Thursday, 27 February 2020

REPAIR / SERVICING TV LG 42LH2000

Technical description and composition of the LG 42LH2000 TV, panel type and applicable modules. The composition of the modules.
LG
Model: 42LH2000 ZA.ARUVLH
Chassis / Version: LD91A / G
Panel: LC420WXE (SB) (A1)
Inverter (backlight): integrated into PSU
PWM Inverter: BD9215F
Power Supply (PSU): EAX55357701 / 32, LGP37-09LH
PWM Power: ICE2PCS06 (PFC), STR-W6252
MOSFET Power: 07N60C3
MainBoard: EAX60686904 (2)
IC MainBoard: Cpu: LGE3368A-LF-SF, NAND: HY27US08121B-TPCB, SPI Flash: W25X32VSIG, Eeprom: IC105- M24512, 24WC08, Audio amplifer: NTP-3100L
Tuner: TDFW-G235D EBL60658001
Specifications 42LH2000
LG 42LH2000
General recommendations for repairing TV LCD
Possible manifestations of defects
- LG 42LH2000 does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to control buttons.
With such manifestations, a malfunction is most likely to be detected in the EAX55357701 power supply module. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is first necessary to check the power switches (07N60C3) and rectifier diodes for a possible partial or complete breakdown.
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.
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. PWM ICE2PCS06 (PFC), STR-W6252 microcircuits can also cause a malfunction (breakdown) of the power switches of the converter and are checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
These manifestations can be triggered by a power module, or by defects in the inverter, as well as a distortion of the currents in the lamps due to their uneven wear. After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, it is necessary to ring in its converter the power switches for breakdown and the secondary windings of the 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 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 EAX60686904 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 Cpu: LGE3368A-LF-SF, NAND: HY27US08121B-TPCB, SPI Flash: W25X32VSIG, Eeprom: IC105-M24512, 24WC08, Audio amplifer: NTP-3100L. 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 TDFW-G235D EBL60658001 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.
Owners and users of the LG 42LH2000 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 42LH2000, 42LH2010 Chassis LD91A



 The appearance of the MainBoard EAX60686904 is shown in the figure below:
EAX60686904
EAX60686904 can be used in TVs:
LG 32LD320 (Panel T315XW03 V1), LG 32LD320-ZA (Panel T315XW03), LG 32LH4000-ZA (Panel LC320WUN), LG 32LH2000 (Panel LK315T3LA57), LG 32LH2010 (Panel LK315T3LA57), LG 32LF2510 ZB (Panel LC320WUN (SA)(B3)), LG 37LH2000 (Panel LC370WXE (SB)(A1)), LG 19LD320 ZA (Panel M185B1-L02 Rev.C3), LG 26LH2000 (Panel T260XW02 V.R), LG 32LG2100 (Panel LC320WXN), LG 22LH2000 ZA (Panel V216B1-L02), LG 42LH2000 ZA.ARUVLH (Panel LC420WXE (SB)(A1)), LG 32LD321 32LD321-ZB (Panel T315XW03 V1), LG 26LD320 (Panel T260XW04 V.3), LG 19LH2000 19LH2000-ZA (Panel M185B1-L03).
The appearance of the power supply
Main features of the device LG 42LH2000:
Installed matrix (LCD panel) LC420WXE (SB) (A1).
To power the backlight, a converter is used, combined with the power supply, controlled by the BD9215F PWM controller.
The necessary supply voltages for all nodes of the LG 42LH2000 TV are generated by the EAX55357701 power supply module or its analogs using ICE2PCS06 (PFC), STR-W6252 microcircuits and 07N60C3 type power switches.
MainBoard - the main board (motherboard) is an EAX60686904 module using Cpu chips: LGE3368A-LF-SF, NAND: HY27US08121B-TPCB, SPI Flash: W25X32VSIG, Eeprom: IC105-M24512, 24WC08, Audio amplifer: NTP-3100L: others.
The TDFW-G235D EBL60658001 tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420WXE-SBA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1366x768, WXGA
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating
Brightness: 500 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit)
Response Time: 5 (G to G)
Frequency: 60Hz
Lamp Type: 18 pcs EEFL Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V