Sunday 19 April 2020

REPAIR / SERVICING TV DEXP F49B8100K

Technical description and composition of the DEXP F49B8100K TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: F49B8100K
Chassis / Version: * 35020422
Panel: MSD63691V-YYY
LED backlight: Direct LED
T-CON: 6870C-0481A
LED driver (backlight): integrated into PSU
PWM LED driver: AP3041
MOSFET LED driver: ME4N25
Power Supply (PSU): L150E02C2 35019730
PWM Power: FAN7930, FSL206MR, FSFR1700
MOSFET Power: 18N50 (PFC)
MainBoard: 35020422 rev-00
IC MainBoard: CPU: MSD63691V, SPI FLASH: W25Q16, 25Q10
Tuner: NoName
Technical Specifications F49B8100K
DEXP F49B8100K
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP F49B8100K TV does not turn on and does not show any signs of turning on, it does not respond to the control buttons or to the remote control.
In some of these cases, the main switching power supply, the L150E02C2 module, is faulty. It is then necessary to measure its output voltages and, if they are absent, you should check the power switches (18N50 (PFC)) and the rectifier diodes of the converters for a short circuit probability.
In case of breakdowns of semiconductors in secondary circuits, the converter can usually operate abnormally in short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. FAN7930, FSL206MR, FSFR1700 PWM controllers, in the absence of visible damage or explicit short-circuit between the terminals, are 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.
The faulty usually in these cases is the backlight matrix (LED-panel). More often the reason for this is the breakdown of the LEDs, or poor contact in the connectors of the strips, less often the LED driver may be malfunctioning.
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 TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 35020422 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). Sometimes it is necessary to check or replace (if necessary) the elements of the MainBoard - CPU: MSD63691V, SPI FLASH: W25Q16, 25Q10. In cases where the BGA processor is used, its malfunction is usually detected by local heating.
Before replacing the NoName tuner, if there is no tuning to the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Once again, remind users! Attempts to independently repair the DEXP F49B8100K TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!

FIRMWARE FOR SPI FLASH  ----------->   DEXP F49B8100K, Main: 35020422 rev-00, Panel: MSD63691V-YYY.

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    KIP+L150E02C2 35019730 Power supply



The appearance of the MainBoard 35020422 is shown in the figure below:
35020422
The appearance of the power supply
Main features of the DEXP F49B8100K device:
Installed matrix (LED panel) MSD63691V-YYY.
The matrix control uses the Timing Controller (T-CON) 6870C-0481A.
To power the backlight LEDs, a converter is used, combined with the power supply, controlled by the AP3041 PWM controller. As the power elements of the LED driver, keys of the ME4N25 type are used.
The necessary supply voltages for all nodes of the DEXP F49B8100K TV are generated by the L150E02C2 power module or its analogs using FAN7930, FSL206MR, FSFR1700 microcircuits and 18N50 type power switches (PFC).
MainBoard - the main board (motherboard) is a module 35020422, using CPU chips: MSD63691V, SPI FLASH: W25Q16, 25Q10 and others.
The NoName tuner provides television reception and channel tuning.
DEXP F49B8100K TV with an LCD display of 1920x1080, a diagonal size of 49 "(124 cm) in 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 3000: 1. In LCD -panels use direct LED backlighting with direct LEDs - Direct LED.The TV features include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphic resolution of 1080p (Full HD).
The F49B8100K 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, WMA, MPEG4, 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, 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, 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 working in the network mode is 120 watts.
Overall dimensions: with stand 1100x700x260 mm, without stand 1100x660x72 mm.
TV Weight: with stand: 13.8 kg, without stand: 13 kg.
Attention! The 1920x1080 Direct LED DEXP F49B8100K 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.