Technical description and composition of the TCL L32B2820 TV, panel type and applicable modules. The composition of the modules.TCL LED
Model: L32B2820
Chassis / Version: MT31BP
Panel: LVW320CSOT E155 V7
LED backlight: 006-P1K3390B
T-CON: MT3151A04-1-XC-9
LED driver (backlight): integrated into MainBoard
PWM LED driver: MP3398A
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: 40-MT31BP-MAA2LG MT31BP
IC MainBoard: CPU: MT5531NDNT, SPI Flash: GD25Q64F, Audio: RT9108NB
Tuner: ST34WN-2T-E
Control: IR: 40-40B380-IRC2LG, Buttons Board: 40-32B280-KEC2LG
Technical Specifications L32B2820
TCL L32B2820
General repair guidelines for TV LCD LED
Possible malfunctions
- The TCL L32B2820 TV does not turn on, does not respond to the remote control and buttons on the control panel, does not light or flash indicators.
In such cases, the common power source, the AC / DC voltage converter, which is combined with the elements of the 40-MT31BP-MAA2LG main board, is often faulty. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of the power switches of the converters and rectifier diodes for the presence of a possible short circuit.
In case of any breakdown of semiconductors in the secondary circuits, the converter can usually work normally in 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 at 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 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, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
As a rule, in such cases there is no display 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 lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
- 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 40-MT31BP-MAA2LG 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). When repairing an MB board, you need to check its CPU components: MT5531NDNT, SPI Flash: GD25Q64F, Audio: MP3398A. Defective items should be replaced. If chips with BGA soldering technology are used, a problem in its implementation is detected by the local heating of the chip.
Before replacing the ST34WN-2T-E tuner, if there is no channel tuning, 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
We recommend the owners of the L32B2820 TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
The appearance of the MainBoard 40-MT31BP-MAA2LG is shown in the figure below:40-MT31BP-MAA2LG
40-MT31BP-MAA2LG can be used in TVs:
ERISSON 32LET82 (Panel LVW320CSOT E145 V2), ERISSON 32LET42T2 (Panel LVW320CSOT E274 V2), ERISSON 32LET41T2 (Panel LVW320CS0T E274 V2), FUSION FLTV-32T21 (Panel LVW320CZOT), SUPRA STV-LC32T420WL (Panel LVW320CSOT E155 V2), SUPRA STV-LC32T850WL (Panel LVW320CSOT E45 V1), SUPRA STV-LC28T662WL (Panel T8-28T3520-LPM20), SUPRA STV-LC24T850WL (Panel 720p HD 1366x768), TELEFUNKEN TF-LED32S29T2 (Panel LVW320CS0T E198 V4), TELEFUNKEN TF-LED24S29T2 (Panel V236BJ1-LE2 Rev.C1), THOMSON T24E12DHU-01B T24E12DHU (Panel LVW240AUDX E2 V6).
Main features of the TCL L32B2820 device:
Installed matrix (LED-panel) LVW320CSOT E155 V7.
The matrix control uses the Timing Controller (T-CON) MT3151A04-1-XC-9.
To power the backlight LEDs, a converter is used, combined with the main board 40-MT31BP-MAA2LG, controlled by the MP3398A PWM controller.
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.
MainBoard - the main board (motherboard) is a 40-MT31BP-MAA2LG module, using CPU chips: MT5531NDNT, SPI Flash: GD25Q64F, Audio: RT9108NB and others.
The ST34WN-2T-E tuner provides television reception and channel tuning.
TCL L32B2820 TV with LVW320CSOT LCD, 32 "(81 cm) diagonal size in 16: 9 format. The brightness of the screen declared by the manufacturer is 250 cd / m² by LED backlighting. Contrast - the ratio of maximum brightness to minimum, is at least 4000 : 1. The technology for making the screen of this TV model uses LED LED backlighting. You can view images in high quality HD at a resolution of 1366x768 pixels in the standard for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be . Works in PAL, SECAM, NTSC analog systems Image processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats:. MP3, MPEG4, JPEG.
The power of the sound system 10 W (2x5 W) provides 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 x2, USB. 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, 1360x768.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 734x480x160 mm, without stand 734x431x80 mm.
TV Weight: with stand: 5.1 kg, without stand: 4.7 kg.
Attention! The LVW320CSOT E155 V7 panel of the TCL L32B2820 LED TV 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.