Technical description and composition of the TOSHIBA 43U7750EV TV, type of panel and applicable modules. The composition of the modules.TOSHIBA LED
Model: 43U7750EV
Chassis / Version: MSD6A638-T8E2
Panel: K430WD7
LED backlight: K420WD7 A3 2014-8-27 4708-K420WD-A3213K01
T-CON: 6870C-0584A
LED driver (backlight): integrated into PSU
Power Supply (PSU): K-PL-L03 KTC-4702-2PLL03-A7131D01-200W 82NE0053C-A
MainBoard: MSD6A638-T8E2
IC MainBoard: CPU: Cortex A53, DDR 1Gb
Tuner: ST18WM-2K-E
Control: Remote: CT-8509, IR: 4707-43L73F-A1233K01, Wi-Fi: BL-R8188NU03 V0.1
Specifications 43U7750EV
TOSHIBA 43U7750EV
General repair guidelines for TV LCD LED
Possible malfunctions
- TOSHIBA 43U7750EV does not turn on, does not respond to buttons and remote control, indicators on the front panel do not light up and do not blink.
In some of these cases, the main switching power supply, the K-PL-L03 module, is faulty. Then it is necessary to measure its output voltages and, in case of their complete or partial absence, it is necessary to check the serviceability of power switches and rectifier diodes of the converters for 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.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM microcircuits are usually checked by replacement with new ones, or obviously working.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason may be a break in the LEDs, in the stabilization of their power supply, or in the violation of the contact connections of the thong connectors,
To check the LED strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the motherboard MSD6A638-T8E2 should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU elements: Cortex A53, DDR 1Gb 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 warming up.
Before changing the ST18WM-2K-E 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 checked for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
It should be remembered! Attempts to independently repair the TOSHIBA 43U7750EV 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!
Repair MainBoard
The appearance of the MainBoard MSD6A638-T8E2 is shown in the figure below:
MSD6A638-T8E2
The appearance of the power supply
Key Features of the TOSHIBA 43U7750EV:
Installed matrix (LED-panel) K430WD7.
The matrix control uses the Timing Controller (T-CON) 6870C-0584A.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the TOSHIBA 43U7750EV TV is carried out by the power module K-PL-L03, or its analogues.
MainBoard - the main board (motherboard) is an MSD6A638-T8E2 module using CPU chips: Cortex A53, DDR 1Gb and others.
The ST18WM-2K-E tuner provides television reception and channel tuning.
Brand: TOSHIBA, Model: 43U7750EV.
Shortly from the TV: LCD, LED backlight, 43 ", 3840x2160, 4K UHD, DVR, sound: 16W, HDMI connectors: 3, Internet access, Wi-Fi, Smart TV.
The composition uses MainBoard MSD6A638-T8E2 and LCD-panel K430WD7.
Power Supply Unit (PSU) K-PL-L03 KTC-4702-2PLL03-A7131D01-200W Power Supply.
TOSHIBA 43U7750EV LED TV with K430WD7 LCD display, diagonal size 43 "(109 cm) in 16: 9 format. The required screen brightness of 260 cd / m² is provided by LED backlight LED. The ratio of maximum brightness to minimum (contrast) is 1100: 1 The LED display technology is implemented in the manufacturing technology of this model’s display, and you can watch movies in the highest possible UHD quality with a resolution of 3840x2160 pixels in 4K UHD standard.
43U7750EV has built-in SMART Software and pre-installed Android Operating System. Connecting to the Internet can be done via Wi-Fi. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the sound system 16 W (2x8 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x3, MHL, USB x2, Ethernet (RJ-45), Wi-Fi 802.11n.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 968x604x206 mm, without stand 968x567x78 mm.
TV Weight: with stand: 8 kg, without stand: 7.9 kg.
Attention! The K430WD7 panel of the TOSHIBA 43U7750EV 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.