Monday 6 April 2020

REPAIR / SERVICING TV AKAI LTA-26N680HCP

Technical description and composition of the AKAI LTA-26N680HCP TV, panel type and applicable modules. The composition of the modules.
AKAI
Model: LTA-26N680HCP
Chassis / Version: LS05 JUG7.820.564-1
Panel: M260TWR1
Inverter (backlight): integrated into PSU; 4 lamp
PWM Inverter: SG3525AN
Power Supply (PSU): MIP260D
PWM Power: L6562 (PFC), F9222L (PWM Resonant)
MainBoard: JUG7.820.564-1 LS05
IC MainBoard: MST719DU-LF,
Tuner: TAF5-C2IP1W
Technical Specifications LTA-26N680HCP
AKAI LTA-26N680HCP
General recommendations for repairing TV LCD
Possible manifestations of defects
- The AKAI LTA-26N680HCP TV does not turn on at all. There is no reaction to the remote control or to the control buttons from the front panel. Indicator lights do not light or flash.
Failure in such cases should be sought in the power supply circuits of the MIP260D. It is necessary to verify the presence of secondary voltages and, if they are absent, check the power switches 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 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 L6562 (PFC), F9222L (PWM Resonant) 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. If all the electrolytic capacitors of the filter according to the inverter power supply are serviceable, you should make sure that the lamps are working, 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 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 JUG7.820.564-1 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). If it is not possible to replace the MB board (SSB), you must check the health of its elements - MST719DU-LF,. Defective components should be replaced.
The malfunction of the TAF5-C2IP1W 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 TV owners! Attempts to self-repair AKAI LTA-26N680HCP are not recommended by the manufacturer and can lead to serious negative consequences!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    LTA-32N658HCP, LTA-32N680HCP, LTC-26N680HCP, LTC-32N680HCP.


 The appearance of the MainBoard JUG7.820.564-1 is shown in the figure below:
JUG7.820.564-1
PSU Advanced
The MIP260D power module is installed in the LTA-26N680HCP TV using the PFC (Power Factor Correction) scheme acting as an active filter to eliminate the higher harmonic components of the current consumption. The step-up converter based on the L6562 PWM controller does not allow the input rectifier filter's electrolytic capacitor to be connected directly to the network directly through open diodes when the charge current is determined by its reactance (of the order of 15-30 ohms at a frequency of 50 Hz). As a result of the conversion, the charging current of the capacitor will be determined in such a way that the envelope of the high-frequency pulses of the input current will repeat the phase and shape of the sine wave of the input voltage. The health check of the PFC unit is carried out by measuring the DC voltage on the capacitor of the rectifier network. In operating mode, it should be around 380V, in standby approximately 300V.
The appearance of the power supply
Key features of the AKAI LTA-26N680HCP device:
Installed matrix (LCD-panel) M260TWR1.
To power the backlight, a converter is used, combined with the power supply, controlled by the SG3525AN PWM controller.
The necessary supply voltages for all nodes of the TV AKAI LTA-26N680HCP are generated by the MIP260D power module or its analogs using L6562 (PFC), F9222L (PWM Resonant) microcircuits.
MainBoard - the main board (motherboard) is a JUG7.820.564-1 module, using MST719DU-LF chips, and others.
The TAF5-C2IP1W tuner provides TV reception and channel tuning.
Information from an alternative source:
Akai LTA-26N680HCP
Panel Type (Matrix): M260TWR1,
Motherboard: LS05 JUG7.820.564-1, MST719DU-LF, Tuner: TAF5-C2IP1W
PSU & Invertor: MIP260D, SG3525AN AKAI LTA-32N658HCP, LTA-32N680HCP, LTC-26N680HCP, LTC-32N680HCP, AKAI LTA-26N680HCP
Additional technical information about the panel:
Brand: IVO
Model: M260TWR1 R1
Type: a-Si TFT-LCD, Panel
Diagonal size: 26.0 inch
Resolution: 1366x768, WXGA
Display Mode: TN, Normally White, Transmissive
Active Area: 575.769x323.712 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 800: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 5 (Tr + Td)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V

 Brand: AKAI, Model: LTA-26N680HCP.
Briefly from the TV: LCD, 720p HD, 26 "(66 cm) diagonal, HDMI: 2.
The composition uses the MainBoard JUG7.820.564-1 LS05 and the LCD panel (matrix) M260TWR1.
Power Supply Unit (PSU) MIP260D Power Supply.
Technical description
AKAI LTA-26N680HCP TV with an M260TWR1 LCD display, 26 "(66 cm) diagonal size in 16: 9 format. The brightness of the screen is 450 cd / m² by CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 800: 1 Dynamic contrast ratio of 2500: 1 is achieved by special control of the backlight.You can view images in high quality HD at a resolution of 1366x768 pixels in the standard of graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog PAL systems , SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i.
The power of the sound system 10 W (2x5 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 x3, audio x4, S-Video, component x2, VGA, HDMI x2. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768.
The power consumed by the TV working in the network mode is 120 watts.
Overall dimensions: 680x546x146 mm.
TV Weight: 13 kg.
Attention! The M260TWR1 panel of the AKAI LTA-26N680HCP 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!