Technical description and composition of the AKAI LCT2016 TV, type of panel and applicable modules. The composition of the modules.AKAI
Model: LCT2016
Panel: 20 inch 640x480
Power Supply (PSU): SMPS LCD-TV 200W
PWM Power: L5991 (PWM 16pin), L6562 (PFC), FSDM0565 (Standby)
MOSFET Power: STP20NM50, STP12NK80
MainBoard: TI-L20160006-01
IC MainBoard: W78E516B MST519V TVP5146 SAA5264PS / M3
Tuner: FQ1236-MK3
Control: T1-L20160013-01
Specifications
AKAI LCT2016
General recommendations for repairing TV LCD
Possible malfunctions
- The AKAI LCT2016 TV does not turn on, does not respond to the remote control and the control panel buttons, does not blink with any indicators.
Most likely, in this case, the main switching power supply (SMPS) SMPS is faulty. It is necessary to measure its secondary output voltage, and in case of their absence, check the serviceability of power switches (STP20NM50, STP12NK80) 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, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and disappears.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or the inverter.After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, you must ring in its converter power keys for breakdown and secondary windings of transformers for an open.
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, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the TI-L20160006-01 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 cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its chips W78E516B MST519V TVP5146 SAA5264PS / M3 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
The malfunction of the tuner FQ1236-MK3 is established after checking the software and all the supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Owners and users of the AKAI LCT2016 TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> AKAI LCT2016
The LCT2016 model uses an 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 AKAI LCT2016:
Installed matrix (LCD-panel) 20 inch 640x480.
The necessary supply voltages for all nodes of the TV AKAI LCT2016 are generated by the SMPS power supply module or its analogs using microcircuits L5991 (PWM 16pin), L6562 (PFC), FSDM0565 (Standby) and power switches of the STP20NM50, STP12NK80 type.
MainBoard - the main board (motherboard) is a TI-L20160006-01 module, using W78E516B MST519V TVP5146 SAA5264PS / M3 chips and others.
The FQ1236-MK3 tuner provides TV reception and channel tuning.