Wednesday, 29 April 2020

REPAIR / SERVICING TV MYSTERY MTV-2425LW

 Technical description and composition of the MYSTERY MTV-2425LW TV, type of panel and applicable modules. The composition of the modules.
MYSTERY LED
Model: MTV-2425LW
Chassis / Version: MS82D
Panel: LC230EUE (SE) (A1)
LED backlight: SML230A24 116722
LED driver (backlight): integrated into PSU
PWM LED driver: OZ9976
Power Supply (PSU): PLE50P PLE50P-2E 81-PBE024-PW6
PWM Power: FAN7930C, OB2283B
MOSFET Power: TK12A50D
MainBoard: 40-0MS82D-MAD2LG
IC MainBoard: CPU: MST6M182VG-LF-Z1, SPI Flash: 25Q32, Audio: STA380BW
Tuner: XF-3SA
Control: IR: 40-23F338-IRB1XG
Technical Specifications MTV-2425LW
MYSTERY MTV-2425LW
General repair guidelines for TV LCD LED
Possible malfunctions
- The MYSTERY MTV-2425LW TV does not turn on, does not respond to the remote control and control panel buttons, indicators do not light up and do not blink.
With such manifestations, a malfunction is most likely to be detected in the PLE50P power supply module. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches (TK12A50D) and rectifier diodes for a probable 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.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. Chips PWM (PWM) FAN7930C, OB2283B are usually checked by replacing with new, 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.
Often in such cases, there is no LED backlight. 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 check the LED lines for breaks 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 TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 40-0MS82D-MAD2LG motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair it, you should check its elements - CPU: MST6M182VG-LF-Z1, SPI Flash: 25Q32, Audio: STA380BW and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
If there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the voltage of the XF-3SA tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
It should be remembered! Attempts to independently repair the MYSTERY MTV-2425LW 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  ----------->   MYSTERY MTV-2425LW MS82D, Main: 40-0MS82D-MAD2LG, Panel: LC230EUE (SE)(A1)



 The appearance of the MainBoard 40-0MS82D-MAD2LG is shown in the figure below:
40-0MS82D-MAD2LG
40-0MS82D-MAD2LG can be used in TVs:
MYSTERY MTV-3012W (Panel V290BJ1-L01 Rev.C1 ), TCL 29T2100 (Panel V290BJ1-LE1 Rev.C1), TCL 29B340 (Panel V290BJ1-L01).
The appearance of the power supply
Main features of the MYSTERY MTV-2425LW device:
Installed matrix (LED panel) LC230EUE (SE) (A1).
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the OZ9976 PWM controller.
The required supply voltages for all nodes of the MYSTERY MTV-2425LW TV are generated by the PLE50P power module or its analogs using FAN7930C, OB2283B microcircuits and TK12A50D type power switches.
MainBoard - the main board (motherboard) is a 40-0MS82D-MAD2LG module using CPU chips: MST6M182VG-LF-Z1, SPI Flash: 25Q32, Audio: STA380BW and others.
The XF-3SA tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: LG Display
Model: LC230EUE-SEA1
Type: a-Si TFT-LCD, Panel
Diagonal size: 23.0 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 509.184x286.416 mm
Surface: Antiglare (Haze 10%), Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (6-bit + Hi-FRC)
Response Time: 5 (G to G)
Frequency: 60Hz
Lamp Type: 17S2P WLED Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V
The MYSTERY MTV-2425LW TV with an LC230EUE LCD display, a diagonal size of 24 "(61 cm) in 16: 9 format. The required screen brightness of 250 cd / m² is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 1000: 1. The LED-panel of this TV has an end LED backlight - Edge LED.The design and technical capabilities of the TV include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic layout according to the standard 1080p (Full HD). Audio or video signal can be processed 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, Xvid , MKV, JPEG.
The power of the sound system 10 W (2x5 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), AV, component, VGA, HDMI, USB. 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, 1280x1024, 1360x768.
The power consumed by the TV in the operating mode from the network is 30 watts.
Dimensions: With stand 642x444x209 mm, Without stand 570x345x70 mm.
Attention! The LC230EUE (SE) (A1) panel of the MYSTERY MTV-2425LW 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.