Technical description and composition of the LG 49UF771V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 49UF771V
Chassis / Version: LC59D / L
Panel: LC490EQE (FN) (M1)
LED driver (backlight): integrated into PSU
Power Supply (PSU): EAX66306501 (2.0)
MainBoard: EAX66387003 (1.0)
IC MainBoard: LGE5332 (LM14A)
Tuner: TDJM-G301D // TDJM-C401D
Technical Specifications 49UF771V
LG 49UF771V
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 49UF771V TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
In some of these cases, the main switching power supply, the EAX66306501 module, is faulty. It is necessary to measure its output voltages and, in case of their absence, check the serviceability of power switches and rectifier diodes in the converters for possible breakdown.
In case of breakdowns of semiconductors in secondary circuits, the converter can usually work abnormally in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse often 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, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
Usually in such cases, a malfunction is detected in the backlight nodes of the LED panel. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with 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. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX66387003 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 must check its components LGE5332 (LM14A). 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 TDJM-G301D // TDJM-C401D 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.
Attention! For users and owners of 49UF771V TVs who do not have the appropriate qualifications, knowledge and experience, we strongly recommend against attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.
The appearance of the MainBoard EAX66387003 is shown in the figure below:EAX66387003
The appearance of the power supply
Main features of the device LG 49UF771V:
Installed matrix (LED-panel) LC490EQE (FN) (M1).
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 49UF771V TV is carried out by the EAX66306501 power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX66387003 module, using LGE5332 chips (LM14A) and others.
Tuner TDJM-G301D // TDJM-C401D provides reception of television programs and tuning to channels.
