Sunday 9 August 2020

REPAIRING / SERVICING TV SKYLINE 43LST5970

Technical description and composition of the SKYLINE 43LST5970 TV, panel type and modules used. The composition of the modules.
SKYLINE LED
Model: 43LST5970
Chassis / Version: TP.MT5510S.PB803
Panel: PT430CT02-1
LED backlight: CC02430D738V04
LED driver (backlight): integrated into MainBoard
PWM LED driver: SO-8
MOSFET LED driver: TO-252
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-252
MainBoard: TP.MT5510S.PB803
IC MainBoard: CPU, eMMC, AUDIO, DC / DC
Tuner: NoName
Specifications 43LST5970
SKYLINE 43LST5970
General recommendations for TV LCD LED repair
Possible manifestations of defects
- The SKYLINE 43LST5970 TV does not turn on at all. No response to the remote control and front panel control buttons. Indicator lamps do not light up or flash.
A malfunction in such cases should be looked for primarily in the circuit of a switching power supply (SMPS) - a mains voltage converter (AC / DC), which is combined with the main board MainBoard TP.MT5510S.PB803 in this model. It is necessary to make sure that its output voltages are present and, if they are completely absent, check the power switches (TO-252) and rectifier diodes for a possible short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can operate in an emergency in the short-circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse is usually cut off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements, which can disable it in 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) PWM SOT23-6, in the absence of external damage and a 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.
As a rule, in such cases there is no display backlight. 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 is also faulty.
To check the LED strips for breakage without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter; a voltage of the order of several tens of volts is required.
- The indicator on the front panel blinks, the TV does not turn on in operating mode, does not respond to the remote control.
Repair or diagnostics of the TP.MT5510S.PB803 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Often the MB (SSB) board needs to be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU, eMMC, AUDIO, DC / DC and replace the failed chips with new ones. Some malfunctions may be associated with the use of BGA soldering technologies in modern Main Board. Typically, such defects are detected by local heating of the chip.
Before replacing the NoName tuner, if there is no tuning to the channels, you must first check the software and the supply voltage at its outputs. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Once again, we remind TV users: do not attempt to repair yourself without the appropriate knowledge, experience and the necessary qualifications! Trust the repair to professionals with sufficient experience in the field of electronic repair.
https://3.bp.blogspot.com/-gyVi0WZt7cE/Xy_ZJcjgYyI/AAAAAAABDYU/2ozH2Xsyw3Mt20V-RnSZxMOXA-9qIiIhwCK4BGAYYCw/s1600/TP.MT5510S.PB803_DCE.jpgAdditional MainBoard Repair
The appearance of the MainBoard TP.MT5510S.PB803 is shown in the figure below:
TP.MT5510S.PB803
The main features of the SKYLINE 43LST5970 device:
Installed matrix (LED panel) PT430CT02-1.
To power the backlight LEDs, a converter combined with the TP.MT5510S.PB803 main board is used, controlled by the SO-8 PWM controller. TO-252 switches 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 using PWM SOT23-6 microcircuits and TO-252 power switches.
MainBoard - the main board (motherboard) is a TP.MT5510S.PB803 module using CPU, eMMC, AUDIO, DC / DC chips and others.
Tuner NoName provides reception of television programs and tuning to channels.

TV SKYLINE 43LST5970 with LCD display PT430CT02-1, diagonal size 43 "(109 cm) 16: 9 format. The required screen brightness of 250 cd / m2 is provided by LED backlighting. Dynamic contrast ratio of 90,000: 1 is achieved by special control of the LEDs. The LCD-panel of the TV is implemented with direct backlighting with LED back-mounted - Direct LED.
There is a convenient function of recording TV programs on a USB-drive with subsequent viewing at another time (TimeShift).
The PT430CT02-1 LCD panel and the TP.MT5510S.PB803 main board software provide viewing of broadcasts and movies in high quality HD at a resolution of 1920x1080 pixels in graphics resolution at 1080p (Full HD).
43LST5970 TV has built-in SMART software and preinstalled Android Operating System. Internet connection can be made via Wi-Fi wireless connection. Supported media file formats: MP3, WMA, MPEG4, Xvid, MKV, JPEG.
Speaker power 20 W (2x10 W) is provided by two speakers. Uses NICAM stereo signal processing system and Sound Surround function.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, VGA, HDMI 1.4 x3, USB x2, Ethernet (RJ-45), Wi-Fi. A headphone output is provided.
The digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
The power consumed by the TV operating in mains mode is 74 W.
Dimensions: with stand 966x599x190 mm, without stand 966x560x90 mm.
TV weight: with stand: 8.8 kg, without stand: 8.5 kg.
Attention! The panel PT430CT02-1 of the SKYLINE 43LST5970 LED TV 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.