Technical description and composition of the LG 49UJ639V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 49UJ639V
Chassis / Version: UD74P
Panel: NC490DGG
LED backlight: NC490DGG-AAFX1-41CA GAN01-1256A-P1
LED driver (backlight): integrated into PSU
Power Supply (PSU): LGP49DJ-17U1 EAX67189201 (1.6) EAY64511101
MainBoard: EAX67133404 (1.0)
IC MainBoard: Realtek K3Lp, FT24C256A, DTA2010M
Tuner: TDJN-G501D
Control: IR: EBR83592703, RF: LGSBWAC72
Specifications 49UJ639V
LG 49UJ639V
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 49UJ639V does not turn on and does not show any signs of performance at all. Does not blink indicators and does not respond to control buttons.
Often in such cases, the EAX67189201 power 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 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.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- 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.
Often in such cases, there is no LED backlight. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EAX67133404 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Testing or replacing elements of Realtek K3Lp, FT24C256A, DTA2010M requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
Before replacing the TDJN-G501D tuner, if there is no tuning for the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Attention to users! Self-repair of the TV LG 49UJ639V without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
SCHEMATIC manual -------------------> LG 49UJ639V Chassis UD74P
The appearance of the MainBoard EAX67133404 is shown in the figure below:EAX67133404
The appearance of the power supply
Main features of the device LG 49UJ639V:
Installed matrix (LED-panel) NC490DGG.
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 TV LG 49UJ639V is carried out by the power module LGP49DJ-17U1, or its analogues.
MainBoard - the main board (motherboard) is an EAX67133404 module, using Realtek K3Lp, FT24C256A, DTA2010M chips, and others.
The TDJN-G501D tuner provides television reception and channel tuning.
