Technical description and composition of the LG 42LE8500 TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 42LE8500
Chassis / Version: LD03E
Panel: LE85M42T240V5
LED driver (backlight): integrated into PSU
Power Supply (PSU): LGP4247-10 EAY60908801
MainBoard: EAX61742610 (0)
IC MainBoard: CPU: LGE3556C, NAND: 04GW3B2DN6E, DDR: NT5TU128M8DE
Tuner: TDFR-G135D
Specifications 42LE8500
LG 42LE8500
General repair guidelines for TV LCD LED
Repair of electronic devices, including the LG 42LE8500 TV, it is advisable to start with an external examination of its external and internal elements. Based on visible external changes in the state of the components, it is usually possible to determine the further direction of troubleshooting and localization of the defect before making the necessary measurements. Experienced repairmen are often aware of the causes of the defect and possible consequences, for example, by ring cracks in the soldering of the leads of the elements, as well as by swollen capacitors or resistors burnt to coal dust and other external indirect signs.
If the LG 42LE8500 does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a malfunction of the LGP4247-10 power module. In some cases, only the processor power regulator may be faulty. It is advisable to start the troubleshooting of the power supply module by checking the state of the electrolytic capacitors of the rectifier filters and the mains fuse. Defective capacitors should be replaced. If the mains fuse is broken, it is necessary to check first of all the power semiconductor elements - rectifier diodes and transistors, which are often found in such a state of breakdown.
If a breakdown of the power switch is detected, it should be remembered that in a switching power supply (IIP) it does not fail by itself for no reason that should be sought by checking other elements of the primary circuit - electrolytic capacitors, a PWM controller, which can only be checked replacement, as well as other semiconductor elements (diodes, transistors, zener diodes).
Sometimes the LG 42LE8500 TV does not have an image, but there is sound, or the image appears and immediately disappears. In this case, there is a high probability of a malfunction of the LE85M42T240V5 backlight LED converter, or an open circuit in the LED circuit is possible. In such cases, first of all, it is necessary to verify the serviceability of all the electrolytic capacitors of the filter by supplying the LED driver itself, including in the power supply unit (power supply unit).
Often in the absence of backlighting, disassembling the panel is required. It is necessary to check the serviceability of the transitions of the LEDs, as well as the reliability of the contact connections in the rulers and connectors.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
If the EAX61742610 (0) motherboard is faulty, first of all it is necessary to check all the linear stabilizers or power converters of its chips, and also, if necessary, update the software. Sometimes you can check the health of MB only by replacement.
Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: LGE3556C, NAND: 04GW3B2DN6E, DDR: NT5TU128M8DE and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
If there is no reception of television channels, but the TV is working properly from external devices, first of all it is necessary to check the voltage of the TDFR-G135D tuner.
Typical defects of LG TVs with LGE3556C processors are provoked by its severe temperature conditions and the quality of the LGE3556C processor itself.Once again, remind users! Attempts to self-repair the LG 42LE8500 TV without the appropriate qualifications and experience can lead to its complete non-repairability!
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, 42LE8500/850N 42LE8500/850N-ZA, 42LE8800/8900 42LE8800/8900-ZA SERVICE MANUAL
The appearance of the MainBoard EAX61742610 is shown in the figure below:EAX61742610
The appearance of the power supply
Main features of the device LG 42LE8500:
Installed matrix (LED-panel) LE85M42T240V5.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the LG 42LE8500 TV is carried out by the LGP4247-10 power module, or its analogues.
MainBoard - the main board (motherboard) is an EAX61742610 module, using CPU chips: LGE3556C, NAND: 04GW3B2DN6E, DDR: NT5TU128M8DE and others.
The TDFR-G135D tuner provides TV reception and channel tuning.