Friday 6 March 2020

REPAIR / SERVICING TV SONY KDL-32WD752

Technical description and composition of the SONY KDL-32WD752 TV, panel type and applicable modules. The composition of the modules.
SONY LED
Model: KDL-32WD752
Chassis / Version: BBE 1-980-335-23
Panel: S320HF58 V5
T-CON: HV320FHB-N80 47-6021073; HX8894-C, i7991, RT6914
LED driver (backlight): integrated into MainBoard
PWM LED driver: BD9423EFV
MOSFET LED driver: D2910
Power Supply (PSU): Adapter AC / DC 19.5V
MainBoard: 1-980-335-23 173587123
IC MainBoard: CPU: MT5566CQVT, NAND: TC58NVG2S0HBAI4
Tuner: CE251ZP
Technical Specifications KDL-32WD752
SONY KDL-32WD752
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The SONY KDL-32WD752 TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
Most often, with such manifestations, the main adapter power module is found to be faulty.
This TV model is equipped with an external power adapter adapter AC / DC 19.5V, which the owner can purchase independently, and repairing it may not always be advisable, however, sometimes there is some reason to open it and eliminate simple typical defects typical of IIPS . 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 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.
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 the excess of maximum current or voltage values. 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.
Often in such cases, there is no 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 is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V for them. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the black to the cathode. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the motherboard 1-980-335-23 should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, update or replace the software (software). If it is not possible to replace the MB board (SSB), you need to check the health of its elements - CPU: MT5566CQVT, NAND: TC58NVG2S0HBAI4. Defective components should be replaced.
If there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the voltage of the CE251ZP tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
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.



Firmware  T-CON GT24C32B ----------------->  SONY KDL-32WD752 T-CON HV320FHB-N80  
BBE 1-980-335-23, Main: 1-980-335-23 173587123, Panel: S320HF58 V5
 
 
 The appearance of MainBoard 1-980-335-23 is shown in the figure below:
1-980-335-23
Main features of the device SONY KDL-32WD752:
Installed matrix (LED-panel) S320HF58 V5.
The matrix control uses the Timing Controller (T-CON) HV320FHB-N80.
To power the backlight LEDs, a converter is used, combined with the main board 1-980-335-23, 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-32WD752 TV, an external adapter type AC / DC 19.5V is used.
MainBoard - the main board (motherboard) is a module 1-980-335-23, using CPU chips: MT5566CQVT, NAND: TC58NVG2S0HBAI4 and others.
The CE251ZP tuner provides TV reception and channel tuning.