Wednesday, 29 July 2020

REPAIR / SERVICING TV SUPRA STV-LC40LT0050F

Technical description and composition of the SUPRA STV-LC40LT0050F TV, panel type and modules used. The composition of the modules.
SUPRA LED
Model: STV-LC40LT0050F
Chassis / Version: V1S09
Panel: V400HJ6-PE1 REV.C3
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3267
MOSFET LED driver: ME15N10-G
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: SMK0760F TO-220F 7A / 600V
MainBoard: CV512H-Q42
IC MainBoard: CPU: S2T512, SPI FLASH: 25Q64FVSIG, Audio: RT9108NB
Tuner: CDT-9NT372-RD60
STV-LC40LT0050F Specifications
SUPRA STV-LC40LT0050F
General recommendations for TV LCD LED repair
Possible manifestations of defects
- SUPRA STV-LC40LT0050F TV does not turn on, does not respond to the remote control and control panel buttons, the indicators are off or flashing.
In this case, first of all, you should check the operability of the main power source - the AC / DC voltage converter, all the elements of which are located on the MainBoard CV512H-Q42. It is necessary to make sure that its output voltages are present and, if they are completely absent, check the power switches (SMK0760F TO-220F 7A / 600V) and rectifier diodes for a possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and with a short circuit in the power elements of the primary circuit, the mains fuse or current sensor in the source of the key is often cut off.
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 PWM SOT23-6, 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 image, the screen is black, there is sound, when the screen is illuminated outside, you can sometimes see barely noticeable outlines of the image.
The backlight of the matrix (LED-panel) is usually faulty in these cases. The reason for this may be an open circuit in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the LED bars for a break 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 tend to light a single 3V 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 an indicator of serviceability. In faulty LEDs, the 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 CV512H-Q42 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). If it is not possible to replace the MB (SSB) board, it is necessary to check the serviceability of its elements - CPU: S2T512, SPI FLASH: GD25Q64, Audio: RT9108NB. Defective components must be replaced.
If you suspect a malfunction of the CDT-9NT372-RD60 tuner, first of all, you need to make sure that the software is correct, as well as the presence of the necessary levels of supply voltages and pulses of data exchange with the processor via the I2C bus on the corresponding terminals of the tuner.
Attention! Users and owners of STV-LC40LT0050F 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.


DOWNLOAD FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC40LT0050F V1S09, Main: CV512H-Q42, Panel: V400HJ6-PE1 REV.C3

 
 The appearance of MainBoard CV512H-Q42 is shown in the figure below:
CV512H-Q42
Main features of SUPRA STV-LC40LT0050F device:
Installed matrix (LED panel) V400HJ6-PE1 REV.C3.
To power the backlight LEDs, a converter combined with the CV512H-Q42 main board is used, controlled by the BIT3267 PWM controller. The keys of the ME15N10-G type 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 circuit using PWM SOT23-6 microcircuits and SMK0760F TO-220F 7A / 600V power switches.
MainBoard - the main board (motherboard) is a CV512H-Q42 module, using CPU: S2T512 microcircuits, SPI FLASH: 25Q64FVSIG, Audio: RT9108NB and others.
The CDT-9NT372-RD60 tuner provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: INNOLUX
Model: V400HJ6-PE1 Rev.C2
Type: a-Si TFT-LCD, CELL
Diagonal size: 40 inch
Resolution: 1920x1080, FHD
Display Mode: MVA, Normally Black, Transmissive
Active Area: 878.112x485.352 mm
Surface: Antiglare (Haze 1%)
Glass Depth: 0.50 + 0.50 mm
Transmissivity: 6.0% (with Polarizer)
Contrast Ratio: 5000: 1
Display Colors: 16.7M (8-bit)
Response Time: 8.5 (G to G)
Frequency: 60Hz
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
SUPRA LED TV STV-LC40LT0050F with LCD V400HJ6-PE1, diagonal 40 "(102 cm) 16: 9. The required screen brightness of 280 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 120,000: 1 is achieved by special control LED operation depending on the illumination of areas in the scene.The model's display technology uses LED LED backlighting.The TV capabilities provide viewing of broadcasts and movies in high quality HD at a resolution of 1920x1080 pixels in graphic resolution according to the standard 1080p (Full HD) .Supported media file formats : MP3, WMA, MPEG4, MKV, JPEG.
Speaker power 16 W (2x8 W) is provided by two speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, 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: 976x605x153 mm.
Attention! SUPRA STV-LC40LT0050F LED TV panel V400HJ6-PE1 REV.C3 is an expensive and unreliable component.
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.