REPAIRING / SERVICING TV LG 49UJ670V

Technical description and composition of the LG 49UJ670V TV, panel type and modules used. The composition of the modules.
LG LED
Model: 49UJ670V
Chassis / Version: EAX67133404
Panel: LC490DGG (FK) (M7)
LED backlight: 6916L-2862A, 6916L-2863A
LED driver (backlight): integrated into PSU
PWM LED driver: MAP3516
MOSFET LED driver: MDD7N25
Power Supply (PSU): EAX67128101 (2.1) LGP49D-17V2
PWM Power: SSC3S927
MainBoard: EAX67133404 (1.0)
IC MainBoard: Realtek K3Lp, FT24C256A, DTA2010M
Tuner: TDJN-G501D EBL61841001
Specifications 49UJ670V
LG 49UJ670V
General recommendations for TV LCD LED repair
Possible manifestations of defects
- LG 49UJ670V TV does not turn on at all. Control lamps do not light up or blink. The TV on the remote control and control panel buttons does not respond.
In such cases, the power supply EAX67128101 usually fails. It is necessary to measure its output supply voltages, and if they are absent, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in semiconductor PN junctions.
In case of breakdowns in the secondary circuits of the converter, it can usually work in an emergency mode in a short-circuit mode, and with a short circuit in the power elements of the primary circuit, the mains fuse or current sensor in the source of the key most often breaks off.
Breakdown of power switches (MosFet) in switching sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency setting or damper, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM controllers (PWM) SSC3S927, if they do not have visible damage to the case and an outright short circuit between the terminals, are usually checked by replacing.
- There is no picture, but there is sound and reaction to the remote control. Or, for a second, the image may appear immediately after switching on.
A malfunction is usually in these cases most likely in the backlight units of the display matrix. 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,
It should be remembered that it is not possible to determine an open circuit in the LED lines without disassembling the panels using a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then you need to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow opening the LED in the forward direction or dual LEds are used, then the PN transition of the emergency zener diode can indirectly serve as an indicator of serviceability. In the event of a malfunction of the LED-a, the PN-junction of the zener diode will either be cut off or broken into the K / Z.
- The indicator blinks or is on constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the EAX67133404 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). Complicated repair of MB (SSB) board is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the Realtek K3Lp, FT24C256A, DTA2010M elements. BGA chip faults are usually easy to detect by warm-up.


 If LG 49UJ670V has no picture, but there is sound, often the LCD backlight LC490DGG (FK) (M7) 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 LC490DGG 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 EAX67133404 often turns out to be faulty, a software failure is also possible.
Then, first of all, you need 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 EAX67133404 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.
strips

Before changing the tuner TDJN-G501D EBL61841001, if it is not possible to tune to television channels, you should make sure that there are supply voltages, which must be measured at the corresponding terminals of the tuner and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be monitored with an oscilloscope

Attention to TV owners! Attempts to repair LG 49UJ670V on your own are not recommended by the manufacturer and can lead to serious negative consequences!

DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    CHASSIS : UD74P for models 49UJ67*V, 49UJ67*V-ZD/ZC, 49UJ655V, 49UJ655V-ZC, 49UJ701V, 49UJ701V-ZC, 49UJ670V, 49UJ675V

Additional MainBoard Repair
The appearance of the MainBoard EAX67133404 is shown in the figure below:
EAX67133404
External view of the power supply
Main features of the LG 49UJ670V device:
Installed matrix (LED-panel) LC490DGG (FK) (M7).
A converter combined with a power supply is used to power the backlight LEDs, it is controlled by the MAP3516 PWM controller. The keys of the MDD7N25 type are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the LG 49UJ670V TV is carried out by the EAX67128101 power module, or its analogs using SSC3S927 microcircuits.
MainBoard - the main board (motherboard) is an EAX67133404 module, using Realtek K3Lp, FT24C256A, DTA2010M and others.
Tuner TDJN-G501D EBL61841001 provides reception of television programs and tuning to channels.

There are files to download for model 49UJ670V from the manufacturer:

Files with updates and instructions:
File Description File Name Type Date Size
SW File (Version 05.80.50). Update instructions TV_Software_Update_Guide_v3.pdf PDF 01/22/2020 2014K
SW File (Version 05.80.50). Firmware (USB) Software_File (Version_05.80.50) .zip ZIP 01/22/2020 831673K
Compatible with 43UJ620V-ZA, 43UJ6307-ZA, 43UJ6309-ZA, 43UJ630V-ZA, 43UJ631V-ZA, 43UJ634V-ZD, 43UJ635V-ZF, 43UJ639V-ZE, 43UJ6517-ZA, 43UJ6519-ZA, 43UJ651V-ZA, 43UJ655V-ZC, 43UJ670V-ZD, 43UJ675V-ZC, 43UJ701V-ZC, 49UJ620V-ZA, 49UJ6307-ZA, 49UJ6309-ZA, 49UJ630V-ZA, 49UJ631V-ZA, 49UJ634V-ZD, 49UJ635V-ZF, 49UJ639V-ZE, 49UJ6517-ZA, 49UJ6519-ZA, 49UJ651V-ZA, 49UJ655V-ZC, 49UJ670V-ZD, 49UJ675V-ZC, 49UJ701V-ZC, 55UJ620V-ZA, 55UJ6307-ZA, 55UJ6309-ZA, 55UJ630V-ZA, 55UJ634V-ZD, 55UJ635V-ZF, 55UJ6517-ZA, 55UJ6519-ZA, 55UJ651V-ZA, 55UJ655V-ZC, 55UJ670V-ZD, 55UJ675V-ZC, 55UJ701V-ZC, 55UK6100PLA, 55UK6100PLB, 60UJ6307-ZA, 60UJ6309-ZA, 60UJ630V-ZA, 60UJ634V-ZD, 60UJ6517-ZA, 60UJ6519-ZA, 60UJ651V-ZA, 65UJ620V-ZA, 65UJ6307-ZA, 65UJ6309-ZA, 65UJ630V-ZA, 65UJ634V-ZD, 65UJ6517-ZA, 65UJ6519-ZA, 65UJ651V-ZA, 65UJ655V-ZC, 65UJ670V-ZD, 65UJ675V-ZC, 65UJ701V-ZC, 65UK6100PLA, 65UK6100PLB, 70UJ675V-ZA, 75UJ651V-ZB, 75UJ675V-ZA.
User Manuals and Instructions:
File type File name Language Date Size
User manual ENG.pdf English 10/26/2017 22894K
Quick Start Guide w3.5_mr_e05_c.zip English, Estonian, Latvian, Lettish, Lithuanian, Russian 10/31/2019 56,267K

The files can be downloaded from the manufacturer's website for the 49UJ670V model.

LG 49UJ670V TV with LCD display LC490DGG (FK) (M7), diagonal size 48.5 "(123 cm) 16: 9 format. The LCD-panel implements the principle of direct backlight display with rear-mounted LEDs - Direct LED.
The LC490DGG sensor and MainBoard EAX67133404 mainboard software are capable of realizing the highest UHD image quality at 3840x2160 resolution in 4K UHD, HDR. Image processing is performed using modern High Dynamic Range (HDR) technology with an extended range of brightness gradations.
The 49UJ670V 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, HEVC (H.265), DivX, MKV, JPEG.
Speaker sound system power 20 W (2x10 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 x4, USB x2, Ethernet (RJ-45), Bluetooth, Wi-Fi 802.11ac, WiDi, Miracast. A headphone jack is provided.
The digital tuner can receive TV channels in the DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2 standards.
The TV uses an EAX67128101 power supply.
Dimensions: With stand 1107x705x259 mm, Without stand 1107x645x79 mm.
Attention! The LC490DGG panel of the LG 49UJ670V 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.