Tuesday 10 March 2020

REPAIR / SERVICING TV SONY KDL-49WD759

Technical description and composition of the TV SONY KDL-49WD759, type of panel and applicable modules. The composition of the modules.
SONY LED
Model: KDL-49WD759
Panel: S490HF58 V0
LED driver (backlight): integrated into MainBoard
PWM LED driver: BD9423EFV
MOSFET LED driver: D2910
Power Supply (PSU): Adapter 19.5V 5.2A ACDP-100D02
MainBoard: 1-980-335-12 (173587112) - A2103243A
IC MainBoard: CPU: MT5566CQVT
Tuner: CE243ZP
Technical Specifications KDL-49WD759
SONY KDL-49WD759
General repair guidelines for TV LCD LED
Possible malfunctions
- The SONY KDL-49WD759 TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
With such manifestations, the Adapter power module usually fails.
The external adapter 19.5V 5.2A ACDP-100D02 power supply is not always subject to repair, especially since the owner can purchase it independently. But, in some cases, it makes sense to open it and eliminate the simple typical defects inherent in converters in pulsed sources. 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 the power switches of the converters and rectifier diodes for the presence of a possible short circuit.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most 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, 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.
Often in such cases, there is no LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- The indicator blinks or glows constantly, the TV does not turn on, 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.
If you suspect a malfunction of the CE243ZP 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 terminals of the tuner.
Attention to users! Self-repair of a SONY KDL-49WD759 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-49WD759:
Installed matrix (LED panel) S490HF58 V0.
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-49WD759 TV, an external adapter type 19.5V 5.2A 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.