Monday 24 February 2020

REPAIR / SERVICING TV LG 42LB561V

Technical description and composition of the LG 42LB561V TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LB561V ZE
Chassis / Version: LC43B / LD43B / LB43T
Panel: LC420DUE (FG) (A3)
T-CON: V14 42 DDR 60HZ Control_ver 0.3 P / N: 6870C-0480A; TL2375EP, SW5084A, 4096
LED driver (backlight): integrated into PSU
PWM LED driver: BD9486F, NR134S
Power Supply (PSU): EAX65423701 (1.9) REV1.0 LGP3942-14PL1
PWM Power: MAP8800, FA6A01N (PWM resonant)
MOSFET Power: 13N60M2
MainBoard: EAX65388005 (1.0) // EAX65388006 (1.0)
IC MainBoard: LGE2132 / A7MKM69C, H27U1G8F2CTR, 74LCX244, TPS65282, 25Q80BVSIG, TAS5733, A8303
Tuner: TDJM-G101D EBL61400501
Specifications 42LB561V
LG 42LB561V
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 42LB561V does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
Usually, with such manifestations, the defect is caused by faulty elements in the main power module EAX65423701. It is necessary to measure its secondary output voltages, and in case of their absence, check the operability of the power switches (13N60M2) of the converters (PFC and the main source), as well as rectifier diodes for possible short circuit.
In case of any breakdown of semiconductors in the secondary circuits of the converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback.
Chips of PWM controllers (PWM) MAP8800 and FA6A01N (PWM resonant) can also cause breakdown of power switches of converters and are checked by replacing with new or obviously working ones.
- 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.
The most likely in these cases is a malfunction of the 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.
To check the LED strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the EAX65388005 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). If it is not possible to replace the MB board (SSB), you need to check the health of its elements - LGE2132 / A7MKM69C, H27U1G8F2CTR, 74LCX244, TPS65282, 25Q80BVSIG, TAS5733, A8303. Defective components should be replaced.
Before replacing the TDJM-G101D EBL61400501 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 LG 42LB561V TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


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*


FIRMWARE SPI FLASH ------------>  LG 42LB561V ZE LC43B/LD43B/LB43T, Main: EAX65388005 (1.0), Panel: LC420DUE (FG)(A3)



 The appearance of the MainBoard EAX65388005 is shown in the figure below:
EAX65388005
EAX65388005 can be used in TVs:
LG 32LB561U (Panel NC320DXN VSBP1), LG 42LB563V (Panel LC420DUE (FG)(A3)), LG 32LB565U ZQ (Panel LC320DXE (FG)(A3)), LG 42LB561V ZE (Panel LC420DUE (FG)(A3)), LG 49LB552V ZA (Panel LC490DUE (FG)(A6) ), LG 42LB565V (Panel LC420DUE (FG)(A3)), LG 32LB628U 32LB628U-ZB.BRUWLDU (Panel LC320DXE (FG)(P2)), LG 47LB561V-ZE 47LB561V (Panel LC470DUE( FG)(A3)).
The appearance of the power supply
Main features of the device LG 42LB561V:
Installed matrix (LED-panel) LC420DUE (FG) (A3).
The matrix control uses the Timing Controller (T-CON) V14.
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 42LB561V TV are generated by the EAX65423701 power module or its analogs using MAP8800, FA6A01N (PWM resonant) microcircuits and 13N60M2 type power switches.
MainBoard - the main board (motherboard) is an EAX65388005 module, using LGE2132 / A7MKM69C, H27U1G8F2CTR, 74LCX244, TPS65282, 25Q80BVSIG, TAS5733, A8303 and others microcircuits.
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