Technical description and composition of the SONY KDL-49WE755 TV, panel type and applicable modules. The composition of the modules.SONY LED
Model: KDL-49WE755
Chassis / Version: BLM
Panel: NS7S490HNO11
LED backlight: 4-595-781 LB49013 V2_00 32 LED (4x8) 6V
LED driver (backlight): 1-981-456-11 (173638711) A2165993A
PWM LED driver: BD9423EFV
MOSFET LED driver: D2910
Power Supply (PSU): ACDP-100D03 Adapter 19.5V
MainBoard: 1-981-541-21 (173641421) A2188948B BLM
IC MainBoard: MT5581SSEJ, D4758GG
Tuner: CE251ZP
Control: IR: 1-981-927-11, WiFi: DNUR-SY3 1-458-959-13
Technical Specifications KDL-49WE755
SONY KDL-49WE755
General repair guidelines for TV LCD LED
Possible manifestations of defects
- SONY KDL-49WE755 does not turn on, does not respond to buttons and remote control, indicators on the front panel do not light up and do not blink.
In such cases, the ACDP-100D03 power supply is usually faulty.
The TV is equipped with an external ACDP-100D03 Adapter 19.5V power supply, which the owner can purchase independently without repair, however, it is often easy to open and eliminate the simplest typical defects. It is necessary to verify the presence of its output voltages and, if they are completely absent, check the power switches and rectifier diodes 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 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. PWM controllers, in the absence of visible damage or explicit short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
The faulty usually in these cases is the backlight matrix (LED-panel). The reason can sometimes be in the power of the LEDs, but more often in their malfunction (breakdown or break), sometimes in the violation of the contact connections of the LED strips.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- 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 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). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - MT5581SSEJ, and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
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 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.
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-49WE755:
Installed matrix (LED-panel) NS7S490HNO11.
The LED driver 1-981-456-11 is used to power the backlight LEDs, it is controlled by the BD9423EFV PWM controller. As power elements of the LED driver, keys of the D2910 type are used.
To power all the internal components of the SONY KDL-49WE755 TV, an external source such as ACDP-100D03 Adapter 19.5V is used.
MainBoard - the main board (motherboard) is a module 1-981-541-21, using microchips MT5581SSEJ, D4758GG and others.
The CE251ZP tuner provides TV reception and channel tuning.