Technical description and composition of the LG 42LG3000 TV, panel type and applicable modules. The composition of the modules.LG
Model: 42LG3000
Chassis / Version: LD84A
Panel: LC420WXN (SA) (A1)
Inverter (backlight): LC420WXN 6632L-0502A PNEL-T716A
PWM Inverter: OZ9966SN
MOSFET Inverter: FDB8447L
Power Supply (PSU): EAX40157601 LGP42-08H - EAY4050520
PWM Power: NCP1207ADR2G (PWM Flyback), SG6961SZ (PFC), NCP1396ADR2G (PWM resonant)
MOSFET Power: SPA04N60C3 (PFC), STP9NK90ZFP, SPA07N60C3
MainBoard: EAX40150702
IC MainBoard: CPU: LGE7363C-LF, SPI Flash: 25L3205DM2I
Tuner: TDFV-G135D
Specifications 52LG5030
LG 42LG3000
General recommendations for repairing TV LCD
Repair of all electronic devices, including the LG TV, based on the LD84A chassis, it is advisable to start with an external examination of its external and internal elements. Using visible changes in the state of components, it is usually possible to determine the further direction of troubleshooting and localization of the defect before the necessary measurements are taken. Electrolytic capacitors of filters with a swollen casing, as well as ring cracks formed in the soldered leads of heating elements, or a layer of coal on burnt resistors sometimes tell the repairman the causes of the malfunction and possible consequences.
In the absence of any signs of operability, when the LG 42LG3000 does not turn on and does not signal anything with the control lights on the panel, there is a possibility of a TV LGP42-08H power supply module malfunctioning. With the same manifestations, the power regulator of the control processor on the motherboard may be faulty. First of all, it is necessary to replace the swollen capacitors of the rectifier filters, if any. If the mains fuse is broken in the power supply, in most cases a breakdown of the power key (s) is detected, which can be integrated with the PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
It should be remembered that in the practice of repair, usually the power switches in switching power supplies (SMPS) do not fail due to their poor quality and, in such cases, it is necessary to look for the cause that led to a malfunction and provoked a breakdown of the key. Most often, the culprits of the accident are dried electrolytic capacitors or dangling resistors in the primary circuit, or the PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuit.
If the LG 42LG3000 does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction of the display backlight, or their power converter - inverter. Sometimes when you turn on the image appears and disappears immediately. In such cases, it is necessary to check the electrolytic capacitors of the power filter of the inverter itself, including in the secondary rectifier of the main PSU. All necessary precautions must be observed when disabling the inverter protection during diagnostics and not leaving it disconnected after the repair is completed.
In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - CPU: LGE7363C-LF, SPI Flash: 25L3205DM2I which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
Attention! For users and owners of 42LG3000 TVs who do not have the appropriate qualifications, knowledge and experience, we strongly recommend against self-repair attempts to avoid negative consequences that could lead to complete non-repairability of the device.
SCHEMATIC DIAGRAM ---------> LG 42LG3000, 42LG3000-ZA Chassis LD84A.
PSU SCHEMATIC DIAGRAM ---------> LGP42-08H EAX40157601 EAY4050520 Power Supply schematic diagram
The appearance of the MainBoard EAX40150702 is shown in the figure below:EAX40150702
EAX40150702 can be used in TVs:
LG 32LG5000-ZA (Panel V315B1-C07), LG 42LG3000 (Panel LC420WXN (SA)(A1)), LG 32LG3000 (Panel LK315T3LZ94), LG 42LG5000 (Panel T420HW01 V.2).
PSU Advanced
The 42LG3000 model uses the EAX40157601 power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, it is a step-up converter based on the SG6961SZ 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 42LG3000:
Installed matrix (LCD panel) LC420WXN (SA) (A1).
An LC420WXN inverter is used to power the backlight lamps, it is controlled by the OZ9966SN PWM controller. As power elements of the inverter, keys of the FDB8447L type are used.
The necessary supply voltages for all nodes of the LG 42LG3000 TV are generated by the EAX40157601 power supply module or its analogs using NCP1207ADR2G (PWM Flyback), SG6961SZ (PFC), NCP1396ADR2G (PWM resonant) microcircuits, and SPA04N60C3 (PFC), ST9 type power switches.
MainBoard - the main board (motherboard) is an EAX40150702 module, using CPU chips: LGE7363C-LF, SPI Flash: 25L3205DM2I and others.
The TDFV-G135D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG.Philips LCD
Model: LC420WXN-SAA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1366x768, WXGA
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.25x523.01 mm
Surface: Antiglare (Haze 13%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1100: 1
Display Colors: 16.7M (8-bit)
Response Time: 5 (G to G)
Frequency: 60Hz
Lamp Type: EEFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V