Technical description and composition of the LG 29LN457U TV, type of panel and applicable modules. The composition of the modules.LG LED
Model: 29LN457U
Chassis / Version: LD31S
Panel: V290BJ1-LE1
LED backlight: V290B1-LE1-TLEM5
T-CON: V290BJ1-XC01
LED driver (backlight): integrated into MainBoard
PWM LED driver: DT1641AS (TPS40210DGQR)
MOSFET LED driver: SMK630D (AOD478)
Power Supply (PSU): Adapter 19V
MainBoard: EAX64991305 1.0
IC MainBoard: CPU: LGE2121-MS; NAND Flash: SAA36381719; SPI Flash: 25Q80; EEPROM: ATML H316 2EC; SOUND: NTP7513;
Tuner: TDSQ-G601D (B)
Control: IR: EAX64661001 (1.4)
Specifications 29LN457U
LG 29LN457U
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 29LN457U TV does not turn on and does not show any signs of being turned on, does not respond to the control buttons or to the remote control.
In some of these cases, a malfunction is detected in the adapter power module.
The owner of the TV can purchase an external power supply unit such as Adapter and repairing it is not always advisable. In any case, the simplest typical defects characteristic of most IIP schemes can be easily detected and eliminated after opening. Then it is necessary to measure its output voltages and, in case of their complete or partial absence, it is necessary to check the serviceability of power switches 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 emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM microcircuits are usually checked by replacement with new ones, or obviously working.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX64991305 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). Sometimes they require checking or replacing (if necessary) the elements of the MainBoard - CPU: LGE2121-MS; NAND Flash: SAA36381719; SPI Flash: 25Q80; EEPROM: ATML H316 2EC; SOUND: NTP7513; . In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
If there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the voltage of the tuner TDSQ-G601D (B) and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention TV owners! Self-repair attempts by LG 29LN457U are not recommended by the manufacturer and can lead to serious negative consequences!
SCHEMATIC MANUAL ---------------------------> LG CHASSIS LA31R / LD31S MODEL: 29LN45**, 29LN45**-Z*
FIRMWARE FOR SPI FLASH---------------------------> LG 29LN457U LD31S, Main: EAX64991305 1.0
To reduce the backlight current in LED drivers with the DT1641AS controller (DT1641S), you can increase the total resistance of the resistors from pin 7 (RISET) to the chassis. The exact proportional dependence may not be observed if there is additional control on this input, then the ratings should be selected empirically.
More details on this page
The appearance of the MainBoard EAX64991305 is shown in the figure below:EAX64991305
EAX64991305 can be used on TVs:
LG 29LN450U (Panel V290BJ1-LE1 REV C1), LG 29LN457U (Panel V290BJ1-LE1).
Main features of the device LG 29LN457U:
Installed matrix (LED-panel) V290BJ1-LE1.
The matrix control uses the Timing Controller (T-CON) V290BJ1-XC01.
To power the backlight LEDs, a converter is used, combined with the EAX64991305 main board, controlled by the DT1641AS PWM controller (TPS40210DGQR). As the power elements of the LED driver, keys of the type SMK630D (AOD478) are used.
To power all the internal components of the LG 29LN457U TV, an external adapter 19V type source is used.
MainBoard - the main board (motherboard) is an EAX64991305 module, using CPU chips: LGE2121-MS; NAND Flash: SAA36381719; SPI Flash: 25Q80; EEPROM: ATML H316 2EC; SOUND: NTP7513; and others.
The TDSQ-G601D (B) tuner allows you to receive television programs and tune to channels.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V290BJ1-LE1
Type: a-Si TFT-LCD, Panel
Diagonal size: 29.0 inch
Resolution: 1366x768, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 631.092x354.816 mm
Surface: Antiglare (Haze 3.5%)
Brightness: 300 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 9.5 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V