Technical description and composition of the LG 42LD425 TV, panel type and applicable modules. The composition of the modules.LG
Model: 42LD425
Panel: LC420WUG (SC) (A1)
Inverter (backlight): with integrated PSU
PWM Inverter: BD9270F
Power Supply (PSU): EAX61124202 / 2
PWM Power: STR-W6053N, HS01G (PFC)
MOSFET Power: 10NM60N (PFC)
MainBoard: EAX63329201 (9) - EBR72642730
IC MainBoard: SPI Flash: W25Q80BVSIG; EEPROM: 24C16WP, 24C08W1
Tuner: TDTJ-S001D
Control: Remote: AKB72915207, IR: 37-42-47 LD420 Rev1.0
Specifications 42LD425
LG 42LD425
General recommendations for repairing TV LCD
Possible malfunctions
- LG 42LD425 does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
With such manifestations, a malfunction may be detected in the EAX61124202 power module. In this case, it is necessary to measure the output voltages of the converters (PFC and the main source) and, if they are missing, check the power switches (10NM60N (PFC)) and rectifier diodes for a short circuit probability.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually work normally in emergency short circuit mode. There are no output voltages. And during short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and less often the current sensor at the source of the key.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback.
The health of the PWM-regulator microcircuits (PWM) STR-W6053N, HS01G (PFC) is usually checked by replacing with new or obviously working 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.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or the inverter.After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, you must ring in its converter power keys for breakdown and secondary windings of transformers for an open.
If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during work, and after their completion it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EAX63329201 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 components SPI Flash: W25Q80BVSIG; EEPROM: 24C16WP, 24C08W1. 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 with external devices, but does not tune into television channels, the TDTJ-S001D 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.
Attention! For users and owners of 42LD425 TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.
The appearance of the MainBoard EAX63329201 is shown in the figure below:EAX63329201
EAX63329201 can be used in TVs:
LG 42LD555-ZC (Panel LC420WUG (SC)(A1)), LG 32LD335 ZA (Panel T315XW03 V.1), LG 37LD425 ZA (Panel T370HW03 V.B), LG 42LD425 (Panel LC420WUG (SC)(A1)), LG 26LD335 26LD335-ZA.BRUDLJU (Panel T260XW04 V.3).
The appearance of the power supply
Main features of the device LG 42LD425:
Installed matrix (LCD panel) LC420WUG (SC) (A1).
To power the backlight, a converter is used, combined with the power supply, controlled by the BD9270F PWM controller.
The necessary supply voltages for all nodes of the LG 42LD425 TV are generated by the EAX61124202 power module or its analogs using STR-W6053N, HS01G (PFC) microchips and 10NM60N (PFC) type power switches.
MainBoard - the main board (motherboard) is an EAX63329201 module using SPI Flash chips: W25Q80BVSIG; EEPROM: 24C16WP, 24C08W1 and others.
The TDTJ-S001D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420WUG-SCA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1450: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + FRC), CIE1931 72%
Response Time: 8/10 (Tr / Td)
Frequency: 60Hz
Lamp Type: 16 pcs EEFL Without Driver
Signal Interface: Mini LVDS, 60 pins
Voltage: 12.0V