Technical description and composition of the LG 42LH5000 TV, panel type and applicable modules. The composition of the modules.LG
Model: 42LH5000 42LH5000-ZB.BRUVLJU
Chassis / Version: LD91B
Panel: LC420WUF (SB) (M1)
T-CON: 6870C-4100D LC420 / 470WUF-SBM1_SBL
Inverter (backlight): integrated into PSU
Power Supply (PSU): PLHL-T839A EAY57681701 2300KPG107A-F
MainBoard: EAX57644502
Tuner: Tuner
Control: MKJ42519618 = MKJ42519601 = MKJ42519615
Specifications 42LH5000
LG 42LH5000
General recommendations for repairing TV LCD
Possible manifestations of defects
- The LG 42LH5000 TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
In such cases, the fault should be sought first in the PLHL-T839A power supply module. It is then necessary to measure its output voltages and, if they are absent, it is necessary to check the power switches and rectifier diodes of the converters for a short-circuit probability.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often 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, 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.
Sometimes, for diagnostic purposes, inverter protection must be disabled. In such cases, special care must be taken during work, and the protection circuits should be restored immediately after the repair is completed.
- 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 EAX57644502 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 there is no reception of television channels, but the TV is working properly from external devices, first of all it is necessary to check the voltage of the tuner tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Owners and users of the LG 42LH5000 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 42LH5000 Chassis LD91B
The appearance of the MainBoard EAX57644502 is shown in the figure below:
EAX57644502
EAX57644502 can be used in TVs:
LG 37LH5000 (Panel LC370WUD (SB)(M1)), LG 47LH5000 ZB (Panel LC470WUF (SB)(M1)), LG 42LH5000 42LH5000-ZB.BRUVLJU (Panel LC420WUF (SB)(M1)).
The appearance of the power supply
Main features of the device LG 42LH5000:
Installed matrix (LCD panel) LC420WUF (SB) (M1).
The matrix control uses the Timing Controller (T-CON) 6870C-4100D.
To power the backlight, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the LG 42LH5000 TV is carried out by the PLHL-T839A power supply module, or its analogs.
MainBoard - the main board (motherboard) is an EAX57644502 module.
The Tuner provides TV reception and channel tuning.