Technical description and composition of the LG 42LF564V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LF564V
Chassis / Version: LC55H
Panel: LC420DUE (MG) (A3)
LED backlight: 6916L-1957E (Innotek DRT 3.0 42 ”_B type Rev01)
T-CON: V14 42 DRC 60Hz Control_Ver 0.3
LED driver (backlight): integrated into PSU
PWM LED driver: LC5901
Power Supply (PSU): EAX66203001 (1.6) LGP3942D-15CH1
MainBoard: EAX66203805 (1.2)
IC MainBoard: CPU: LGE2136, SPI Flash: MX25L8035EM2I, EEPROM: 24C256
Tuner: TDJM-G301D
Specifications 42LF564V
LG 42LF564V
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 42LF564V TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
Most likely in this case, the main switching power supply (IIPS) EAX66203001 is faulty. It is necessary to measure its output voltages and, if they are absent, to check for short-circuit probabilities in the converters, power switches and rectifier diodes.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually work normally in emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and less often the current sensor at the source of the key.
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 commands from the remote control. Or the image appears immediately after turning on and disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
When trying to identify a break in the LED lines, it should be borne in mind that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
- 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 EAX66203805 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. Checking or replacing CPU elements: LGE2136, SPI Flash: MX25L8035EM2I, EEPROM: 24C256 requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
The TDJM-G301D tuner malfunction 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! For users and owners of 42LF564V 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.
SCHEMATIC DIAGRAM ---------> LG 42LF564V Chassis LC55H
You can reduce the backlight current in televisions with LGP3942D-15CH1 power supplies (EAX66203001) by increasing the resistance of the current sensor. The nominal current in the LEDs is 250 mA. Current sensor - resistor R816 rated 3 Ohm. If you increase the rating to 4.3 Ohm, the current decreases to 175 mA.
The appearance of the MainBoard EAX66203805 is shown in the figure below:EAX66203805
EAX66203805 can be used in TVs:
LG 32LF564U (Panel LC320DXE (MG)(A3)), LG 42LF550V (Panel LC420DUE (MG)(A6)), LG 32LF560U ZB (Panel NC320DXN VSBP5 ), LG 42LF560V (Panel LC420DUE (MG)(A3)), LG 32LF562V (Panel NC320DUN-VBBP3 (EAJ63171201)), LG 32LF564V (Panel NC320DUN VBBP3), LG 32LF560V (Panel NC320DUN-VBBP3), LG 49LF620V 49LF620V-ZB (Panel LC490DUE (MG)(P2)), LG 42LF551C (Panel LC420DUE-MGA6).
The appearance of the power supply
Main features of the device LG 42LF564V:
Installed matrix (LED-panel) LC420DUE (MG) (A3).
The matrix control uses the Timing Controller (T-CON) V14.
To power the backlight LEDs, a converter is used, combined with the power supply, controlled by the LC5901 PWM controller.
The formation of the necessary supply voltages for all nodes of the LG 42LF564V TV is carried out by the EAX66203001 power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX66203805 module, using CPU chips: LGE2136, SPI Flash: MX25L8035EM2I, EEPROM: 24C256 and others.
The TDJM-G301D tuner provides TV reception and channel tuning.