Thursday, 31 December 2020

REPAIRING / SERVICING TV LG 32LH590U

 Technical description and composition of the LG 32LH590U TV, panel type and modules used. The composition of the


modules.

LG LED
Model: 32LH590U

Chassis / Version: LD66K / LD66Y

Panel: HC320DXN-VSVS1-511X

LED backlight: 15.5Y 32INCH A-TYPE REV0.0 160323

LED driver (backlight): integrated into MainBoard

PWM LED driver: MP3378E

MOSFET LED driver: TO-252

Power Supply (PSU): Adapter 19V

MainBoard: EAX66853404 (1.1)

IC MainBoard: EEPROM: 24C256

Tuner: TDJM-G301D EBL61741401

Control: Wi-Fi: TWFM-B006D, IR + Button: EBR80772001 SRG9CA0000A

Specifications 32LH590U
LG 32LH590U
General recommendations for TV LCD LED repair
Possible manifestations of defects

- LG 32LH590U does not turn on, indicators on the front panel are not lit or blinking. The TV does not respond to the control buttons and the remote control.

With such manifestations, the adapter power supply usually fails.
The owner of the TV can purchase an external power supply Adapter 19V on his own, and its repair is not always advisable, but sometimes it makes sense to open it and eliminate simple defects typical of the SMPS. Then we recommend measuring its output voltages and, if they are absent, you should check the serviceability of the power switches and rectifier diodes of the converters for a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in an emergency mode of short circuit without output voltages, and with a short circuit in the elements of the primary circuit, the mains fuse most often breaks off immediately and, less often, the current sensor in the source of the key.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or knowingly working properly.

- There is no picture, but there is sound and reaction to commands from the remote control. Or the image appears immediately after switching on and disappears.

The most likely problem in these cases is a malfunction of the LED backlight. The reason may be in the breakage of the backlight LEDs, in the stabilization of their power supply, or in the violation of the contact connections of the strings 15.5Y 32INCH A-TYPE REV0.0 160323.
It is impossible to identify an open circuit in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and a voltage of several tens of volts is required to open their junctions. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Usually, Chinese multimeters lightly light one 3-volt LED if you connect the probes to it in the forward direction (red probe to the anode, black to the cathode). 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 broken through in the K / Z.

If LG 32LH590U has no picture, but there is sound, often the HC320DXN-VSVS1-511X display backlight 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 when the external light hits the screen.

Replacing the LEDs requires disassembling the HC320DXN-VSVS1-511X LCD panel - a process that requires experience and qualifications from the master. I do not recommend doing such work on your own to TV owners 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 the 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 EAX66853404 often turns out to be faulty, a software failure is also possible.
Then, first of all, you need 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 the normal range, it is necessary to trace the passage of LVDS signals from the MainBoard EAX66853404 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.

- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals the standby mode.

Repair or diagnostics of the EAX66853404 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 complex MB (SSB) repairs and with the necessary skills and equipment, it may sometimes be necessary to replace its EEPROM chips: 24C256 and other possible faulty components. Malfunctions associated with the use of BGA soldering technologies are usually easily diagnosed by the warm-up method.

Before replacing the tuner TDJM-G301D EBL61741401, if there is no tuning to the channels, you must first check the software and the supply voltage at its outputs. You also need to make sure that the tuner and processor can exchange data via the I2C bus

Attention! Users and owners of 32LH590U TVs who do not have the appropriate qualifications, knowledge and experience are strongly discouraged from attempting to repair themselves in order to avoid negative consequences that may lead to complete non-repairability of the device.

Driver current limiting after backlight repair. Information from the master.

Reduce the backlight current from 400 mA to 280 mA - replaced the resistor R614 at the ISET MP3378E control input pin 3. Set the nominal value to 10 kOhm.
Driver current limitation. MP3378E. general information

To reduce the backlight current in LED drivers with the MP3378E PWM controller, it is necessary to proportionally increase the total resistance of the resistors from pin 3 (ISET) to the case. Calculation of current in milliamperes and resistance in kilo-ohms 977 / Rset for each channel. Parallel channels are summed. For example, for four parallel channels and a RISET 10 KOhm resistance, the total current will be 97.7 * 4 = 391 mA.

DOWNLOAD SCHEMATIC DIAGRAM MP3378E PWM controller   ------------------>   MP3378E

 

The appearance of the MainBoard EAX66853404 is shown in the figure below:

EAX66853404




EAX66853404 can be used in TVs:

LG 32LH595U (Panel HC320DXN-ABVS2-5112), LG 32LH570U (Panel HC320DXN-VHVS1-214X).

Main features of the LG 32LH590U device:

Installed matrix (LED panel) HC320DXN-VSVS1-511X.
To power the backlight LEDs, a converter combined with the EAX66853404 main board is used, controlled by the MP3378E PWM controller. TO-252 switches are used as power elements of the LED driver.
To power all internal components of the LG 32LH590U TV, an external adapter 19V is used.
MainBoard - the main board (motherboard) is an EAX66853404 module, using EEPROM chips: 24C256 and others.
Tuner TDJM-G301D EBL61741401 provides reception of television programs and tuning to channels.


Instructions and updates

There are files to download for the 32LH590U model from the manufacturer:

Files with updates and instructions:
File Description File Name Type Date Size
SW File (Version 05.30.80). Update instructions TV_Software_Update_Guide_v3.pdf PDF 09/04/2020 2014K
SW File (Version 05.30.80). Firmware (USB) Software_File (Version_05.30.80) .zip ZIP 04.09.2020 755968K
Compatible with 32LH590U-ZE, 32LH595U-ZA, 32LH6047-ZB, 32LH604V-ZB, 32LH609V-ZF, 43LH590V-ZA, 43LH590V-ZD, 43LH595V-ZE, 43LH6047-ZB-43LAH604V 43LH630V-ZJ, 49LH590V-ZA, 49LH590V-ZD, 49LH595V-ZE, 49LH6047-ZB, 49LH604V-ZA, 49LH604V-ZB, 49LH609V-ZF, 49LH630V-ZJ, 55LH60HV60 ZB, 55LH604H60 ZBL ZF, 55LH630V-ZJ.

User Manuals and Instructions:
Document Language Date Size
Quick Start Guide English - English, Estonian, Latvian, Lettish, Lithuanian, Russian 07/01/2020 59 734K
Quick Start Guide English - English, Estonian, Latvian, Lettish, Lithuanian, Russian 07/01/2020 No data
User manuals English - English, Estonian, Latvian, Lettish, Lithuanian 09.20.2016 21094K

Files can be downloaded from the manufacturer's website for the 32LH590U model.


LG 32LH590U TV with HC320DXN-VSVS1-511X LCD, 32 "(81 cm) 16: 9 format diagonal. The LCD-panel implements the principle of direct backlight display with rear-mounted LEDs - Direct LED.
The HC320DXN-VSVS1-511X sensor and MainBoard EAX66853404 software provide high quality HD viewing at 1366x768 pixels and 720p (HD Ready).
TV model 32LH590U has built-in SMART software and webOS operating system installed. The connection to the network can be carried out via Wi-Fi wireless connection. Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG.
Speaker power of 6 W (2x3 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, Ethernet (RJ-45), Wi-Fi 802.11n, WiDi, Miracast. The digital tuner is capable of receiving television channels in the DVB-T, DVB-T2, DVB-C, DVB-S2 standards.

The TV uses an external adapter 19V power supply.

Dimensions: With stand 641x435x186 mm, Without stand 641x396x57 mm.

Attention! The HC320DXN-VSVS1-511X panel of the LG 32LH590U 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.