Technical description and composition of the DEXP 28A3100 TV, type of panel and applicable modules. The composition of the modules.DEXP LED
Model: 28A3100
Chassis / Version: CV59SH-E32
Panel: CX275DLEDM
LED backlight: RF-AD280E32-0501S-01
T-CON: MT3151A05-30XC-1
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3267
MOSFET LED driver: D4454
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
Mainboard: CV59SH-E32
IC MainBoard: CPU: TSUM59XUS, SPI FLASH: GD25Q32, Audio: APA2614
Tuner: RDA5156
Specifications 28A3100
DEXP 28A3100
General repair guidelines for TV LCD LED
Possible manifestations of defects
- DEXP 28A3100 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.
The malfunction in such cases should first be sought in the power elements of a switching power supply (IIP) - a network voltage converter (AC / DC), which in this model of TV is combined with the MainBoard CV59SH-E32 main board. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches and rectifier diodes in the converters for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM SOT23-6 PWM chips are usually checked by replacing with new ones, or obviously working.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
As a rule, in such cases there is no display backlight. The reason can 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.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the CV59SH-E32 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). In cases of attempts to repair the MB (SSB) board, it is necessary to check the health of its elements - CPU: TSUM59XUS, SPI FLASH: GD25Q32, Audio: APA2614 which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
Before changing the RDA5156 tuner, if it is not possible to tune to television channels, make sure that there are supply voltages that must be measured at the corresponding tuner pins and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Attention! For users and owners of 28A3100 TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.
FIRMWARE FOR SPI FLASH -----------> EEPROM DEXP 28A3100, Main: CV59SH-E32, Panel: CX275DLEDM
The appearance of the MainBoard CV59SH-E32 is shown in the figure below:CV59SH-E32
CV59SH-E32 can be used in TVs:
DEXP 29A3000 (Panel CX290DLEDM), DEXP 32A3400 (Panel CX315DLEDM), DEXP 28A3100 (Panel CX275DLEDM), RUBIN RB-32SE9 (Panel CX315DLEDM).
Main features of the DEXP 28A3100 device:
Installed matrix (LED-panel) CX275DLEDM.
The matrix control uses the Timing Controller (T-CON) MT3151A05-30XC-1.
To power the backlight LEDs, a converter is used, combined with the CV59SH-E32 main board, controlled by the BIT3267 PWM controller. As the power elements of the LED driver, keys of the D4454 type are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a CV59SH-E32 module, using CPU chips: TSUM59XUS, SPI FLASH: GD25Q32, Audio: APA2614 and others.
The RDA5156 tuner provides television reception and channel tuning.
DEXP 28A3100 TV with a CX275DLEDM LCD display, diagonal size 28 "(71 cm) in 16: 9 format. The required brightness of the screen is 250 cd / m² LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 1000: 1. In LCD -panels use direct LED backlighting - Direct LED. You can watch programs and movies and images in high quality HD at a resolution of 1366x768 pixels in the standard for graphic decomposition 720p (HD Ready). The input high-frequency or video signal is decoded into tax systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, JPEG.
The power of the sound system 10 W (2x5 W) provide two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI x2, USB x2. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768.
TV Weight: with stand: 5.05 kg, without stand: 4 kg.
Attention! The CX275DLEDM panel of a DEXP 28A3100 LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.