Monday 9 March 2020

REPAIR / SERVICING TV SONY KDL-40W705C

Technical description and composition of the SONY KDL-40W705C TV, panel type and applicable modules. The composition of the modules.
SONY LED
Model: KDL-40W705C
Panel: NS5S400VND11
LED backlight: 4-564-297 - LM41-00111A
T-CON: 15Y-S40FF11MB7S4LV0.1
LED driver (backlight): 1-894-073-11 - 173532911
PWM LED driver: BD9397EFV
MOSFET LED driver: MBR5U100
Power Supply (PSU): Adapter
MainBoard: 1-894-792-21 - 173566021 BAXL2
IC MainBoard: CXD4748GB, CXD4743GB, TH58NVG3S0HTAI0, YDA179-S
Tuner: 1-894-336-12 - 173543312
Control: IR: 1-894-388-11 - 173546511, Wi-fi: J20H076
Technical Specifications KDL-40W705C
SONY KDL-40W705C
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The SONY KDL-40W705C TV does not turn on, the indicators on the front panel do not light up and do not blink. The remote control does not respond to the control buttons.
With such manifestations, the Adapter power module usually fails.
The owner of the TV can purchase an external power supply unit such as Adapter and repairing it is not always advisable. In any case, the simplest typical defects characteristic of most IIP schemes can be easily detected and eliminated after opening. It is necessary to measure the output voltages in the secondary circuits, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. The PWM chip can also cause a malfunction of the power switch of the converter and is checked by replacement.
- There is no image, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately disappears
The most likely in these cases is a malfunction of the LED backlight. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
To check the LED lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 1-894-792-21 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuit 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 board - CXD4748GB, TH58NVG3S0HTAI0, YDA179-S. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
The malfunction of the tuner 1-894-336-12 - 173543312 is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
TV users and owners need to remember that attempts to self-repair a SONY KDL-40W705C TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!

Service Manual 40 pages of 2015 for  the ------->  KDL-32W705C, KDL-40W705C, KDL-40W705C / 9, KDL-48W705C, KDL-48W705C / 9.

The appearance of MainBoard 1-894-792-21 is shown in the figure below:
1-894-792-21
1-894-792-21 can be used in TVs:
SONY KDL-40W705C (Panel NS5S400VND11), SONY KDL-32W705C (Panel T320HVN05.3).
Main features of the device SONY KDL-40W705C:
Installed matrix (LED panel) NS5S400VND11.
The matrix control uses the Timing Controller (T-CON) 15Y-S40FF11MB7S4LV0.1.
The LED driver 1-894-073-11 is used to power the backlight LEDs, it is controlled by the BD9397EFV PWM controller. As power elements of the LED driver, keys of the MBR5U100 type are used.
To power all the internal components of the SONY KDL-40W705C TV, an external adapter type source is used.
MainBoard - the main board (motherboard) is a 1-894-792-21 module, using CXD4748GB, CXD4743GB, TH58NVG3S0HTAI0, YDA179-S and others.
The tuner 1-894-336-12 - 173543312 provides reception of television programs and tuning to channels.