REPAIRING / SERVICING TV DNS M46DM8

Technical description and composition of the DNS M46DM8 TV, panel type and modules used. The composition of the modules.
DNS LED
Model: M46DM8
Chassis / Version: T.SIS231.T76
Panel: LSC460HN03 1920x1080
LED backlight: MKN-DLED46-08
T-CON: 13Y_S120PAVLMB3C2LV0.0; RT6911, RT9164A, RT6503A
LED driver (backlight): integrated into PSU
PWM LED driver: LD7530
MOSFET LED driver: MDF7N65B
Power Supply (PSU): AMP3618-39D-AK MP3618-MY46
PWM Power: OB2273 (PWM SOT23-6), LD7530, 28019A
MOSFET Power: MDF4N65B, MDF7N65B
MainBoard: T.SIS231.T76 LSC460HN03 // CV9209H-T (36T0856 H)
IC MainBoard: 25Q64P, NT5CB64M16FP-DH, TPA3110LD2, RT7237
Tuner: DVB-T2 (Si2168)
M46DM8 Specifications
DNS M46DM8
General recommendations for TV LCD LED repair
Possible malfunctions
- DNS M46DM8 will not turn on, LEDs on the front panel are off or flashing. The TV does not respond to the control buttons and the remote control.
In such cases, the fault should be looked for primarily in the MP3618-MY46 power supply module. It is then necessary to measure its output voltages and, if they are absent, the power switches (MDF4N65B, MDF7N65B) and rectifier diodes of the converters should be checked for the probability of a short circuit.
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 the current sensor at 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 disable it in the key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying a PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) OB2273 (PWM SOT23-6), LD7530, 28019A, in the absence of external damages and short circuit between the terminals, are checked by replacing them with known good ones.
- There is no image, there is sound, it reacts to the remote control, the channels are switched. In some cases, the image appears when turned on and disappears immediately.
The most likely problem in these cases is a malfunction of the LED backlight. The reason may 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 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 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 T.SIS231.T76 motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Complicated MB (SSB) repair is possible only in the conditions of a service center with the necessary equipment. Checking or replacing elements 25Q64P, NT5CB64M16FP-DH, TPA3110LD2, RT7237 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 the warm-up method.
If there is no reception of TV channels, but the TV is working properly from external devices, first of all, you need to check the supply voltage of the DVB-T2 tuner (Si2168) and update the software. I2C communication pulses must be monitored with an oscilloscope.

Attention to users! Self-repair of the DNS M46DM8 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!

Additional MainBoard Repair
The appearance of the MainBoard T.SIS231.T76 is shown in the figure below:
T.SIS231.T76
T.SIS231.T76 can be used in TVs:
DNS M46DM8 (Panel LSC460HN03 1920x1080), DNS M50DM8 (Panel T500HVN01.V0).

External view of the power supply
Key features of the DNS M46DM8:
Installed matrix (LED panel) LSC460HN03 1920x1080.
The matrix control uses the Timing Controller (T-CON) 13Y_S120PAVLMB3C2LV0.0 ;.
A converter combined with a power supply is used to power the backlight LEDs, and is controlled by an LD7530 PWM controller. Key types MDF7N65B are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the DNS M46DM8 TV is carried out by the AMP3618-39D-AK power module, or its analogs using OB2273 (PWM SOT23-6), LD7530, 28019A microcircuits and power switches such as MDF4N65B, MDF7N65B.
MainBoard - the main board (motherboard) is a T.SIS231.T76 module, using 25Q64P, NT5CB64M16FP-DH, TPA3110LD2, RT7237 and others.
Tuner DVB-T2 (Si2168) provides reception of television programs and tuning to channels.
DNS TV M46DM8 with LCD LSC460HN03, diagonal size 46 "(117 cm) 16: 9 format. The required brightness of the screen 350 cd / m2 is provided by LED backlighting. 6000: 1 dynamic contrast is achieved by special control of LED operation depending on the illumination The LCD panel uses direct backlighting of pixels with LEDs - Direct LED.
The LSC460HN03 1920x1080 matrix and the MainBoard T.SIS231.T76 software provide viewing of broadcasts and movies in high quality HD at a resolution of 1920x1080 pixels in graphics resolution at 1080p (Full HD). The input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and formation of a digital signal occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG.
Speaker power 24 W (2x12 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, use the VGA (D-Sub 15) connector on the TV case, this interface supports resolutions: 640x480, 800x600, 1360x768, 1920x1080. The digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
The TV uses the AMP3618-39D-AK power supply.
Dimensions: With stand 1072x700x240 mm, Without stand 1072x642x83 mm.
TV weight: 15.3 kg.
Attention! The LSC460HN03 1920x1080 DNS M46DM8 LED TV panel 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.