Technical description and composition of the LG 24LF450U TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 24LF450U
Chassis / Version: MT55 LD41A
Panel: V236BJ1-LE2 REV.C1
T-CON: V236BJ1-XCE2; CM1801B, CM501, CM601
LED driver (backlight): integrated into MainBoard
PWM LED driver: DT1641AS
Power Supply (PSU): LCAP16B-E Adapter 19V 2.2A
MainBoard: EAX65377508 (1.0)
IC MainBoard: CPU: LGE2134, Eeprom: 24C256, SPI: MX25L8005, Nand: H27U1G8, SOUND: TAS5733
Tuner: TDJM-G101D
Technical Specifications 24LF450U
LG 24LF450U
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 24LF450U TV does not turn on. There is no reaction to the remote control and to the control buttons from the front panel. Indicator lights do not light or flash.
Failure in such cases should be sought in the LCAP16B-E power supply circuits.
The external power adapter LCAP16B-E Adapter 19V 2.2A 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 the secondary output voltage, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for a 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.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM (PWM). It is checked only by replacement with a known good one.
- 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.
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 line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V for them. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the black to the cathode. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the EAX65377508 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). When repairing an MB board, you need to check its CPU components: LGE2134, Eeprom: 24C256, SPI: MX25L8005, Nand: H27U1G8, SOUND: TAS5733. Defective items should be replaced. If chips with BGA soldering technology are used, a problem in its implementation is detected by the local heating of the chip.
If the TV works normally from external devices, but does not tune into television channels, the TDJM-G101D may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.
Service manual and schematic diagram LG 24LF450U Chassis LW45A.
CHASSIS : LW45A; MODEL : 24LF45*A, 24LF45*A-T*
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 EAX65377508 is shown in the figure below:EAX65377508
EAX65377508 can be used in TVs:
LG 24LF450U (Panel V236BJ1-LE2 REV.C1), LG 22LF450U (Panel V236BJ1-LE2).
The appearance of the power supply
Main features of the device LG 24LF450U:
Installed matrix (LED panel) V236BJ1-LE2 REV.C1.
The matrix control uses the Timing Controller (T-CON) V236BJ1-XCE2 ;.
To power the backlight LEDs, a converter is used, combined with the EAX65377508 main board, controlled by the DT1641AS PWM controller.
To power all the internal components of the LG 24LF450U TV, an external source of the LCAP16B-E Adapter 19V 2.2A type is used.
MainBoard - the main board (motherboard) is an EAX65377508 module, using CPU chips: LGE2134, Eeprom: 24C256, SPI: MX25L8005, Nand: H27U1G8, SOUND: TAS5733 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