Technical description and composition of the DEXP 42A8200 TV, panel type and applicable modules. The composition of the modules.DEXP LED
Model: 42A8200
Chassis / Version: 35019017
Panel: 420B1LED6K FHD
LED backlight: EDGE LED
LED driver (backlight): KLD-L033E04-01 LED DR = 53v
Power Supply (PSU): KPS-L090C2 35017755
PWM Power: TEA1733
MOSFET Power: 4N60L-B
MainBoard: 35019017
IC MainBoard: SPI Flash: W25Q16DV, 25X10
Tuner: NoName
Specifications 42A8200
DEXP 42A8200
General repair guidelines for TV LCD LED
Possible manifestations of defects
- DEXP 42A8200 does not turn on and does not show any signs of performance at all. Does not blink indicators and does not respond to control buttons.
Typically, with such manifestations, the defect is caused by faulty elements in the KPS-L090C2 main power module. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches (4N60L-B) and rectifier diodes for a possible partial or complete breakdown.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
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) TEA1733, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately disappears
The most likely in these cases is a malfunction of the LED backlight. 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.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. 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 indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the 35019017 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). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its SPI Flash chips: W25Q16DV, 25X10 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
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.
TV users and owners must remember that attempts to self-repair a DEXP 42A8200 TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!
FLASH DEXP 42A8200, Main: 35019017, Panel: 420B1LED6K FHD
The appearance of MainBoard 35019017 is shown in the figure below:35019017
35019017 can be used in TVs:
DEXP 49A8200 (Panel KPL+490B1LED2K), DEXP 42A8200 (Panel 420B1LED6K FHD), DNS 42AK9000 (Panel KPL+420B1LED6K p/n: 72001350K).
The appearance of the power supply
Main features of the DEXP 42A8200 device:
Installed matrix (LED-panel) 420B1LED6K FHD.
The LED driver KLD-L033E04-01 is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the DEXP 42A8200 TV are generated by the KPS-L090C2 power module or its analogs using TEA1733 microcircuits and 4N60L-B type power switches.
MainBoard - the main board (motherboard) is a module 35019017, using SPI Flash chips: W25Q16DV, 25X10 and others.
The NoName tuner provides television reception and channel tuning.
A DEXP 42A8200 TV with a 420B1LED6K LCD, 42 "(107 cm) diagonal size of 16: 9 format. The required screen brightness of 350 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum is 1200: 1. In this Models use a panel with an end arrangement of backlight LEDs - Edge LED.
There is support for 3D images using passive polarization technology. TV features include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphical decomposition standard 1080p (Full HD).
The 42A8200 is equipped with SMART software, embedded 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, 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, audio x2, component, VGA, HDMI x4, MHL, USB x3, Ethernet (RJ-45), Wi-Fi. 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, 1024x768, 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 958x622x250 mm, without stand 958x566x44 mm.
TV Weight: 15.6 kg.
Attention! The 420B1LED6K FHD DEXP 42A8200 LED TV panel 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.