Friday 24 April 2020

REPAIR / SERVICING TV SHIVAKI STV-55LED17

Technical description and composition of the TV SHIVAKI STV-55LED17, type of panel and applicable modules. The composition of the modules.
SHIVAKI LED
Model: STV-55LED17
Chassis / Version: TP.S512.PC821
Panel: CX550DLEDM
LED backlight: MS-L0697 V6 022-P2K2630A
T-CON: TT5461B07-3-C-1
LED driver (backlight): integrated into MainBoard
PWM LED driver: LD7750
MOSFET LED driver: 80R900P
Power Supply (PSU): integrated into MainBoard
PWM Power: NCP1607B, LD5530
MOSFET Power: MDF13N50B, 70R900P
MainBoard: TP.S512.PC821
IC MainBoard: CPU: S2T512, SPI FLASH: W25Q64BV, Audio: TPA3110D2, 1117
Tuner: R840 & XF-3SDT-H
Control: IR: 200-GJR-LE32280-0H
Technical Specifications STV-55LED17
SHIVAKI STV-55LED17
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The SHIVAKI STV-55LED17 TV does not turn on and does not show any signs of turning on, it does not respond to the control buttons or to the remote control.
In this case, first of all, you should check the operability of the main power source - AC / DC network voltage converter, all of whose elements are located on the MainBoard TP.S512.PC821 board. It is necessary to measure its output voltages, and in case of their absence, check the serviceability of power switches (MDF13N50B, 70R900P) of converters and rectifier diodes for the probability of short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback circuits (OOS) of stabilization. PWM controllers (PWM) NCP1607B, LD5530, if they do not have visible damage to the case and open fault between the terminals, are usually checked by replacement.
- 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.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. 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 is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, black to the cathode). In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode 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 TP.S512.PC821 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - CPU: S2T512, SPI FLASH: W25Q64BV, Audio: TPA3110D2, 1117 with new or obviously working ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltages at the terminals of the R840 & XF-3SDT-H tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
We recommend the owners of the STV-55LED17 TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    MainBoard TP.S512.PC821

FIRMWARE FOR SPI FLASH  ----------->   SHIVAKI STV-55LED17, Main: TP.S512.PC821, Panel: CX550DLEDM


 The appearance of MainBoard TP.S512.PC821 is shown in the figure below:
TP.S512.PC821
TP.S512.PC821 can be used in TVs:
AKAI LEA-49K40M (Panel LSC490HN04-W), DEXP F48B7000V (Panel LCS480HN07), SHIVAKI STV-48LED15 (Panel LSC480HN05-B01), SHIVAKI STV-49LED17 (Panel LSC490HN03-W), SHIVAKI STV-50LED13 (Panel V500HJ1-PE8), THOMSON T48D16SF-01B (Panel LVF480SSDX E8 V1).
Main features of the SHIVAKI STV-55LED17 device:
Installed matrix (LED-panel) CX550DLEDM.
The matrix control uses the Timing Controller (T-CON) TT5461B07-3-C-1.
To power the backlight LEDs, a converter is used, combined with the TP.S512.PC821 main board, controlled by the LD7750 PWM controller. As the power elements of the LED driver, keys of the 80R900P type are used.
The power module is combined with the MainBoard and is made according to a flyback AC / DC voltage converter circuit using NCP1607B, LD5530 microcircuits and power switches of the MDF13N50B, 70R900P type.
MainBoard - the main board (motherboard) is a TP.S512.PC821 module, using CPU chips: S2T512, SPI FLASH: W25Q64BV, Audio: TPA3110D2, 1117 and others.
The R840 & XF-3SDT-H tuner provides TV reception and channel tuning.
TV SHIVAKI STV-55LED17 with LCD display CX550DLEDM, diagonal size 55 "(140 cm) 16: 9 format. The required brightness of the screen 350 cd / m² is provided by LED backlight LED. Contrast, as the ratio of maximum brightness to minimum, is 5000: 1. LED TV backlighting technology is implemented in the TV screen manufacturing technology of this TV model. You can watch movies in the highest possible UHD quality with a resolution of 3840x2160 pixels in 4K UHD standard. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the sound system 20 W (2x10 W) provides two 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), VGA, HDMI x3, USB. An output for connecting headphones is provided.
The digital tuner is capable of receiving television channels in the standards DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2.
Overall dimensions: with stand 1240x775x253 mm, without stand 1240x716x81 mm.
Mass of the TV: 14.1 kg.
Attention! The CX550DLEDM panel of a SHIVAKI STV-55LED17 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.