when I boot my pi, everything is fine, but when I connect any usb device(they worked before), it just turns off and only will show the red light and a faint green glow for about 3 mins until it works again.

My usb devices are:

  • Nexxtech keyboard and mouse combo
  • tp-link WN725N
  • As i said below, it was working for about 1 year, also i didn't change the usb devices at all @RpiUser123
    – patrick
    Jul 13, 2014 at 20:32
  • The Pi does tend to reboot when you plug USB devices in, particularly those with a slightly higher power draw.
    – recantha
    Jul 29, 2014 at 5:00

2 Answers 2


To improve on Enes' answer a bit, the Pi has regulators that will kill the Pi to protect the circuitry if a surge is detected.

Hot-plugging (plugging in a USB device while the host device is running) will cause a sudden jump in current requested, which often will trip these regulators.

This is a known issue, especially with a less powerful PSU. You can combat this by using a more powerful PSU, one that has a higher amperage because a higher amperage is a stronger current; stronger current means better chance of continuous power when more power is requested.

Another thing you can do to stop this from happening is to use an externally powered USB hub, externally and powered being very crucial. This method works because instead of pulling power for the Pi's components (SoC, Ethernet, USB ports, etc.,) all of the power can be used for the USB devices.


Wireless adaptors needs very high current. Raspberry pi can not supply enough current for them. Use this wireless adaptor with a external powered Usb Hub.

  • it worked before
    – patrick
    Jul 13, 2014 at 14:15
  • Did you change the power supply of pi?
    – Enes Genc
    Jul 13, 2014 at 16:55
  • no, i didn't change the pi
    – patrick
    Jul 13, 2014 at 20:32
  • The power supply could have gone bad. Like @EnesGenç suggest, try another power supply.
    – PhillyNJ
    Jul 13, 2014 at 23:08
  • I think it did go bad
    – patrick
    Jul 15, 2014 at 15:23

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