Wednesday, 29 July 2020

REPAIR / SERVICING TV SUPRA STV-LC40LT0010F

Technical description and composition of the SUPRA STV-LC40LT0010F TV, panel type and modules used. The composition of the modules.
SUPRA LED
Model: STV-LC40LT0010F
Chassis / Version: V3T09
Panel: C400F17-E31-S (G82)
LED driver (backlight): integrated into MainBoard
PWM LED driver: SOT23-6
MOSFET LED driver: TO-252
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-252
MainBoard: JUC7.820.00205281
IC MainBoard: CPU: MSD3663LSA-005N, SPI FLASH: GD25Q64B
Tuner: DVB + SAT
STV-LC40LT0010F Specifications
SUPRA STV-LC40LT0010F
General recommendations for TV LCD LED repair
Possible manifestations of defects
- SUPRA STV-LC40LT0010F TV does not turn on. There are no signs of operability. The indicators on the front panel do not light up or blink, the TV does not respond to the remote control and control buttons.
In such cases, the main power source, the AC / DC converter of the mains voltage, which is combined with the MainBoard JUC7.820.00205281, may be faulty. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches (TO-252) and rectifier diodes in the converters for a short circuit.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually operate normally in an emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and, less often, the current sensor in the source of the key.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements, which can disable it in key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying the PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) PWM SOT23-6, in the absence of external damage and a short circuit between the terminals, are checked by replacing them with a known good one.
- There is no picture, there is sound, it reacts to the remote control, the channels are switched. In some cases, the image appears when turned on and disappears immediately.
Often in such cases there is no backlighting of the LED panel. The reason for this may be an open circuit in the LED circuit, or a problem in stabilizing their power supply.
To check the LED strips for breakage without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter; a voltage of the order of several tens of volts is required.
- 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 JUC7.820.00205281 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Complex repair of MB (SSB) board is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the CPU elements: MSD3663LSA-005N; SPI FLASH: GD25Q64B. Malfunctions in BGA chips are usually easy to detect by warm-up.
Attention! Users and owners of STV-LC40LT0010F 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.
Main features of SUPRA STV-LC40LT0010F device:
Installed matrix (LED panel) C400F17-E31-S (G82).
To power the backlight LEDs, a converter combined with the JUC7.820.00205281 main board is used, controlled by the SOT23-6 PWM controller. TO-252 switches are used as power elements of the LED driver.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter using PWM SOT23-6 microcircuits and TO-252 power switches.
MainBoard - the main board (motherboard) is a JUC7.820.00205281 module, using CPU chips: MSD3663LSA-005N, SPI FLASH: GD25Q64B and others.
The DVB + SAT tuner provides reception of television programs and tuning to channels.

SUPRA LED TV STV-LC40LT0010F with LCD C400F17-E31-S, diagonal 40 "(102 cm) in 16: 9 format. The required screen brightness of 280 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 120,000: 1 is achieved special control of the LEDs depending on the illumination of areas in the scene. The display technology of the model uses LED LED backlight. The TV's capabilities provide for viewing programs and films in high quality HD at a resolution of 1920x1080 pixels in graphic resolution according to the standard 1080p (Full HD). Supported formats multimedia files: MP3, WMA, MPEG4, Xvid, DivX, MKV, JPEG.
Speaker power 16 W (2x8 W) is provided by two speakers. Uses NICAM stereo signal processing system and Sound Surround function.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, VGA, HDMI x3, USB x2. A headphone output is provided. The digital tuner is capable of receiving TV channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: 1005x625x160 mm.
Attention! Panel C400F17-E31-S (G82) SUPRA LED TV STV-LC40LT0010F is an expensive and unreliable element.
Do not allow any impacts 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 non-repairable.