Wednesday, 26 February 2020

REPAIR / SERVICING TV LG 42LE5300

Technical description and composition of the LG 42LE5300 TV, panel type and applicable modules. The composition of the modules.
LG
Model: 42LE5300
Chassis / Version: LD01D
Panel: LC420EUH (SC) (A1)
Lamp backlight: LG INNOTEK 42 V5 3660L-0352A, 3660L-0353A
Inverter (backlight): integrated into PSU
PWM Inverter: AS3693B, MEGA48PA
Power Supply (PSU): PLDF-L903A EAY60803101
PWM Power: VIPER27H (Standby), ICE2PCS04 (PFC), L6599D
MOSFET Power: TK4P60DB
MainBoard: EAX62003901 (1) EBU60981905
IC MainBoard: LGE107D, M24C16, MX25L8005, NTP-7000
Tuner: EBL60720403
Specifications 42LE5300
LG 42LE5300
General recommendations for repairing TV LCD
Possible malfunctions
- LG 42LE5300 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.
In such cases, the PLDF-L903A power supply is usually faulty. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches (TK4P60DB) and rectifier diodes for a probable 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 power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode, or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers VIPER27H (Standby), ICE2PCS04 (PFC), L6599D, in the absence of visible damage or explicit short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
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 they are finished, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- The indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.

Repair or diagnostics of the EAX62003901 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 - LGE107D, M24C16, MX25L8005, NTP-7000 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.
If there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the voltage of the tuner EBL60720403 and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Owners and users of the LG 42LE5300 TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!


schematic diagram ------------>  LG 42LE5300 Chassis LD01D



 The appearance of the MainBoard EAX62003901 is shown in the figure below:
EAX62003901
The appearance of the power supply
Main features of the device LG 42LE5300:
Installed matrix (LCD panel) LC420EUH (SC) (A1).
To power the backlight, a converter is used, combined with a power supply, controlled by a PWM controller AS3693B, MEGA48PA.
The necessary supply voltages for all nodes of the LG 42LE5300 TV are generated by the PLDF-L903A power module, or its analogs using VIPER27H (Standby), ICE2PCS04 (PFC), L6599D microcircuits and TK4P60DB type power switches.
MainBoard - the main board (motherboard) is an EAX62003901 module, using LGE107D, M24C16, MX25L8005, NTP-7000 and other chips.
The tuner EBL60720403 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUH-SCA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 1.06B (8-bit + Dithering), CIE1931 72%
Response Time: 8/12 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: Mini LVDS, 120 pins
Voltage: 12.0V