Monday 6 April 2020

REPAIR / SERVICING TV AKAI LTA-32N680HCP

Technical description and composition of the AKAI LTA-32N680HCP TV, panel type and applicable modules. The composition of the modules.
AKAI
Model: LTA-32N680HCP
Chassis / Version: LS02
Panel: CLAA320WF01U
T-CON: CPT 320WF01C, CPW1c060RS,
Power Supply (PSU): MLT868 REV1.2
PWM Power: L6562D (PFC), SG3525AN
MainBoard: LS02 / AX68
IC MainBoard: 24LC64B, 25X80AVSIG, D1216AJTA-48-E, TDA9886TS, 74HC4052D, TDA7266SA, EM636165TS-7G, 432A2GLT, AH63009
Technical Specifications LTA-32N680HCP
AKAI LTA-32N680HCP
General recommendations for repairing TV LCD
Possible manifestations of defects
- The AKAI LTA-32N680HCP TV does not turn on, does not respond to the remote control and the control panel buttons, and does not blink with any indicators.
With such manifestations, in most cases, the MLT868 power module 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 a 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 the excess of maximum current or voltage values. 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) L6562D (PFC), SG3525AN. It is checked only by replacement with a known good one.
- 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 their completion, 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 LS02 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 - 24LC64B, 25X80AVSIG, D1216AJTA-48-E, TDA9886TS, 74HC4052D, TDA7266SA, EM636165TS-7G, 432A2GLT, AH63009. Defective components should be replaced.
Attention TV owners! Self-repair attempts by AKAI LTA-32N680HCP 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 LS02 is shown in the figure below:LS02
PSU Advanced
The MLT power supply module is made using the Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced into the power supply by the device. The PFC node is a Step-Up Converter based on a L6562D PWM controller that evenly distributes high-frequency pulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of an increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Key features of the AKAI LTA-32N680HCP device:
Installed matrix (LCD panel) CLAA320WF01U.
The matrix control uses the Timing Controller (T-CON) CPT.
The required supply voltages for all nodes of the TV AKAI LTA-32N680HCP are generated by the MLT868 power module or its analogs using L6562D (PFC), SG3525AN microcircuits.
MainBoard - the main board (motherboard) is an LS02 module, using microchips 24LC64B, 25X80AVSIG, D1216AJTA-48-E, TDA9886TS, 74HC4052D, TDA7266SA, EM636165TS-7G, 432A2GLT, AH63009 and others.
Additional technical information about the panel:
Brand: CPT
Model: CLAA320WF01U
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: MVA, Normally Black, Transmissive
Active Area: 697.68x392.26 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1500: 1
Display Colors: 16.7M (8-bit), CIE1931 75%
Response Time: 6 (G to G)
Frequency: 60Hz
Lamp Type: 7 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 12.0V

 Brand: AKAI, Model: LTA-32N680HCP.
Shortly from the TV: LCD, 32 ", 1366x768, 720p HD, there is PIP, sound: 10W, HDMI connectors: 2.
The composition uses MainBoard LS02 / AX68 and an LCD panel (matrix) CLAA320WF01U.
Power Supply Unit (PSU) MLT868 REV1.2 Power Supply.
AKAI LTA-32N680HCP TV with CLAA320WF01U LCD, 32 "(81 cm) diagonal size in 16: 9 format. 500 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 1500: 1. It is possible to 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 systems PAL, SECAM, NTSC. Graphic processing and digital signal generation takes place in the mill artah 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, S-Video, component, SCART x2, RGB, VGA, HDMI x2. An output for connecting headphones is provided. 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, 1280x1024, 1360x768.
The power consumed by the TV working in the network mode is 150 watts.
Overall dimensions: With a support 800x600x270 mm, Without a support 800x540x110 mm.
TV Weight: 14 kg.
Attention! The CLAA320WF01U panel of the AKAI LTA-32N680HCP 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!