No announcement yet.

USB hub is powering CPU fan.

  • Filter
  • Time
  • Show
Clear All
new posts

  • USB hub is powering CPU fan.

    Well I have come across a very strange problem after I started using my powered USB hub today. When I shutdown the computer the CPU fan slows but doesn't completely stop. The only other thing that was getting power was the USB hub, so I unplugged it and sure enough, the fan stopped! I plugged the hub back in and the fan starts up again! If I shutdown the computer and start it back up the computer wont reboot unless I turn it back off, unplug and replug the hub then turn the computer back on. Has anyone heard of this before?

  • #2
    Usually guys tap the 5VDC for the USB HUB off their PSU, so when the PSU goes off, power is removed from the hub as well.


    • #3
      From where is the USB Hub receiving power? If its from a source separate from the PSU, you may need to consider either powering it from there or using a relay to cut power once the computer shuts down.


      • #4
        A tip: put a diode or small relay in between your USB cable (or maybe cut the power completely)...

        Good luck!

        List of front-ends/usefull apps
        XTroniC | XTroniC Direct


        • #5
          Thanks for the replys. The computer is in its testing phase on the bench at the moment and eventually the hub will be powered off the PSU. I was just a bit concerned in the mean time that the hub is feeding power back into the computer while it is off, ill just have to make sure the hub is off when the computer is. The hub is just plugged into the wall. I like the idea for the diode, very clever.