Thursday 9 April 2020

REPAIR / SERVICING TV AIWA 40LE7120S

Technical description and composition of the AIWA 40LE7120S TV, type of panel and applicable modules. The composition of the modules.
AIWA LED
Model: 40LE7120S
Chassis / Version: 5800-A7N02G-0P00
Panel: SDL400FY (QD0-C00) (05) REV.R1
LED backlight: YAL03-00730300-02
LED driver (backlight): integrated into MainBoard
PWM LED driver: OZ9902DGN
Power Supply (PSU): integrated into MainBoard
PWM Power: FA8A01
MOSFET Power: TO-252
MainBoard: 5800-A7N02G-0P00 VER00.02
IC MainBoard: SPI Flash: MX25L1606E
Tuner: NoName
Specifications 40LE7120
AIWA 40LE7120S
General repair guidelines for TV LCD LED
Possible malfunctions
- The AIWA 40LE7120 TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
In this case, first of all, it is necessary to check the operability of the main power source - the AC / DC network voltage converter, all of whose elements are located on the MainBoard 5800-A7N02G-0P00 board. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of power switches (TO-252) of converters and rectifier diodes for the presence of a possible short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode, or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. FA8A01 PWM controllers, in the absence of visible damage or explicit short-circuit between the terminals, are checked by replacing with new, or obviously working.
- 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.
Usually in such cases there is no backlight LED-panel (matrix). The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. The LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, black to the cathode). In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- 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 5800-A7N02G-0P00 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). Sometimes it is necessary to check or replace (if necessary) the elements of the MainBoard - SPI Flash: MX25L1606E board. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
Before replacing the NoName tuner, if there is no tuning to the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
It should be remembered! Attempts to independently repair the AIWA 40LE7120 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!




The appearance of the MainBoard 5800-A7N02G-0P00 is shown in the figure below:
5800-A7N02G-0P00
Key Features of AIWA 40LE7120S:
Installed matrix (LED panel) SDL400FY (QD0-C00) (05) REV.R1.
To power the backlight LEDs, a converter is used, combined with the main board 5800-A7N02G-0P00, controlled by the OZ9902DGN PWM controller.
The power module is combined with the MainBoard and is designed according to the flyback AC / DC voltage converter using FA8A01 microcircuits and TO-252 type power switches.
MainBoard - the main board (motherboard) is a 5800-A7N02G-0P00 module, using SPI Flash chips: MX25L1606E and others.
The NoName tuner provides television reception and channel tuning.

Trademark: AIWA, Model: 40LE7120.
Briefly from the TV: LCD, LED backlight, 40 ", 1920x1080, 1080p Full HD, DVR, there is a satellite tuner, sound: 12W, HDMI connectors: 2.
The composition includes MainBoard 5800-A7N02G-0P00 VER00.02 and LCD-panel SDL400FY (QD0-C00) (05) REV.R1. The power supply is combined with the MainBoard.
AIWA 40LE7120 TV with SDL400FY LCD display, 40 "(102 cm) diagonal size in 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. Dynamic contrast ratio of 100,000: 1 is achieved by special control of the LEDs. In manufacturing technology The display of this model is implemented LED backlight.
The SDL400FY panel (QD0-C00) (05) REV.R1 and the software of the motherboard 5800-A7N02G-0P00 provide viewing of broadcasts and films in high quality HD at a resolution of 1920x1080 pixels in a graphical decomposition according to the standard 1080p (Full HD).
Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG.
The power of the sound system 12 W (2x6 W) provides 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, HDMI x2, MHL, USB. An output for connecting headphones is provided. The digital tuner is capable of receiving television channels in the standards DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2.
Overall dimensions: with stand 907x566x215 mm, without stand 907x523x52 mm.
The mass of the TV: 8.2 kg.
Attention! The panel of the SDL400FY (QD0-C00) (05) REV.R1 of the AIWA 40LE7120 LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.