Technical description and composition of the DEXP 42A8100 TV, type of panel and applicable modules. The composition of the modules.DEXP LED
Model: 42A8100
Chassis / Version: JUC7.820.00115963
Panel: C420F14-E3-L (G1)
T-CON: 6870C-0469A; SW0871, TPS65175A
LED driver (backlight): integrated into PSU
PWM LED driver: OB3350CP
MOSFET LED driver: MDD14N25
Power Supply (PSU): MPS40D-1MG 240
PWM Power: PWM SOT23-6
MainBoard: JUC7.820.00115963 & JUC7.820.00102480
IC MainBoard: 25Q80BS, MSB101AD, THGBM5G5A1JBAIR, NT5CB128M16FP-D1, NT5CB256M16CP-D1, Y176 / 1412V, 25Q32BS
Tuner: NoName
Specifications 42A8100
DEXP 42A8100
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP 42A8100 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.
In such cases, the fault should be sought first in the MPS40D-1MG power supply module. It is necessary to measure its output voltages, and in case of their absence, check the operability of the power switches of the converters and rectifier diodes for the probability of a short circuit.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most 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, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
In some of these cases, the malfunction is caused by the lack of a backlight display. 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 JUC7.820.00115963 motherboard should be started by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). Board repair and replacement of 25Q80BS, MSB101AD, THGBM5G5A1JBAIR, NT5CB128M16FP-D1, NT5CB256M16CP-D1, Y176 / 1412V, 25Q32BS microchips are carried out with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
In cases where there is no 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 NoName tuner. 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.
Attention! For users and owners of 42A8100 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.
FLASH DEXP 42A8100, Main: JUC7.820.00115963 & JUC7.820.00102480, Panel: C-420F14-E3-L(G1)
The appearance of the MainBoard JUC7.820.00115963 is shown in the figure below:JUC7.820.00115963
The appearance of the power supply
Main features of the DEXP 42A8100 device:
Installed matrix (LED-panel) C420F14-E3-L (G1).
The matrix control uses the Timing Controller (T-CON) 6870C-0469A ;.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the OB3350CP PWM controller. As power elements of the LED driver, keys of the MDD14N25 type are used.
The necessary supply voltages for all nodes of the DEXP 42A8100 TV are generated by the MPS40D-1MG power module, or its analogs using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a JUC7.820.00115963 module, using 25Q80BS, MSB101AD, THGBM5G5A1JBAIR, NT5CB128M16FP-D1, NT5CB256M16CP-D1, Y176 / 1412V, 25Q32BS microcircuits and others.
The NoName tuner provides television reception and channel tuning.
DEXP 42A8100 TV with C-420F14-E3-L LCD, 42 "(107 cm) diagonal size of 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum is 3000: 1. This 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 graphical decomposition according to the standard 1080p (Full HD).
The 42A8100 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, WMA, MPEG4, DivX, MKV, JPEG.
The power of the acoustic system of sound 20 W (2x10 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, component, VGA, HDMI x4, 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 960x605x225 mm, without stand 960x555x70 mm.
TV Weight: with stand: 11.5 kg, without stand: 10.7 kg.
Attention! The C-420F14-E3-L (G1) panel of a DEXP 42A8100 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.
