Technical description and composition of the DNS C28DC2000 TV, panel type and modules used. The composition of the modules.DNS LED
Model: C28DC2000
Chassis / Version: LS1B
Panel: M280X13-E1-H
T-CON: MT3151A05-3-XC-1
LED driver (backlight): integrated into PSU
PWM LED driver: MP4012
Power Supply (PSU): R-HS055D-1MF 11, XR7.820.247V1.2
PWM Power: PWM SOT23-6 (SG6848 or LD7535 or OB2273 ...)
MOSFET Power: TF8N65
MainBoard: JUC7.820.00084054 LS1B 32C2000
IC MainBoard: Spi Flash: 25Q64BSIG
Tuner: DT21WN-2A-E // DT21WM-24-E
Control: IR: JUG7.820.1423
Specifications C28DC2000
DNS C28DC2000
General recommendations for TV LCD LED repair
Malfunctions of the R-HS055D-1MF 11, XR7.820.247V1.2 power supply module can be expressed in different ways, for example, the DNS C28DC2000 does not turn on at all and the control lamps on its front panel do not light up or blink, all signs of operability are missing. When diagnosing and repairing the power supply, first of all, replace the swollen capacitors of the secondary rectifier filter and check the fuse and, if it is broken, the cause must be identified. Often in such cases an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module - rectifier diodes and TF8N65 transistors in the primary circuit.
The reasons for the breakdown of the power switch in switching power supplies (SMPS) can be different, for example, a malfunction of semiconductor elements or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as failure of the PWM SOT23-6 PWM regulator chip (SG6848 or LD7535 or OB2273. ..) or breaks of resistors in its strapping.
If the DNS C28DC2000 does not have an image, there is sound and the channels are switched, there is a possibility of a malfunction in the M280X13-E1-H panel backlight LED circuit, or their power converter - LED driver. Sometimes, when turned on, the image appears and immediately disappears. In such cases, it is necessary to check the electrolytic capacitors of the backlight unit power filter.
Often, in the absence of backlight, disassembly of the panel is required. It is necessary to check the serviceability of the LED transitions, as well as the reliability of the contact connections in the lines and connectors.
When diagnosing, it must be borne in mind that it is impossible to check for an open in the circuit of the LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally a current source. By opening the panel, you can check each LED separately. Typically, Chinese multimeters will lightly light one 3-volt LED if you connect the probes to it in the forward direction. For dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of LED health. In the event of a malfunction of the LED, its zener diode will either be cut off, or broken through in the K / Z.
Repair of the JUC7.820.00084054 LS1B 32C2000 motherboard must begin with diagnostics and testing of all linear stabilizers and power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM.
In cases of complex MB (SSB) repairs and with the necessary skills and equipment, it may sometimes be necessary to replace its Spi Flash chips: 25Q64BSIG and other possible faulty components. Malfunctions associated with the use of BGA soldering technologies are usually easily 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 DT21WN-2A-E // DT21WM-24-E tuner and update the software. I2C communication pulses must be monitored with an oscilloscope.
Attention to the owners! Attempts to repair the DNS C28DC2000 TV yourself are not recommended by the manufacturer and can lead to serious negative consequences!
DOWNLOAD FIRMWARE FOR SPI FLASH -----------> DNS C28DC2000 LS1B, Main: JUC7.820.00084054 LS1B 32C2000 , Panel: M280X13-E1-H
The appearance of the MainBoard LS1B is shown in the figure below:LS1B
JUC7.820.00084054 can be used in TVs:
BBK 40LEM-3080/FT2C (Panel ECG390AH-LD2 (SN)), BBK 32LEM-3081/T2C (Panel M320X13-E2-H), BBK 32LEM-1003/T2C (Panel M320X13-E4-L HD), DEXP 28A3000 (Panel R-HS055D-1MF), DEXP 50A7000 (Panel C500F13-E3-A), DNS C28DC2000 (Panel M280X13-E1-H), DNS C39DC2000 (Panel M390F13-E1-A), ERISSON 42LEC2000 (Panel M420F13-E1-L (G1)), ERISSON 55LEC2000 (Panel M550F13-E1-A 1080p Full HD), ERISSON 28LEC2000 (Panel M280X13-E1-H), RUBIN RB-32SD8T2C (Panel M320X13-E3-H), TELEFUNKEN TF-LED32S12T2 (Panel M320X12-E9-A(1)).
External view of the power supply
Main features of the DNS C28DC2000 device:
Installed matrix (LED panel) M280X13-E1-H.
Matrix control uses Timing Controller (T-CON) MT3151A05-3-XC-1.
A converter combined with a power supply is used to power the backlight LEDs, and is controlled by the MP4012 PWM controller.
The formation of the necessary supply voltages for all nodes of the DNS C28DC2000 TV is carried out by the R-HS055D-1MF power module, or its analogs using PWM SOT23-6 microcircuits (SG6848 or LD7535 or OB2273 ...) and TF8N65 type power switches.
MainBoard - the main board (motherboard) is a JUC7.820.00084054 module, using Spi Flash chips: 25Q64BSIG and others.
Tuner DT21WN-2A-E // DT21WM-24-E provides reception of television programs and tuning to channels.
DNS C28DC2000 TV with LCD M280X13-E1-H, 28 "(71 cm) 16: 9 format diagonal. The required screen brightness of 280 cd / m2 is provided by LED backlighting. Contrast - the ratio of maximum to minimum brightness is 4000: 1. The LCD panel uses Direct LED backlighting.
The M280X13-E1-H sensor and MainBoard JUC7.820.00084054 software provide high quality HD viewing at 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, WMA, 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 x2, component, HDMI x3, USB. 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, 1360x768. The digital tuner is capable of receiving television channels in the DVB-T, DVB-C, DVB-T2 standards.
The TV uses the R-HS055D-1MF power supply.
Dimensions: With stand 640x440x165 mm, Without stand 640x389x86 mm.
TV weight: 5.5 kg.
Attention! The M280X13-E1-H panel of the DNS C28DC2000 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.