Technical description and composition of the DNS M50DM8 TV, panel type and modules used. The composition of the modules.DNS LED
Model: M50DM8
Chassis / Version: T.SIS231.T76
Panel: T500HVN01.V0
LED backlight: MKN-DLED50-08-A02, MKN-DLED50-08-B02
T-CON: 50T10-C02 T500HVD02.0 CTRL BD
LED driver (backlight): integrated into PSU
PWM LED driver: LD7530
Power Supply (PSU): AMP3618-39D-AK MP3618-MY1
PWM Power: OB2273 (PWM SOT23-6), LD7530, 28019A
MainBoard: T.SIS231.T76 T500HVN01.0
IC MainBoard: 25Q64P, NT5CB64M16FP-DH, TPA3110LD2, RT7237
Tuner: Si2168 DVB-T2
Specifications M50DM8
DNS M50DM8
General recommendations for TV LCD LED repair
Possible manifestations of defects
- DNS M50DM8 TV does not turn on at all. No response to the remote control and front panel control buttons. Indicator lamps do not light up or flash.
With similar manifestations, in some cases, the AMP3618-39D-AK power supply module is faulty. It is then necessary to measure its output voltages and, in their absence, the power switches and rectifier diodes of the converters should be checked for the probability of a short circuit.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually operate normally in an emergency short-circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and, less often, the current sensor in the source of the key.
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 picture, but there is sound and reaction to commands from the remote control. Or the image appears immediately after switching on and disappears.
Usually, in such cases, a malfunction is detected in the LED panel backlight nodes. 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 check the health of the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED separately with a simple Chinese multimeter (powered by 9 volts) in the P-N transition test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black one to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. The serviceability of the PN junction of the Zener diode indirectly indicates the serviceability of the LED-a
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.
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). In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - 25Q64P, NT5CB64M16FP-DH, TPA3110LD2, RT7237 which may need to be replaced with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its pins with the board (detected by warming up).
A malfunction of the Si2168 DVB-T2 tuner is established after checking the software and all supply voltages at its outputs. The data exchange of the tuner with the processor via the I2C bus can be monitored with an oscilloscope.
Attention to users! Self-repair of the DNS M50DM8 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 M50DM8:
Installed matrix (LED panel) T500HVN01.V0.
Matrix control uses Timing Controller (T-CON) 50T10-C02.
A converter combined with a power supply is used to power the backlight LEDs, and is controlled by an LD7530 PWM controller.
The formation of the necessary supply voltages for all nodes of the DNS M50DM8 TV is carried out by the AMP3618-39D-AK power module, or its analogs using OB2273 (PWM SOT23-6), LD7530, 28019A microcircuits.
MainBoard - the main board (motherboard) is a T.SIS231.T76 module, using 25Q64P, NT5CB64M16FP-DH, TPA3110LD2, RT7237 and others.
The Si2168 DVB-T2 tuner provides reception of television programs and tuning to channels.
DNS M50DM8 TV with LCD T500HVN01.V0, diagonal size 50 "(127 cm) 16: 9 format. The required brightness of the screen of 350 cd / m2 is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum brightness is 6000: 1. The LCD panel uses direct pixel backlighting with back-mounted LEDs - Direct LED.The T500HVN01.V0 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, 1024x768, 1280x1024, 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 1115x740x240 mm, Without stand 1115x684x84 mm.
Attention! The panel T500HVN01.V0 of the DNS M50DM8 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.