Technical description and composition of the SUPRA STV-LC28T662WL TV, panel type and modules used. The composition of the modules.SUPRA LED
Model: STV-LC28T662WL
Chassis / Version: 40-MT31BP-MAA2LG
Panel: T8-28T3520-LPM20
LED driver (backlight): integrated into MainBoard
PWM LED driver: MP3398A
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6 (RT7738)
MainBoard: 40-MT31BP-MAA2LG
IC MainBoard: CPU: MT5531NDNT; SPI Flash: GD25Q64F; SOUND: RT9108NB
Tuner: 07-600C13-SA2G ST34WN-2T-E
STV-LC28T662WL Specifications
SUPRA STV-LC28T662WL
General recommendations for TV LCD LED repair
Repair and diagnostics of any electronic device, in particular SUPRA STV-LC28T662WL, it is advisable to begin with a careful external examination of the internal and external elements. According to some external signs of a change in the state of some elements, sometimes it becomes possible to make assumptions about the nature of the defect, as well as to determine the further direction of troubleshooting. Swollen electrolytic or sintered capacitors, charred resistors, ring cracks in the soldering of the element terminals - all this can significantly help the master to determine the causes and consequences of the malfunctions in the TV.
In the case when the STV-LC28T662WL does not turn on, does not respond to the remote control and front panel buttons, does not blink lights and does not show any signs of operability, the power module is probably faulty in this case. If it is working properly with such manifestations, it is necessary to check the processor power regulator (converter) on the motherboard. When repairing a power supply, it is advisable to start diagnostics with checking the mains fuse and electrolytic capacitors of the filters of the converter's secondary rectifiers. In the event of a break in the fuse, the cause should be sought in the power semiconductor elements of the pulse converter of the main power supply unit. It is necessary first of all to check the diodes of the rectifier bridge of the mains voltage and the power switch (s) of the converter.
The reasons for the breakdown of the power switch in switching power supplies (SMPS) can be different, for example, a malfunction of semiconductor elements or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as a failure in the operation of the PWM regulator microcircuit or breaks of resistors in its strapping.
If, when SUPRA STV-LC28T662WL is turned on, there is no image, or it appears for a second and disappears, but there is sound, most likely there is a malfunction in the T8-28T3520-LPM20 panel backlight LED circuit, or in their power converter. It is necessary to check the electrolytic capacitors of the filter of the secondary rectifiers in the common power supply.
It is often necessary to disassemble the panel to check the health of the LEDs, as well as the contact connections in the connectors and solders.
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.
On the 40-MT31BP-MAA2LG motherboard, in case of a malfunction, you should first check the operability of all stabilizers or power converters of microcircuits and, if necessary, update the software (software).
In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - SPI Flash: GD25Q64 with new or known good ones. In cases where BGA technologies are used, defects are usually localized by heating.
If there is no reception of TV channels, but the TV is working properly from external devices, first of all, you need to check the supply voltage of the tuner 07-600C13-SA2G ST34WN-2T-E.
Owners and users of the SUPRA STV-LC28T662WL TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!
FIRMWARE FOR SPI FLASH -----------> SUPRA STV-LC28T662WL, Main: 40-MT31BP-MAA2LG, Panel: T8-28T3520-LPM20
The appearance of the MainBoard 40-MT31BP-MAA2LG is shown in the figure below:40-MT31BP-MAA2LG
40-MT31BP-MAA2LG can be used in TVs:
ERISSON 32LET82 (Panel LVW320CSOT E145 V2), ERISSON 32LET42T2 (Panel LVW320CSOT E274 V2), ERISSON 32LET41T2 (Panel LVW320CS0T E274 V2), FUSION FLTV-32T21 (Panel LVW320CZOT), SUPRA STV-LC32T420WL (Panel LVW320CSOT E155 V2), SUPRA STV-LC32T850WL (Panel LVW320CSOT E45 V1), SUPRA STV-LC28T662WL (Panel T8-28T3520-LPM20), SUPRA STV-LC24T850WL (Panel 720p HD 1366x768), TELEFUNKEN TF-LED32S29T2 (Panel LVW320CS0T E198 V4), TELEFUNKEN TF-LED24S29T2 (Panel V236BJ1-LE2 Rev.C1), THOMSON T24E12DHU-01B T24E12DHU (Panel LVW240AUDX E2 V6).
Main features of SUPRA STV-LC28T662WL device:
Installed matrix (LED panel) T8-28T3520-LPM20.
To power the backlight LEDs, a converter combined with the 40-MT31BP-MAA2LG main board is used, controlled by the MP3398A 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 (RT7738) microcircuits.
MainBoard - the main board (motherboard) is a 40-MT31BP-MAA2LG module, using CPU chips: MT5531NDNT; SPI Flash: GD25Q64F; SOUND: RT9108NB and others.
Tuner 07-600C13-SA2G ST34WN-2T-E provides reception of TV programs and tuning to channels.
SUPRA LED TV STV-LC28T662WL with LCD T8-28T3520-LPM20, 28 "(71 cm) diagonal, 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 80000: 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 media file formats: MP3, WMA, MPEG4 , MKV, JPEG.
Speaker power of 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, audio x2, component, VGA, HDMI x2, 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. The digital tuner is capable of receiving television channels in the DVB-T, DVB-C, DVB-T2 standards.
Dimensions: With stand 503x342x155 mm, Without stand 503x312x50 mm.
Attention! SUPRA STV-LC28T662WL LED TV panel T8-28T3520-LPM20 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 unrepairable.