Technical description and composition of the SONY KDL-43WE754 TV, panel type and applicable modules. The composition of the modules.SONY LED
Model: KDL-43WE754
Chassis / Version: BLM 1-981-541-21
Panel: LC430DUY (SK) (A1)
LED backlight: NLAW20455 E_R515100560L43F00213NJ
T-CON: 6870C-0718A
LED driver (backlight): 1-981-455-11 173638611 A2165988A
PWM LED driver: BD9423EFV
Power Supply (PSU): Adapter AC / DC 19.5V
MainBoard: 1-981-541-21 173641421 A2188948B
IC MainBoard: MT5581SSEJ, 25Q16, D4758GG
Tuner: CE251ZP
Technical Specifications KDL-43WE754
SONY KDL-43WE754
General repair guidelines for TV LCD LED
Possible malfunctions
- The SONY KDL-43WE754 TV does not turn on, does not respond to the remote control and buttons on the control panel, does not light up or blink indicators.
Most likely in this case, the main switching power supply (IPS) Adapter is faulty.
The owner of the TV can purchase the adapter AC / DC 19.5V external power supply independently, and it’s not always advisable to repair it, but sometimes it makes sense to open it and eliminate the simple defects typical of IPS. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches and rectifier diodes of the converters for a probable 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 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 an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, the screen is black, there is sound, with external illumination of the screen, you can sometimes see barely noticeable outlines of the image.
The most likely in these cases is a malfunction of the LED backlight. Often the cause is a malfunction of the LEDs (open circuit, short circuit ...), or the connectors of the strips (strings), less often the LED driver is malfunctioning.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the motherboard 1-981-541-21 should begin by checking the stabilizers and power converters needed to power the microcircuit 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 MT5581SSEJ, 25Q16, D4758GG and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If you suspect a malfunction of the CE251ZP tuner, first of all, you need to verify the correctness of the software, as well as the presence of the necessary voltage levels and pulses of data exchange with the processor via the I2C bus at 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.
The appearance of MainBoard 1-981-541-21 is shown in the figure below:1-981-541-21
Main features of the device SONY KDL-43WE754:
Installed matrix (LED-panel) LC430DUY (SK) (A1).
The matrix control uses the Timing Controller (T-CON) 6870C-0718A.
The LED driver 1-981-455-11 is used to power the backlight LEDs, it is controlled by the BD9423EFV PWM controller.
To power all the internal components of the SONY KDL-43WE754 TV, an external adapter type AC / DC 19.5V is used.
MainBoard - the main board (motherboard) is a module 1-981-541-21, using microchips MT5581SSEJ, 25Q16, D4758GG and others.
The CE251ZP tuner provides TV reception and channel tuning.