Wednesday, 27 January 2021

REPAIRING / SERVICING TV LG 49UF640V

 Technical description and composition of the LG 49UF640V TV, panel type and modules used. The composition of the modules.

LG LED
Model: 49UF640V ZA

Chassis / Version: EAX66485504

Panel: NC490DGG-SADP1

LED backlight: LGE_WICOP_49INCH_UHD_REV06_B_150710

LED driver (backlight): integrated into PSU

PWM LED driver: SOP-16

MOSFET LED driver: TO-252

Power Supply (PSU): EAX66490701 (1.5) EAY64009501

PWM Power: SOP-18

MOSFET Power: TO-252

MainBoard: EAX66485504 (1.0) EBT64028601

IC MainBoard: CPU, eMMC, DRAM, DC / DC, AUDIO

Tuner: TDJM-G301D EBL6156000

49UF640V Specifications
LG 49UF640V
General recommendations for TV LCD LED repair
Possible malfunctions

- LG 49UF640V TV does not turn on at all. No response to the remote control and front panel control buttons. Indicator lamps do not light up or flash.

In some of these cases, the main switching power supply, the EAX66490701 module, is faulty. Its output voltages should be measured and, in their absence, the serviceability of the power switches (TO-252) and rectifier diodes in the converters should be checked for possible breakdown.
In case of breakdowns in the secondary circuits, the converter can operate in short-circuit mode, and in case of short-circuit in the elements of the primary circuit, the mains fuse usually breaks off.
Breakdown of Mos-Fet switches used in switching power supplies is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM regulator, in frequency-setting or damper circuits, as well as in negative feedback stabilization. PWM microcircuits (PWM) SOP-18 are usually checked by replacing them with new ones, or knowingly working.

- 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.

The backlight of the matrix (LED panel) is usually faulty in these cases. The reason can sometimes be in the power supply of the LEDs, but more often in their malfunction (breakdown or open circuit), sometimes in the violation of the contact connections of the LED strips LGE_WICOP_49INCH_UHD_REV06_B_150710.
To identify an open circuit in the LED lines without disassembling the panel, a current source is required. It is impossible to open the junctions connected in series with a simple multimeter; a voltage of several tens of volts is required.

- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals the standby mode.

Repair or diagnostics of the EAX66485504 motherboard should start with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Repair of the board and replacement of CPU, eMMC, DRAM, DC / DC, AUDIO microcircuits are made if the necessary equipment and the corresponding element base are available. Failures associated with the use of BGA soldering technologies can be localized by warming up.

If LG 49UF640V has no picture, but there is sound, often the NC490DGG-SADP1 display backlight 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 NC490DGG-SADP1 LCD panel - a process that requires experience and qualifications from the technician. 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 light through the holes in the panel case.
In this case, the panel may also be faulty - damage to 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 EAX66485504 often turns out to be faulty, a software failure is also possible.
Then, first of all, you need to check the panel supply voltage, 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 normal limits, it is necessary to trace the passage of LVDS signals from the MainBoard EAX66485504 with an oscilloscope, as well as synchronization signals to the loops with 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.

If the TV operates normally from external devices, but does not tune to TV channels, the TDJM-G301D EBL6156000 tuner may be faulty. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the reason for the inoperability of the tuner may be a software failure.

Attention! Users and owners of 49UF640V TVs who do not have the appropriate qualifications, knowledge and experience are strongly discouraged from attempting to repair themselves in order to avoid negative consequences that can lead to complete non-repairability of the device.


DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------> CHASSIS : LD59R / LD5ZR  FOR MODELS:    43UF640*, 49UF640*, 43/49UF640*-ZA, 43UF6407, 43UF640V, 49UF6407, 49UF640V.


Additional MainBoard Repair

The appearance of the MainBoard EAX66485504 is shown in the figure below:






EAX66485504

External view of the power supply

Main features of LG 49UF640V device:

Installed matrix (LED panel) NC490DGG-SADP1.
To power the backlight LEDs, a converter combined with a power supply is used, controlled by the SOP-16 PWM controller. TO-252 switches are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the LG 49UF640V TV is carried out by the EAX66490701 power supply module, or its analogs using SOP-18 microcircuits and TO-252 power switches.



MainBoard - the main board (motherboard) is an EAX66485504 module using CPU, eMMC, DRAM, DC / DC, AUDIO and others.
Tuner TDJM-G301D EBL6156000 provides reception of television programs and tuning to channels.



Instructions and updates

There are files to download for the 49UF640V model from the manufacturer:

Files with updates and instructions:
File Description File Name Type Date Size
SW File (Version 03.16.00). Update instructions TV_Software_Update_Guide_v3.pdf PDF 06/18/2020 2014K
SW File (Version 03.16.00). Firmware (USB) Software_File (Version_03.16.00) .zip ZIP 18.06.2020 515617K
 

Compatible with 43UF6407-ZA, 43UF6409-ZA, 43UF640V-ZA, 49UF6407-ZA, 49UF6409-ZA, 49UF640V-ZA.
SW File (Version 03.15.50) for models 43UF640V-ZA, 49UF640V-ZA, 43UF6407-ZA, 49UF6407-ZA. Update instructions TV_Software_Update_Guide_v3.pdf PDF 09.11.2017 1938K

User Manuals and Instructions:
Document Language Date Size
Quick Start Guide English - English, Estonian, Latvian, Lettish, Lithuanian, Russian 24/11/2015 13420K
Quick Start Guide English - English, Estonian, Latvian, Lettish, Lithuanian, Russian 24/11/2015 No data
User manuals English - English, Estonian, Latvian, Lettish, Lithuanian 09.02.2015 24 705K

Files can be downloaded from the manufacturer's website for the 49UF640V models



TV LG 49UF640V with LCD NC490DGG-SADP1, diagonal size 49 "(124 cm) 16: 9 format. The display technology of this model is implemented with LED backlighting.
The NC490DGG-SADP1 sensor and the MainBoard EAX66485504 software are capable of realizing the highest UHD quality at 3840x2160 4K UHD resolution.
The 49UF640V 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. The input analog video signal is decoded in PAL, SECAM, NTSC systems. Graphic processing of a digital signal is carried out in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p, 2160p. Supported media file formats: MP3, WMA, MPEG4, DivX, JPEG. Stereo sound is provided by two built-in 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, audio x2, component, HDMI x2, USB, Ethernet (RJ-45), Wi-Fi. A VGA (D-Sub 15) connector is provided to connect a computer or laptop to this TV model. This interface supports standard resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080, 3840x2160. The digital tuner is capable of receiving TV channels in the DVB-T, DVB-T2, DVB-C, DVB-S2 standards.

The TV uses an EAX66490701 power supply.

Dimensions: With stand 975x621x209 mm, Without stand 975x582x81 mm.

Attention! Panel NC490DGG-SADP1 LED-TV LG 49UF640V 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.