Tuesday 10 March 2020

REPAIR / SERVICING TV SONY KDL-49WD757

Technical description and composition of the TV SONY KDL-49WD757, type of panel and applicable modules. The composition of the modules.
SONY LED
Model: KDL-49WD757
Chassis / Version: 1-980-335-12
Panel: S490HF58 V1
T-CON: 47-6021080 20150915 HV490FHD-N8K
LED driver (backlight): integrated into MainBoard
PWM LED driver: BD9423EFV
MOSFET LED driver: D2910
Power Supply (PSU): Adapter AC / DC 19.5V ACDP-100D02
MainBoard: 1-980-335-12 A2103243A
IC MainBoard: CPU: MT5566CQVT
Tuner: CE243ZP
Technical Specifications KDL-49WD757
SONY KDL-49WD757
General repair guidelines for TV LCD LED
Possible malfunctions
- SONY KDL-49WD757 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.
Failure in such cases should begin to look in the adapter power supply circuits.
The power source in this model is an external Adapter AC / DC 19.5V ACDP-100D02, usually TV owners can purchase them on their own, and repairing them may not be practical. But sometimes it’s easy to open the block and eliminate simple typical defects that are characteristic of most IIPs. It is necessary to measure its output supply voltage, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in semiconductor PN junctions.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM), if they do not have visible damage to the chassis and open short circuit between the terminals, are usually checked by replacement.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
The most likely in these cases is a malfunction of the LED backlight. More often the reason for this is the breakdown of the LEDs, or poor contact in the connectors of the strips, less often the LED driver may be faulty.
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 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 1-980-335-12 should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, update or replace the software (software). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing CPU elements: MT5566CQVT requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
In the absence of tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltages at the terminals of the CE243ZP tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Attention to users! Self-repair of a SONY KDL-49WD757 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!



The appearance of MainBoard 1-980-335-12 is shown in the figure below:
1-980-335-12
Main features of the device SONY KDL-49WD757:
Installed matrix (LED-panel) S490HF58 V1.
The matrix control uses the Timing Controller (T-CON) 47-6021080.
To power the backlight LEDs, a converter is used, combined with the main board 1-980-335-12, 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-49WD757 TV, an external adapter type AC / DC 19.5V ACDP-100D02 is used.
MainBoard - the main board (motherboard) is a module 1-980-335-12, using CPU chips: MT5566CQVT and others.
The CE243ZP tuner provides television reception and channel tuning.


Brand: SONY, Model: KDL-49WD757.
Briefly from the TV: LCD, LED backlight, 49 ", 1920x1080, 1080p Full HD, DVR, sound: 20W, HDMI: 2, Internet access, Wi-Fi, Smart TV.
On the official site of Sony there is firmware (Firmware) - updating the software to version v8.219 from 07/03/2019.
The composition uses MainBoard 1-980-335-12 (173587112) A2103243A and LCD-panel (matrix) S490HF58V1.
Power Supply Unit (PSU) ACDP-100D02 Power Supply adapter.