Technical description and composition of the DEXP 42A9000 TV, type of panel and applicable modules. The composition of the modules.DEXP LED
Model: 42A9000
Chassis / Version: JUC7.820.00119162
Panel: C420U13-E1-L
LED backlight: EDGE LED JUCA7.300.00109918-JJ
LED driver (backlight): integrated into PSU
Power Supply (PSU): JCM50D-12M5
MainBoard: JUC7.820.00119162
IC MainBoard: GD25Q80B
Tuner: NoName
Specifications 42A9000
DEXP 42A9000
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The DEXP 42A9000 TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
In such cases, the malfunction should be sought first in the JCM50D-12M5 power supply module. 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 probable short circuit.
In case of breakdowns of diodes in the secondary circuits, the converter can operate in emergency short circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM), if they do not have visible damage to the chassis and open short circuit between the terminals, are usually checked by replacement.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V for them. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the black to the cathode. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the JUC7.820.00119162 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements GD25Q80B. BGA chip malfunctions are usually easy to detect by warming up.
If a NoName tuner is suspected of a malfunction, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary supply voltage levels and data exchange pulses with the processor via the I2C bus at the corresponding tuner pins.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.
FIRMWARE FOR SPI FLASH -----------> DEXP 42A9000, Main: JUC7.820.00119162, Panel: C420U13-E1-L
The appearance of the MainBoard JUC7.820.00119162 is shown in the figure below:JUC7.820.00119162
The appearance of the power supply
Main features of the DEXP 42A9000 device:
Installed matrix (LED-panel) C420U13-E1-L.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the DEXP 42A9000 TV is carried out by the JCM50D-12M5 power module, or its analogues.
MainBoard - the main board (motherboard) is a JUC7.820.00119162 module, using GD25Q80B chips and others.
The NoName tuner provides television reception and channel tuning.
DEXP 42A9000 TV with C420U13-E1-L LCD, 42 "(107 cm) diagonal size in 16: 9 format. Contrast - the ratio of maximum brightness to minimum is 4000: 1. This model uses a panel with the end position of the backlight LEDs - Edge LED: You can watch movies and images in the highest possible UHD quality at a resolution of 3840x2160 pixels in the 4K UHD standard.
The 42A9000 is equipped with SMART software, integrated applications and the ability to work on the Internet. Connecting to the Internet can be done via Wi-Fi. The input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, JPEG.
The power of the sound system 16 W (2x8 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 x3, USB x3, Ethernet (RJ-45), Wi-Fi. 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, 1920x1080. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 960x610x195 mm, without stand 960x555x60 mm.
TV Weight: with stand: 13.8 kg, without stand: 13 kg.
Attention! The C420U13-E1-L panel of a DEXP 42A9000 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.