Steve T wrote:
> Running XP-SP3 with all updates current. I have a WACOM tablet, driver is
> latest version plugged into a USB port in rear of DELL PC. I'll boot up and
> get error message,"USB device not recognized...". I check Device Manager and
> no flags are showing. I simply plug into another USB port and I get message
> that "Human Interface Device found" and my tablet now works. The next day I
> boot up and the same error message pops up and the fix is to reverse what I
> did the previous day, just plug back into yesterday's "bad USB port". Any
> ideas what I am chasing here? Thank you, Steve T.
>
I don't know what exactly your problem could be, and the following are
just some leads to tools and suggestions.
*******
Implicit in what you're saying here, is unplugging it and plugging it
into the *same* port, isn't getting the device recognized. That you
have to change ports for it to work.
To test Russ's theory that the issue is electrical, try unplugging it
for two minutes (sufficient time for a Polyfuse to recrystallize), then
plug it into the *same* port. If it malfunctions on the same port again,
the implication would be it is a software problem.
In terms of overcurrent protection on a port, on a desktop it is likely
to be implemented in pairs. The connectors on a "stack of two" USB ports
are likely connected to the same Polyfuse. Moving the USB cable from one
port in a "stack of two", to the other, should not materially affect the
electrical powering situation, and if there was an overcurrent problem, the
misbehavior should continue once you move from one port in the stack
to the other. All my motherboards here are fused in such a way. Laptops
seem to be different, in that a laptop may use a silicon device for
controlling overcurrent, and a small 8 pin DIP cuts off the current.
Laptops should be much more precise about overcurrent, as a result.
And the laptop policing of current flow, should be separate for each
port.
I haven't tried looking through the registry for it, but USB
devices are remembered from one usage to another. For example, if
the USB device has a serial number, then Windows can give a more consistent
response to the device, as it would recognize it had been used before.
If a device doesn't have a serial number, then each plug-in causes
re-installation (perhaps using built-in software stacks such as
HID or USB Mass Storage).
You can look in the file "setupapi.log" and see installation activity
at work.
You can also use UVCView, to look at the config data coming from the device.
I doubt that is going to help in this case, because all you're going to
see, is no endpoints set up for the failed case, and endpoints set up
in the success case. (UVCView is a Microsoft program, no longer offered
for download. The copies on archive.org were also removed, presumably
at Microsoft's request.)
*******
ftp://ftp.efo.ru/pub/ftdichip/Utilities/UVCView.x86.exe
http://www.users.on.net/~fzabkar/USB_IDs/UVCView.x86.exe
File size is 167,232 bytes.
MD5sum is 93244d84d79314898e62d21cecc4ca5e
This is a picture of what the UVCView info looks like.
http://www.die.de/blog/content/binary/usbview.png
Some information on the parameters seen in UVCView.
http://www.beyondlogic.org/usbnutshell/usb5.htm
*******
That leaves some kind of registry issue. There are some
troubleshooting suggestions here, for various sets of
symptoms.
http://www.uwe-sieber.de/usbtrouble_e.html
An example of removing USB so all devices can be
rediscovered, is detailed here.
http://www.usbman.com/Guides/Cleanup Device Manager Safe Mode.htm
Paul