Thursday, 30 July 2020

REPAIRING / SERVICING TV SUPRA STV-LC32T860WL

Technical description and composition of the SUPRA STV-LC32T860WL TV, panel type and modules used. The composition of the modules.
SUPRA LED
Model: STV-LC32T860WL
Chassis / Version: V1N03
Panel: HV320WX2-201
LED backlight: CRH-ES32B35350803427REV1.1
T-CON: HV320WXC-200 X-PCB-X0.0
LED driver (backlight): integrated into MainBoard
PWM LED driver: OZ9902CGN
MOSFET LED driver: CS630 A4H
Power Supply (PSU): integrated into MainBoard
PWM Power: FAN6755
MOSFET Power: 7N65L
MainBoard: 35018209 KL32GT616-BOE-248YTK
IC MainBoard: SPI FLASH Winbond: 25S32BVS1G, HDMI: IT6633E-P, Sound: STA333W
Tuner: TDA18273
Control: IR: 35017149 32611 REV-01
STV-LC32T860WL Specifications
SUPRA STV-LC32T860WL
General recommendations for TV LCD LED repair
Possible manifestations of defects
- SUPRA STV-LC32T860WL 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 supply, the mains voltage AC / DC converter, which is combined with the MainBoard 35018209 board, may be faulty. diodes of converters for the presence of a possible short circuit.
In case of breakdowns in the secondary circuits of the converter, it can usually work in an emergency mode in a short circuit mode, 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 most 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. FAN6755 PWM controllers, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or known to be working properly.
- There is no picture, but there is sound and reaction to the remote control. Or, for a second, the image may appear immediately after switching on.

A malfunction is usually in these cases most likely in the backlight units of the display matrix. The reason may be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.

It should be remembered that it is not possible to determine an open circuit in the LED lines without 
disassembling the panels using a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then you need to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction, or dual LEds are used, then the PN transition of the emergency zener diode can indirectly serve as an indicator of serviceability. In the event of a malfunction of the LED-a, the PN-transition of the zener diode will either be cut off or broken through in the SC.

- The indicator blinks or is on constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the motherboard 35018209 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). In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - SPI FLASH Winbond: 25S32BVS1G, HDMI: IT6633E-P, Sound: STA333W which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its pins with the board (indicated by warming up).
If there is no tuning for terrestrial or cable TV channels, you should make sure that the software is correct, as well as in accordance with the nominal supply voltages at the terminals of the TDA18273 tuner. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Attention to TV owners! Attempts to repair SUPRA STV-LC32T860WL yourself are not recommended by the manufacturer and can lead to serious negative consequences!
Additional MainBoard Repair
The appearance of MainBoard 35018209 is shown in the figure below:
35018209
Main features of SUPRA STV-LC32T860WL device:

Installed matrix (LED-panel) HV320WX2-201.
Matrix control uses the HV320WXC-200 Timing Controller (T-CON).
To power the backlight LEDs, a converter combined with the main board 35018209 is used, controlled by the OZ9902CGN PWM controller. The keys of the CS630 A4H 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 using FAN6755 microcircuits and 7N65L power switches.
MainBoard - the main board (motherboard) is a 35018209 module, using SPI FLASH Winbond chips: 25S32BVS1G, HDMI: IT6633E-P, Sound: STA333W and others.
The TDA18273 tuner provides reception of television programs and tuning to channels.

Additional technical information about the panel:
Brand: BOE
Model: HV320WX2-201
Type: a-Si TFT-LCD, CELL
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: AFFS, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Glass Depth: 0.70 + 0.70 mm
Transmissivity: 6.6% (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-LC32T860WL with LCD HV320WX2-201, 32 "(81 cm) 16: 9 diagonal. The required screen brightness of 300 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 90,000: 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 backlight 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 multimedia file formats: MP3, WMA, MPEG4, Xvid , DivX, MKV, JPEG.
Speaker power of 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, audio x2, component, SCART, VGA, HDMI x3, USB. 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.

Dimensions: With stand 731x468x179 mm, Without stand 731x433x77 mm.
Attention! The HV320WX2-201 panel of the SUPRA STV-LC32T860WL 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.