bob said:
Hi,
i found my desktop USB no longer functioning after I connect a usb hub to a
usb port connector on the motherboard. Even I remove the usb hub or reset
the cmos/bios settings dosen't help. It seems that no power output from all
the usb ports/usb port connectors. I am sure its hardware related as I have
restored the Windows image and the problem is still there. Anything I can do
now ? My motherboard is Asus P5PL2
thanks in advance
Does your motherboard have Intel ICH5/ICH5R Southbridge ?
They have a known problem, where the USB ports can fail.
This is the only public acknowledgment of a problem. In
the case of one motherboard owner, they got a new chip soldered
to their motherboard.
http://tw2005.giga-byte.com/Motherboard/Support/FAQ/FAQ_456.htm
This is an example of an ICH5 just after failure.
http://farm1.static.flickr.com/99/306837150_34ecdbc9b4_o.jpg
A failure can occur one of two ways. In a catastrophic failure,
the computer will no longer boot. The burn mark will be present
on the chip. That chip normally does not have a heatsink on
top of it, so the burn mark will be visible. The chip would be
in the lower right hand corner of the motherboard.
The burn mark appears above the balls on the bottom of the
chip, that power the USB I/O pads.
If the wires inside burn out first, before significant heat
has built up in that area, the chip may survive. The computer
in that case, continues to boot. If you look in Device Manager,
in the USB section, everything looks OK. But no matter what
USB port you plug into, nothing happens. It is possible
that is what happened to you.
ICH5/ICH5R is the only chip that this happens to with any
frequency. If you have knowledge of what chipset is inside
your computer, you may be able to figure it out. Visually
examining the motherboard, for the presence of that chip,
is one way to check.
Replacing the USB ports, by using a $10 PCI USB2 card,
is a way to work around the failure.
Another way to guess at whether you have something close
to that chip on your computer, is look in Device Manager.
The entries here 24D2, 24D4, 24D7, 24DE are USB1.1 blocks,
while the "Standard Enhanced", if you checked "Properties"
and looked at "Device ID", you might see 24DD on it. This
would hint you have the chip in question. If yours looks different,
then it could be some other problem.
http://www.usbman.com/Guides/checki4.jpg
Paul