Monday 6 April 2020

REPAIR / SERVICING TV AKAI LTA-20E304

Technical description and composition of the AKAI LTA-20E304 TV, panel type and applicable modules. The composition of the modules.
AKAI
Model: LTA-20E304
Panel: 20 inch
Inverter (backlight): XAD117LF B1 HAIDER
PWM Inverter: OZ9910 (16)
MOSFET Inverter: AO4606 (SO8)
Power Supply (PSU): adapter NU60-2120500-13 12v 5a
PWM Power: 1207A (SO8)
MainBoard: EJS8201V1 1735AX2H
IC MainBoard: MT8201, 29LV800, 24C16, TDA1517
Tuner: JS-6BM / 131F9HS GBIP7.820.3199-1 050526
Technical Specifications LTA-20E305
AKAI LTA-20E304
General recommendations for repairing TV LCD
Possible malfunctions
- AKAI LTA-20E304 does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to control buttons.
Usually with such manifestations, the defect is caused by faulty elements in the main adapter power module.
This TV model is equipped with an external power adapter type NU60-2120500-13 12v 5a, which the owner can purchase independently, and repairing it may not always be advisable, however, sometimes it makes some sense to open it and eliminate simple typical defects typical for IIP. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary first of all to check the power switches and rectifier diodes for a possible partial or complete breakdown.
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) 1207A (SO8). It is checked only by replacement with a known good one.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
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.
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 TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the EJS8201V1 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). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements MT8201, 29LV800, 24C16, TDA1517. BGA chip malfunctions are usually easy to detect by warming up.
If a tuner JS-6BM / 131F9HS GBIP7.820.3199-1 050526 is suspected, it is first necessary to verify the correctness of the software, as well as the presence of the required power supply voltage levels and data exchange pulses with the processor via the I2C bus on the corresponding tuner pins.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    LTA-20E304, LTA-20E305, LTA-20E304MT, LTA-20E305MT, LTA-20E305DMT

 Key Features of the AKAI LTA-20E304:
Installed matrix (LCD-panel) 20 inch.
An XAD117LF inverter is used to power the backlight, controlled by the OZ9910 PWM controller (16). As power elements of the inverter, keys of the type AO4606 (SO8) are used.
To power all the internal components of the AKAI LTA-20E304 TV, an external adapter type NU60-2120500-13 12v 5a is used using 1207A (SO8) chips.
MainBoard - the main board (motherboard) is an EJS8201V1 module, using chips MT8201, 29LV800, 24C16, TDA1517 and others.
The tuner JS-6BM / 131F9HS GBIP7.820.3199-1 050526 provides the reception of television programs and tuning to channels.