Friday 17 April 2020

REPAIR / SERVICING TV DEXP 19A3000

Technical description and composition of the DEXP 19A3000 TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: 19A3000
Chassis / Version: CVMV29L-F
Panel: CX185LEDM
LED backlight: EDGE LED
LED driver (backlight): integrated into T-CON
Power Supply (PSU): Adapter 12V
MainBoard: CVMV29L-F
IC MainBoard: Cpu: TSUMV59XU-Z1, Flash: Winbond 25Q32BVSIG, SOUND: NS4263, Power Stb: 1117
Tuner: CDT-3NP5I1-10 (R620D)
Specifications 19A3000
DEXP 19A3000
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP 19A3000 TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
With such manifestations, the Adapter power module usually fails.
This model of TV is equipped with an external power adapter adapter type 12V, which the owner can purchase independently, and repairing it may not always be advisable, however, sometimes it makes sense to open it and eliminate simple typical defects typical of IPS. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches and rectifier diodes for a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work abnormally in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
In such cases, the most likely malfunction of the LED backlight elements. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
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 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). When repairing an MB board, it is necessary to check its components Cpu: TSUMV59XU-Z1, Flash: Winbond 25Q32BVSIG, SOUND: NS4263, Power Stb: 1117. Faulty elements should be replaced. If chips with BGA soldering technology are used, a problem in its implementation is detected by the local heating of the chip.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the tuner CDT-3NP5I1-10 (R620D). It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
It should be remembered! Attempts to independently repair the DEXP 19A3000 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!

FIRMWARE FOR SPI FLASH  ----------->   DEXP 19A3000, Main: CVMV29L-F, Panel: CX185LEDM

 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 19A3000 device:
Installed matrix (LED-panel) CX185LEDM.
An integrated LED driver is used to power the backlight LEDs.
To power all internal components of the DEXP 19A3000 TV, an external adapter 12V type is used.
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.
A DEXP 19A3000 TV with a CX185LEDM LCD display, a 19 "(48 cm) diagonal size of 16: 9 format. The required screen brightness of 200 cd / m² is provided by LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 1000: 1. In this the model uses a panel with the end position of the backlight LEDs - Edge 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 analog . Govyh systems PAL, SECAM, NTSC Image processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p Supported multimedia file formats:. MP3, MPEG4, 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, 1360x768.
Overall dimensions: 438x278x51 mm.
Mass of the TV: 2.3 kg.
Attention! The CX185LEDM panel of a DEXP 19A3000 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.