Technical description and composition of the LG 24LB450U TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 24LB450U ZB
Chassis / Version: LD41A
Panel: V236BJ1-LE2 REV.C1
LED backlight: LG Innotek 23.6inch Rev0.1 140310
LED driver (backlight): integrated into MainBoard
PWM LED driver: DT1641AS
MOSFET LED driver: AOD478 N-Channel 100V, 11A, TO-252
Power Supply (PSU): PSAB-L205B 19V 2.1A p EAY62850202
MainBoard: EAX65377507 (1.0)
IC MainBoard: LGE21332, H27U1G8F2CTR, M24C256, MX25L8006EM2I, TAS5733
Tuner: TDJM-G101D
Technical Specifications 24LB450U
LG 24LB450U
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 24LB450U TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
With such manifestations, in some cases, the PSAB-L205B power module is faulty. 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 breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually 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, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately disappears
Usually in such cases, a malfunction is detected in the backlight nodes of the LED panel. 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.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- 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). Often, the MB (SSB) card needs to be replaced in case of complex faults that are difficult to detect. When trying to repair, you should check its elements - LGE21332, H27U1G8F2CTR, M24C256, MX25L8006EM2I, TAS5733 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.
Before changing the tuner TDJM-G101D, if it is not possible to tune to television channels, you should make sure that there are supply voltages that 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 controlled by an oscilloscope
Attention! For users and owners of 24LB450U TVs who do not have the appropriate qualifications, knowledge and experience, we strongly recommend against self-repair attempts to avoid negative consequences that could lead to complete non-repairability of the device.
Service manual and schematic diagram -----------------------> LG 24LB450U Chassis MT55/LD41A.
CHASSIS : LA40A / LD41A; MODEL : 24LB45**, 24LB45**-Z*
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 Rev.C1), LG 22MT55V 22MT55V-PZ (Panel LM215WF3 (SL)(K1)), LG 22LB450U (Panel 1366x768 HD).
Main features of the device LG 24LB450U:
Installed matrix (LED panel) V236BJ1-LE2 REV.C1.
To power the backlight LEDs, a converter is used, combined with the main board EAX65377507, controlled by the DT1641AS PWM controller. As the power elements of the LED driver, keys of the type AOD478 N-Channel 100V, 11A, TO-252 are used.
The formation of the necessary supply voltages for all nodes of the LG 24LB450U TV is carried out by the PSAB-L205B power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX65377507 module, using LGE21332, H27U1G8F2CTR, M24C256, MX25L8006EM2I, TAS5733 and other chips.
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
