Hello.
I have a problem with my Asus X540YA PC, it starts and shutdown immediately after 5 seconds.
Unfortunately I did not find the diagram of this motherboard (X540YA rev 3.0 motherboard, DAXKAFMB6E0 REV:E) and it is hard for me to find the real problem.
I identified that all the voltages are good (5V, 3.3V, 0.9V, 1.5V, 1.8V) except those of the CPU.
During the few seconds of starting the power consumption is 20 mA (no shortcut).
I have read the BIOS and its contents is good.
I think my problem is the absence of +12VSUS signal. The problem is that I do not understand how this voltage is generated, it seems to come from a network of shottky diodes (BAT54SDW) but I do not understand the voltage that I have noted.
Below (photo 1) are the voltage that I note on this diode network on an assembly found on another Asus motherboard but which seems to use this same piece of assembly.
I tested the diode array, without removing it from the board, and the diodes seem good except maybe the diode on pin 1 because the measurement with pins 2,4 and 6 indicates a capacitance of 95 nF with an ERS= 16 ohm. I don't know if this is normal considering that the component is soldered on the motherboard.
I don't understand how this diode network works, I have the impression that input 1 (5V = +5VSUS) is correct. But what do you think about the voltage -9,7V on pin 6 ?
In any case the result is that there is 0V on the output pin 5 which gives +12VSUS.
Other mesure on the motherborad on photo 2.
Thank you for your help.
I have a problem with my Asus X540YA PC, it starts and shutdown immediately after 5 seconds.
Unfortunately I did not find the diagram of this motherboard (X540YA rev 3.0 motherboard, DAXKAFMB6E0 REV:E) and it is hard for me to find the real problem.
I identified that all the voltages are good (5V, 3.3V, 0.9V, 1.5V, 1.8V) except those of the CPU.
During the few seconds of starting the power consumption is 20 mA (no shortcut).
I have read the BIOS and its contents is good.
I think my problem is the absence of +12VSUS signal. The problem is that I do not understand how this voltage is generated, it seems to come from a network of shottky diodes (BAT54SDW) but I do not understand the voltage that I have noted.
Below (photo 1) are the voltage that I note on this diode network on an assembly found on another Asus motherboard but which seems to use this same piece of assembly.
I tested the diode array, without removing it from the board, and the diodes seem good except maybe the diode on pin 1 because the measurement with pins 2,4 and 6 indicates a capacitance of 95 nF with an ERS= 16 ohm. I don't know if this is normal considering that the component is soldered on the motherboard.
I don't understand how this diode network works, I have the impression that input 1 (5V = +5VSUS) is correct. But what do you think about the voltage -9,7V on pin 6 ?
In any case the result is that there is 0V on the output pin 5 which gives +12VSUS.
Other mesure on the motherborad on photo 2.
Thank you for your help.
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