Technical description and composition of the AKAI LCT2715 TV, type of panel and applicable modules. The composition of the modules.AKAI
Model: LCT2715
Chassis / Version: MK8205
Panel: V270W1-L03
Power Supply (PSU): 200W_SMPS
PWM Power: L5991 (PWM 16pin), L6562 (PFC), FSDM0565 (Standby)
MOSFET Power: STP12NK80, STP20NM50, STP22NF0
MainBoard: E7802-004001
IC MainBoard: MT8205G WM8776 AZ34063A-PWM RC4558 MAX202E
Tuner: FQ1236-MK3
Control: E7501-051001
Specifications
AKAI LCT2715
General recommendations for repairing TV LCD
Possible manifestations of defects
- The AKAI LCT2715 TV does not turn on and does not show any signs of operability at all. There is no reaction to either the remote control or the front panel control buttons.
With such manifestations, a malfunction is most likely to be detected in the 200W_SMPS power module. It is necessary to measure the secondary output voltage, and in case of their absence, check the serviceability of the power switches (STP12NK80, STP20NM50, STP22NF0) of 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. PWM chip L5991 (PWM 16pin), L6562 (PFC), FSDM0565 (Standby) 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.
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 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 E7802-004001 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). If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - MT8205G WM8776 AZ34063A-PWM RC4558 MAX202E. Defective components should be replaced.
Before changing the FQ1236-MK3 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 check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Attention to users! Self-repair of the AKAI LCT2715 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> AKAI LCT2715
The LCT2715 model uses a 200W_SMPS power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, it is a boost converter based on the L6562 PWM controller, which eliminates the charge current of the electrolytic capacitor of the rectifier filter directly from the network through open diodes, when its charging current is determined by its reactance.
As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network in operating mode.
Key Features of the AKAI LCT2715:
Installed matrix (LCD panel) V270W1-L03.
The necessary supply voltages for all nodes of the TV AKAI LCT2715 are generated by the power supply module 200W_SMPS, or its analogs using microcircuits L5991 (PWM 16pin), L6562 (PFC), FSDM0565 (Standby) and power switches of the type STP12NK80, STP20NM50, STP22NF0.
MainBoard - the main board (motherboard) is an E7802-004001 module, using chips MT8205G WM8776 AZ34063A-PWM RC4558 MAX202E and others.
The FQ1236-MK3 tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: CMO
Model: V270W1-L03
Type: a-Si TFT-LCD, Panel
Diagonal size: 27.0 inch
Resolution: 1280x720, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 597.12x335.88 mm
Surface: Antiglare (Haze 40%), Hard coating (2H), Reflection 2.0% (Max.)
Brightness: 500 cd / m²
Contrast Ratio: 900: 1
Display Colors: 16.7M (8-bit), CIE1931 75%
Response Time: 15/10 (Tr / Td); 16.6 (G to G)
Frequency: 60Hz
Lamp Type: 14 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V