Friday 10 April 2020

REPAIR / SERVICING TV AKIRA LCT-D22HE02ST

Technical description and composition of the TV AKIRA LCT-D22HE02ST, type of panel and applicable modules. The composition of the modules.
AKIRA
Model: LCT-D22HE02ST
Panel: M220EW01 V.0
Lamp backlight: Edge LED
Inverter (backlight): JSI-220401 INV070330 V1.0
PWM Inverter: TL494C
MOSFET Inverter: AO4610
Power Supply (PSU): Adapter 12V
MainBoard: 7500-ABLTV190-004
IC MainBoard: MST9E19A-LF TDA1517P - VLF, DVD MT1389DE
Tuner: M09WPP-2P-E
Appearance
AKIRA LCT-D22HE02ST
General recommendations for repairing TV LCD
Possible manifestations of defects
- The AKIRA LCT-D22HE02ST TV does not turn on, does not respond to the remote control and control panel buttons, and does not blink with any indicators.
In such cases, the fault should be sought first in the power module. It is necessary to measure the secondary output supply voltage, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM (PWM). It is checked only by replacement with a known good one.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
These manifestations can be triggered by the power module, or by inverter defects, as well as by the distortion of the currents in the lamps due to their uneven wear. If all the electrolytic capacitors of the filter according to the power supply of the inverter are serviceable, you should make sure that the lamps are in good working condition, then you need to check the converter keys and the secondary windings of the transformers.
Sometimes, for diagnostic purposes, it is necessary to disable the inverter protection. In such cases, special care must be taken during work, and the protection circuits should be restored immediately after the repair is completed.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 7500-ABLTV190-004 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). In some cases, to repair the MB (SSB) board, it may be necessary to replace the chips - MST9E19A-LF TDA1517P - ULF, DVD MT1389DE with new or obviously working ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
The malfunction of the M09WPP-2P-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 controlled by an oscilloscope.
Once again, remind users! Attempts to independently repair the AKIRA LCT-D22HE02ST TV without the appropriate qualifications and necessary experience can lead to its complete non-repairability!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    AKIRA LCT-22HE02ST MST9E19A

 Key Features of the AKIRA LCT-D22HE02ST:
Installed matrix (LCD panel) M220EW01 V.0.
The JSI-220401 inverter is used to power the backlight lamps, it is controlled by the TL494C PWM controller. As power elements of the inverter, keys of the AO4610 type are used.
To power all the internal components of the AKIRA LCT-D22HE02ST TV, an external adapter 12V type source is used.
MainBoard - the main board (motherboard) is a module 7500-ABLTV190-004, using chips MST9E19A-LF TDA1517P - ULF, DVD MT1389DE and others.
The M09WPP-2P-E tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: AUO
Model: M220EW01 V6
Type: a-Si TFT-LCD, Panel
Diagonal size: 22.0 inch
Resolution: 1680x1050, WSXGA +
Active Area: 473.76x296.1 mm
Display Colors:, CIE1931 92%