Technical description and composition of the DNS M28AM8 TV, panel type and modules used. The composition of the modules.DNS LED
Model: M28AM8
Chassis / Version: TP.VST59.P86
Panel: MT3151A05
LED backlight: MT3151A05-1-XC-7, ST2751A01-1
LED driver (backlight): integrated into MainBoard
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: TP.VST59.P86
IC MainBoard: CPU: TSUMV59XU, SPI Flash: 25Q32BSIG, AUDIO: TPA3110D2
Tuner: Tuner
Specifications M28AM8
DNS M28AM8
General recommendations for TV LCD LED repair
Possible manifestations of defects
- DNS M28AM8 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.
First of all, in such cases, you should make sure that the common switching power supply (SMPS) - the AC / DC voltage converter of the mains voltage - is working. All source elements in this TV model are located on the MainBoard TP.VST59.P86. It is necessary to measure its output voltages, and if they are absent (full or partial), the serviceability of the power switches of the converters and rectifier diodes should be checked for a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually operate in an emergency mode in a short-circuit mode, and in case of a short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Breakdown of Mos-Fet switches used in switching power supplies is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency setting or damper circuits, as well as in negative feedback stabilization. PWM microcircuits (PWM) IC_Power are usually checked by replacing them with new ones, or known to be working properly.
- There is no image, there is sound, it reacts to the remote control. Or, immediately after switching on for a second, the image may appear and immediately disappear.
A malfunction is usually in these cases most likely in the backlight units of the display matrix. The reason for this may be an open circuit in the LED circuit, or a problem in stabilizing their power supply.
To identify an open circuit in the LED lines without disassembling the panel, a current source is required. It is impossible to open the junctions connected in series with a simple multimeter; a voltage of several tens of volts is required.
- The indicator blinks or is on constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the TP.VST59.P86 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). Repair of the board and replacement of CPU: TSUMV59XU, SPI Flash: 25Q32BSIG, AUDIO: TPA3110D2 microcircuits are performed with the necessary equipment and the corresponding element base. Malfunctions associated with the use of BGA soldering technologies can be localized by the warm-up method.
In cases where there is no tuning for terrestrial or cable TV channels, you should make sure that the software is correct, as well as that the supply voltages on the Tuner outputs are consistent. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Users and owners of TVs should remember that attempts to repair the DNS M28AM8 TV on their own without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
DOWNLOAD FIRMWARE FOR SPI FLASH -----------> DNS M28AM8, Main: TP.VST59.P86, Panel: MT3151A05
The appearance of the MainBoard TP.VST59.P86 is shown in the figure below:TP.VST59.P86
Main features of the DNS M28AM8 device:
Installed matrix (LED panel) MT3151A05.
To power the backlight LEDs, a converter combined with the TP.VST59.P86 main board is used.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a TP.VST59.P86 module using CPU chips: TSUMV59XU, SPI Flash: 25Q32BSIG, AUDIO: TPA3110D2 and others.
Tuner Tuner provides reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: CSOT
Model: MT3151A05-4
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: HVA, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 62%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: WLED
Signal Interface: LVDS (1 ch, 8-bit)
Voltage: 12.0V
DNS TV M28AM8 with LCD MT3151A05, 28 "(71 cm) 16: 9 diagonal. The required brightness of the screen 350 cd / m2 is provided by LED backlight. Contrast - the ratio of maximum brightness to minimum is 3500: 1. In LCD -panel uses direct pixel illumination with rear-mounted LEDs - Direct LED.
Matrix MT3151A05 and software MainBoard TP.VST59.P86 provide viewing of images in high quality HD at a resolution of 1366x768 pixels in 720p (HD Ready). The input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal shaping takes place in the 480i, 480p, 576i, 576p, 720p standards. Supported media file formats: MP3, MPEG4, DivX, MKV, JPEG.
Speaker power 20 W (2x10 W) is provided by two speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, SCART, VGA, HDMI x3, USB. A headphone output is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector on the TV case is used, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768.
The TV uses a power supply unit as part of the MainBoard.
Dimensions: With stand 673x460x175 mm, Without stand 673x411x72 mm.
TV weight: 5.8 kg.
Attention! The MT3151A05 panel of the DNS M28AM8 LED TV is an expensive and unreliable element.
Do not allow any impact 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 unrepairable.