receive TV channels in the DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2 standards.
The TV uses a 168P-L4R032-W1 power supply.
Dimensions: with stand 1104x710x251 mm, without stand 1104x649x91 mm.
TV weight: with stand: 11.3 kg, without stand: 11 kg.
Attention! The SDL490FY panel of the LG 49LJ540V LED TV is an expensive and unreliable element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.