Technical description and composition of the LG 24LH451U TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 24LH451U ZE
Chassis / Version: LD60A
Panel: V236BJ1-LE2
LED driver (backlight): integrated into MainBoard
PWM LED driver: MP3378E
Power Supply (PSU): Adapter 19V
MainBoard: EAX66873503 (1.2)
IC MainBoard: CPU: LGE6351, Audio: M28720, SPI FLASH: 25L8005, Eeprom: 4G25 (24C256)
Tuner: EBL61741401 TDJA-G301D
Control: EBR81968402
Technical Specifications 24LH451U
LG 24LH451U
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 24LH451U TV does not turn on and does not show any signs of turning on, does not respond to the control buttons or to the remote control.
With such manifestations, a malfunction is most likely to be 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. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches and rectifier diodes for a possible partial or complete breakdown.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work abnormally in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse often 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. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- 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 some of these cases, the malfunction is caused by a lack of backlighting on the display. 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 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 junction indirectly indicates a LED-a
- The indicator blinks or glows constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the EAX66873503 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). If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - CPU: LGE6351, Audio: M28720, SPI FLASH: 25L8005. Defective components should be replaced.
If the TV works normally from external devices, but does not tune into television channels, the EBL61741401 TDJA-G301D tuner 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 24LH451U Chassis LD60A MODEL : 24LH450U, 24LH450U-ZE, 24LH451U.
To reduce the backlight current in LED drivers with the MP3378E PWM controller, it is necessary to proportionally increase the total resistance of the resistors from pin 3 (RISET) to the chassis. Calculation of current in milliamperes and resistance in kilo-ohms 977 / Rset for each channel. Parallel channels are summed. For example, for four parallel channels and a RISET 10 KOhm resistance, the total current will be 97.7 * 4 = 391 mA.
More details on this page
The appearance of the MainBoard EAX66873503 is shown in the figure below:EAX66873503
EAX66873503 can be used in TVs:
LG 22LH450V PZ (Panel HM215EUN-SLMP1 - 41XX), LG 24LH450U (Panel V236BJ1-LE2A), LG 28LH451U (Panel HC275EXN-ABVP1-41XX), LG 20MT48VF 20MT48VF-PZ (Panel 1366x768 720p HD).
Main features of the device LG 24LH451U:
Installed matrix (LED-panel) V236BJ1-LE2.
To power the backlight LEDs, a converter is used, combined with the main board EAX66873503, controlled by the MP3378E PWM controller.
To power all the internal components of the LG 24LH451U TV, an external adapter 19V type source is used.
MainBoard - the main board (motherboard) is an EAX66873503 module using CPU chips: LGE6351, Audio: M28720, SPI FLASH: 25L8005, Eeprom: 4G25 (24C256) and others.
The tuner EBL61741401 TDJA-G301D provides reception of television programs and tuning to channels.
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