P4P800-E Deluxe USB
 

I have this board running Win XP SP1 with 1gig of DDR memory. Every now and
then at no particular time frame my USB ports stop working. Any device that
requires power stops. My scanner and printer continue to work. The only way to
get the powered USB devices to work is to reboot the machine.
Any ideas on how to fix this?
TIA
Andy

In article ,
(Sgt Andrew) wrote:

I have this board running Win XP SP1 with 1gig of DDR memory. Every now and
then at no particular time frame my USB ports stop working. Any device that
requires power stops. My scanner and printer continue to work. The only way to
get the powered USB devices to work is to reboot the machine.
Any ideas on how to fix this?
TIA
Andy

The USB ports are protected by polyfuses. These are fuses that open
circuit when they get hot, and close again when they cool off.

The fuses are there to protect against a short circuit on the USB
+5V from damaging the motherboard. Generally, a USB port is allowed
500mA of current, and if it draws more than that, the port will
be powered off.

Check that you aren't using a non-compliant device. An example
is the Alcatel "frog" ADSL modem, which draws slightly more
than 500mA.

If you must use the device in question, a possible work around
is to use a powered USB 2.0 hub to run the device. Sometimes
they are a little more forgiving than a motherboard.

You can see samples of the polyfuses, just above the USB56 and
USB78 headers. It is possible the power is also switched
by MOSFETs somewhere as well (not sure).

Another reason for USB ports to "wink out", is if there is
some kind of power management issue. I think there is an option
somewhere in the Device Manager, to allow Windows to power down
stuff that is not active, and that is another possible source
of your problem. Since your scanner and printer are working, it
isn't likely to be power management.

For your amusement, I found a link to a doc on usbman.org . Usbman
has some info on USB and sometimes has fixes for USB problems. This
doc is from Intel and describes some of the stuff I mentioned above.

http://www.usb.org/developers/whitep...therboards.pdf

HTH,
Paul

Thanks but I don't think thats my problem.
The USB mouse only draws 20ma. and a self powerd hub i have hooked up to a
different USB port stops working. In fact all the USB ports stop working with
any device that requires power.
Andy



I have this board running Win XP SP1 with 1gig of DDR memory. Every now and
then at no particular time frame my USB ports stop working. Any device that
requires power stops. My scanner and printer continue to work. The only way
to
get the powered USB devices to work is to reboot the machine.
Any ideas on how to fix this?
TIA
Andy

The USB ports are protected by polyfuses. These are fuses that open
circuit when they get hot, and close again when they cool off.

The fuses are there to protect against a short circuit on the USB
+5V from damaging the motherboard. Generally, a USB port is allowed
500mA of current, and if it draws more than that, the port will
be powered off.

Check that you aren't using a non-compliant device. An example
is the Alcatel "frog" ADSL modem, which draws slightly more
than 500mA.

If you must use the device in question, a possible work around
is to use a powered USB 2.0 hub to run the device. Sometimes
they are a little more forgiving than a motherboard.

You can see samples of the polyfuses, just above the USB56 and
USB78 headers. It is possible the power is also switched
by MOSFETs somewhere as well (not sure).

Another reason for USB ports to "wink out", is if there is
some kind of power management issue. I think there is an option
somewhere in the Device Manager, to allow Windows to power down
stuff that is not active, and that is another possible source
of your problem. Since your scanner and printer are working, it
isn't likely to be power management.

For your amusement, I found a link to a doc on usbman.org . Usbman
has some info on USB and sometimes has fixes for USB problems. This
doc is from Intel and describes some of the stuff I mentioned above.

http://www.usb.org/developers/whitep...therboards.pdf

HTH,
Paul