Technical description and composition of the LG 42LX6500 TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LX6500 ZD
Chassis / Version: LD03R
Panel: LC420EUS (SC) (A1)
LED driver (backlight): integrated into PSU; 136.4V 0.66A
PWM LED driver: AS3693B, MEGA48PA
Power Supply (PSU): YP42LPBD - EAY60803203
PWM Power: VIPER27H (Standby), R2A20112 (PFC), L6599D (PWM)
MOSFET Power: STP9NK50Z, 21NM60ND
MainBoard: EAX62116803 (2)
IC MainBoard: CPU: LGE3556CP, LG5111B, NAND: 04GW3B2DN6, M24C512WG, F0513A, NT5TU128M8DE
Tuner: TDFR-G155D
Specifications 42LX6500
LG 42LX6500
General repair guidelines for TV LCD LED
If the TV does not turn on, no indicators on its front panel are lit or blinking. Also, if the TV does not respond to the remote control and buttons, does not make any sounds or any signs of operability when turned on, there is a certain chance that the EAY60803203 - YP42LPBD power module is faulty and needs repair. Sometimes with similar manifestations a problem can only occur in the absence of standby power. In the general case, first of all, it is necessary to check the electrolytic capacitors of the secondary rectifier filters and the fuse at the input of the network. If it is broken, then you should check for breakdown of the PN junctions of the rectifier bridge diodes and the key transistor of the converter, which can either be on a separate radiator or integrated with a PWM controller in a common chip. Options are available STP9NK50Z.
As a rule, the keys in switching power supplies (SMPS) are reliable enough and rarely fail for no reason to be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM chip is verified by replacing it with a known good one.
If the LG 42LX6500 does not have an image, but there is sound, there may be a malfunction of the backlighting LEDs of the LC420EUS (SC) (A1) panel or their power converter - LED driver.
The lack of backlight often occurs due to an open circuit in the LED circuit. There is a need for disassembling the panel and checking the LEDs themselves, as well as the same contact connections in the connectors and rations of the terminals.
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 an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
Repair of the EAX62116803 motherboard (2) must begin with the diagnosis and verification of all linear stabilizers and power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM.
In some cases, to repair the MB board (SSB), it may be necessary to replace the chips - CPU: LGE3556CP, LG5111B, NAND: 04GW3B2DN6, M24C512WG, F0513A, NT5TU128M8DE with new or obviously working ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
If the TV works normally from external devices, but does not tune into television channels, the TDFR-G155D 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.
Typical defects of LG TVs with LGE3556C processors are provoked by its severe temperature conditions and the quality of the LGE3556C processor itself.It should be remembered! Attempts to repair the LG 42LX6500 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
External manifestations may be different - the tuner or external inputs do not work, or the TV does not turn on, for example, the control lamp blinks or hangs on the screen saver.
If, when the processor warms up, performance is restored, in such cases a reball can sometimes help. Then there is the opportunity to extend the life of the TV with the help of an additional heat sink or cooler. When replacing the processor, it should be borne in mind that they are discontinued and all LGE3556C, which sellers ALIexpress send, in most cases control units, are often already faulty.
SCHEMATIC DIAGRAM -----------> LG CHASSIS: LD03R; MODEL: 42LX6500/650N, 42X6500/650N-ZD, 42LX6800/6900, 42X6800/6900-ZD
The appearance of the MainBoard EAX62116803 is shown in the figure below:EAX62116803
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the YP42LPBD module provides for the use of a Power Factor Correction node. The PFC circuit is a flyback converter based on the R2A20112 PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device LG 42LX6500:
Installed matrix (LED-panel) LC420EUS (SC) (A1).
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller AS3693B, MEGA48PA.
The necessary supply voltages for all nodes of the LG 42LX6500 TV are generated by the YP42LPBD power module or its analogs using VIPER27H (Standby), R2A20112 (PFC), L6599D (PWM) microchips and power switches of the STP9NK50Z, 21NM60ND type.
MainBoard - the main board (motherboard) is an EAX62116803 module using CPU chips: LGE3556CP, LG5111B, NAND: 04GW3B2DN6, M24C512WG, F0513A, NT5TU128M8DE and others.
The TDFR-G155D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUS-SCA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 930.24x523.26 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 1400: 1
Display Colors: 1.06B (8-bit + FRC), CIE1931 72%
Response Time: 6/6 (Tr / Td)
Frequency: 240Hz
Lamp Type: WLED Without Driver
Signal Interface: Mini LVDS, 160 pins
Voltage: 12.0V