Tuesday 14 July 2020

REPAIR / SERVICING TV SUPRA STV-LC2395FL

Technical description and composition of the TV SUPRA STV-LC2395FL, type of panel and applicable modules. The composition of the modules.
SUPRA LED
Model: STV-LC2395FL
Chassis / Version: V1K03
Panel: LC230EUE (TD) (A1)
MainBoard: MST739 35015005 REV-00
IC MainBoard: CPU: MST739KE-LF, SPI FLASH: EN25F80, EEPROM: 24C64
Tuner: AFT7 / W119G
Technical Specifications STV-LC2395FL
SUPRA STV-LC2395FL
General repair guidelines for TV LCD LED
Repair of the TV SUPRA STV-LC2395FL should begin with the diagnosis of a malfunction, which involves a careful examination of the external and internal elements of the device. According to some external signs of a change in the state of some elements, it is sometimes possible to make assumptions about the nature of the defect, as well as determine the further direction of the troubleshooting. Elements with visible damage, for example, capacitors swelled up after boiling the electrolyte, charred resistors in certain nodes of the circuit, as well as ring cracks in solders will help the master to guess the causes and possible consequences of the malfunction.
If the SUPRA STV-LC2395FL does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a power module malfunction. In some cases, only the processor power regulator may be faulty. When repairing the power supply, it is advisable to start the diagnostics by checking the mains fuse and the electrolytic capacitors of the filters of the converter secondary rectifiers. In the event of a fuse breaking, the reason should be sought in the power semiconductor elements of the pulse converter of the main power supply. First of all, it is necessary to check the diodes of the bridge of the rectifier of the mains voltage and the power switch (s) of the converter.
As a rule, the keys in switching power supplies (SMPS) are reliable enough and rarely fail for no reason to be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM chip is checked by replacing it with a known good one.
In cases where the SUPRA STV-LC2395FL TV has lost its image, and the sound is there and all other functions are operational, there is a possibility of a malfunction of the LED driver (converter for powering the backlight LEDs of the LC230EUE (TD) panel (A1)). When you turn on the TV, the image may appear briefly and disappear immediately. It must be borne in mind that with such manifestations the LEDs themselves also fail.
A malfunction in the backlight circuits often occurs due to an open in the power circuit of the LED lines. It requires disassembling the panel and checking the LEDs themselves, the soldering of their outputs, as well as the reliability of the connections in the connectors and the soldering of the conclusions of the connectors.
When trying to identify a break in the LED lines, it should be borne in mind that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
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).
In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - CPU: MST739KE-LF, SPI FLASH: EN25F80, EEPROM: 24C64 which may require replacement with new ones. If the BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
Before replacing the AFT7 / W119G tuner, if there is no tuning to the channels, you must first check the power supply voltage at its terminals, including the power supply of varicaps (30-33V).
Attention to the owners! Attempts to self-repair a SUPRA STV-LC2395FL TV are not recommended by the manufacturer and can lead to serious negative consequences!


FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC2395FL V1K03, MAIN MST739 REV-00, PANEL LC230EUE(TD)(A1)

The appearance of the MainBoard MST739 is shown in the figure below:
MST739
Main features of the SUPRA STV-LC2395FL device:
Installed matrix (LED panel) LC230EUE (TD) (A1).
The required supply voltage for all nodes of the TV SUPRA STV-LC2395FL provides a switching power supply.
MainBoard - the main board (motherboard) is an MST739 module using CPU chips: MST739KE-LF, SPI FLASH: EN25F80, EEPROM: 24C64 and others.
The AFT7 / W119G tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC230EUE-TDA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 23.0 inch
Resolution: 1920x1080, FHD
Display Mode: TN, Normally White, Transmissive
Active Area: 509.184x286.416 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (8-bit)
Response Time: 1.3 / 3.7 (Tr / Td)
Frequency: 60Hz
Lamp Type: 2 strings WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V
LED TV SUPRA STV-LC2395FL with LCD LC230EUE, diagonal size 23 "(58 cm) 16: 9 format. The required brightness of the screen is 250 cd / m² LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 1000: 1. Dynamic contrast ratio of 50,000: 1 is achieved by special control of the LEDs depending on the lighting in the plot.This model uses an LED panel with an end-mounted LED backlight - Edge LED.The TV features include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in graphic decomposition according to the standard 1080p (Full HD). The input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p.
The power of the sound system 4 W (2x2 W) provide two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV x2, audio x3, component, VGA, HDMI. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768.
The power consumed by the TV in the operating mode from the network is 38 watts.
Overall dimensions: With a support 587x415x209 mm, Without a support 587x377x34 mm.
Attention! The LC230EUE (TD) (A1) panel of a SUPRA STV-LC2395FL LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.