Friday, 28 February 2020

REPAIR / SERVICING TV LG 42LS560T

Technical description and composition of the LG 42LS560T TV, panel type and applicable modules. The composition of the modules.
LG LED
Model: 42LS560T 42LS560T-ZC
Chassis / Version: LD21B
Panel: T420HVN01.1
LED backlight: 74.42T23.001-2-DS1 - 12C15D - 420TA05 V0; 64 LED 530mm
T-CON: T315HW07 VB 31T14-C0J 31T14-COJ
LED driver (backlight): 4H + V3416.001 / B
PWM LED driver: DF3421
MOSFET LED driver: PA610AD
Trans LED driver: SPC-25090-470E
Power Supply (PSU): EAX64427001 EAY62608801 LGP42L-12P
PWM Power: FAN7930BMX (PFC), ICE3BR4765JZ (Standby DIP-7), L6599AD
MOSFET Power: STD10NM60N (PFC), STD7NM60N
MainBoard: EAX64909901 - EBR75149828 - 310430354945 - 310432880861
IC MainBoard: LGE2111A-T8, NAND FLASH: H27U1G8F2BTR, SPI: W25Q80, EEPROM: 24C256, AUDIO: STA380BWE
Tuner: TDSN-G301 EBL61080001
Control: IR: LM35-55 - MB32B00 - EBR74986702
Specifications 42LS560T
LG 42LS560T
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The LG 42LS560T 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, a malfunction is most likely to be detected in the EAX64427001 power supply module. It is then necessary to measure its output voltages and, if they are absent, you should check the power switches (STD10NM60N (PFC), STD7NM60N) and rectifier diodes of the converters for a short circuit probability.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short-circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more 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 FAN7930BMX (PFC), ICE3BR4765JZ (Standby DIP-7), L6599AD are usually checked by replacing with new, or obviously working.
- 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.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason can be both in the power 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 indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the EAX64909901 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 need to check its components LGE2111A-T8, NAND FLASH: H27U1G8F2BTR, SPI: W25Q80, EEPROM: 24C256, AUDIO: STA380BWE. 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.
The failure of the TDSN-G301 EBL61080001 tuner is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Attention TV owners! Attempts at self-repair of LG 42LS560T are not recommended by the manufacturer and can lead to serious negative consequences!


 SCHEMATIC DIAGRAM ---------->  LG LG CHASSIS LD21B; 42LS5600, 42LS560S, 42LS560T, 42LS5610, 42LS561T, 42LS5620 SERVICE MANUAL.

 PSU  SCHEMATIC DIAGRAM ---------->  LGP42L-12P EAX64427001 EAY62608801

 The appearance of the MainBoard EAX64909901 is shown in the figure below:
EAX64909901
EAX64909901 can be used on TVs:
LG 42LM580T-ZA (Panel LC420EUE (SE)(F1)), LG 42LM340T (Panel LC420DUN (SE)(U3)), LG 32LM580T (Panel LC320EUN (SE)(F3)), LG 42LM585T ZD (Panel LC420EUE (SE)(F1)), LG 42LM615T (Panel LC420EUE (SE)(F1)), LG 42LS560T 42LS560T-ZC (Panel T420HVN01.1).
PSU Advanced
The EAX64427001 power supply module is made using the Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced into the power supply by the device. The PFC is a Step-Up Converter based on the FAN7930BMX PWM controller, which evenly distributes high-frequency pulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of an increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 42LS560T:
The matrix (LED panel) T420HVN01.1 is installed.
The matrix control uses the Timing Controller (T-CON) T315HW07.
To power the backlight LEDs, the 4H + V3416.001 LED driver is used, it is controlled by the DF3421 PWM controller. An LED driver has a SPC-25090-470E transformer installed. As the power elements of the LED driver, keys of the type PA610AD are used.
The necessary supply voltages for all nodes of the LG 42LS560T TV are generated by the EAX64427001 power module or its analogs using FAN7930BMX (PFC), ICE3BR4765JZ (Standby DIP-7), L6599AD microcircuits and power switches of the STD10NM60N (PFC), STD7NM60N type.
MainBoard - the main board (motherboard) is an EAX64909901 module using LGE2111A-T8 chips, NAND FLASH: H27U1G8F2BTR, SPI: W25Q80, EEPROM: 24C256, AUDIO: STA380BWE and others.
The TDSN-G301 EBL61080001 tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: AUO
Model: T420HVN01.1 CELL
Type: a-Si TFT-LCD, CELL
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: AMVA3, Normally Black
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 2%), Hard coating (3H)
Glass Depth: 0.50 + 0.50 mm
Transmissivity: 5.7% (with Polarizer)
Contrast Ratio: 3000
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V