Friday, 21 August 2020

REPAIRING / SERVICING TV DNS C39DC2000

Technical description and composition of the DNS C39DC2000 TV, panel type and modules used. The composition of the modules.
DNS LED
Model: C39DC2000
Chassis / Version: JUC7.820
Panel: M390F13-E1-A
LED backlight: 2013CH390 13Y LED 3228
LED driver (backlight): integrated into PSU
Power Supply (PSU): R-HS086D-1MF11 (XR7.820.243V1.2)
PWM Power: PWM SOT23-6 (SG6848 or LD7535 or OB2273 ...) + PFC SO-8
MainBoard: JUC7.820.00084054 LS1B 32C2000
IC MainBoard: Spi Flash: 25Q64BSIG
Tuner: DT21WN-2A-E
Control: IR: JUG7.820.1423 LS13 3100
Specifications C39DC2000
DNS C39DC2000
General recommendations for TV LCD LED repair
A malfunction of the power supply is often  - the TV does not turn on, does not make any sounds, does not shine or blink with any indicators. In general, first of all, it is necessary to check the electrolytic capacitors of the filters of the secondary rectifiers and the fuse at the mains input. If it is cut off, then the diodes of the rectifier bridge and the key transistor of the converter, which can be located either on a separate heatsink or integrated with a PWM controller into a common microcircuit, should be checked for a breakdown of PN junctions. Options are possible.
As a rule, switches in switching power supplies (SMPS) are quite reliable and rarely fail without reasons that should be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM microcircuit is checked by replacing it with a known good one.
If, when turning on the TV, the image appears and immediately disappears, or is absent initially when turned on, but there is sound and other functions work, there is a high probability of malfunction of the display backlight LEDs, or the LED driver (power converter of the panel backlight unit M390F13-E1-A).
It is often necessary to disassemble the panel to check the health of the LEDs, as well as the contact connections in the connectors and solders.
When trying to detect a break in the LED lines, it should be borne in mind that it is difficult to do this without disassembling the panel. For example, a current source is required to open PN junctions connected in series.
When trying to repair the motherboard, you should first check the serviceability of linear stabilizers or microcircuit power converters and, if necessary, update the software (software).
Repair of the board and replacement of Spi Flash: 25Q64BSIG microcircuits are made if the necessary equipment and the corresponding element base are available. Malfunctions associated with the use of BGA soldering technologies can be localized by the warm-up method.
If the TV operates normally from external devices, but does not tune to TV channels, the DT21WN-2A-E tuner may be faulty. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the reason for the inoperability of the tuner may be a software failure.
Attention to the owners! Attempts to repair the DNS C39DC2000 TV yourself are not recommended by the manufacturer and can lead to serious negative consequences!

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Additional MainBoard Repair
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 C39DC2000 device:
Installed matrix (LED panel) M390F13-E1-A.
A converter combined with a power supply is used to power the backlight LEDs.
The formation of the necessary supply voltages for all nodes of the DNS C39DC2000 TV is carried out by the R-HS086D-1MF11 power module, or its analogs using PWM SOT23-6 microcircuits (SG6848 or LD7535 or OB2273 ...) + PFC SO-8.
MainBoard - the main board (motherboard) is a JUC7.820.00084054 module, using Spi Flash chips: 25Q64BSIG and others.
The DT21WN-2A-E tuner provides reception of television programs and tuning to channels.


DNS C39DC2000 TV with LCD M390F13-E1-A, diagonal 39 "(99 cm) in 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum to minimum brightness is 4000: 1. The LCD panel uses direct pixel backlighting with Direct LED.
The M390F13-E1-A matrix and the MainBoard JUC7.820.00084054 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 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, audio x2, component, VGA, 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, 1280x1024, 1360x768, 1920x1080. The digital tuner is capable of receiving television channels in the DVB-T, DVB-C, DVB-T2 standards.
The TV uses the R-HS086D-1MF11 power supply.
Dimensions: With stand 884x578x260 mm, Without stand 640x389x86 mm.
TV weight: 10 kg.
Attention! The M390F13-E1-A panel of the DNS C39DC2000 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.