Technical description and composition of the LG 32LF620U TV, panel type and modules used. The composition of the modules.LG LED
Model: 32LF620U
Chassis / Version: LC55H / LD55T / LB55T
Panel: LC320DXE (MG) (P2)
LED backlight: Innotek 32 DRT3.0
LED driver (backlight): integrated into PSU
PWM LED driver: BD559
MOSFET LED driver: 5N41
Power Supply (PSU): EAX66171501 (2.1) LGP32D-15CH1
PWM Power: SSC3S111
MOSFET Power: MDF11N65B
MainBoard: EAX66203805 (1.2) EBU63186622
IC MainBoard: CPU: LGE2136, SPI Flash: MX25L8035EM2I, EEPROM: 24C256, Audio: TAS5733
Tuner: TDJM-G301D EBL61560001
Specifications 32LF620U
LG 32LF620U
General recommendations for TV LCD LED repair
Possible manifestations of defects
- LG 32LF620U TV does not turn on at all. No response to the remote control and front panel control buttons. Indicator lamps do not light up or flash.
Usually, with similar manifestations, the defect is caused by faulty elements in the main power supply module EAX66171501. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches (MDF11N65B) and rectifier diodes for possible partial or complete breakdown.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work in an emergency in the short-circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Breakdown of Mos-Fet switches used in switching power supplies is often caused by malfunctions of other elements, for example, in the power supply circuit of the PWM regulator, in frequency setting or damper circuits, as well as in negative feedback stabilization. PWM microcircuits (PWM) SSC3S111 are usually checked by replacing them with new ones, or knowingly working.
- There is no picture, but there is sound and all other functions work. Sometimes when you turn it on, the image appears and disappears for a second.
As a rule, in this case, the backlight of the LED panel is faulty. The reason can sometimes be in the power supply of the LEDs, but more often in their malfunction (breakdown or breakage), sometimes in the violation of the contact connections of the LED strips.
When diagnosing, it must be borne in mind that it is impossible to check for an open in the circuit of the LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally a current source. By opening the panel, you can check each LED separately. Typically, Chinese multimeters will lightly light one 3-volt LED if you connect the probes to it in the forward direction. For dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of LED health. In the event of a malfunction of the LED, its zener diode will either be cut off or pierced in the K / Z.
- The indicator on the front panel blinks, the TV does not turn on in operating mode, does not respond to the remote control.
Repair or diagnostics of the EAX66203805 motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - CPU: LGE2136, SPI Flash: MX25L8035EM2I, EEPROM: 24C256, Audio: TAS5733 which may require replacement with new ones. If a BGA processor is installed, there is a possibility that the soldering of the contacts of its pins with the board is broken (detected by warming up).
If the LG 32LF620U has no picture, but there is sound, often the LCD backlight LC320DXE (MG) (P2) simply does not work. Moreover, in LED TVs, the LEDs inside the panel usually fail, less often the LED driver.
In such cases, you can see a barely noticeable image with a successful hit of external light on the screen.
Replacing the LEDs requires disassembling the LC320DXE LCD panel, a process that requires experience and qualifications from the technician. We do not recommend doing such work on your own to the owners of TVs and craftsmen who do not have experience in repairing LCD panels
If there is no image, and the backlight is on, the screen becomes slightly lighter when turned on, and in an open TV you can see light through the holes in the panel case.
In this case, the panel may also be faulty - damage to the strips, loops, for example, as a result of moisture ingress after unsuccessful washing of the screen, the T-CON (Timing Controller) board may be faulty. But the main board MainBoard EAX66203805 often turns out to be faulty, a software failure is also possible.
Then, first of all, it is necessary to check the panel supply voltage, fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, it is necessary to trace the passage of LVDS signals from the MainBoard EAX66203805 with an oscilloscope, as well as synchronizing signals to the loops with drivers.
Flooded or unsuccessfully washed screens of LED TVs can be restored, in about half of the cases, usually if significant damage has not formed in the loops and panel strips.
If the TV operates normally from external devices, but does not tune into TV channels, the TDJM-G301D EBL61560001 tuner may be faulty. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the reason for the inoperability of the tuner may be a software failure.
Attention! Users and owners of 32LF620U TVs who do not have the appropriate qualifications, knowledge and experience are strongly discouraged from trying to repair themselves in order to avoid negative consequences that can lead to the complete non-repairability of the device.
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).
External view of the power supply
Main features of the LG 32LF620U device:
The matrix (LED panel) LC320DXE (MG) (P2) is installed.
To power the backlight LEDs, a converter combined with a power supply is used, controlled by a BD559 PWM controller. The keys of the 5N41 type are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the LG 32LF620U TV is carried out by the EAX66171501 power module, or its analogs using SSC3S111 microcircuits and MDF11N65B power switches.
MainBoard - the main board (motherboard) is an EAX66203805 module, using CPU chips: LGE2136, SPI Flash: MX25L8035EM2I, EEPROM: 24C256, Audio: TAS5733 and others.
Tuner TDJM-G301D EBL61560001 provides reception of television programs and tuning to channels.
LG 32LF620U TV with LCD display LC320DXE (MG) (P2), diagonal size 32 "(81 cm) 16: 9 format. The LCD panel implements the principle of direct backlight display with rear LEDs - Direct LED.
There is support for 3D images using passive polarization technology.
The LC320DXE sensor and MainBoard EAX66203805 software provide high quality HD viewing at 1366x768 pixels in 720p (HD Ready). The input analog video signal is decoded in PAL, SECAM, NTSC systems. Graphic processing of a digital signal is carried out in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p, 2160p. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
Speaker power 20 W (2x10 W) is provided by two speakers. The NICAM stereo audio processing system and the Sound Surround function are used.
Communication with other devices via an external interface is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x2, USB. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is provided. This interface supports standard resolutions: 640x480, 800x600, 1024x768.
The digital tuner can receive TV channels in the DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2 standards.
The TV uses an EAX66171501 power supply.
Attention! The LC320DXE panel of the LG 32LF620U LED TV is an expensive and unreliable element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.