Technical description and composition of the SONY KDL-40EX720 TV, panel type and applicable modules. The composition of the modules.SONY LED
Model: KDL-40EX720
Chassis / Version: AZ2F_3a-2
Panel: LTY400HF09 181134011
LED backlight: LJ64-02825A, LJ64-02825B - STS400A28_40LED_rev.3_100903
LED driver (backlight): integrated into PSU + 1-883-300-21 // 1-883-300-11, 1-732-438-11, Y4009550A
Trans LED driver: TSE50A239 FIS
Power Supply (PSU): APS-293 (CH) 1-883-924-12
PWM Power: MIP2H2 (7), CXA3812M, CXA3810M (PFC & PWM resonant)
MOSFET Power: P9NK50ZFP, F5K60M
MainBoard: 1-883-753-93 A1803701C BATV
IC MainBoard: CXD4727GB, K4B2G1646C-HCH9, SIL9287BCNU, GL850G
Control: RM-ED044, IR: A-1792-877-A 1-883-758-11
Technical Specifications KDL-40EX720
SONY KDL-40EX720
General repair guidelines for TV LCD LED
SONY KDL-40EX720 TV, like many other electronic devices, it is advisable to start repairing by inspecting all external and internal elements. It often happens that visible damage to elements or connections helps determine the direction of the troubleshooting. In some cases, faulty elements can be seen with the naked eye, for example, charred resistors or swollen metal-ceramic capacitors, or electrolytic in rectifier filters. Ring cracks formed in the soldered terminals of transformers or heating elements of the circuit are also frequent sources of many malfunctions with a variety of external manifestations.
If the TV does not turn on, no indicators on its front panel are lit or blinking. Also, if the TV does not respond to the remote control and buttons, does not make any sounds or any signs of operability when turned on, there is a certain chance that the APS-293 (CH) 1-883-924-12 power supply module is defective and needs repair. Sometimes with similar manifestations a problem can only occur in the absence of processor power, which is typical for certain SONY models. 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.
If a breakdown of the power switch is detected, it should be remembered that in a switching power supply (IIP) it does not fail by itself without any reasons that should be sought by checking other elements of the primary circuit - electrolytic capacitors, PWM controller MIP2H2 (7), which can be checked only by replacement, as well as other semiconductor elements (diodes, transistors, zener diodes).
If, when you turn on the TV, the image appears and immediately disappears, or is missing initially when you turn on, but the sound has other functions that work, there is a high probability of a malfunction of the LED driver (power converter for the backlight LEDs of the LTY400HF09 181134011 panel). In such cases, the general power module is also subject to verification, in which the electrolytic capacitors of the rectifier filter supplying the LED driver should be checked.
A malfunction in the backlight circuits often occurs due to an open in the power circuit of the LED lines. It requires disassembling the panel and checking the LEDs themselves, the rations of their terminals, as well as the reliability of the connections in the connectors and rations of the terminals.
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.
Motherboard 012544 Rev101 must be checked if there is no reaction to the remote control and function buttons, the standby indicator blinks or lights up continuously. In such cases, if the converters or power regulators of the microcircuit are working, a software update may be necessary.
If it is not possible to replace the MB (SSB) card, you must check the health of its elements - CXD4727CB. Defective components should be replaced.
Owners and users of the SONY KDL-40EX720 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-32EX720/721/723/724/725/726/727/728/729, KDL-37EX720/723/725, KDL-40EX720/721/723/724/725/726/727/728/729, KDL-46EX720/721/723/724/725/726/727/728/729, KDL-55EX720/721/723/725
The appearance of MainBoard 1-883-753-93 is shown in the figure below:1-883-753-93
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the APS-293 module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the CXA3810M & PWM resonant PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the device SONY KDL-40EX720:
Installed matrix (LED-panel) LTY400HF09 181134011.
To power the backlight LEDs, a converter is used, combined with a power supply. The LED driver is equipped with a TSE50A239 FIS transformer.
The necessary supply voltages for all nodes of the SONY KDL-40EX720 TV are generated by the APS-293 power module or its analogs using MIP2H2 (7), CXA3812M, CXA3810M (PFC & PWM resonant) microcircuits and power switches of the P9NK50ZFP, F5K60M type.
MainBoard - the main board (motherboard) is a 1-883-753-93 module, using CXD4727GB, K4B2G1646C-HCH9, SIL9287BCNU, GL850G and others.
