Friday 17 April 2020

REPAIR / SERVICING TV DEXP 32A3400

Technical description and composition of the DEXP 32A3400 TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: 32A3400
Chassis / Version: CV59SH-E32
Panel: CX315DLEDM
LED backlight: CX32071235A2 Direct Led
T-CON: MT3151A05-3-XC-1
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3267
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
Mainboard: CV59SH-E32
IC MainBoard: CPU: TSUM59XUS, SPI FLASH: GD25Q32, Audio: APA2614
Tuner: NoName RDA5156
Specifications 32A3400
DEXP 32A3400
General repair guidelines for TV LCD LED
Possible malfunctions
- DEXP 32A3400 does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
In such cases, the main power source - the AC / DC voltage converter, which is combined with the MainBoard CV59SH-E32 board, may turn out to be faulty. It is necessary to measure its output voltages and, in case of their absence, check the serviceability of power switches and rectifier diodes in the converters for possible breakdown.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often 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 responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. 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.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
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). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: TSUM59XUS, SPI FLASH: GD25Q32, Audio: APA2614 and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
If the TV works normally from external devices, but does not tune into television channels, the NoName tuner may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Attention TV owners! Attempts to self-repair DEXP 32A3400 are not recommended by the manufacturer and can lead to serious negative consequences!

FIRMWARE FOR SPI FLASH  ----------->   DEXP 32A3400 , Main: CV59SH-E32, Panel: CX315DLEDM


 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 32A3400 device:
Installed matrix (LED-panel) CX315DLEDM.
The matrix control uses the Timing Controller (T-CON) MT3151A05-3-XC-1.
To power the backlight LEDs, a converter is used, combined with the CV59SH-E32 main board, controlled by the BIT3267 PWM controller.
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 tuner NoName RDA5156 provides the reception of television programs and tuning to channels.
DEXP 32A3400 TV with a CX315DLEDM LCD, 32 "(81 cm) diagonal size of 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 1200: 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. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the sound system 6 W (2x3 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, 1360x768.
Overall dimensions: with stand 735x497x180 mm,.
TV Weight: with stand: 6.3 kg, without stand: 4.9 kg.
Attention! The CX315DLEDM panel of a DEXP 32A3400 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.