Technical description and composition of the GOLDSTAR LT-28T405R TV, panel type and modules used. The composition of the modules.GoldStar LED
Model: LT-28T405R
Chassis / Version: MT31BP
Panel: LVW280CS0T E26 V3
LED backlight: T0T 28B2550 3030C 5S1P
T-CON: MT3151A05-3-XC-1
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 MIPE07R41 REV1.5
IC MainBoard: CPU: MT5531NDNT 1429-BCAH; SPI Flash: 25Q64F; SOUND: RT9108NB
Tuner: ST34WN-2T-E
Control: IR: 40-32B260-IRA2LG
LT-28T405R Specifications
GOLDSTAR LT-28T405R
General recommendations for TV LCD LED repair
Possible malfunctions
- The GoldStar LT-28T405R TV does not turn on and does not show any signs of turning on, does not respond to the control buttons and the remote control.
First of all, in such cases, you should make sure that the common switching power supply (SMPS) - the AC / DC voltage converter of the mains voltage - is working. All source elements in this TV model are located on the MainBoard 40-MT31BP-MAA2LG. Its output voltages should be measured and, in their absence, the power switches and rectifier diodes should be checked for the probability of a short circuit in the converters.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually operate in an emergency mode in a short-circuit mode, and in case of a short circuit in the power elements of the primary circuit, the mains fuse often breaks.
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, if they do not have visible damage to the case and an open short circuit between the pins, are usually checked by replacing.
- There is no picture, 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.
Most likely in these cases is a malfunction of the LED panel backlight. The reason for this may be an open circuit in the LED circuit, or a problem in stabilizing their power supply.
When trying to detect a break in the LED lines, it should be borne in mind that it is difficult to do this without disassembling the panel. For example, a current source is required to open PN junctions connected in series.
- 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 40-MT31BP-MAA2LG 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). In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - CPU: MT5531NDNT 1429-BCAH; SPI Flash: 25Q64F; SOUND: MP3398A which may require replacement. 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 (detected by warming up).
The malfunction of the ST34WN-2T-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.
Owners and users of the GoldStar LT-28T405R TV should remember that self-repair without special knowledge, skills and qualifications may be fraught with negative consequences that can lead to complete non-repairability of the device!
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 GOLDSTAR LT-28T405R device:
Installed matrix (LED-panel) LVW280CS0T E26 V3.
Matrix control uses Timing Controller (T-CON) MT3151A05-3-XC-1.
To power the backlight LEDs, a converter combined with the 40-MT31BP-MAA2LG main board is used, controlled by the MP3398A 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 microcircuits.
MainBoard - the main board (motherboard) is a 40-MT31BP-MAA2LG module, using CPU chips: MT5531NDNT 1429-BCAH; SPI Flash: 25Q64F; SOUND: RT9108NB and others.
The ST34WN-2T-E tuner provides reception of television programs and tuning to channels.
GOLDSTAR LT-28T405R TV with TCL LCD, 28 "(71 cm) 16: 9 diagonal. The required brightness of the screen 240 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 60,000: 1 is achieved by special control of LED operation. The LCD-panel of the TV is implemented with direct backlighting with rear-mounted LEDs - Direct LED.It is possible to view images in high quality HD at a resolution of 1366x768 pixels in a graphic resolution of 720p (HD Ready) .Input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC Graphic processing and digital signal shaping takes place in 480i, 480p, 576i, 576p, 720p, 1080i standards Supported media file formats: MP3, WMA, MPEG4, DivX, JPEG.
Speaker power 12 W (2x6 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), component, VGA, HDMI x2, USB. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector on the TV case is used, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768.
The digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Dimensions: without stand 650x470x80 mm.
Attention! Panel TCL LVW280CSOT E26 V3 LED-TV GOLDSTAR LT-28T405R 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.