Faint but noticable sound when Laptop is shut down.

[Mayes]

My laptop, ASUS X550JX-DM266T, makes a very feint but noticable sound.. almost like a component is pulsing electicity but with a noise, i can't explain it and i don't know what it is but it's annoying.

The sound doesnt happen while laptop is being charged or is connected to the power supply, but once i let it run only on battery the sound is back. The sound also dissapear when the laptop is On (maybe the sound becomes suppressed or changes into a different sound alltogether, i dont know)

The sound occurs on the front left side of the laptop, under the hood so to speak.

Anyone else has/had this problem? What can it be?

 

[kanewolf]

Could it be the hard drive spinning down? That would possibly make a noise that decreases in pitch over time as the drive slows.

 

[Mayes]

I dont think so but i guess its possible, the sound keeps pulsing through out the time the laptop is running on batteries - mind you, when its shut down, not even sleep mode. :X

 

[Marius_20]

I have an Elitebook 1030 G1. Has the same faint electrical whining when shut down/sleep but only when on batery power. As soon as I connect the charger the noise is gone. Have spoken with an electronics guru. He told me that it is a coil whine from the switching power supply that monitors when the power button is pressed in order to start the laptop. He also told me that it is a different circuit battery/ac power, so that is why only when on battery I can hear it.