The USB ports on my Thinkpad ( T42 ) have died. XP says they are
working fine but
the don't work at all. I believe the port(s) may have experienced an
electrical short when
plugging in a usb device.

I use the laptop with a docking station where the keyboard and mouse
are hooked up
via usb and the ports do not work with the docking station or when
connected directly
to the laptop itself. I've tried both bus-powered and self powered
devices and neither
work.

I even tried booting a linux distro off CD/DVD. It booted fine but the
USB ports were
dead under linux as well so I'm fairly sure this is a hardware issue.

Is there any sort of current limiting device (i.e. fuse) on the
motherboard or internally
for USB that can be replaced ? Anyone have a similar issue with USB ? A
friend mentioned
replacing the motherboard but the parts and labor add up quick. I
suppose I could
use a cardbus usb adapter but it would be nice to fix this on the cheap
if possible.

<tbalon******.com> wrote in message
news:1162831675.806619.3700@f16g2000cwb.googlegrou ps.com...
> The USB ports on my Thinkpad ( T42 ) have died. XP says they are
> working fine but
> the don't work at all. I believe the port(s) may have experienced an
> electrical short when
> plugging in a usb device.

Some computers have physical fuses in them guarding the +5V line on the USB
port -- you may have blown this fuse if you did short the port.
Unfortuntaely, on a laptop, you'd have to take it apart to replace the fuse,
which would be quite involved.

To test this hypothesis, you might hack up a USB cable such that you can apply
+5V *power* to the USB device from an out-board power supply, but still keep
Gnd, D+, and D- connected back to the laptop.

"Joel Kolstad" <JKolstad71HatesSpam******.com> wrote in message
news:12kvo3gct5ufic5@corp.supernews.com...
> <tbalon******.com> wrote in message
> news:1162831675.806619.3700@f16g2000cwb.googlegrou ps.com...
>> The USB ports on my Thinkpad ( T42 ) have died. XP says they are
>> working fine but
>> the don't work at all. I believe the port(s) may have experienced an
>> electrical short when
>> plugging in a usb device.
>
> Some computers have physical fuses in them guarding the +5V line on the
> USB port -- you may have blown this fuse if you did short the port.
> Unfortuntaely, on a laptop, you'd have to take it apart to replace the
> fuse, which would be quite involved.
>
> To test this hypothesis, you might hack up a USB cable such that you can
> apply +5V *power* to the USB device from an out-board power supply, but
> still keep Gnd, D+, and D- connected back to the laptop.
>

Or try a self powered hub.

"Joel Kolstad" <JKolstad71HatesSpam******.com> wrote in message
news:12kvo3gct5ufic5@corp.supernews.com...
> <tbalon******.com> wrote in message
> news:1162831675.806619.3700@f16g2000cwb.googlegrou ps.com...
>> The USB ports on my Thinkpad ( T42 ) have died. XP says they are
>> working fine but
>> the don't work at all. I believe the port(s) may have experienced an
>> electrical short when
>> plugging in a usb device.
>
> Some computers have physical fuses in them guarding the +5V line on the
> USB port -- you may have blown this fuse if you did short the port.
> Unfortuntaely, on a laptop, you'd have to take it apart to replace the
> fuse, which would be quite involved.
>

Any computer, or hub using fuses in the USB power lines breaches the USB
specifications and is prohibited from being marked with the USB logo.

Para 7.2.1.2.1 of the USB spec specfically states that "The over current
limiting machanism must be self resetting without user mechanical
intervention". Generally this will by a PTC element, though electronic
regulation is permissible.

The spec also requires that the over-current condition is signalled back to
the host port ad that the operating system detects and warns of the
condition.

I am aware of physical damage to the data lines that has given rise to a
port incorrectly signalling an over-current condition. However, this should
not occur by just innadvertantly connecting a data line to the 5v line as
this is how fast and slow devices are detected.

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message
news:4552e647$1_1@glkas0286.greenlnk.net
> "Joel Kolstad" <JKolstad71HatesSpam******.com> wrote in message
> news:12kvo3gct5ufic5@corp.supernews.com...
>> <tbalon******.com> wrote in message
>> news:1162831675.806619.3700@f16g2000cwb.googlegrou ps.com...
>>> The USB ports on my Thinkpad ( T42 ) have died. XP says they are
>>> working fine but
>>> the don't work at all. I believe the port(s) may have experienced an
>>> electrical short when
>>> plugging in a usb device.
>>
>> Some computers have physical fuses in them guarding the +5V line on
>> the USB port -- you may have blown this fuse if you did short the
>> port. Unfortuntaely, on a laptop, you'd have to take it apart to
>> replace the fuse, which would be quite involved.
>>
>
> Any computer, or hub using fuses in the USB power lines breaches the
> USB specifications and is prohibited from being marked with the USB
> logo.
> Para 7.2.1.2.1 of the USB spec specfically states that "The over
> current limiting machanism must be self resetting without user
> mechanical intervention". Generally this will by a PTC element,
> though electronic regulation is permissible.
>
> The spec also requires that the over-current condition is signalled
> back to the host port ad that the operating system detects and warns
> of the condition.
>
> I am aware of physical damage to the data lines that has given rise
> to a port incorrectly signalling an over-current condition. However,
> this should not occur by just innadvertantly connecting a data line
> to the 5v line as this is how fast and slow devices are detected.

I have seen this message if I plug in my MP3 player using a Belkin hub.
Same device plugged in to a Cable to Go hub (both not self powered)
works fine.

--
Bill