Saturday 7 March 2020

REPAIR / SERVICING TV SONY KDL-40NX720

Technical description and composition of the SONY KDL-40NX720 TV, panel type and applicable modules. The composition of the modules.
SONY
Model: KDL-40NX720
Chassis / Version: AZ2F
Panel: LSY400HF01 // FDLL400NT01 A-1808-274-A
T-CON: EDL_4LV0.3 FDLL400NT01 SM4109, ISL24835
Inverter (backlight): LDBLK
PWM Inverter: BD9276EFV, 2904 (8), 1045 (8),
MOSFET Inverter: R5005
Trans Inverter: TSE50A239 FIS
Power Supply (PSU): APS-239 / W (CH) G4 1-883-924-12
PWM Power: MIP2H2 (7),
MOSFET Power: P9NK50ZE, K5A50D, FL4037
MainBoard: BAT_L 1-883-754-21
IC MainBoard: RTL8201ES, TDK 6T213LF, CXD4727GB, Si19287BCNU, GL850G MN1GD07G21, PS54425, D9583D (32), RP1E070 (6)
Control: RM-ED044
Technical Specifications KDL-40NX720
SONY KDL-40NX720
General recommendations for repairing TV LCD
Repair of a SONY KDL-40NX720 TV is advisable to start with an external inspection of all its constituent elements, both internal electronic components and external. Inspection is also subject to body elements, control buttons, screen, connectors and cords. Many visible signs make it possible to determine the future 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.
If the power supply module APS-239 / W (CH) G4 1-883-924-12 is malfunctioning, the external manifestations may be different, for example, the SONY KDL-40NX720 does not turn on at all and there is no indication of the control lights on the front panel. It is advisable to start the troubleshooting of the power supply module by checking the mains fuse. If it is broken, it is necessary to check first of all the power semiconductor elements - rectifier diodes and the power switch of the P9NK50ZE, K5A50D, FL4037 converter, which are often found in a breakdown state in such situations.
The reasons for the breakdown of the power switch of the flyback converter of the power module can be different, for example, a malfunction of semiconductor cells or electrolytic capacitors in the stabilization circuits of the primary circuit, as well as a failure in the operation of the MIP2H2 PWM controller microcircuit, or broken resistors in its bundle.
When using a power factor correction unit (PFC) in the power modules, troubleshooting becomes somewhat more complicated and requires additional experience and knowledge of their operation.
If when you turn on the SONY KDL-40NX720 there is no image, or it appears for a second and disappears completely, but there is sound, most likely either the backlight or the power converter (inverter) are malfunctioning. It is necessary to check the electrolytic capacitors of the filter of the secondary rectifiers in the general power supply unit.
Often, attempts to repair an LDBLK inverter are hampered by the fact that the fault diagnosis is complicated by the operation of its protection, which is designed to turn off the inverter in emergency conditions - when the lamps are depressurized, breaks or short circuits in high-voltage connections and other emergency situations. Lock protection to localize the defect is popular among repairmen.
In such cases, the risk of failure of the power elements of the inverter is most likely, and special care is required during work, and after their completion, it is necessary to restore the protection circuit for further safe operation of the TV by the owner in normal mode.
In the event of a malfunction, on the BAT L motherboard, first of all, check the operability of all power stabilizers of the microcircuits and, if necessary, update the software (software). Board repair and chip replacement RTL8201ES, TDK 6T213LF, CXD4727GB, Si19287BCNU, GL850G MN1GD07G21, PS54425, D9583D (32), RP1E070 (6) are carried out with the necessary equipment, and the corresponding element base.
Owners and users of the SONY KDL-40NX720 TV must remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!


Service manual / schematic diagram ------------->   Sony KDL-40/46/55NX720 CHASSIS AZ2-F


 The appearance of MainBoard BAT_L is shown in the figure below:
BAT_L
BAT_L can be used on TVs:
SONY KDL-40NX720 (Panel LSY400HF01), SONY KDL-55NX720 (Panel LSY550HJ02), SONY KDL-46HX920 (Panel FQLF460DT01).
The appearance of the power supply
Main features of the device SONY KDL-40NX720:
The matrix (LCD panel) LSY400HF01 or FDLL400NT01 A-1808-274-A is installed.
The matrix control uses the Timing Controller (T-CON) EDL_4LV0.3.
An LDBLK inverter is used to power the backlight, it is controlled by the BD9276EFV PWM controller, 2904 (8), 1045 (8) ,. The transformer TSE50A239 FIS is installed in the inverter converter. As power elements of the inverter, keys of the R5005 type are used.
The necessary supply voltages for all nodes of the SONY KDL-40NX720 TV are generated by the APS-239 power module, or its analogues using MIP2H2 microcircuits (7), and power switches of the type P9NK50ZE, K5A50D, FL4037.
MainBoard - the main board (motherboard) is a BAT_L module, using chips RTL8201ES, TDK 6T213LF, CXD4727GB, Si19287BCNU, GL850G MN1GD07G21, PS54425, D9583D (32), RP1E070 (6) and others.