Friday 31 July 2020

REPAIRING / SERVICING TV SUPRA STV-LC32T740WL

Technical description and composition of the SUPRA STV-LC32T740WL TV, panel type and modules used. The composition of the modules.
SUPRA LED
Model: STV-LC32T740WL
Chassis / Version: V1P12
Panel: HV320WHB-N80
LED backlight: K320WD A4 4708-K320WD-A4213K01
LED driver (backlight): integrated into MainBoard
PWM LED driver: PWM 8pin
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: P75-3463GSXV6.0
IC MainBoard: CPU: MSD3463GSA, SPI FLASH: MX25L6406E
STV-LC32T740WL Specifications
SUPRA STV-LC32T740WL
General recommendations for TV LCD LED repair
Possible manifestations of malfunctions
- SUPRA STV-LC32T740WL TV does not turn on, does not respond to the remote control and control panel buttons, indicators are off or flashing.
First of all, in such cases, you should make sure that the common switching power supply (SMPS) - the AC / DC voltage converter of the mains voltage - is working. All source elements in this TV model are located on the MainBoard P75-3463GSXV6.0. It is necessary to measure its output voltages, and in case of their absence (full or partial), the serviceability of the power switches of the converters and rectifier diodes should be checked for a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work in an emergency mode in a 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 power switches (MosFet) in switching sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency setting or damper, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM regulators (PWM) PWM SOT23-6, if they have no visible damage to the case and an open short circuit between the pins, are usually checked by replacing.
- There is no image, there is sound, it reacts to the remote control. Or the image may appear for a second when turned on and disappear immediately.
Usually, in such cases, a malfunction is detected in the nodes of the backlight 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 health of the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED separately with a simple Chinese multimeter (powered by 9 volts) in the P-N transition test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black one to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. The serviceability of the PN junction of the Zener diode indirectly indicates the serviceability of the LED-a
- The TV does not turn on, the indicator signals standby or operating mode, or blinks.
Repair or diagnostics of the P75-3463GSXV6.0 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). Often the MB (SSB) board needs to be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: MSD3463GSA, SPI FLASH: MX25L6406E and replace the failed chips with new ones. Some malfunctions may be associated with the use of BGA soldering technologies in modern Main Board. Typically, such defects are detected by local heating of the chip.
Once again, we remind TV users: do not attempt to repair yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair to professionals with sufficient experience in the field of electronic repair.

DOWNLOAD FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC32T740WL V1P12, Main: P75-3463GSXV6.0, Panel: HV320WHB-N80

 The appearance of the MainBoard P75-3463GSXV6.0 is shown in the figure below:
P75-3463GSXV6.0
P75-3463GSXV6.0 can be used in TVs:
DEXP F40B7000K (Panel LSC400HN02-G02), DEXP H32B7000K / B (Panel HV320WHB-N00), SUPRA STV-LC32T740WL (Panel HV320WHB-N80).
Main features of SUPRA STV-LC32T740WL device:
The matrix (LED panel) HV320WHB-N80 is installed.
To power the backlight LEDs, a converter combined with the P75-3463GSXV6.0 main board is used, controlled by a PWM 8pin PWM controller.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a P75-3463GSXV6.0 module, using CPU chips: MSD3463GSA, SPI FLASH: MX25L6406E and others.
Additional technical information about the panel:
Brand: BOE
Model: HV320WHB-N80
Type: a-Si TFT-LCD, CELL
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: ADS, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare (Haze 1%), Hard coating (3H)
Transmissivity: 6.2% (with Polarizer)
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit)
Response Time: 8 (G to G)
Frequency: 60Hz
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V
SUPRA LED TV STV-LC32T740WL with LCD HV320WHB-N80, 32 "(81 cm) 16: 9. The required screen brightness of 280 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 80,000: 1 is achieved by special control operation of LEDs depending on the illumination of areas in the scene.This model uses an LED-panel with an edge arrangement of backlighting LEDs - Edge LED.It is possible to view broadcasts and films and images in high quality HD at a resolution of 1366x768 pixels in the standard graphic resolution 720p (HD Ready) .Input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal shaping occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, MKV , JPEG.
Speaker power 10 W (2x5 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, VGA, HDMI x3, USB x2. A headphone output is provided. To connect a computer or laptop to this TV model, use the VGA (D-Sub 15) connector on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768. The digital tuner is capable of receiving TV channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: 800x515x140 mm.
Attention! The HV320WHB-N80 panel of the SUPRA STV-LC32T740WL LED TV 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.