Technical description and composition of the TV TCL F40B3804, type of panel and applicable modules. The composition of the modules.TCL LED
Model: F40B3804
Chassis / Version: 40-MT31EPA-MAC2HG
Panel: LVF400CMDX E1 V2
LED driver (backlight): integrated into MainBoard
PWM LED driver: MP3398A
MOSFET LED driver: AOD256
Power Supply (PSU): integrated into MainBoard
PWM Power: RT7736B
MOSFET Power: MDF10N65B
MainBoard: 40-MT31EPA-MAC2HG
IC MainBoard: SPI Flash: W25Q64FVSIG
Tuner: ST34WN-2T-E 07-600C13-SA2G
Technical Specifications F40B3804
TCL F40B3804
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The TCL F40B3804 does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
In such cases, the main power source, the AC / DC voltage converter, which is combined with the MainBoard 40-MT31EPA-MAC2HG, may turn out to be faulty. It is necessary to measure the output voltages in its secondary circuits, and if they are completely absent, check the serviceability of power switches (MDF10N65B) and rectifier diodes for possible breakdown (short circuit).
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more 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 chips RT7736B are usually checked by replacing with new, or obviously working.
- 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.
Often in such cases, there is no 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.
To check the LED strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, sometimes you can detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 40-MT31EPA-MAC2HG 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 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 ST34WN-2T-E 07-600C13-SA2G. 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 to users! Self-repair of the TCL F40B3804 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
FIRMWARE FOR SPI FLASH -----------> TCL F40B3804, Main: 40-MT31EPA-MAC2HG, Panel: LVF400CMDX E1 V2
To reduce the backlight current, the total resistance of the resistors relative to the housing on the ISET pin of the MP3398A should be proportionally increased. ISET (current setting) - pin 8 in the SOIC-20 package or pin 6 in the SOIC-16 package.
The appearance of the MainBoard 40-MT31EPA-MAC2HG is shown in the figure below:40-MT31EPA-MAC2HG
40-MT31EPA-MAC2HG can be used in TVs:
TCL F40B3804 (Panel LVF400CMDX E1 V2), TCL F40B3803 (Panel V400HJ6-PE1 Rev.C2).
Main features of the TCL F40B3804 device:
Installed matrix (LED-panel) LVF400CMDX E1 V2.
To power the backlight LEDs, a converter is used, combined with the main board 40-MT31EPA-MAC2HG, controlled by the MP3398A PWM controller. As the power elements of the LED driver, keys of the AOD256 type are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using RT7736B microcircuits and power switches of the MDF10N65B type.
MainBoard - the main board (motherboard) is a 40-MT31EPA-MAC2HG module, using SPI Flash chips: W25Q64FVSIG and others.
The tuner ST34WN-2T-E 07-600C13-SA2G provides the reception of television programs and tuning to channels.
TCL F40B3804 TV with an LVF400CMDX LCD display, diagonal size 40 "(102 cm) in 16: 9 format. The brightness of the screen, declared by the manufacturer, is 310 cd / m² by LED backlighting. The LED screen backlighting technology is implemented in this TV model. The design and technical capabilities of the TV include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in graphic decomposition according to the standard 1080p (Full HD). The input high-frequency or video signal can be processed in analog . PAL system, SECAM, NTSC Image processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p, 1080i, 1080p Supported multimedia file formats:. MP3, WMA, MPEG4, JPEG.
The power of the sound system 32 W (2x16 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), SCART, HDMI x2, MHL, USB, Ethernet (RJ-45). 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, 1280x1024, 1360x768, 1920x1080.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
The power consumed by the TV in the operating mode from the network is 50 watts.
Overall dimensions: with stand 908x565x240 mm, without stand 908x530x87 mm.
The mass of the TV: 7.2 kg.
Attention! The panel of the LVF400CMDX E1 V2 LED-TV TCL F40B3804 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.
