Technical description and composition of the SUPRA STV-LC1917WD TV, panel type and modules used. The composition of the modules.SUPRA
Model: STV-LC1917WD
Chassis / Version: CVMV26L-G
Panel: 720p HD, 1366x768
MainBoard: CVMC26L-G
IC MainBoard: Flash K24C32
STV-LC1917WD Specifications
SUPRA STV-LC1917WD
General recommendations for TV LCD repair
SUPRA TV made on the CVMV26L-G chassis, like many other electronic devices, it is advisable to start repairing with an inspection of all external and internal elements. It often happens that visible damage to elements or connections helps determine the direction of troubleshooting. If charred resistors, swollen electrolytic or sintered capacitors, ring cracks in the soldering of the terminals of transformers or heating elements are found, it is advisable to establish the causes and consequences of the malfunction, as well as to check the connected elements and assemblies.
If the TV does not turn on, none of the indicators on its front panel will light or blink. Also, if the TV does not respond to the remote control and buttons, does not emit any sounds and any signs of operability when turned on, there is a certain probability that the power module is faulty and needs repair. Sometimes a problem with similar manifestations can occur only in the absence of processor power, which is typical for certain SUPRA models. It is advisable to start diagnostics of the power supply module by checking the condition of the electrolytic capacitors of the rectifier filters and the mains fuse. Defective capacitors should be replaced. If the mains fuse is broken, it is necessary to check first of all the power semiconductor elements - rectifier diodes and transistors, which are often found in a breakdown state in such situations.
Power switches in switching power supplies (SMPS) fail for no reason very rarely and, in case of their breakdown, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices and resistors in the primary circuit. The reason may be a malfunction of the PWM regulator microcircuit, which can only be checked by replacing it with a new or known good one.
If, when SUPRA STV-LC1917WD is turned on, there is no image, or it appears for a second and disappears completely, but there is sound, most likely either the backlight lamps or their power converter (inverter) are faulty. It is necessary to check the electrolytic capacitors of the filter of the secondary rectifiers in the common power supply. When disabling protection for diagnostic purposes, it must be remembered that in this case there is a risk of failure of the power elements of the inverter. Upon completion of the diagnosis, all standard protection circuits must be restored.
Repair or diagnostics of the CVMC26L-G motherboard should begin with checking the stabilizers or power converters of its microcircuits. If necessary, you should update the software (software). Complicated repair of MB (SSB) board is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the Flash K24C32 elements. Malfunctions in BGA chips are usually easy to detect by warm-up.
The SUPRA STV-LC1917WD has no picture when a signal is present, often caused by a malfunction of the display backlight. Moreover, the problem can be both inside the LCD panel (matrix), for example, a malfunction of CCFL (EEFL) lamps, and outside in their power source - an inverter.
Without backlighting, sometimes you can see a barely noticeable image with a certain successful hit of external light on the screen.
Often, to repair the backlight, disassembling the LCD panel is required - a painstaking process that requires increased attention and accuracy from the master. In such cases, there is a possibility, with the slightest negligence, to damage the glass or loops and the TV may become unrepairable.
We strongly do not recommend doing such work to owners of TVs and craftsmen who do not have experience in repairing LCD panels! Moreover, at home (at the owner's home).
If there is no image in the presence of backlight, the screen becomes slightly lighter when turned on, and if the TV is open, the light from the lamps can be seen through the holes in the panel case.
In this case, there may be a malfunction inside the panel, damage to strips, loops, the T-CON board (Timing Controller) may be defective. But often the main board MainBoard turns out to be faulty, a software failure is also possible.
In such cases, the master first of all needs to check the main supply voltage of the panel at the LVDS connector, the fuses on the T-CON board or the panel brackets, as well as the supply and reference voltages for the line and column drivers - VGH, VGL, Vcom.
If all of the above measurements are within the normal range, then the oscilloscope should track the passage of LVDS signals from the MainBoard, as well as synchronizing signals from T-CON to loops with drivers.
Remember! Attempts to repair the SUPRA STV-LC1917WD TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
DOWNLOAD FIRMWARE FOR SPI FLASH -----------> SUPRA STV-LC1917WD, Main: CVMC26L-G
The appearance of the MainBoard CVMV26L-G is shown in the figure below:CVMV26L-G
The CVMV26L-G motherboard uses a TSUMV26KE-LF (TSUMV36KE-LF) processor, combined with a scaler, SPI FLASH 520Kb and EEPROM 24C02C.
It is advisable to start repairing the MainBoard with checking the voltage converters and linear stabilizers, which are necessary to provide power in operating and standby modes. Check the power supply of the LCD panel 5V or 12V, depending on the type of panel used, it is necessary to measure directly at the LVDS connector. If, with the necessary supply voltages, the TV does not come out of Stand-by mode, does not respond to the remote control and control buttons, you should update the SPI Flash software.
Main features of SUPRA STV-LC1917WD device:
Installed matrix (LCD panel) 720p HD, 1366x768.
The necessary supply voltages for all nodes of the SUPRA STV-LC1917WD TV are provided by a switching power supply.
MainBoard - the main board (motherboard) is a CVMC26L-G module, using Flash K24C32 chips and others.
SUPRA STV-LC1917WD LCD TV with 19 "(48 cm) diagonal 16: 9 format LCD TV. Brightness of the screen 250 cd / m² provided by CCFL (EEFL) fluorescent lamps backlighting. Dynamic contrast ratio 4000: 1 achieved by special control work of backlight 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 formation of a digital signal occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p Supported media file formats: MP3, WMA, MPEG4, DivX, VideoCD, SVCD, Picture CD, JPEG.
The power of the sound system of 6 W (2x3 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, S-Video, SCART, VGA, HDMI, USB. A headphone output is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector on the TV case is used, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768.
The power consumed by the TV in operating mode from the network is 35 watts.
Dimensions: With stand 461x356x184 mm, Without stand 461x298x77 mm.
TV weight: 4.8 kg.
Attention! The SUPRA STV-LC1917WD LCD TV panel is its most expensive component.
Avoid hitting the glass and putting pressure on the screen surface to avoid irreversible damage to the LCD panel!