Re: Connecting to USB port shuts off computer
Digger wrote:
> This just started happening about a week ago. When I try to connect my iPod
> or cell phone via their respective cables to the USB ports the computer shuts
> off. I've done a system restore and checked the Device Manager and nothing
> seems to have the answer.
You are overloading +5VSB coming from the power supply. If the motherboard
is old enough, there will be a USBPWxx jumper header, where you can
switch between using +5VSB or +5V for the USB port. +5V has more amps
to offer, so using +5V will not cause the computer to reset.
The +5VSB not only powers part of your computer, but is also
part of the "PS_ON#" signal from motherboard to PSU. If +5VSB
is flattened (by being shorted), then the power supply will
switch off.
The iPod may be attempting to draw battery charging current.
As a test, you can try plugging something other than an
iPod, such as a mouse, as it only draws 100mA or less. If
the computer stays running, then you'd have a suspicion
that either the power supply is weak, or something else
in the computer is using more than its share of +5VSB.
The +5VSB rating is printed on the label on the side
of the power supply. My brand new supply, is rated for
+5VSB at 3 amps, a bit stronger than the old supply.
A motherboard might typically use 1 amp while the
computer sleeps, from that rail, but modern
motherboards also run the USB ports from that
rail, and that could potentially lead to an
overload, if you have stuff like USB scanner,
USB ADSL modem, iPod or other stuff that are
known current hogs.
Paul