Thursday, 27 February 2020

REPAIR / SERVICING TV LG 42LK450-TG

Technical description and composition of the LG 42LK450-TG TV, panel type and applicable modules. The composition of the modules.
LG
Model: 42LK450-TG
Chassis / Version: LB01M
Panel: V420H2-L05
T-CON: V315H3-CE7
Inverter (backlight): T871135.00
PWM Inverter: BD9215
Power Supply (PSU): EAX63543801 / 9 LGP42-11P
PWM Power: HS01G (PFC), ICE3BR4765JZ (Standby DIP-7), L6599AD
MOSFET Power: 10NM60N
Mainboard: EAX64272803
IC MainBoard: LGE2111-E8, MX25L8006EM
Tuner: TDSS-G101D
Specifications 42LK450
LG 42LK450-TG
General recommendations for repairing TV LCD
Repair of all electronic devices, including the LG TV, made on the basis of the LB01M chassis, it is advisable to start with an external examination of its external and internal elements. Visible damage to elements can sometimes indicate the direction of the search for a defect even before the necessary measurements are taken. Ring cracks in the soldering of the leads of the heating elements, swollen electrolytic capacitors, a charred paint layer on the resistors - all this for the repairman can be a significant clue in the assumptions about the causes and consequences of the malfunction.
If the 42LK450-TG TV does not turn on, does not make any sounds when it is turned on, and also no indicators on the front panel light or blink - there is a high probability of a malfunction in the power module. In some cases, only the stabilizer or power converter of the control processor may be malfunctioning, which is typical for some LG models. It is advisable to start the troubleshooting of the power supply module by checking the state of the electrolytic capacitors of the rectifier filters and the mains fuse. Defective capacitors should be replaced. If the mains fuse is broken, it is necessary to check first of all the power semiconductor elements - rectifier diodes and transistors, which are often found in such a state of breakdown.
The reasons for the breakdown of the power switch in switching power supplies (IIPS) can be different, for example, a malfunction of semiconductor cells or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as a failure in the operation of the PWM controller chip or broken resistors in its bundle.
If the LG 42LK450-TG has no image, but there is sound and the TV is controlled by the remote control, a malfunction in the display backlight nodes is likely. The lamps or the power converter - inverter may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the inverter, and check the LCD lamps by connecting external and obviously serviceable for diagnosis to the connectors. It is necessary to take into account that in cases of inverter protection shutdown (in order to be able to diagnose) there is a risk of failure of the inverter power elements and take special care. After carrying out repairs, the protection circuit must be restored for further safe operation of the TV.
The EAX64272803 motherboard must be checked if there is no reaction to the remote control and function buttons, the standby indicator blinks or lights up continuously. In such cases, if the converters or power regulators of the microcircuit are working, a software update may be necessary. Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements LGE2111-E8, MX25L8006EM, Tuner: TDSS-G101D. BGA chip malfunctions are usually easy to detect by warming up.
We recommend the owners of the 42LK450-TG TV for repair only to qualified specialists with experience! Self-repair attempts without the appropriate knowledge and skills can lead to serious negative consequences!


SCHEMATIC DIAGRAM --------->  LG 42LK450, 42LK450-TG, 42LK452, 42LK452-TJ Chassis LB01M


 The appearance of the MainBoard EAX64272803 is shown in the figure below:
EAX64272803
EAX64272803 can be used in TVs:
LG 42LK450-TG (Panel V420H2-L05), LG 32LK430 ZG (Panel LC320WUN (SC)(A2)), LG 42LK430 (Panel LC420WUE (SC)(A2)), LG 42CS560 ZD (Panel LC420WUE (SC)(A3)), LG 32LV3400 ZG (Panel LC320EUN (SD)(V2)), LG 32CS560 (Panel LC320WUN (SC)(A2)), LG 32LK455 32LK455C (Panel EAX64272803).
PSU Advanced
The 42LK450-TG model uses the EAX63543801 / 9 LGP42-11P power supply unit using the PFC (Power Factor Correction) node - an active filter of higher harmonics of the current consumption. In fact, it is a step-up converter based on the HS01G PWM controller, which eliminates the charge current of the electrolytic capacitor of the rectifier filter directly from the network through open diodes when its charging current is determined by its reactance.
As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network in operating mode.
The appearance of the power supply
Main features of the device LG 42LK450-TG:
Installed matrix (LCD panel) V420H2-L05.
The matrix control uses the Timing Controller (T-CON) V315H3-CE7.
To power the backlight, an inverter T871135.00 is used, it is controlled by the BD9215 PWM controller.
The necessary supply voltages for all nodes of the LG 42LK450-TG TV are generated by the EAX63543801 power supply module or its analogs using HS01G (PFC), ICE3BR4765JZ (Standby DIP-7), L6599AD microcircuits and 10NM60N power switches.
MainBoard - the main board (motherboard) is an EAX64272803 module using LGE2111-E8, MX25L8006EM microcircuits and others.
The TDSS-G101D tuner provides TV reception and channel tuning.
Information from an alternative source:
LG 42LK450-TG chassis LB01M
Panel Type (Matrix): V420H2-L05,
Motherboard: EAX64272803, LGE2111-E8, MX25L8006EM, Tuner: TDSS-G101D
T-con: V315H3-CE7
Invertor: T871135.00, BD9215
PSU: EAX63543801 / 9
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V420H2-L05
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 11%), Hard coating (3H)
Brightness: 400 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8.0 (G to G)
Frequency: 60Hz
Lamp Type: 12 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V