Technical description and composition of the TV AKAI LES-50V46M, type of panel and modules used. Module composition.
Composition Specifications
AKAI LES-50V46M
Smart TV LES-50V46M | Year of manufacture: 2015
Screen diagonal: 50" (127 cm)
Aspect ratio: 16:9
Resolution: 1920x1080
Frequency refresh rate: 50 Hz
LCD panel type: T500HVN08.8
LED backlight: Yes
Smart: Yes. Wi-Fi support: yes
Operating system: Android
Support HD: 1080p Full HD
Progressive scan: Yes
TV standards: PAL, SECAM, NTSC
Digital tuner: DVB-T, DVB-T2, DVB-C
Teletext: Yes
DTV formats: 480i, 480p, 576i, 576p, 720p, 1080i
Multimedia: MP3, WMA, MPEG4, DivX, MKV, JPEG
Stereo sound: there is
Sound Power: 16W (2x8W)
Acoustics: two speakers
Interface: Component, SCART, VGA, HDMI x2, USB x2, Ethernet (RJ-45), Wi-Fi 802.11n
Headphone jack: yes
TV weight: 13.6 kg
Dimensions: With stand 1132x705x235 mm
Without stand 1132x665x83mm.
AKAI LED Model: LES-50V46M
Chassis/Version: TP.MS3463S.PC821
Panel: T500HVN08.8 (AUO)
LED backlight: AS358M
LED driver (backlight): integrated into MainBoard
PWM LED driver: PWM SOT23-6, AS358
MOSFET LED driver: N-FET TO-220F
Power Supply (PSU): integrated into MainBoard
PWM Power: PFC, PWM
MOSFET Power: TO-220, TO252
MainBoard: TP.MS3463S.PC821
IC MainBoard: CPU: MSD3463GSA-U6, SPI Flash: 25Q64CSIG, Audio: TPA3110LD2
TP: NoName
General advice about LCD LED TV repair
Possible problems
- AKAI LES-50V46M does not turn on, the indicators on the front panel are not lit or flashing. The TV does not respond to the control buttons and remote control.
In this case the main power supply can be defective - AC/DC converter, elements of which in this model are located on the common MainBoard TP.MS3463S.PC821. It is necessary to measure its output voltages and if there are no such voltages check the power switches (TO-220, TO252) and the rectifier diodes for possible short circuits in the converters.
When diodes breakdown in the secondary circuits, the inverter can operate in the emergency short-circuit mode without output voltages, and when the power elements of the primary circuit are shorted, the mains fuse and/or the current sensor at the source of the key usually break down.
Breakdown of Mos-Fet switches used in pulse power supplies is often caused by faults in other elements, e.g. in the PWM power supply circuit, in the frequency-retaining or damping circuits, and in the Negative Feedback Stabilization circuit. PWM PFC, PWM chips are usually checked by replacing them with new ones or with ones known to be in good working order.
- No picture, but there is sound and remote control responds. Or the image appears at power on and immediately disappears.
Failure in most of these cases is detected in the nodes and elements of LED panel backlight. The cause may be found in the failure of the LEDs, in violation of the AS358M LED strips contact connections, or in providing them with power (LED-driver).
It is impossible to detect a breakage in the line of LEDs without disassembling the panel with a simple multimeter. LEDs are connected in series and in order to open their junctions you will need several dozens of volts. Ideally a current source would be suitable for this purpose. You can open up the panel and check each LED separately. Usually, Chinese multimeters will light up one 3 volt LED slightly if you connect the probes to it in the forward direction (red probe to the anode, black probe to the cathode). For twin 6-volt LEDs, the PN junction of its faulty regulator can be an indicator of the health of the LED. If the LED is faulty, it will either be open or shorted.
If the AKAI LES-50V46M has no picture but has sound, often the T500HVN08.8 display backlight simply does not work. Moreover, in LED TVs the LEDs inside the panel usually fail, less often the LED-driver.
In such cases, you can see a barely noticeable image when external light hits the screen.
To replace the LEDs requires disassembly of the LCD-panel T500HVN08.8 - the process requiring a master of experience and skill. We do not recommend to perform such works by yourself to owners of TV sets and craftsmen who have no experience in LCD panel repair.
READ HOW TO REPAIR THE TV LED BACKLIGHT --------------> HERE.
If there is no image, but backlighting works - the screen becomes a little lighter when you turn on the TV, and in the open TV you can see the light through the holes in the body of the panel.
In this case the panel may be defective - damage to the strips, cables, for example, as a consequence of moisture after an unsuccessful washing of the screen, the T-CON board (Timing Controller) may be defective. But quite often the MainBoard TP.MS3463S.PC821 is also defective, so software defects are also possible.
Then first it is necessary to check the panel power supply voltage, the fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, you need to trace by oscilloscope the LVDS signals from MainBoard TP.MS3463S.PC821, as well as synchronizing signals to driver stubs.
Filled or unsuccessfully washed LED TV screens can be restored in about half of the cases, usually if there is no significant damage to the panel stubs and slats.
- The TV set does not enter the operating mode, the remote control is unresponsive. Front panel LED is either constantly on or is blinking.
Repair or diagnostic of the TP.MS3463S.PC821 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and the matrix. If necessary, update or replace the software (firmware). When repairing MB board, you must check its components CPU: MSD3463GSA-U6, SPI Flash: 25Q64CSIG, Audio: TPA3110LD2. Defective elements should be replaced. If chips with BGA soldering technology are used, the problem in its implementation is detected by the method of local heating of the chip.
If the TV set works normally from external devices, but does not tune to the TV channels, there may be a problem with the NoName tuner. In these cases you should first make sure that there is a supply voltage on the corresponding pins of the tuner. Also, make sure that the tuner and the processor are communicating via the I2C bus. Sometimes a software malfunction can be the reason for the tuner not working.
Once again, please remind TV users not to try to repair it yourself, without the appropriate knowledge, experience, and necessary qualification! Trust repairs to professionals with sufficient experience in the field of electronic repair.
DOWNLOAD SCHEMATIC DIAGRAM / PSU SERVICE MANUAL ------------------> TP.MS3463S.PC821 Power supply.
Refinement after the repair of the backlight. TP.MS3463S.PC821. Information from the master.
Decreased backlight current from 290 mA to 220 mA - removed one of the 1.6 Ohm resistors in the driver current sensor on the TP.MS3463S.PC821 board.
The current sensor is an assembly of 1.6, 2.2 Ohm resistors in the LED driver node next to GD3 and EB301.
Driver current limitation. TP.MS3463S.PC821. General Information.
To reduce the backlight current, you can remove one of the resistors in the driver current sensor on the TP.MS3463S.PC821 board.
The current sensor is an assembly of six 1.6-2.2 Ohm resistors, located next to GD3 and EB301 in the LED driver assembly.
TP.MS3463S.PC821 current backlight.
Ways to limit the current in LED backlight drivers:
There
is a lot of information on the Internet about ways to limit the current
in the LED backlighting for different TVs and LED drivers. A lot of it
is written plausibly but sometimes it is written by people far from
electronics in order to publish any popular content on hot topics to
boost web-sites ratings.
It's impossible to talk about each case
separately within one article, because even similar models may have
different panels and different boards with their own driver variants.
But there are basic principles that are clear to craftsmen with even minimal knowledge and skill.
Other popular, complex and controversial current limit cases will be published as information becomes available.
There are three basic ways to reduce the backlight current.
1. By increasing the resistance of the LED current sensor - a low-resistance measuring resistor in the cathode (LED-) circuit.
2. Increasing the ratings of the resistors on the ISET (current setting) input of the LED driver chip.
3. changing the resistor ratings in the divider on the ADIM (Dimming) control input.
The fundamental difference between input ISET and ADIM is that ISET - input inverted, as FB, and ADIM - direct.
More on MainBoard Repair
The appearance of the MainBoard TP.MS3463S.PC821 is shown in the figure below:
TP.MS3463S.PC821
The main features of the device AKAI LES-50V46M:
A T500HVN08.8 (AUO) matrix (LED panel) is installed.
To power the LED backlight using a converter, combined with the main board TP.MS3463S.PC821, is controlled by a PWM SOT23-6, AS358. N-FET TO-220F switches are used as power elements of LED driver.
The power module is combined with MainBoard and is designed as reverse-going AC/DC converter with PFC, PWM chips and TO-220, TO252 type power switches.
MainBoard - the main board (motherboard) is a module TP.MS3463S.PC821, with the use of chip CPU: MSD3463GSA-U6, SPI Flash: 25Q64CSIG, Audio: TPA3110LD2 and others.
The NoName tuner allows you to receive TV programs and tune to channels.
TV AKAI LES-50V46M with LCD T500HVN08.8 diagonal 50 "(127 cm) format 16:9. In the manufacturing technology of the display model is implemented LED backlighting.
LCD panel T500HVN08.8 and software of MainBoard TP.MS3463S.PC821 provide for the realization of images in high quality HD with 1920x1080 pixels resolution in 1080p (Full HD) graphic decomposition.
Model LES-50V46M TV has built-in SMART software and pre-installed the Android operating system. Connection to the network can be made via Wi-Fi wireless connection. Input antenna or video signal can be processed in PAL, SECAM, NTSC analog systems. Graphical processing and formation of a digital signal takes place in the standards 480i, 480p, 576p, 576p, 720p, 1080i. Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG.
The sound system has a capacity of 16 W (2x8 W), provided by two speakers. NICAM STEREO audio processing system is used.
External interface (connection to other devices) is supported by standard inputs and outputs: antenna input (RF), component, SCART, VGA, HDMI x2, USB x2, Ethernet (RJ-45), Wi-Fi 802.11n. There is a headphone output. To connect a computer or laptop to this TV model uses a VGA (D-Sub 15) connector on the TV body, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080. The digital tuner can receive TV channels in the standards DVB-T, DVB-T2, DVB-C.
The TV set has a power supply as part of the MainBoard.
Overall dimensions: With stand 1132x705x235 mm, without stand 1132x665x83 mm.
TV weight 13.6 kg.
Warning. The panel T500HVN08.8 LED-TV AKAI LES-50V46M is expensive and unreliable element of the TV.
Do not allow any impacts on the glass and pressure on the screen surface to avoid damage to the LED panel!
Also it is not safe to get liquid on the screen. Sometimes one drop is enough if it drips down the glass onto the cables and the TV becomes unrepairable.