Technical description and composition of the THOMSON 28B2500 TV, panel type and modules used. The composition of the modules.THOMSON LED
Model: 28B2500
Chassis / Version: TP.MS18VG.P77
Panel: LVW280CSOT E13V1
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6 LD7536R
MainBoard: TP.MS18VG.P77
IC MainBoard: CPU: MST3M182VGC-LF-TZ, FLASH: GD25Q32BSIG
Tuner: R620D
Specifications 28B2500
THOMSON 28B2500
General recommendations for TV LCD LED repair
Possible manifestations of defects
- THOMSON 28B2500 TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or blink, the TV does not respond to the remote control and control buttons.
A malfunction in such cases should be looked for in the elements of the power source - the mains voltage converter (AC / DC), which is located on the MainBoard TP.MS18VG.P77. Then we recommend measuring its output voltages and, if they are absent, you should check the serviceability of the power switches and rectifier diodes of the converters for a possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and with a short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key often breaks off.
Breakdown of power switches (MosFet) in switching sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency setting or damper, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM regulators (PWM) PWM SOT23-6 LD7536R, if they do not have visible damage to the case and an outright short circuit between the pins, are usually checked by replacing.
- There is no image, there is sound, it reacts to the remote control, the channels are switched. In some cases, the image appears when turned on and disappears immediately.
Often, in such cases, there is no backlighting of the LED panel. The reason for this may be an open circuit in the LED circuit, or a problem in stabilizing their power supply.
When diagnosing, it must be borne in mind that it is impossible to check for an open in the circuit of the LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally a current source. By opening the panel, you can check each LED separately. Typically, Chinese multimeters will lightly light one 3-volt LED if you connect the probes to it in the forward direction. For dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of LED health. In the event of a malfunction of the LED, its zener diode will either be cut off or pierced in the K / Z.
- The indicator on the front panel blinks, the TV does not turn on in operating mode, does not respond to the remote control.
Repair or diagnostics of the TP.MS18VG.P77 motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and the matrix. If necessary, you should update or replace the software (software). In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - CPU: MST3M182VGC-LF-TZ, FLASH: GD25Q32BSIG which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its pins with the board (indicated by warming up).
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 outputs. You also need to make sure that the tuner and processor can exchange data via the I2C bus.
If THOMSON 28B2500 has no image, but there is sound, often the LVW280CSOT 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 with a successful hit of external light on the screen.
Replacing the LEDs requires disassembling the LVW280CSOT 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 TP.MS18VG.P77 often turns out to be faulty, a software failure is also possible.
Then, first of all, you need to check the panel 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 the normal range, it is necessary to trace the passage of LVDS signals from MainBoard TP.MS18VG.P77 with an oscilloscope, as well as synchronizing signals to 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.
Attention to users! Self-repair of the THOMSON 28B2500 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
DOWNLOAD FIRMWARE FOR SPI FLASH -----------> THOMSON 28B2500, Main: TP.MS18VG.P77, Panel: LVW280CSOT E13V1
The appearance of the MainBoard TP.MS18VG.P77 is shown in the figure below:TP.MS18VG.P77
TP.MS18VG.P77 can be used in TVs:
ERISSON 24LET35 (Panel LVW240CMOT E1 V2), ERISSON 19LET35 (Panel M185XTN01.3), FUSION FLTV-24C10 (Panel LVW230SSOT E1 V2), FUSION FLTV-32C10 (Panel LVW320CSOT E81 V7), HYUNDAI H-LED32V19 (Panel LVW320CSOT E45 V10), HYUNDAI H-LED32V23 (Panel LVW320C80T E64 V5), TCL 19T2100 (Panel M185XTN01.2), TELEFUNKEN TF-LED32S23 (Panel LVW320CS0T E146 V1), THOMSON 32B2600 (Panel LVW320C8OT EB1), THOMSON 28B2500 (Panel LVW280CSOT E13V1).
The main features of the THOMSON 28B2500 device:
Installed matrix (LED panel) LVW280CSOT E13V1.
To power the backlight LEDs, a converter combined with the TP.MS18VG.P77 main board is used, controlled by the OB3350CP PWM controller.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter using PWM SOT23-6 LD7536R microcircuits.
MainBoard - the main board (motherboard) is a TP.MS18VG.P77 module, using CPU chips: MST3M182VGC-LF-TZ, FLASH: GD25Q32BSIG and others.
The R620D tuner provides reception of television programs and tuning to channels.
LED TV THOMSON 28B2500 with LCD LVW280CSOT, diagonal size 28 "(71 cm) 16: 9 format. The declared brightness of the screen 240 cd / m2 is provided by modern LED backlight LED. The ratio of maximum brightness to minimum (contrast) is not less than 4000 : 1. The LCD panel uses Edge LED backlighting. You can view in high quality HD at a resolution of 1366x768 pixels in 720p standard (HD Ready). The input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. The digital signal (graphic format) is formed in the 480i, 480p, 576i, 576p, 720p, 1080i standards, and the multimedia formats are supported: MP3, WMA, MPEG4, JPEG.
Speaker power 10 W (2x5 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, USB. A standard VGA (D-Sub 15) connector is used to connect a laptop or computer. This interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768.
Dimensions: with stand 651x467x192 mm, without stand 651x406x92 mm.
Attention! The LVW280CSOT E13V1 panel of the THOMSON 28B2500 LED TV is an expensive and unreliable element.
Do not allow any impact 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.
