Monday 24 February 2020

REPAIR / SERVICING TV LG 42LB569V

Technical description and composition of the LG 42LB569V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LB569V 42LB569V-ZX.BRUWLDU
Chassis / Version: LC43B / LD43B / LB43T
Panel: LC420DUE (FG) (A3)
LED backlight: LG Innotek DRT 3.0 42_B type / 42_A type Rev01 (2014.01.07)
T-CON: 6870C-0480A, 6870S-1681B, 6870S-1682B
LED driver (backlight): integrated into PSU
PWM LED driver: BD9486F, NR134S
Power Supply (PSU): EAX65423701 (2.1)
PWM Power: MAP8800 (PFC), FA6A01N, NR134S
MOSFET Power: TK7P60W
MainBoard: EAX65388006 (1.0) EBU62356101
IC MainBoard: LGE2131, A7MKN51C, H27U1G8F2CTR, 25L8006E, H5TQ1G63EFR, TAS5733, 4580M-E1, TPS65282
Tuner: TDJM-G101D EBL61400501
Control: Remote: AKB73715679
Specifications 42LB569V
LG 42LB569V
General repair guidelines for TV LCD LED
Possible malfunctions
- The LG 42LB569V TV does not turn on and does not show any signs of operability at all. There is no reaction to the remote control and control buttons from the front panel.
With such manifestations, the EAX65423701 power supply module usually fails. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches (TK7P60W) and rectifier diodes in the converters for a short circuit.
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.
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 chips MAP8800 (PFC), FA6A01N, NR134S are usually checked by replacing with new ones, or obviously working.
- 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.
As a rule, in such cases there is no display backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. 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 blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the EAX65388006 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 - LGE2131, A7MKN51C, H27U1G8F2CTR, 25L8006E, H5TQ1G63EFR, TAS5733, 4580M-E1, TPS65282 and replace the 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 there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the power supply of the TDJM-G101D EBL61400501 tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention! For users and owners of 42LB569V TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could 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 ------------>  CHASSIS : LD43B/LD44B MODEL : 42LB56** 42LB56**-Z*.



The appearance of the MainBoard EAX65388006 is shown in the figure below:
EAX65388006
EAX65388006 can be used in TVs:
LG 32LB561V (Panel LC320DUE), LG 32LB561U (Panel NC320DXN VSBP1), LG 42LB629V ZM (Panel LC420DUE (FG)(P2) ), LG 32LB563U (Panel NC320DXN VSBP1), LG 42LB552V ZA (Panel LC420DUE (FG)(A6)), LG 32LB552U (Panel NC320DXN-VSBP4), LG 32LB563V (Panel LC320DUE (FG)(A3)), LG 42LB561V ZE (Panel LC420DUE (FG)(A3)), LG 42LB569V 42LB569V-ZX.BRUWLDU (Panel LC420DUE (FG)(A3)).
The appearance of the power supply
Main features of the device LG 42LB569V:
Installed matrix (LED-panel) LC420DUE (FG) (A3).
The matrix control uses the Timing Controller (T-CON) 6870C-0480A.
To power the backlight LEDs, a converter is used, combined with a power supply, it is controlled by the BD9486F, NR134S PWM controller.
The necessary supply voltages for all nodes of the LG 42LB569V TV are generated by the EAX65423701 power supply module or its analogs using MAP8800 (PFC), FA6A01N, NR134S microchips and TK7P60W power switches.
MainBoard - the main board (motherboard) is an EAX65388006 module, using chips LGE2131, A7MKN51C, H27U1G8F2CTR, 25L8006E, H5TQ1G63EFR, TAS5733, 4580M-E1, TPS65282 and others.
Tuner TDJM-G101D EBL61400501 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC420DUE-FGA3
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: IPS, Normally Black, Transmissive
Active Area: 927.94x521.96 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V


Schematic diagram ------------>  CHASSIS : LD43B/LD44B MODEL : 42LB56** 42LB56**-Z*.