Technical description and composition of the LG 49UK7550 TV, panel type and modules used. The composition of the modules.LG LED
Model: 49UK7550
Chassis / Version: LJ8 Chassis
Panel: LC490EQG FL M1
LED backlight: 6916L-3103A 6916L-3103B 6922L-0241A
LED driver (backlight): integrated into MainBoard
PWM LED driver: 64-LQFP
MOSFET LED driver: TO-252
Power Supply (PSU): EAX67645501 EAY64808601
PWM Power: PFC, PWM (SO-14)
MOSFET Power: N-FET TO-220F, TO-252
MainBoard: EAX67872805 (1.1) EBT65198603
IC MainBoard: CPU, eMMC, DRAM, AUDIO, DC / DC
Tuner: TDJA-G601D
Specifications 49UK7550
LG 49UK7550
General recommendations for TV LCD LED repair
Possible malfunctions
- LG 49UK7550 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.
With such manifestations, the power supply module EAX67645501 usually fails. 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 (N-FET TO-220F, TO-252) and the rectifier diodes of the converters for a possible short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can operate in an emergency mode in a short-circuit mode, and in case of a short circuit in the power elements of the primary circuit, the mains fuse is usually cut 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 the PWM regulator, in frequency setting or damper circuits, as well as in negative feedback stabilization. PWM microcircuits (PWM) PFC, PWM (SO-14) are usually checked by replacing them with new ones, or knowingly working properly.
- There is no image, there is sound, it reacts to the remote control. Or the image may appear for a second when turned on and immediately disappear.
Often, in such cases, there is no backlighting of the LED panel. Often the cause of a malfunction is the lack of current in the LED circuit, for example, their open or short circuit, or a violation of the contact connections of the connectors.
To check the health of the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED separately with a simple Chinese multimeter (powered by 9 volts) in the P-N transition test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black one to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. The serviceability of the PN junction of the Zener diode indirectly indicates the serviceability of the LED-a
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals the standby mode.
If LG 49UK7550 has no picture, but there is sound, often the LCD backlight of the LC490EQG FL M1 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 LC490EQG 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 panelsIf 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 EAX67872805 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 EAX67872805 with an oscilloscope, as well as synchronizing 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.
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Repair or diagnostics of the EAX67872805 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 - CPU, eMMC, DRAM, AUDIO, DC / DC which may need to be replaced with new ones. If a BGA processor is installed, there is a possibility that the soldering of the contacts of its pins with the board is broken (detected by warming up).
If there is no tuning for terrestrial or cable TV channels, you should make sure that the software is correct, as well as that the supply voltages on the TDJA-G601D tuner outputs match. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Once again, we remind TV users: do not try to repair yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repairs to professionals with sufficient experience in the field of electronic repair.
Additional MainBoard RepairThe appearance of the MainBoard EAX67872805 is shown in the figure below:
EAX67872805
Main features of the LG 49UK7550 device:
Installed matrix (LED panel) LC490EQG FL M1.
To power the backlight LEDs, a converter combined with the EAX67872805 main board is used, controlled by a 64-LQFP 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 49UK7550 TV is carried out by the EAX67645501 power module, or its analogs using PFC, PWM (SO-14) microcircuits and N-FET TO-220F, TO-252 power switches.
MainBoard - the main board (motherboard) is an EAX67872805 module, using CPU, eMMC, DRAM, AUDIO, DC / DC chips and others.
Tuner TDJA-G601D provides reception of television programs and tuning to channels.
There are files to download for model 49UK7550PLA from the manufacturer:Files with updates and instructions:
File Description File Name Type Date Size
SW File (Version 05.10.45). Update instructions TV_Software_Update_Guide_v3.pdf PDF 28.03.2020 2014K
SW File (Version 05.10.45). Firmware (USB) Software_File (Version_05.10.45) .zip ZIP 28.03.2020 864323K
Compatible with 43UK6200PLA, 43UK6300LLB, 43UK6300MLB, 43UK6300PLB, 43UK6390PLG, 43UK6400PLF, 43UK6450PLC, 43UK6470PLC, 43UK6500LLA, 43UK6500MLA, 43UK6500PLA, 43UK6510PLB, 43UK6550PLD, 43UK6710PLB, 43UK6750PLD, 43UK6950PLB, 49UK6200PLA, 49UK6300MLB, 49UK6300PLB, 49UK6390PLG, 49UK6400PLF, 49UK6450PLC, 49UK6470PLC, 49UK7500PLC, 49UK7550LLA, 49UK7550MLA, 49UK7550PLA, 50UK6300LLB, 50UK6300MLB, 50UK6300PLB, 50UK6410PLC, 50UK6470PLC, 50UK6500LLA, 50UK6500MLA, 50UK6500PLA, 50UK6510PLB, 50UK6710PLB, 50UK6750PLD, 50UK6950PLB, 55UK6200PLA, 55UK6300LLB, 55UK6300MLB, 55UK6300PLB, 55UK6400PLF, 55UK6470PLC, 55UK6500LLA, 55UK6500MLA, 55UK6500PLA, 55UK6510PLB, 55UK6550PLD, 55UK6710PLB, 55UK6750PLD, 55UK6950PLB, 55UK7500PLC, 55UK7550LLA, 55UK7550MLA, 55UK7550PLA, 60UK6200PLA, 65UK6300LLB, 65UK6300MLB, 65UK6300PLB, 65UK6400PLF, 65UK6470PLC, 65UK6500MLA, 65UK6500PLA, 65UK6710PLB, 65UK6750PLD, 65UK6950PLB, 65UK7550LLA, 65UK7550MLA, 65UK7550PLA, 70UK6500PLB, 70UK6710PLA, 70UK6950PLA, 75UK6200PLB, 75UK6500PLA, 75UK6750PLB.
User Manuals and Instructions:
Document Language Date Size
Quick Start Guide English - English, Estonian, Latvian, Lettish, Lithuanian, Russian 07.14.2020 No data
Quick Start Guide English - English, Estonian, Latvian, Lettish, Lithuanian, Russian 14/07/2020 55 963K
Quick start instructions Russian 05/06/2018 4125K
Files can be downloaded from the manufacturer's website for model 49UK7550PLA.
LG 49UK7550 TV with LCD display LC490EQG-FLM1, diagonal size 48.5 "(123 cm) in 16: 9 format. This model uses a panel with edge LED backlighting - Edge LED.
The LC490EQG-FLM1 sensor and MainBoard EAX67872805 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 49UK7550 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. 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 EAX67645501 power supply.
Dimensions: with stand 1102x717x248 mm, without stand 1102x644x64 mm.
TV weight: with stand: 14.5 kg, without stand: 13 kg.
Attention! The LC490EQG-FLM1 panel of the LG 49UK7550 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.