Thursday 23 April 2020

REPAIR / SERVICING TV SHIVAKI STV-24LED20W

Technical description and composition of the SHIVAKI STV-24LED20W TV, type of panel and applicable modules. The composition of the modules.
SHIVAKI LED
Model: STV-24LED20W
Chassis / Version: TP.MS3663S.PA671
Panel: D24-F2000
LED backlight: 230 mA
T-CON: M236HJJ-P02
LED driver (backlight): integrated into MainBoard
PWM LED driver: 8pin
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-252
MainBoard: TP.MS3663S.PA671
IC MainBoard: CPU: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P
Tuner: CDT-9NT372-RF01
Technical Specifications STV-24LED20W
SHIVAKI STV-24LED20W
General repair guidelines for TV LCD LED
Possible malfunctions
- The SHIVAKI STV-24LED20W TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
In such cases, the AC / DC voltage converter, which is combined with the main board TP.MS3663S.PA671, is often faulty. In the absence of the necessary supply voltage in the secondary circuits of the converters, it is necessary to check the power switches (TO-252) and rectifier diodes for a possible partial or complete breakdown.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
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. PWM SOT23-6 PWM controllers, in the absence of visible damage or obvious short-circuit between the terminals, are checked by replacing with new ones, or 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.
In such cases, the most likely malfunction of the LED backlight elements. Usually the cause of the malfunction is in the breakage of the LEDs, or in the connectors of the LED strips, but sometimes the LED driver also turns out to be faulty.
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 indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the TP.MS3663S.PA671 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). If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - SPI FLASH MX25L6436F, AUDIO: YD1517P. Defective components should be replaced.
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 voltage at the terminals of the tuner CDT-9NT372-RF01. 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.
Owners and users of the SHIVAKI STV-24LED20W 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  ----------->   SHIVAKI STV-24LED20W, Main: TP.MS3663S.PA671, Panel: D24-F2000

 The appearance of MainBoard TP.MS3663S.PA671 is shown in the figure below:
TP.MS3663S.PA671
Main features of the SHIVAKI STV-24LED20W device:
Installed matrix (LED-panel) D24-F2000.
The matrix control uses the Timing Controller (T-CON) M236HJJ-P02.
To power the backlight LEDs, a converter is used, combined with the main board TP.MS3663S.PA671, controlled by an 8pin PWM controller.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits and TO-252 type power switches.
MainBoard - the main board (motherboard) is a TP.MS3663S.PA671 module, using CPU chips: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P and others.
The tuner CDT-9NT372-RF01 provides the reception of television programs and tuning to channels.
TV SHIVAKI STV-24LED20W with LCD D24-F2000, diagonal size 23.6 "(60 cm) 16: 9 format. The required brightness of the screen is 150 cd / m² LED backlight LED. Contrast, as the ratio of maximum brightness to minimum, is 1000: 1. LED TV backlighting is implemented in the technology for making this TV model’s screen.The TV’s design and technical capabilities include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic resolution of 1080p (Full HD) Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the acoustic system of sound 6 W (2x3 W) provide 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), AV, component, VGA, HDMI, 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.
The power consumed by the TV in the operating mode from the network is 40 watts.
Overall dimensions: with stand 554x365x146 mm, without stand 554x335x77 mm.
TV Weight: with stand: 2.5 kg, without stand: 2.4 kg.
Attention! The D24-F2000 panel of a SHIVAKI STV-24LED20W 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.