Technical description and composition of the LG 39LB570V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 39LB570V
Chassis / Version: LD46B
Panel: T390HVF02.0
T-CON: 42T34-C01 T420HVN06.1
LED driver (backlight): integrated into PSU
PWM LED driver: BD9486F
MOSFET LED driver: 4NF20, MDD3752
Power Supply (PSU): EAX65423701 (2.0) LGP3942-14PL1
PWM Power: MAP8800 (PFC), FA6A01N (PWM resonant)
MOSFET Power: TK7P60W, 60R360P
MainBoard: EAX65610904 EBR78617401
IC MainBoard: H5TQ4G63AFR, 24C256, NTP751
Tuner: TDJM-G101D EBL61400501
Specifications 39LB570V
LG 39LB570V
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The LG 39LB570V TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
In such cases, the EAX65423701 power supply is usually faulty. It is necessary to measure its output supply voltages, and in case of their absence, check the serviceability of power switches (TK7P60W, 60R360P) of converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In case of breakdowns of semiconductors in the 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.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM) MAP8800 (PFC), FA6A01N (PWM resonant), if they do not have visible damage to the case and open fault between the terminals, are usually checked by replacement.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
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 detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, 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 TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the EAX65610904 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). Often, the MB (SSB) card needs to be replaced in case of complex faults that are difficult to detect. When trying to repair, you should check its elements - H5TQ4G63AFR, 24C256, NTP751 and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
If the TV works normally from external devices, but does not tune into television channels, the TDJM-G101D EBL61400501 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.
Owners and users of the LG 39LB570V TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!
Backlight Current Limit:
In televisions with power supplies LGP3942-14PL1 (EAX65423701), the backlight current sensor - the resistor block R811-R818 consists of four pairs of 4.3 Ohm each. You can reduce the backlight current by 25% by removing one pair of resistors.
schematic diagram -------------> LG 39LB570V Chassis LD46B
YEAR 2014 MODELS 39LB5700, 39LB570V, 39LB572V.
The appearance of the MainBoard EAX65610904 is shown in the figure below:EAX65610904
EAX65610904 can be used in TVs:
LG 32LB582V ZG (Panel LC320DUE (FG)(A4)), LG 42LB570V (Panel LC420DUE (FG)(A4)), LG 42LB5800 (Panel LC420DUE (P6)(A4)), LG 42LB580V (Panel LC420DUE (FG)(A4)), LG 32LB570U 32LB570U-ZJ (Panel NC320DXN VSBP2), LG 39LB580V (Panel T390HVF02.0 HC390DUN-VCHS1), LG 32LB580V ZB (Panel LC320DUE (FG)(A4)).
The appearance of the power supply
Main features of the device LG 39LB570V:
Installed matrix (LED-panel) T390HVF02.0.
The matrix control uses the Timing Controller (T-CON) 42T34-C01.
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the BD9486F PWM controller. As power elements of the LED driver, keys of the type 4NF20, MDD3752 are used.
The necessary supply voltages for all nodes of the LG 39LB570V TV are generated by the EAX65423701 power module or its analogs using MAP8800 (PFC), FA6A01N (PWM resonant) microcircuits and TK7P60W, 60R360P power switches.
MainBoard - the main board (motherboard) is an EAX65610904 module, using H5TQ4G63AFR, 24C256, NTP751 and others.
Tuner TDJM-G101D EBL61400501 provides the reception of television programs and tuning to channels.