Technical description and composition of the TCL LED40D2900AS TV, panel type and applicable modules. The composition of the modules.TCL LED
Model: LED40D2900AS
Chassis / Version: SI512SP1
Panel: LVF395ND1L
LED backlight: 40D2900 A, 40HR330M08A7 V1
T-CON: V400HJ6-PE 6B01M001M300T
LED driver (backlight): integrated into MainBoard
PWM LED driver: GB98AERN
MOSFET LED driver: TO-252
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-220
MainBoard: TP.S512.PB776 SI512SP1
IC MainBoard: CPU: 9206B, SPI FLASH: 25Q64, AUDIO: TPA3110LD2
Tuner: DVB + SAT
Control: IR: 2018I346
Technical Specifications LED40D2900S
TCL LED40D2900AS
General repair guidelines for TV LCD LED
Possible malfunctions
- The TCL LED40D2900AS 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 this case, the main power source, the AC / DC voltage converter, whose elements in this model are located on the MainBoard TP.S512.PB776 general board, may turn out to be faulty. It is necessary to measure its output voltages and, in case of their absence, check the serviceability of power switches (TO-220) and rectifier diodes in the converters for possible breakdown.
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.
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. PWM SOT23-6 PWM controllers, in the absence of visible damage or obvious 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.
In such cases, the most likely malfunction of the LED backlight elements. Often the cause of the malfunction is the lack of current in the LED circuit, for example, an open or short circuit, or a violation of the contact connections of the connectors.
It is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, black to the cathode). In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as a health indicator. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the TP.S512.PB776 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software).
Before changing the DVB + SAT tuner, if it is not possible to tune to television channels, make sure that there are supply voltages that must be measured at the corresponding tuner pins and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Attention! Users and owners of LED40D2900AS TVs who do not have the appropriate qualifications, knowledge and experience are strongly advised against self-repair attempts to avoid negative consequences that could lead to complete non-repairability of the device.
You can reduce the backlight current in LED drivers with the GB98AERN controller by proportionally increasing the total resistance of the resistors from pin 6 (ISET) to the chassis.
The appearance of MainBoard TP.S512.PB776 is shown in the figure below:TP.S512.PB776
Main features of the TCL LED40D2900AS device:
Installed matrix (LED-panel) LVF395ND1L.
The matrix control uses the Timing Controller (T-CON) V400HJ6-PE.
To power the backlight LEDs, a converter is used, combined with the TP.S512.PB776 main board, controlled by the GB98AERN PWM controller. As power elements of the LED driver, keys of the TO-252 type are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits and TO-220 type power switches.
MainBoard - the main board (motherboard) is a TP.S512.PB776 module, using CPU chips: 9206B, SPI FLASH: 25Q64, AUDIO: TPA3110LD2 and others.
The DVB + SAT tuner provides television reception and channel tuning.