Sunday 19 April 2020

REPAIR / SERVICING TV DEXP F40B7000K

Technical description and composition of the DEXP F40B7000K TV, panel type and applicable modules. The composition of the modules.
DEXP LED
Model: F40B7000K
Chassis / Version: P75-3463GSXV6.0
Panel: ME4005YTSF // LSC400HN02-G02
LED backlight: ELED40KJ4X22 006.L & ELED40KJ4X22 006.R
T-CON: 15Y_40FF11MB7S4LV0.2
LED driver (backlight): integrated into MainBoard
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT-23-6
MainBoard: P75-3463GSXV6.0
IC MainBoard: CPU: MSD3463GSA, SPI FLASH: MX25L6406E
Control: IR: TE48Y03 21002701 2014-5-13 REV-02
Technical Specifications F40B7000K
DEXP F40B7000K
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP F40B7000K TV does not turn on and does not show any signs of turning on at all. There are no reactions to the control buttons or the remote control.
In such cases, the common power source is often faulty - an AC / DC voltage converter, which is combined with the elements of the main board P75-3463GSXV6.0. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary first of all to check the power switches and rectifier diodes for a possible partial or complete breakdown.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. The PWM SW-23-6 PWM chip may also cause a malfunction of the power switch of the converter and is checked by replacement.
- 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
In most 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 health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the motherboard P75-3463GSXV6.0 should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: MSD3463GSA, SPI FLASH: MX25L6406E and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.

It should be remembered! Attempts to independently repair the DEXP F40B7000K 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!



 The appearance of the MainBoard P75-3463GSXV6.0 is shown in the figure below:
P75-3463GSXV6.0
P75-3463GSXV6.0 can be used in TVs:
DEXP F40B7000K (Panel LSC400HN02-G02), DEXP H32B7000K/B (Panel HV320WHB-N00), SUPRA STV-LC32T740WL (Panel HV320WHB-N80).
Main features of the DEXP F40B7000K device:
Installed matrix (LED panel) ME4005YTSF or LSC400HN02-G02.
The matrix control uses the Timing Controller (T-CON) 15Y_40FF11MB7S4LV0.2.
To power the backlight LEDs, a converter is used, combined with the main board P75-3463GSXV6.0.
The power module is combined with MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT-23-6 microcircuits.
MainBoard - the main board (motherboard) is a P75-3463GSXV6.0 module, using CPU chips: MSD3463GSA, SPI FLASH: MX25L6406E and others.
A DEXP F40B7000K TV with an LSC400HN02-G02 LCD, 40 "(102 cm) diagonal size, 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 3500: 1. This model uses a panel with the end position 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 graphic resolution according to the standard 1080p (Full HD). Input high-frequency or video signal The channel is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, MPEG4, MKV, 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, component, VGA, HDMI x3, USB x2. 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, 1360x768, 1920x1080. The digital tuner is capable of receiving television channels in the standards DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2.
The power consumed by the TV working in the network mode is 75 watts.
Overall dimensions: with stand 920x570x220 mm, without stand 820x535x52 mm.
TV Weight: with stand: 7.8 kg, without stand: 7.5 kg.
Attention! The LSC400HN02-G02 panel of a DEXP F40B7000K 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.