Technical description and composition of the LG 24LB457U TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 24LB457U
Chassis / Version: MT55 / LD41A
Panel: V236BJ1-LE2 Rev. C1
LED backlight: LG Innotek 23.6inch Rev0.1 140310
T-CON: MT3151A05-3-XC-1
LED driver (backlight): integrated into MainBoard
PWM LED driver: DT1641AS
MOSFET LED driver: SMK630D
Power Supply (PSU): Adapter 19V
MainBoard: EAX65377507 (1.0)
IC MainBoard: LGE2134, AT24C256C, MX25L8006E, H27U1G8F2CTR-BC, BA7657F, TAS5733, AOD478
Tuner: TDJM-G101D
Specifications 24LB457U
LG 24LB457U
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 24LB457U TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
Failure in such cases should begin to look in the adapter power supply circuits.
The external adapter 19V power supply is not always subject to repair, especially since the owner can purchase it independently. But, in some cases, it makes sense to open it and eliminate the simple typical defects inherent in converters in pulsed sources. It is necessary to measure its output voltages and, in case of their absence, check the serviceability of power switches and rectifier diodes in the converters for possible breakdown.
In case of diode breakdowns in the secondary circuits, the converter can operate in emergency short-circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key 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 (OOS) stabilization circuits. 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 is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To check the health in 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 test each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black 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. A zener diode PN transition is indirectly indicative of a LED-a
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the EAX65377507 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). Board repair and replacement of LGE2134, AT24C256C, MX25L8006E, H27U1G8F2CTR-BC, BA7657F, TAS5733, AOD478 microcircuits are carried out with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
If there is no reception of television channels, but the TV is working properly from external devices, first of all it is necessary to check the voltage of the tuner TDJM-G101D and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Owners of the 24LB457U TV are advised to contact qualified personnel with the necessary work experience for repairs! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
Service manual and schematic diagram LG 24LB457U Chassis LD41A
FIRMWARE SPI FLASH LG 24LB457U MT55 / LD41A, Main: EAX65377507 (1.0), Panel: V236BJ1-LE2 Rev.C1
To reduce the backlight current in LED drivers with a 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 EAX65377507 is shown in the figure below:EAX65377507
EAX65377507 can be used in TVs:
LG 28LB450U ZB (Panel 328041563 Kenmos), LG 24LB450U ZB (Panel V236BJ1-LE2 REV.C1), LG 24MT45V LG 24MT45V-PZ (Panel V236BJ1-LE2 Rev.C1), LG 24LB457U (Panel V236BJ1-LE2 LG 22MT55V 22MT55V-PZ (Panel LM215WF3 (SL) (K1)), LG 22LB450U (Panel 1366x768 HD).
Main features of the device LG 24LB457U:
Installed matrix (LED-panel) V236BJ1-LE2 Rev. C1.
The matrix control uses the Timing Controller (T-CON) MT3151A05-3-XC-1.
To power the backlight LEDs, a converter is used, combined with the main board EAX65377507, controlled by the DT1641AS PWM controller. As power elements of the LED driver, keys of the SMK630D type are used.
To power all the internal components of the LG 24LB457U TV, an external adapter 19V type source is used.
MainBoard - the main board (motherboard) is an EAX65377507 module, using chips LGE2134, AT24C256C, MX25L8006E, H27U1G8F2CTR-BC, BA7657F, TAS5733, AOD478 and others.
The TDJM-G101D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V236BJ1-LE2
Type: a-Si TFT-LCD, Panel
Diagonal size: 23.6 inch
Resolution: 1366x768, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 521.471x293.184 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8.5 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V
