Saturday 18 July 2020

REPAIR / SERVICING TV SUPRA STV-LC1957WL

  Technical description and composition of the SUPRA STV-LC1957WL TV, panel type and modules used. The composition of the modules.
SUPRA LED
Model: STV-LC1957WL
Chassis / Version: V1L02
Panel: ECG18501-L03
LED driver (backlight): JUG7.820.846-4-15025 REV: 2.2.1H
PWM LED driver: 7101PB
Power Supply (PSU): PW52057 B
MainBoard: JUG7.820.1060-2
IC MainBoard: MST6E181VS-LF-Z1, Flash: Q32A-100HIP, Sound: 1517P
Tuner: CDT-3FP2I2-34
Technical Specifications STV-LC19571WL
SUPRA STV-LC1957WL
General recommendations for TV LCD LED repair
Repair of electronic equipment usually begins with its external inspection and diagnosis of the malfunction. In this case, you should examine all the internal components of the TV SUPRA STV-LC1957WL, as well as the external elements of the housing. Sometimes, based on visible changes in the components of the device, it is possible to draw some conclusions and decide on the direction of further troubleshooting even before the necessary measurements are taken. Swollen electrolytic or cermet capacitors, charred resistors, ring cracks in the soldered terminals of the elements - all this can significantly help the master to determine the causes and consequences of the malfunction of the TV.
In the absence of any signs of operability, when the SUPRA STV-LC1957WL does not turn on and does not signal anything with the control lights on the panel, there is a possibility of a malfunction of the TV's PW52057B power module. With the same manifestations, the power regulator of the control processor on the motherboard may be faulty. When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. When it is broken, the power elements of the transistors and diodes of the rectifier bridge should be checked for avalanche (thermal) breakdown.
The reasons for the breakdown of the power switch in switching power supplies (SMPS) can be different, for example, a malfunction of semiconductor elements or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as a failure in the operation of a PWM controller microcircuit or breaks in resistors in its strapping.
In cases where the SUPRA STV-LC1957WL TV has lost the image, but there is sound and all other functions are operational, there is a possibility of a malfunction of the LED driver (the converter for powering the backlight LEDs of the ECG18501-L03 panel). When you turn on the TV, the image may appear briefly and disappear immediately. It must be borne in mind that with such manifestations the LEDs themselves also fail.
Often there is a need for disassembling the panel to check the health of the LEDs, as well as contact connections in the connectors and soldering.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the circuit of the LED lines without disassembling the panels using a tester or a 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.
If the JUG7.820.1060-2 motherboard is faulty, first of all it is necessary to check all linear stabilizers or power converters of its chips, and also, if necessary, update the software. Sometimes it is possible to check the health of the MB only by replacing it.
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 - MST6E181VS-LF-Z1, Flash: Q32A-100HIP, sound: 1517P 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 CDT-3FP2I2-34 tuner, if there is no tuning for the channels, first check the supply voltage at its terminals, including the varicap supply (30-33V).
Attention to users! Self-repair of the SUPRA STV-LC1957WL TV without appropriate qualifications and experience can lead to its complete non-repairability!

FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC1957WL (V1L02), Main MST6E181VS-LF-Z1, Panel: ECG18501-L03



 The appearance of the MainBoard JUG7.820.1060-2 is shown in the figure below:
JUG7.820.1060-2
The appearance of the power supply
Main features of SUPRA STV-LC1957WL device:
Installed matrix (LED panel) ECG18501-L03.
The LED driver JUG7.820.846-4-15025 is used to power the backlight LEDs, it is controlled by the 7101PB PWM controller.
The formation of the necessary supply voltages for all nodes of the SUPRA STV-LC1957WL TV is carried out by the PW52057 power module, or its analogues.
MainBoard - the main board (motherboard) is a JUG7.820.1060-2 module, using the MST6E181VS-LF-Z1 chips, Flash: Q32A-100HIP, sound: 1517P and others.
The CDT-3FP2I2-34 tuner provides reception of television programs and tuning to channels.
LED TV SUPRA STV-LC19571WL with LCD, diagonal 19 "(48 cm) in 16: 9 format. The required screen brightness of 350 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum is 600: 1 Dynamic contrast ratio of 20,000: 1 is achieved by special control of the LEDs depending on the lighting in the plot. in the standard of graphic decomposition 720p (HD Ready) .Input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal formation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported file formats multimedia: MP3, WMA, JPEG.
The power of the sound system 4 W (2x2 W) provide two speakers. It uses the NICAM stereo signal processing system and Sound Surround.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI, USB. A headphone output 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.
The power consumed by the TV in operating mode from the network is 30 W.
Overall dimensions: 513x394x110 mm.
TV weight: 4.3 kg.
Attention! SUPRA STV-LC19571WL LED TV panel 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.