Thursday 23 April 2020

REPAIR / SERVICING TV SHIVAKI STV-32LEDG7

Technical description and composition of the TV SHIVAKI STV-32LEDG7, type of panel and applicable modules. The composition of the modules.
SHIVAKI LED
Model: STV-32LEDG7
Chassis / Version: MSD308PV7.0-C
Panel: V315H3-LE4 REV.C1
LED backlight: EDGE LED
T-CON: V315H3-XRE3
Power Supply (PSU): CTN180-P
PWM Power: PFC, PWM-Resonsnt, STB (SOT23-6)
MainBoard: MSD308PV7.0 C
IC MainBoard: CPU: MSD308PX-LF-Z1, SPI FLASH: 25Q32, DC / DC: AIC2857F
Tuner: NoName
Technical Specifications STV-32LEDG7
SHIVAKI STV-32LEDG7
General repair guidelines for TV LCD LED
Possible malfunctions
- The SHIVAKI STV-32LEDG7 TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
Typically, with such manifestations, the defect is caused by faulty elements in the CTN180-P main power module. It is necessary to measure its output voltages, and in case of their absence, check the operability of the power switches of the converters and rectifier diodes for the probability of a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. In the case of PFC, PWM-Resonsnt, STB (SOT23-6) PWM controllers, in the absence of visible damage or open faults between the terminals, they are checked by replacing them with new ones, or those that are obviously working.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
As a rule, in such cases there is no display backlight. The reason can 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 the open circuit in the LED lines without disassembling the panels with 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 it is necessary 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 LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the MSD308PV7.0 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: MSD308PX-LF-Z1, SPI FLASH: 25Q32, DC / DC: AIC2857F and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
Before changing the NoName tuner, if there is no possibility of tuning to television channels, you should make sure that there are supply voltages that must be measured at the corresponding tuner pins and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
TV users and owners must remember that attempts to self-repair a SHIVAKI STV-32LEDG7 TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    CTN180-P Power supply


 Main features of the SHIVAKI STV-32LEDG7 device:
Installed matrix (LED panel) V315H3-LE4 REV.C1.
The matrix control uses the Timing Controller (T-CON) V315H3-XRE3.
The necessary supply voltages for all nodes of the SHIVAKI STV-32LEDG7 TV are generated by the CTN180-P power supply module or its analogs using PFC, PWM-Resonsnt, STB (SOT23-6) microcircuits.
MainBoard - the main board (motherboard) is an MSD308PV7.0 module, using CPU chips: MSD308PX-LF-Z1, SPI FLASH: 25Q32, DC / DC: AIC2857F and others.
The NoName tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V315H3-LE4
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1920x1080, FHD
Display Mode: MVA, Normally Black, Transmissive
Active Area: 698.4x392.85 mm
Surface: Antiglare (Haze 11%), Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 6000: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8.5 (G to G)
Frequency: 60Hz
Lamp Type: WLED Embedded (LED Driver)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V
TV SHIVAKI STV-32LEDG7 with LCD V315H3-LE4, diagonal size 32 "(81 cm) 16: 9 format. The required brightness of the screen 400 cd / m² is provided by LED backlight LED. Contrast, as the ratio of maximum brightness to minimum, is 5000: 1. The LED-panel of this TV has end-face LED backlighting - Edge LED. The design and technical capabilities of the TV include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic resolution according to the standard 1080p (Full HD). Input high frequency or video signal can be processed by analog systems, PAL, SECAM, NTSC Image processing and generation of the digital signal occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p Supported multimedia file formats:.. MP3, MPEG4, JPEG.
The power of the sound system 30 W (3x10 W) provide 3 speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, SCART, RGB, VGA, HDMI x3, USB. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1920x1080.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C standards.
The power consumed by the TV in the operating mode from the network is 80 watts.
Overall dimensions: 792x531x180 mm.
The mass of the TV: 11.8 kg.
Attention! The V315H3-LE4 REV.C1 panel of the SHIVAKI STV-32LEDG7 LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.