Friday 17 April 2020

REPAIR / SERVICING TV DEXP 22A7000

  Technical description and composition of the DEXP 22A7000 TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: 22A7000
Chassis / Version: CVMV29L-F
Panel: CX215LEDM
LED backlight: EDGE LED
Power Supply (PSU): PSU 12V, 5V Integrated
MainBoard: CVMV29L-F
IC MainBoard: Cpu: TSUMV59XU-Z1, Flash: Winbond 25Q32BVSIG, SOUND: NS4263, Power Stb: 1117
Tuner: CDT-3NP5I1-10 (R620D)
Specifications 22A7000
DEXP 22A7000
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP 22A7000 TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
Most likely in this case, the main switching power supply (PSU) of the PSU is faulty. It is then necessary to measure its output voltages and, if they are absent, it is necessary to check the power switches and rectifier diodes of the converters for a short-circuit probability.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually work normally in 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 at the source of the key.
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 microcircuits are usually checked by replacement 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.
Usually in such cases, a malfunction is detected in the backlight nodes of the LED panel. 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 check the LED lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the CVMV29L-F 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). If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - Cpu: TSUMV59XU-Z1, Flash: Winbond 25Q32BVSIG, SOUND: NS4263, Power Stb: 1117. Faulty components should be replaced.
The malfunction of the tuner CDT-3NP5I1-10 (R620D) is established after checking the software and all the supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Once again, remind users! Attempts to independently repair the DEXP 22A7000 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!

FIRMWARE FOR SPI FLASH  ----------->   DEXP 22A7000, Main: CVMV29L-F, Panel: CX215LEDM

FIRMWARE FOR SPI FLASH  ----------->   DEXP 22A7000, Main: CVMV29L-F variant 2

 The appearance of the MainBoard CVMV29L-F is shown in the figure below:
CVMV29L-F
CVMV29L-F can be used in TVs:
DEXP H24C3000E (Panel CX236DLEDM), DEXP H16B3000ED (Panel N156BGE-L21), DEXP F22B3000E (Panel T215HVN01.1 CX215LEDM), DEXP 16A3000 (Panel N156BGE-L2 1366x768 WXGA ), DEXP 19A3000 (Panel CX185LEDM), DEXP 22A7000 (Panel CX215LEDM), MYSTERY MTV-1628LW (Panel N156BGE-L21), MYSTERY MTV-1629LW (Panel N156BGE-L21), SUPRA STV-LC16741WL (Panel NT156WHM-N12), SUPRA STV-LC16740WL (Panel LTN156AT32).
Main features of the DEXP 22A7000 device:
Installed matrix (LED-panel) CX215LEDM.
The formation of the necessary supply voltages for all nodes of the DEXP 22A7000 TV is carried out by the PSU power module, or its analogues.
MainBoard - the main board (motherboard) is a CVMV29L-F module, using Cpu chips: TSUMV59XU-Z1, Flash: Winbond 25Q32BVSIG, SOUND: NS4263, Power Stb: 1117 and others.
The tuner CDT-3NP5I1-10 (R620D) provides the reception of television programs and tuning to channels.
DEXP 22A7000 TV with a CX215LEDM LCD display, diagonal size 22 "(56 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 3000: 1. In this The model uses a panel with the end-face positioning of the backlight LEDs - Edge LED.The TV features include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic resolution according to the standard 1080p (Full HD). Input high-frequency or video signal ekodiruetsya analog PAL system, SECAM, NTSC Image processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats:.. MP3, 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, USB. 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.
Overall dimensions: with stand 500x327x177 mm, without stand 500x303x54 mm.
TV Weight: with stand: 2.9 kg, without stand: 2.65 kg.
Attention! The CX215LEDM panel of a DEXP 22A7000 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.