Monday 9 March 2020

REPAIR / SERVICING TV SONY KDL-43W755C

Technical description and composition of the TV SONY KDL-43W755C, type of panel and applicable modules. The composition of the modules.
SONY LED
Model: KDL-43W755C
Panel: V430FWME01
LED backlight: EVERLIGHT LBM430M1403-AA-2 (HF) (0) (L) / (HF) (0) (R)
T-CON: T550HVN08.2 CTRL BD, 55T23-C03
LED driver (backlight): 15STM6S-ABC02 Rev1.0
Power Supply (PSU): ACDP-100D01 ACDP-100A1A Adapter 19.5V 5.2A
MainBoard: 1-893-880-21 (173525521) BMX
IC MainBoard: KLMAG2GEND-B031, BD28620MUV
Tuner: CE241ZP
Control: Remote: RMT-TX100E, IR: 1-894-388-11 173546511, Wi-fi: AK8J20H084AC J20H084AC
Technical Specifications KDL-43W755C
SONY KDL-43W755C
General repair guidelines for TV LCD LED
Possible manifestations of defects
- SONY KDL-43W755C does not turn on and does not show any signs of performance at all. Does not blink indicators and does not respond to control buttons.
In such cases, the ACDP-100A1A power supply is usually faulty.
External power supply ACDP-100A1A ACDP-100D01 Adapter 19.5V 5.2A is not always subject to repair, especially since the owner can purchase it on their own. 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, check the operability of the power switches of the converters and rectifier diodes for the probability of a 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 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, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The indicator blinks or glows constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the 1-893-880-21 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). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its KLMAG2GEND-B031, BD28620MUV chips and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
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 CE241ZP tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
We recommend the owners of the KDL-43W755C TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!




The appearance of MainBoard 1-893-880-21 is shown in the figure below:
1-893-880-21
The appearance of the power supply
Main features of the device SONY KDL-43W755C:
Installed matrix (LED panel) V430FWME01.
The matrix control uses the Timing Controller (T-CON) T550HVN08.2.
The LED driver 15STM6S-ABC02 is used to power the backlight LEDs.
To power all the internal components of the SONY KDL-43W755C TV, an external source such as ACDP-100D01 ACDP-100A1A Adapter 19.5V 5.2A is used.
MainBoard - the main board (motherboard) is a module 1-893-880-21, using microchips KLMAG2GEND-B031, BD28620MUV and others.
The CE241ZP tuner provides TV reception and channel tuning.