Luminous Landscape Forum

Equipment & Techniques => Computers & Peripherals => Topic started by: PeterAit on March 18, 2016, 09:39:04 am

Title: USB port question
Post by: PeterAit on March 18, 2016, 09:39:04 am

I got a new SD card reader and unlike the old one it has a pilot light. The pilot light is on all the time, even when the computer is off. What gives?

Title: Re: USB port question
Post by: brianrybolt on March 18, 2016, 09:56:00 am

For whatever reason, it's telling you it's there and ready to be used.  Quien Sabe?

Title: Re: USB port question
Post by: Chris Livsey on March 18, 2016, 11:33:35 am

PSUs have a +5V Standby rail which is always on even if computer is off, and most mother boards use it for powering USB devices so they can charge on power off. The supply is also usually to the onboard LAN adapter and PS/2 ports to allow wake on LAN and keyboard.
The configuration is various, it may be BIOS controlled, jumpers on the board or power settings if you want to change it, alternatively you could just really turn off the power at the main switch.

Title: Re: USB port question
Post by: degrub on March 18, 2016, 10:57:53 pm

Some USB ports will remain on. Others turn off when the machine shuts down.

Frank

Title: Re: USB port question
Post by: E.J. Peiker on March 23, 2016, 03:14:38 pm

MBs that have the powered USB when the computer is off feature usually have a BIOS setting that allows you to turn it off.