Wednesday 5 August 2020

REPAIRING / SERVICING TV SUPRA STV-LC32250WL

Technical description and composition of the SUPRA STV-LC32250WL TV, panel type and modules used. The composition of the modules.
SUPRA LED
Model: STV-LC32250WL
Chassis / Version: V1N08
Panel: C320X13-E3-L (G2)
T-CON: MDF7N65B
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
MOSFET LED driver: AODD4454
Power Supply (PSU): integrated into MainBoard
PWM Power: NCP1251
MOSFET Power: MDF7N65B
MainBoard: JUC7.820.00081373
IC MainBoard: SPI FLASH: Q32B-14HIP
Tuner: R620D
STV-LC32250WL Specifications
SUPRA STV-LC32250WL
General recommendations for TV LCD LED repair
Possible manifestations of defects
- SUPRA STV-LC32250WL does not turn on and does not show any signs of operability at all. Does not blink indicators and does not respond to control buttons.
A malfunction in such cases should be looked for in the elements of the power source - the mains voltage converter (AC / DC), which is located on the MainBoard JUC7.820.00081373. Then you should measure its output voltages and, in case of their complete or partial absence, it is necessary to check the serviceability of the power switches (MDF7N65B) and rectifier diodes of the converters for a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually operate in an emergency in the 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 controllers (PWM) NCP1251, if they do not have visible damage to the case and an outright short circuit between the terminals, are usually checked by replacing.
- There is no picture, but there is sound and all other TV functions are working. The image sometimes appears for a second immediately after switching on and disappears.
In such cases, the most likely malfunction of the LED panel backlighting elements. The reason can sometimes be in the power supply of the LEDs, but more often in their malfunction (breakdown or breakage), sometimes in the violation of the contact connections of the LED strips.
When trying to detect 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.
- The TV does not turn on, the indicator signals standby or operating mode, or blinks.
Repair or diagnostics of the JUC7.820.00081373 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). In cases of complex MB (SSB) repairs and with the necessary skills and equipment, it may sometimes be necessary to replace its SPI FLASH: Q32B-14HIP chips and other possible faulty components. Malfunctions associated with the use of BGA soldering technologies are usually easily diagnosed by the warm-up method.
If the TV operates normally from external devices, but does not tune to TV channels, the R620D tuner may be defective. In such cases, first of all, you should make sure that the supply voltage is present at its corresponding terminals. It is also necessary to make sure that the data exchange between the tuner and the processor is possible via the I2C bus. Sometimes the reason for the inoperability of the tuner may be a software failure.
Attention to users! Self-repair of the SUPRA STV-LC32250WL TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


DOWNLOAD FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC32250WL V1N08, Main: JUC7.820.00081373, Panel: C320X13-E3-L (G2) 


The appearance of the MainBoard JUC7.820.00081373 is shown in the figure below:
JUC7.820.00081373
JUC7.820.00081373 can be used in TVs:
AKAI LEA-32C25M (Panel M320X13-E1-H), ERISSON 32LEC2300 (Panel M320X13-E1-L), FUSION FLTV-28L32B (Panel M280X13-E1-H).
Main features of SUPRA STV-LC32250WL device:
Installed matrix (LED panel) C320X13-E3-L (G2).
Matrix control uses the Timing Controller (T-CON) MDF7N65B.
To power the backlight LEDs, a converter combined with the JUC7.820.00081373 main board is used, controlled by the OB3350CP PWM controller. The keys of the AODD4454 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 NCP1251 microcircuits and MDF7N65B power switches.
MainBoard - the main board (motherboard) is a JUC7.820.00081373 module, using SPI FLASH chips: Q32B-14HIP and others.
The R620D tuner provides reception of television programs and tuning to channels.
SUPRA LED TV STV-LC32250WL with LCD C320X13-E3-L, 32 "(81 cm) 16: 9 diagonal. The required screen brightness of 400 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 60,000: 1 is achieved special control of the 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 of graphic decomposition 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 480i, 480p, 576i, 576p, 720p, 1080i, 1080p standards Supported multimedia file formats: MP3, MPEG4, JPEG ...
Speaker power 12 W (2x6 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, audio x2, component, SCART, VGA, HDMI x3, USB. 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.
Dimensions: With stand 737x493x210 mm, Without stand 737x443x100 mm.
Attention! Panel C320X13-E3-L (G2) of SUPRA STV-LC32250WL 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.