Technical description and composition of the LG 55LM620T TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 55LM620T 55LM620T-ZE
Chassis / Version: LD22 / LC22 GP4
Panel: LC550EUE (SE) (F1)
T-CON: FND TM120 ver0.2 (6870C-0401B)
LED driver (backlight): integrated into PSU; 78V 1.25A
PWM LED driver: UC2843BD1, AAT2430AISX, R5F100BCAFP
MOSFET LED driver: STF19NF20, PHT4NQ10LT
Power Supply (PSU): EAX64744301 LGP55H-12LPB LCOPJ625128015836 (1.8)
PWM Power: HS01G (PFC), A6059H (STB), L6599AD
MOSFET Power: STF18NM60N, STF13NM60N
MainBoard: EAX64307906 (1.0) P.H.J BAR CODE G4_M_TU234
IC MainBoard: LCE2112, H5TQ2G63DFR, KLM2G1HE3F, MICOM R5F100GEA, TPS65178, STA3808WE, 24C16;
Tuner: TDSN-G351D
Technical Specifications 55LM620T
LG 55LM620T
General repair guidelines for TV LCD LED
Possible malfunctions
- LG 55LM620T does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
Most often, with such manifestations, the main power supply module EAX64744301 is found to be faulty. It is necessary to measure its output voltages and, if they are absent, check the serviceability of power switches (STF18NM60N, STF13NM60N) and rectifier diodes in the converters for possible breakdown.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers HS01G (PFC), A6059H (STB), L6599AD, in the absence of visible damage or explicit short-circuit between the terminals, are 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.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- 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 EAX64307906 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). 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 - LCE2112, H5TQ2G63DFR, KLM2G1HE3F, MICOM R5F100GEA, TPS65178, STA3808WE, 24C16; 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 the TV works normally from external devices, but does not tune into television channels, the TDSN-G351D 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.
Once again, remind users! Attempts to self-repair the LG 55LM620T TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
Service manual / schematic diagram ------------> LG 55LM620S, 55LM620T, 55LM625S -ZE/-ZG Chassis LC22.
To reduce the backlight current in LED drivers with the AAT2430AISX controller, increase the resistance of the resistor from terminal 50 (ISET) to the housing, for example, from 3 KOhm to 4.7 KOhm. Currents will proportionally decrease in each of the 16 channels. With a parallel connection of channels, currents are summed.
EAX64307906
EAX64307906 can be used in TVs:
LG 32LM640T ZA (Panel LC320EUA PE F2), LG 32LS570T (Panel LC320EUN (SE)(M2)), LG 47LM620S (Panel LC470EUE (SE)(F4)), LG 42LM670T (Panel LC420EUG(PE)(F2)), LG 42LM640T 42LM640S (Panel LC420EUG (PE)(F1)), LG 42LM620T (Panel LC420EUE (SE)(F1)), LG 47LM660T (Panel LC470EUG (PE)(F1)), LG 42LS570T (Panel T420HVN01.0), LG 42LS570S ZB (Panel LC420EUE (SE)(M1)), LG 42LM669T (Panel LC420EUG (PE)(F2)), LG 42LM669S (Panel LC420EUG (PE)(F1)), LG 37LM620T (Panel LC370EUN (SE)(F2)), LG 47LM669 (Panel LC470EUG (PE)(F2)), LG 32LS570S ZB (Panel LC320EUN (SE)(M2)), LG 47LM620T (Panel LC470EUE (SE)(F3)), LG 47LM761T ZA (Panel LC470EUH (PE)(F1), LG 32LM620S (Panel LC320EUN (SE)(F2) ), LG 47LM670T 47LM670T-ZA.BRUWLJU (Panel LC470EUG (PE)(F1)), LG 42LM660S 42LM660S-ZA.BRUWLJU (Panel LC420EUG (PE)(F1)), LG 42LM660T 42LM660T-ZA.BRUWLJU (Panel LC420EUG (PE)(F1) ), LG 32LM620T (Panel LC320EUN (SE)(F3)), LG 55LM620T 55LM620T-ZE (Panel LC550EUE (SE)(F1)).
The appearance of the power supply
Main features of the device LG 55LM620T:
Installed matrix (LED-panel) LC550EUE (SE) (F1).
The matrix control uses the Timing Controller (T-CON) FND.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by a PWM controller UC2843BD1, AAT2430AISX, R5F100BCAFP. As the power elements of the LED driver, keys of the STF19NF20, PHT4NQ10LT type are used.
The necessary supply voltages for all nodes of the LG 55LM620T TV are generated by the EAX64744301 power supply module or its analogs using HS01G (PFC), A6059H (STB), L6599AD microchips and power switches of the STF18NM60N, STF13NM60N type.
MainBoard - the main board (motherboard) is an EAX64307906 module using LCE2112, H5TQ2G63DFR, KLM2G1HE3F, MICOM R5F100GEA, TPS65178, STA3808WE, 24C16 microcircuits; and others.
The TDSN-G351D tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC550EUE-SEF1
Type: a-Si TFT-LCD, Panel
Diagonal size: 55 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 1209.6x680.4 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 360 cd / m²
Contrast Ratio: 1600: 1
Display Colors: 16.7M (8-bit), CIE1931 68%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
