Monday 9 March 2020

REPAIR / SERVICING TV SONY KDL-42W653A

Technical description and composition of the TV SONY KDL-42W653A, type of panel and applicable modules. The composition of the modules.
SONY LED
Model: KDL-42W653A
Chassis / Version: RB1G_LW_FHD
Panel: T420HVF04.2
LED backlight: 74.42T31.002-0-DX1
LED driver (backlight): ST420AU-4S01 Rev1.0
PWM LED driver: BD9492
MOSFET LED driver: STU30N01,
Power Supply (PSU): ACDP-120N01 Adapter 19.5v 6.2a
MainBoard: 1-888-390-11 BLE A1955079A
IC MainBoard: CXD4748GB, CXD4743GB, NAND: TC58NVG3S0FTAI0
Tuner: A1951270A TU
Control: RM-ED053 149199511
Technical Specifications KDL-42W653A
SONY KDL-42W653A
General repair guidelines for TV LCD LED
Repair and diagnostics of any electronic device, in particular SONY KDL-42W653A, it is advisable to start with a careful external examination of internal and external elements. Many visible changes in the state of the elements make it possible to determine the further direction of troubleshooting and localization of the defect. Swollen electrolytic or cermet capacitors, charred resistors, ring cracks in the soldered terminals of the elements - all this can significantly help the master to determine the causes and consequences of the malfunction of the TV.
In the case when the KDL-42W653A does not turn on, does not respond to the remote control and front panel buttons, does not blink bulbs and does not show any signs of operability, the ACDP-120N01 19.5v 6.2a power supply module is probably faulty in this case. If it is serviceable with such manifestations, it is necessary to check the power supply stabilizer (converter) of the processor on the motherboard. When repairing the power supply, it is advisable to start the diagnostics by checking the mains fuse and the electrolytic capacitors of the filters of the converter secondary rectifiers. In the event of a fuse breaking, the reason should be sought in the power semiconductor elements of the pulse converter of the main power supply. First of all, it is necessary to check the diodes of the bridge of the rectifier of the mains voltage and the power switch (s) of the converter.
It should be remembered that in the practice of repair, usually the power switches in switching power supplies (SMPS) do not fail due to their poor quality and, in such cases, it is necessary to look for the cause that led to a malfunction and provoked a breakdown of the key. Most often, the culprits of the accident are dried electrolytic capacitors or dangling resistors in the primary circuit, or the PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuits.
If the SONY KDL-42W653A does not have an image, but there is sound, the backlight LEDs on the T420HVF04.2 panel or their power converter may malfunction. You should also make sure that the electrolytic capacitors of the secondary rectifiers of the common power supply are working.
Often there is a need for disassembling the panel to check the health of the LEDs, as well as contact connections in the connectors and soldering.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source.
In cases of attempts to repair the BLE A1955079A motherboard, it is necessary to check the operability of the stabilizers or power converters of its microcircuits and, if possible, update the software (software). BGA chips can in most cases be diagnosed by local heating.
Before changing the A1951270A TU tuner, if it is not possible to tune to television channels, make sure that there are supply voltages, including varicap power (30-33V), which must be measured at the corresponding tuner terminals.
Attention to the owners! Attempts at self-repair of the SONY KDL-42W653A TV are not recommended by the manufacturer and can lead to serious negative consequences!


Service manual / Schematic Diagram ------------------>   Sony KDL-32W600A/603A/W605A/607A/650A/651A/653A/654A/655A/656A/658A/670A/674A, KDL-42W650A/651A/653A/654A/655A/656A/657A/658A/670A/674A. CHASSIS  RB1G


 The appearance of MainBoard 1-888-390-11 is shown in the figure below:
1-888-390-11
1-888-390-11 can be used in TVs:
SONY KDL-42W653A (Panel T420HVF04.2), SONY KDL-50W656A (Panel T500HVF03.0).
The appearance of the power supply
Main features of the device SONY KDL-42W653A:
The matrix (LED panel) T420HVF04.2 is installed.
The LED driver ST420AU-4S01 is used to power the backlight LEDs, it is controlled by the BD9492 PWM controller. As power elements of the LED driver, keys of the STU30N01, type are used.
To power all the internal components of the SONY KDL-42W653A TV, an external source such as ACDP-120N01 Adapter 19.5v 6.2a is used.
MainBoard - the main board (motherboard) is a 1-888-390-11 module, using CXD4748GB, CXD4743GB, NAND: TC58NVG3S0FTAI0 and others.
The A1951270A TU tuner provides TV reception and channel tuning.