Technical description and composition of the LG 42LE5500 TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LE5500 ZA
Chassis / Version: LD03E
Panel: LC420EUH (SC) (A1)
LED backlight: 3660L-0352A 401 // 3660L-0353A 401
LED driver (backlight): integrated into PSU; 118V 660mA (42 inch LG)
PWM LED driver: AS3693B, MEGA48PA
Power Supply (PSU): PLDF-L903A EAY60803101 3PCGC10008A-R
PWM Power: VIPER27H (Standby), ICE2PCS04 (PFC), L6599D
MOSFET Power: TK4P60DB
MainBoard: EAX61742609 EBT60992801
IC MainBoard: LGE3556C, M24C16, MX25L4005CM2I, NAND 04GW3B2DN6E, TDA19997HL / C1, NTP-7000
Tuner: TDFR-G155D EBL60740402
Specifications 42LE5500
LG 42LE5500
General repair guidelines for TV LCD LED
Sometimes the LG 42LE5500 TV just does not turn on. No control lights on the front panel are lit or blinking, the TV does not respond to the remote control and does not make any sounds or any signs of life when turned on. The most likely cause of the malfunction is the failure of the common PLDF-L903A EAY60803101 3PCGC10008A-R power supply module. If it is working properly, you must check the standby batteries on the Main Board. 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 cut off, then it is necessary to check the diodes of the rectifier bridge and the key transistor of the converter for a breakdown of the PN junctions, which can either be on a separate radiator or integrated with a PWM controller in a common chip. Possible options.
Mos-Fet keys used in switching power supplies (SMPS) rarely fail for no reason to look for when checking other circuit elements. Often the breakdown is caused by malfunctions of electrolytic capacitors or semiconductor elements in the primary circuit, or by a break in the resistors in the stabilization circuits. The PWM controller chip can also cause a breakdown of the power switch of the converter.
If there is no image when you turn on the LG 42LE5500, or it appears and immediately disappears, but there is sound, most likely there is a malfunction in the backlight LED circuit of the LC420EUH (SC) (A1) panel, or in the LED node of the driver-converter of their power supply.
In most cases of lack of backlight, it becomes necessary to disassemble the panel in order to check the LEDs, connectors, loops and all contact connections. If one or several LEDs does not work in one line, therefore, they are broken and should be replaced.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
When trying to repair the motherboard, you should first check the serviceability of linear stabilizers or power converters of microcircuits and, if necessary, update the software (software).
Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements LGE3556C, M24C16, MX25L4005CM2I, NAND 04GW3B2DN6E, TDA19997HL / C1, NTP-7000. BGA chip malfunctions are usually easy to detect by warming up.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the TDFR-G155D EBL60740402 tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
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 42LE5500 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: LD03E; MODE: 42LE5500/550N, 42LE5500/550N-ZA, 42LE5800/5900 42LE5800/5900-ZA, 42LE5510/5810, 42LE5510/5810-ZB, 42LE5910, 42LE5910-ZB
The appearance of the MainBoard EAX61742609 is shown in the figure below:EAX61742609
EAX61742609 can be used in TVs:
LG 42LE5500 ZA (Panel LC420EUH (SC)(A1)), LG 47LE5500 ZA (Panel LC470EUH (SC)(A1)).
PSU Advanced
The 42LE5500 TV is equipped with a PLDF-L903A power module using the PFC (Power Factor Correction) circuitry acting as an active filter to eliminate the higher harmonic components of the current consumption. The boost converter based on the ICE2PCS04 PWM controller does not allow the input rectifier filter's electrolytic capacitor to be connected to the network directly through open diodes when the charge current determines its reactance (about 15-30 ohms at a frequency of 50 Hz). As a result of the conversion, the charging current of the capacitor will be determined in such a way that the envelope of the high-frequency pulses of the input current will repeat the phase and shape of the sine wave of the input voltage. The health check of the PFC unit is carried out by measuring the DC voltage on the capacitor of the rectifier network. In operating mode, it should be around 380V, in standby approximately 300V.
The appearance of the power supply
Main features of the LG 42LE5500 device:
Installed matrix (LED-panel) LC420EUH (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 42LE5500 TV are generated by the PLDF-L903A power module or its analogs using VIPER27H (Standby), ICE2PCS04 (PFC), L6599D microcircuits and TK4P60DB type power switches.
MainBoard - the main board (motherboard) is an EAX61742609 module, using microchips LGE3556C, M24C16, MX25L4005CM2I, NAND 04GW3B2DN6E, TDA19997HL / C1, NTP-7000 and others.
Tuner TDFR-G155D EBL60740402 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC420EUH-SCA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 42 inch
Resolution: 1920x1080, FHD
Display Mode: 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 + Dithering), CIE1931 72%
Response Time: 8/12 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: Mini LVDS, 120 pins
Voltage: 12.0V