Technical description and composition of the LG 42LW650S TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LW650S
Chassis / Version: LD12C
Panel: LC420EUF (SD) (F1)
T-CON: 6870C-0358A
LED driver (backlight): EAX628654 rev 1.0 (UH = 56v, UL = 12v)
PWM LED driver: AS3695C, STM821C3
MOSFET LED driver: KF4N20LW
Power Supply (PSU): EAX628654 rev 1.0
MainBoard: EAX63686303 (3)
IC MainBoard: LGE35230 / LGE7303C-LF, 24C16WP, 25X20BV
Tuner: TDFR-G256D
Specifications 42LW650S
LG 42LW650S
General repair guidelines for TV LCD LED
Repair of the LG 42LW650S TV is advisable to start with a careful external examination of both internal and external elements. Sometimes, based on visible changes in the components of the device, it is possible to draw some conclusions and determine the direction of further troubleshooting, even before the necessary measurements are taken. If charred resistors, swollen electrolytic or cermet capacitors, ring cracks in the soldered terminals of transformers or heating elements are detected, it is advisable to establish the causes and consequences of the malfunction that has arisen, as well as to check the connected elements and assemblies.
In the case when the 42LW650S does not turn on, does not respond to the remote control and the front panel buttons, does not blink bulbs and does not show any signs of operability, the EAX628654 rev 1.0 power supply module is probably faulty in this case. If it is serviceable with such manifestations, it is necessary to check the power supply stabilizer (converter) of the processor on the motherboard. If there are no swollen filter capacitors of the secondary rectifiers, the diagnostics of the power supply should be started by checking the fuse and, if it is broken, first of all, check all power semiconductor elements primary circuit - diodes and transistors for the probability of avalanche or thermal 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 42LW650S has no image, there is sound and the channels are switched, there is a possibility of a malfunction in the backlight LED circuit of the LC420EUF (SD) (F1) panel, or their power converter - LED driver. 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 LED driver itself, including in the secondary rectifier of the main PSU.
Often in the absence of backlighting, disassembling the panel is required. It is necessary to check the health of the transitions of the LEDs, as well as the reliability of the contact connections in the rulers and connectors.
It should be remembered that it is not possible to determine the break in the LED lines without disassembling the panels using a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair only to professionals with sufficient experience in the field of electronic equipment repair.
SCHEMATIC DIAGRAM -----------> LG 42LW650G/S/T/W, 42LW659S, 42LW650G/S/T/W-ZC, 42LW659S-ZC Chassis LD12C
The appearance of the MainBoard EAX63686303 is shown in the figure below:EAX63686303
The appearance of the power supply
Main features of the device LG 42LW650S:
Installed matrix (LED-panel) LC420EUF (SD) (F1).
The matrix control uses the Timing Controller (T-CON) 6870C-0358A.
The EAX628654 LED driver is used to power the backlight LEDs, it is controlled by the AS3695C, STM821C3 PWM controller. As the power elements of the LED driver, keys of the KF4N20LW type are used.
The formation of the necessary supply voltages for all nodes of the LG 42LW650S TV is carried out by the EAX628654 power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX63686303 module, using LGE35230 / LGE7303C-LF, 24C16WP, 25X20BV and other chips.
The TDFR-G256D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUF-SDF1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (2H)
Brightness: 400 cd / m²
Contrast Ratio: 1600: 1
Display Colors: 16.7M / 1.06B (8-bit / 8-bit + Dithering), CIE1931 72%
Response Time: 5/6 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (4 ch, 8/10-bit), 92 pins
Voltage: 12.0V
