Saturday, 29 February 2020

REPAIR / SERVICING TV LG 43UF680V

Technical description and composition of the LG 43UF680V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 43UF680V
Chassis / Version: LC59L
Panel: LC430EGE
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX66453801 (1.7)
MainBoard: EAX66564303 (1.0)
IC MainBoard: CPU: LGE5332 (LM14A), SPI Flash: 25Q32, EEPROM: 24C256, DRAM: K4B4G1646D-BCMA
Tuner: TDJM-G301D p / n: EBL61560001
Specifications 43UF680V
LG 43UF680V
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The LG 43UF680V TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
Most likely in this case, the main switching power supply (IIPS) EAX66453801 is faulty. It is then necessary to measure its output voltages and, if they are absent, you should check the power switches and rectifier diodes of the converters for the probability of a short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback circuits (OOS) of stabilization. PWM controllers (PWM), if they do not have visible damage to the chassis and open short circuit between the terminals, are usually checked by replacement.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
As a rule, in such cases there is no display backlight. The reason can be both in the power of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
To check the LED strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EAX66564303 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: LGE5332 (LM14A), SPI Flash: 25Q32, EEPROM: 24C256, DRAM: K4B4G1646D-BCMA and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
If a tuner TDJM-G301D p / n is suspected to be malfunctioning: EBL61560001, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary power supply voltage levels and data exchange pulses with the processor via the I2C bus on the corresponding tuner pins.

 If the LG 43UF680V has no picture, but there is sound, the LC430EGG-FHM1 display backlight often 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 LC430EGG-FHM1 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 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 EAX66564303 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, 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 EAX66564303 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.

Owners and users of the LG 43UF680V TV should 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!


DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>     LG 43UF6800 Chassis LC59L    for models  43UF680* 43UF680*-ZA, 43UF6807, 43UF680V, 43UF6857



 Main features of the device LG 43UF680V:
Installed matrix (LED-panel) LC430EGE.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the LG 43UF680V TV is carried out by the EAX66453801 power supply module, or its analogs.
MainBoard - the main board (motherboard) is an EAX66564303 module using CPU chips: LGE5332 (LM14A), SPI Flash: 25Q32, EEPROM: 24C256, DRAM: K4B4G1646D-BCMA and others.
Tuner TDJM-G301D p / n: EBL61560001 provides the reception of television programs and tuned to channels.


 LG 43UF680V LCD TV with LC430EGG-FHM1 LCD, 43 "(109 cm) 16: 9 format diagonal. This model uses a panel with edge LED backlighting - Edge LED.
The LC430EGG-FHM1 sensor and MainBoard EAX66564303 software are capable of realizing the highest UHD image quality at 3840x2160 4K UHD resolution.
The 43UF680V 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, HEVC (H.265), MKV, JPEG.
Speaker 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 x2, USB, Ethernet (RJ-45), Bluetooth, Wi-Fi, WiDi, Miracast. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is provided. This interface supports standard resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080, 3840x2160.
The digital tuner can receive TV channels in the DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2 standards.
The TV uses an EAX66453801 power supply.
Dimensions: With stand 971x628x180 mm, Without stand 971x570x56 mm.
Attention! Panel LC430EGG-FHM1 LED-TV LG 43UF680V 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.