The Amber Light

Those that know me well will know that I hate random lights on when I am trying to sleep and this is the tale of the motherboard that refused to turn off.

For the last few weeks, I have been upgrading my PC and although it is not yet done (still need to get more RAM, a new I/O panel and whatnot) the computer itself turns on and works fine although it is a very loud device (the I/O panel has a temperature sensor on it to fix this).

With the upgrading now nearly being done and having used a needed update, I decided I might as well try the Final Fantasy XIV beta to see if it ran. It ran perfectly I really could not fault it (my review on Final Fantasy XIV will be the Playstation 3 version) and after playing it with my brother for a while I decided to call it a night and go to bed.

So I shut down the computer, take out the plug and then walk over to the bed when I noticed something – the motherboard light was still on. Thinking that it was likely just some static or something I decided to nod off thinking little of it. A few hours later my brother woke me up and says.

Laying in bed

Me: “Eh, what you mean.”

Brother: “The light is on.”

Me: “Then turn it off.”

Brother: “I can’t.”

Me: “Just remove the power cord from the PC.”

Brother: “I have. It really will NOT turn off.”

So forcing myself out of bed with a somewhat confused face I wonder over to my PC and my brother was right – the PC was still powered on and better yet the Serial ATA drive was still powered, the keyboard and mouse was still powered and even the USB wifi was still powered.

Yes, my computer was still on with no physical power cord being plugged in. Having now getting slightly worried that my upgraded PC may suddenly burst into flames we decided to have a look and there was nothing inside it that we could see that could explain why it is still powered up.

... I need a new mobile phone.
… I need a new mobile phone.

With this in mind I decided to go back to sleep. Well about five hours later I got woken up again with my brother saying it is still on and that searched online and the error is a Dell message saying the motherboard is broken. Being confused as it is a brand new motherboard and the fact it is not getting any power, I decided to have another look in the hope I could find out why or at least disconnect the drives before they started to spin like mad.

So to recap this computer has been unplugged for about 6-7 hours and the power light is still on and that I tried to remove the static. Well it seems after a while from poking around and trying to see what is wrong with it, the computer was still actually getting power from a very unlikely source and wait for it …. the USB port.

Now if you know anything about computers, you will know that a computer USB’s works in “usb host controller” mode. This means the computer will give power for any device that is connected to it and for some reason, some unknown reason the computer was being powered by a different device.

So having removed all USB cables I found the one that was doing it – the Onlap Monitor which still had a lot of battery power in it.

So there you have it. I spent all night in a half-worried state my computer would suddenly set on fire when it was being powered by a monitor that had a battery although I do not recall a USB host controller can even ACCEPT power from a different device.

Need to reference?

Ellis, M. (2013). The Amber Light. [online] Snat's Narratives & Tales. Available at: [Accessed 07 Dec 2023].

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Richard Lawrence

That’s not fair, your machine suddenly does something impossible, and my PSU dies on the same night.

Still, WOW, I didn’t know that was possible, I wouldn’t have thought there would be enough power through a USB port to power an entire SFF Desktop.


Join the club. However I do not know if I stress it if it will last, I would imagine it will die a slow painful death.

What I am confused about is HOW is it powering up via a USB cable – USB hosts don’t do that to what I recall.

Richard Lawrence

Twilight Zone, that’s what it was, you got some of that Twilight Zone mist on your desktop.


I have actually long worked out what was happening πŸ˜‰