Saturday 18 July 2020

REPAIR / SERVICING TV SUPRA STV-LC19740WL

Technical description and composition of the TV SUPRA STV-LC19740WL, type of panel and applicable modules. The composition of the modules.
SUPRA LED
Model: STV-LC19740WL
Chassis / Version: V2N08
Panel: HM185WX3-401
T-CON: HM185WX1-400.X0.0
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: MDF7N60B
MainBoard: TP.VST59.P67
IC MainBoard: CPU TSUMV59XE-Z1, SPI Flash W25Q32FVSIG
Tuner: NoName
STV-LC19740WL Specifications
SUPRA STV-LC19740WL
General repair guidelines for TV LCD LED
Possible manifestations of defects
- SUPRA STV-LC19740WL does not turn on and does not show any signs of operability at all. Does not blink indicators and does not respond to control buttons.
A malfunction in such cases, first of all, should be sought in the power elements of a switching power supply (SMPS) - a mains voltage converter (AC / DC), which in this TV model is combined with the MainBoard TP.VST59.P67 main board. It is necessary to measure its output voltages and, in case of their absence, check the serviceability of power switches (MDF7N60B) and rectifier diodes in the converters for possible breakdown.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and with a short circuit in the power elements of the primary circuit, the mains fuse or current sensor in the source of the key is often cut off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. 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, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. 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.
To test the LED strips, to open all the transitions of the LEDs, you need several tens of volts or more, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED junctions in forward bias, you can sometimes detect the presence of a protective zener diode PN junction by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not turn on, the indicator signals standby or working mode, or blinks.
Repair or diagnostics of the TP.VST59.P67 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, update or replace the software (software). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU TSUMV59XE-Z1, SPI Flash W25Q32FVSIG elements requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
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 monitored with an oscilloscope
It should be remembered! Attempts to self-repair the SUPRA STV-LC19740WL TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!

FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC19740WL V2N08, Main: TP.VST59.P67, Panel: HM185WX3-401.

FIRMWARE FOR SPI FLASH  ----------->   SUPRA STV-LC19740WL, Main: 35017525, Panel: HT185WX1-300

 The appearance of the MainBoard TP.VST59.P67 is shown in the figure below:
TP.VST59.P67
TP.VST59.P67 can be used in TVs:
SHIVAKI 22LED6 (Panel T215HVN010), SHIVAKI STV-24LED6 STV-24LED6W (Panel V236BJ1-P01), SUPRA STV-LC16500WL (Panel B156XTN03.2), SUPRA STV-LC22551FL (Panel L509A215N01F-1), SUPRA STV-LC19740WL (Panel HM185WX3-401).
Main features of the SUPRA STV-LC19740WL device:
Installed matrix (LED-panel) HM185WX3-401.
The matrix control uses the Timing Controller (T-CON) HM185WX1-400.X0.0.
To power the backlight LEDs, a converter combined with the TP.VST59.P67 main board is used, controlled by the OB3350CP PWM controller.
The power module is combined with the MainBoard and is made according to the scheme of a flyback AC / DC voltage converter using PWM SOT23-6 microcircuits and power switches of the MDF7N60B type.
MainBoard - the main board (motherboard) is a TP.VST59.P67 module, using CPU TSUMV59XE-Z1, SPI Flash W25Q32FVSIG and others.
Tuner NoName provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: BOE
Model: HM185WX3-401
Type: a-Si TFT-LCD, CELL
Diagonal size: 18.5 inch
Resolution: 1366x768, WXGA
Display Mode: TN, Normally White, Transmissive
Active Area: 409.8x230.4 mm
Surface: Antiglare (Haze 25%), Hard coating (3H), Antireflection
Glass Depth: 0.50 + 0.50 mm
Transmissivity: 5.4% (with Polarizer)
Contrast Ratio: 1000: 1
Display Colors: 16.7M (6-bit + Hi-FRC)
Response Time: 1.5 / 3.5 (Tr / Td)
Frequency: 60Hz
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V
LED TV SUPRA STV-LC19740WL with LCD HM185WX3-401, diagonal size 18.5 "(47 cm) 16: 9 format. The required brightness of the screen 250 cd / m² is provided by LED backlight LED. Dynamic contrast ratio of 60000: 1 is achieved by special control LEDs work depending on the illuminated areas in the plot.In this model, an LED panel with the end position of the backlight LEDs, Edge LED, is used. The input high-frequency or video signal is decoded in analogue systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, MKV , JPEG.
The power of the sound system 6 W (2x3 W) provide two speakers. The audio processing system NICAM STEREO is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI, 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, 1360x768.
The power consumed by the TV in the operating mode from the network is 32 watts.
Dimensions: With stand 450x338x188 mm, Without stand 450x292x62 mm.
Attention! Panel HM185WX3-401 LED TV SUPRA STV-LC19740WL 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.