Friday 10 April 2020

REPAIR / SERVICING TV AKIRA LCT-32EL0SSTP

Technical description and composition of the TV AKIRA LCT-32EL0SSTP, type of panel and applicable modules. The composition of the modules.
AKIRA
Model: LCT-32EL0SSTP
Chassis / Version: VCB4100
Panel: LC320W01
MainBoard: VCB4100
IC MainBoard: CPU: VCT49X, MST5151; AUDIO: TPA3004D2
Tuner: TECH2949PG40B (D)
Appearance
AKIRA LCT-32EL0SSTP
General recommendations for repairing TV LCD
Possible malfunctions
- The AKIRA LCT-32EL0SSTP TV does not turn on, does not respond to the remote control and control panel buttons, and does not blink with any indicators.
In most of these cases, the main switching power supply is faulty. It is necessary to measure its secondary output voltages, 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.
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. The PWM chip can also cause a malfunction of the power switch of the converter and is checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
These manifestations can be triggered by a power module, or by defects in the inverter, as well as a distortion of the currents in the lamps due to their uneven wear. After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, it is necessary to ring in its converter the power switches for breakdown and the secondary windings of the 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 indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the VCB4100 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). When repairing an MB board, it is necessary to check its CPU components: VCT49X, MST5151; AUDIO: TPA3004D2. 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.
The malfunction of the TECH2949PG40B (D) 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.
Attention to users! Self-repair of the AKIRA LCT-32EL0SSTP TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    AKIRA LCT-32EL0SSTP
 The appearance of the MainBoard VCB4100 is shown in the figure below:
Vcb4100
Key features of the AKIRA LCT-32EL0SSTP device:
Installed matrix (LCD-panel) LC320W01.
The required supply voltage for all nodes of the TV AKIRA LCT-32EL0SSTP provides a switching power supply.
MainBoard - the main board (motherboard) is a VCB4100 module using CPU chips: VCT49X, MST5151; AUDIO: TPA3004D2 and others.
Tuner TECH2949PG40B (D) provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG.Philips LCD
Model: LC320W01-SL20
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 697.68x392.26 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 800: 1
Display Colors: 16.7M (8-bit)
Response Time: 8/10 (Tr / Td); 8 (G to G)
Frequency: 60Hz
Lamp Type: 18 pcs EEFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V