Tuesday, 28 July 2020

REPAIR / SERVICING TV SUPRA STV-LC40T871FL

Technical description and composition of the SUPRA STV-LC40T871FL TV, panel type and modules used. The composition of the modules.
SUPRA LED
Model: STV-LC40T871FL
Chassis / Version: TP.SIS231.PT85 / V1N
Panel: JHD400GF
LED backlight: JHD400GF-E32 \ 2033 \ SV0 \ SKD3 \ FM \ ROH
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
MOSFET LED driver: AOD4454
Power Supply (PSU): integrated into MainBoard
PWM Power: LD7536 (PWM SOT23-6)
MOSFET Power: N-FET TO-220
MainBoard: TP.SIS231.PT85
IC MainBoard: CPU: SIS231, DRAM: NT5CB64M16FP-DH, SPI Flash: 25Q64, TPA3110LD2, SI2168, RT7237
Tuner: NoName
STV-LC40T871FL Specifications
SUPRA STV-LC40T871FL
General recommendations for TV LCD LED repair
Possible manifestations of malfunctions
- SUPRA STV-LC40T871FL does not turn on, indicators on the front panel do not light or flash. The TV does not respond to control buttons and the remote control.
In such cases, the AC / DC converter of the mains voltage, which is combined with the main board TP.SIS231.PT85, is often faulty. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches and rectifier diodes for possible partial or complete breakdown.
In the event of diode breakdowns in the secondary circuits, the converter can operate in an emergency mode of short circuit without output voltages, and with a short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor in the source of the key usually breaks off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can disable it in the key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying the PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) LD7536 (PWM SOT23-6), in the absence of external damage and short circuit between the terminals, are checked by replacing them with a known good one.
- 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.
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.
When diagnosing, it must be borne in mind that it is impossible to check for an open in the circuit of the LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally a current source. By opening the panel, you can check each LED separately. Typically, Chinese multimeters light up one 3-volt LED slightly if the probes are connected to it in the forward direction. For dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of LED health. In the event of a malfunction of the LED, its zener diode will either be cut off or broken into the K / Z.
- 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 TP.SIS231.PT85 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and the matrix. If necessary, you should update or replace the software (software). Complex repair of MB (SSB) is possible only in a service center with the necessary equipment. Checking or replacing elements CPU: SIS231, NAND: NT5CB64M16FP-DH, SPI Flash: 25Q64, TPA3110LD2, SI2168, RT7237 requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by the warm-up method.
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 NoName tuner and update the software. I2C communication pulses must be monitored with an oscilloscope.
Owners of the STV-LC40T871FL TV are advised to contact only qualified specialists with the necessary experience for repair! Attempts to repair yourself without the appropriate knowledge and skills can lead to irreversible negative consequences!


DOWNLOAD FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC40T871FL, Main: TP.SIS231.PT85, Panel: JHD400GF

DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ----->     Power supply Chassis TP.SIS231.PT85


 The appearance of the MainBoard TP.SIS231.PT851 is shown in the figure below:
TP.SIS231.PT851
TP.SIS231.PT85 can be used in TVs:
DNS M39DM8 (Panel V390HJ1-P02 Rev C1), DNS S32DC1 (Panel T320XVD01.0), DNS E32D18 (Panel ST3151A05-5 CX315DLEDM), DNS V32D8100S (Panel LSC320HN04-002), ERISSON 40LEP92 (Panel LSC400HN01 G01), ROLSEN RL-39S1502T2C (Panel V390BJ1-L01-D00), RUBIN RB-40D5FT2C (Panel 390HJ5-XCPE1), RUBIN RB-40SE9FT2C (Panel CX400DLEDM), SUPRA STV-LC32T871WL (Panel JHD315GH-E31), SUPRA STV-LC40T871FL (Panel JHD400GF), TELEFUNKEN TF-LED32S26T2 (Panel MT3151A05).
Main features of SUPRA STV-LC40T871FL device:
Installed matrix (LED panel) JHD400GF.
The backlight LEDs are powered by a converter combined with the TP.SIS231.PT85 main board, controlled by the OB3350CP PWM controller. The keys of the AOD4454 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 circuit using LD7536 microcircuits (PWM SOT23-6) and N-FET TO-220 power switches.
MainBoard - the main board (motherboard) is a TP.SIS231.PT85 module, using CPU: SIS231 chips, DRAM: NT5CB64M16FP-DH, SPI Flash: 25Q64, TPA3110LD2, SI2168, RT7237 and others.
Tuner NoName provides reception of television programs and tuning to channels.
LED TV SUPRA STV-LC40T871FL with LCD JHD400GF, diagonal 40 "(102 cm) 16: 9. The required screen brightness of 300 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 100,000: 1 is achieved by special control of LED operation depending on the illumination of the areas in the scene.This model uses an LED panel with an edge LED backlighting - Edge LED.The TV capabilities provide viewing of programs and films in high quality HD at a resolution of 1920x1080 pixels in graphics resolution at 1080p (Full HD). The 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, 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, RGB, VGA, HDMI x3, 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, 1280x1024, 1360x768, 1920x1080. The digital tuner is capable of receiving TV channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Dimensions: With stand 931x595x240 mm, Without stand 931x552x72 mm.
TV weight: 7.7 kg.
Attention! SUPRA STV-LC40T871FL LED TV panel JHD400GF 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.