Friday 10 April 2020

REPAIR / SERVICING TV AKIRA LCT-D19MT02ST

Technical description and composition of the TV AKIRA LCT-D19MT02ST, type of panel and applicable modules. The composition of the modules.
AKIRA
Model: LCT-D19MT02ST
Chassis / Version: MSDV1901-ZC01-02
Panel: SVA190WX02TB
Inverter (backlight): integrated into PSU
PWM Inverter: MP1048EM
MOSFET Inverter: 4804B
Power Supply (PSU): integrated into Mainboard
PWM Power: CM0765R
MainBoard: MSDV1901-ZC01-02 (B) MST9E19A
IC MainBoard: MST9E19A-LF, 25X40VNIG, AT24C32AN, TFA9843J
Tuner: JS-6H2 / 121
Technical Specifications LCT-D19MT02ST
AKIRA LCT-D19MT02ST
General recommendations for repairing TV LCD
Possible malfunctions
- The AKIRA LCT-D19MT02ST TV does not turn on and does not show any signs of operability. There is no reaction to either the remote control or the control buttons from the front panel.
In most of these cases, the power source that is combined with the MainBoard mainboard turns out to be faulty. It is necessary to measure its secondary output voltages, in case of their absence, check the serviceability of power switches and rectifier diodes of AC / DC converters for possible short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. PWM chip CM0765R can also cause a malfunction of the power switch of the converter and is checked by replacement.
- 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.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or the inverter.After checking all the electrolytic capacitors of the filters that are involved in the power supply to the inverter, you must ring in its converter power keys for breakdown and secondary windings of transformers for an open.
If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required during work, and after they are finished, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- 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 motherboard MSDV1901-ZC01-02 (B) 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 components MST9E19A-LF, 25X40VNIG, AT24C32AN, TFA9843J. 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 changing the JS-6H2 / 121 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
TV users and owners must remember that attempts to self-repair an AKIRA LCT-D19MT02ST TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!







Key Features of the AKIRA LCT-D19MT02ST:
Installed matrix (LCD panel) SVA190WX02TB.
To power the backlight, a converter is used, combined with a power supply, controlled by the MP1048EM PWM controller. Keys of type 4804B are used as power elements of the inverter.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using CM0765R microcircuits.
MainBoard - the main board (motherboard) is a module MSDV1901-ZC01-02 (B), using microchips MST9E19A-LF, 25X40VNIG, AT24C32AN, TFA9843J and others.
The JS-6H2 / 121 tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: SVA-NEC
Model: SVA190WX02TB
Type: a-Si TFT-LCD, Panel
Diagonal size: 19.0 inch
Resolution: 1440x900, WXGA +
Display Mode: TN, Normally White, Transmissive
Active Area: 408.24x255.15 mm
Brightness: 300 cd / m²
Contrast Ratio: 800: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 72%
Response Time: 1.3 / 3.7 (Tr / Td)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V

Brand: AKIRA, Model: LCT-D19MT02ST.
Shortly from the TV: LCD, built-in DVD player, 19 ", 1440x900, 720p HD, sound: 6 watts.
The composition uses MainBoard MSDV1901-ZC01-02 (B) MST9E19A and LCD panel (matrix) SVA190WX02TB. The power supply is combined with the MainBoard.
Technical description
TV AKIRA LCT-D19MT02ST with LCD display SVA190WX02TB, diagonal size 19 "(48 cm) 16:10 format. Screen brightness of 300 cd / m² is provided by backlight CCFL (EEFL) lamps. Contrast - the ratio of maximum brightness to minimum is at least 850 : 1. It is possible to view in high quality HD at a resolution of 1440x900 pixels in 720p (HD Ready) standard. The input high-frequency or video signal is decoded in PAL, SECAM, NTSC analog systems. Digital signal generation (graphic format) is performed in 480i, 480p, 576i standards , 576p. Multimedia formats supported: MP3, MPEG4, VideoCD, SVCD, JPEG.
The power of the acoustic system of sound 6 W (2x3 W) provide 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, S-Video, component, SCART, RGB, VGA. A standard VGA (D-Sub 15) connector is used to connect a laptop or computer. This interface supports resolutions: 640x480, 800x600, 1024x768.
Overall dimensions: With stand 731x468x166 mm, Without stand 731x437x87 mm.
Attention! The SVA190WX02TB panel of the AKIRA LCT-D19MT02ST LCD TV is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!