Technical description and composition of the TCL LED55D2730B TV, panel type and modules used. The composition of the modules.
TCL LED
Model: LED55D2730B
Chassis / Version: 40-MT31SS-MAC2HG
Panel: LVF550CSOT E13
LED backlight: YHA-4C-LB3205-YHEX1
T-CON: ST5461B05-2-XC-2 (1-XL-2)
LED driver (backlight): integrated into PSU
PWM LED driver: GB98ADN
MOSFET LED driver: APM1105NU 16A 100V TO-252
Power Supply (PSU): SHG5504B10-101H 81-PBE055-H91
PWM Power: FA5591N, FA6A11N, TPS560200
MOSFET Power: JCS13N50FT, JCS5N50FT
MainBoard: 40-MT31SS-MAC2HG
IC MainBoard: SPI Flash: W25Q64BV, AUDIO: TAS5707
Tuner: DT21CN-2-E
Specifications LED55D2730B
TCL LED55D2730B
General recommendations for TV LCD LED repair
Possible manifestations of malfunctions
- TV TCL LED55D2730B does not turn on, does not respond to the remote control and control panel buttons, does not light or blink indicators.
With similar manifestations, a malfunction is most likely found in the SHG5504B10-101H power module. It is necessary to make sure that its output voltages are present and, if they are completely absent, check the power switches (JCS13N50FT, JCS5N50FT) and rectifier diodes for a possible short circuit.
In case of any breakdowns of semiconductors in the secondary circuits, the converter can usually operate normally in an emergency short circuit mode. There are no output voltages. And with a short circuit in the power elements of the primary circuit, as a rule, the mains fuse breaks and, less often, the current sensor in the source of the key.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers FA5591N, FA6A11N, TPS560200, in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or known to be working properly.
- There is no picture, but there is sound, it reacts to the remote control Or the image appears when turned on and disappears immediately
Most likely in these cases is a malfunction of the LED panel backlight. Often the cause of the malfunction is the lack of current in the LED circuit, for example, their open or short circuit, or the violation of the contact connections of the connectors of the YHA-4C-LB3205-YHEX1 brackets.
To check the health of 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 separately with a simple Chinese multimeter (powered by 9 volts) in the P-N transition test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black one 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. The serviceability of the PN junction of the Zener diode indirectly indicates the serviceability of the LED-a
If TCL LED55D2730B has no image, but there is sound, often the LVF550CSOT E13 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 the external light hits the screen.
Replacing the LEDs requires disassembling the LVF550CSOT LCD panel - a process that requires experience and qualifications from the master. We do not recommend doing such work on your own to the owners of TVs and craftsmen who do not have experience in repairing LCD panels
If there is no image, and the backlight is on, the screen becomes slightly lighter when turned on, and in an open TV you can see light through the holes in the panel case.
In this case, the panel may also be faulty - damage to strips, loops, for example, as a result of moisture ingress after unsuccessful washing of the screen, the T-CON (Timing Controller) board may be faulty. But the main board MainBoard 40-MT31SS-MAC2HG often turns out to be faulty; a software failure is also possible.
Then, first of all, you need to check the panel supply voltage, 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 the normal range, it is necessary to use an oscilloscope to trace the passage of LVDS signals from the MainBoard 40-MT31SS-MAC2HG, as well as synchronization signals to the loops with drivers.
Flooded or unsuccessfully washed screens of LED TVs can be restored, in about half of the cases, usually if significant damage has not formed in the loops and panel strips.
READ HOW TO REPAIR THE TV LED BACKLIGHT --------------> HERE.
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the 40-MT31SS-MAC2HG motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Complicated MB (SSB) repair is possible only in the conditions of a service center with the necessary equipment. Checking or replacing SPI Flash: W25Q64BV, AUDIO: TAS5707 requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by the warm-up method.
The malfunction of the DT21CN-2-E tuner is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be monitored with an oscilloscope.
Remember! Attempts to self-repair the TCL LED55D2730B 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!
DOWNLOAD SCHEMATIC DIAGRAM / POWER SUPPLY ------------------> SHG5504B10-101H Power supply.
Driver current limitation. GB98ADN. general information
To reduce the backlight current of the LED driver with the GB98ADN control microcircuit, it is necessary to increase the total resistance of the resistors at pin 2 of ISET GB98ADN to the case. When using two or more microcircuits, the revision must be made in the same way in each channel.
Additional MainBoard Repair
The appearance of the MainBoard 40-MT31SS-MAC2HG is shown in the figure below:
40-MT31SS-MAC2HG
External view of the power supply
Key features of the TCL LED55D2730B device:
Installed matrix (LED-panel) LVF550CSOT E13.
Matrix control uses Timing Controller (T-CON) ST5461B05-2-XC-2.
A converter combined with a power supply is used to power the backlight LEDs, and is controlled by the GB98ADN PWM controller. APM1105NU 16A 100V TO-252 switches are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the TCL LED55D2730B TV is carried out by the SHG5504B10-101H power module, or its analogues using the FA5591N, FA6A11N, TPS560200 microcircuits and power switches of the JCS13N50FT, JCS5N50FT type.
MainBoard - the main board (motherboard) is a 40-MT31SS-MAC2HG module, using SPI Flash chips: W25Q64BV, AUDIO: TAS5707 and others.
The DT21CN-2-E tuner provides reception of television programs and tuning to channels.
TV TCL LED55D2730B with LCD LVF550CSOT, diagonal size 55 "(140 cm) 16: 9 format. The technology of manufacturing the screen of this TV model is realized with LED backlighting.
The LVF550CSOT sensor and MainBoard 40-MT31SS-MAC2HG software realize high quality HD images at a resolution of 1920x1080 pixels in 1080p (Full HD) graphics. Supported media file formats: MP3, WMA, MPEG4, JPEG.
Speaker power 10 W (2x10 W) is provided by two speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, VGA, HDMI x2, USB. A headphone output is provided. The digital tuner is capable of receiving television channels in the DVB-T, DVB-T2, DVB-C standards.
The power supply used is SHG5504B10-101H.
Dimensions: with stand 928x590x180 mm, without stand 928x540x54 mm.
TV weight: with stand: 10 kg, without stand: 9.33 kg.
Attention! The LVF550CSOT E13 panel of the TCL LED55D2730B LED TV is an expensive and unreliable element.
Avoid any impacts on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.
