Technical description and composition of the LG 49LF550V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 49LF550V
Chassis / Version: LD55T
Panel: LC490DUE (MG) (A6)
LED backlight: DRT3.0 49 inch
T-CON: 6870C-0481A
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX66203101 (1.8) LGP4760R1-15CH2 PLDH-L403A
MainBoard: EAX66203803 (1.0) EBU63186621 63186621
IC MainBoard: CPU: LGE2134, NAND Flash: TC58NVG0S3HTA00, SPI Flash: MX25L8035EM2I, EEPROM: 24C256
Tuner: TDJM-G301D
Specifications 49LF550V
LG 49LF550V
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 49LF550V TV does not turn on and does not show any signs of turning on, it does not respond to the control buttons or to the remote control.
With such manifestations, the EAX66203101 power module usually fails. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches and rectifier diodes for a probable short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power 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, 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, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the black to the cathode. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as a health indicator. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- 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 EAX66203803 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). In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - CPU: LGE2134, NAND Flash: TC58NVG0S3HTA00, SPI Flash: MX25L8035EM2I, EEPROM: 24C256 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).
Before changing the tuner TDJM-G301D, if it is not possible to tune to television channels, make sure that there are supply voltages, which must be measured at the corresponding terminals of the tuner and checked for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Owners of the 49LF550V TV are advised to contact qualified personnel with the necessary work experience for repairs! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
Service manual / schematic diagram ----------------> LG 49LF550V Chassis LD55T
The appearance of the MainBoard EAX66203803 is shown in the figure below:EAX66203803
The appearance of the power supply
Main features of the device LG 49LF550V:
Installed matrix (LED-panel) LC490DUE (MG) (A6).
The matrix control uses the Timing Controller (T-CON) 6870C-0481A.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the LG 49LF550V TV is carried out by the EAX66203101 power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX66203803 module using CPU chips: LGE2134, NAND Flash: TC58NVG0S3HTA00, SPI Flash: MX25L8035EM2I, EEPROM: 24C256 and others.
The TDJM-G301D tuner provides TV reception and channel tuning.
