Hi,
last night, I have plugged a pendrive to a frontal usb port on my pc (P4 2.8
GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned off
instantly.
It's simply "Dead."
I've tried to unplug all the components, video card, RAM, HD and I've
installed all on another machine and they work perfectly... I've tried to
reset the CMOS, to unplug the frontal usb ports to see in they were in short
circuit but nothing. The led on the mother board is still turned off.

Any ideas? MB burned?

Thanks in advance,

Massimiliano

Did you try the PSU on another rig?

Once you eliminate that then its def the mb

"Massimiliano" <(E-Mail Removed)> wrote in message
news:_cw5e.1197763$(E-Mail Removed)...
> Hi,
> last night, I have plugged a pendrive to a frontal usb port on my pc (P4
2.8
> GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned off
> instantly.
> It's simply "Dead."
> I've tried to unplug all the components, video card, RAM, HD and I've
> installed all on another machine and they work perfectly... I've tried to
> reset the CMOS, to unplug the frontal usb ports to see in they were in
short
> circuit but nothing. The led on the mother board is still turned off.
>
> Any ideas? MB burned?
>
> Thanks in advance,
>
> Massimiliano
>
>
>
>

Thanks for your fast reply :-)
I forgot to mention that the first thing I've made was replacing the PSU...
Thanks anyway.

Max


"Ginchy" <(E-Mail Removed)> ha scritto nel messaggio
news:d363lk$sgq$(E-Mail Removed)...
> Did you try the PSU on another rig?
>
> Once you eliminate that then its def the mb
>
> "Massimiliano" <(E-Mail Removed)> wrote in message
> news:_cw5e.1197763$(E-Mail Removed)...
> > Hi,
> > last night, I have plugged a pendrive to a frontal usb port on my pc (P4
> 2.8
> > GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned off
> > instantly.
> > It's simply "Dead."
> > I've tried to unplug all the components, video card, RAM, HD and I've
> > installed all on another machine and they work perfectly... I've tried
to
> > reset the CMOS, to unplug the frontal usb ports to see in they were in
> short
> > circuit but nothing. The led on the mother board is still turned off.
> >
> > Any ideas? MB burned?
> >
> > Thanks in advance,
> >
> > Massimiliano
> >
> >
> >
> >
>
>

In article <kdz5e.1198936$(E-Mail Removed)>, "Massimiliano"
<(E-Mail Removed)> wrote:

> Thanks for your fast reply :-)
> I forgot to mention that the first thing I've made was replacing the PSU...
> Thanks anyway.
>
> Max
>

Have a look at this:

http://tw.giga-byte.com/Motherboard/...AQ/FAQ_456.htm

It seems the ICH5/ICH5R are sensitive to static discharge. If
the static enters a USB port (the USB port is hosted by the
Southbridge ICH5), it causes an electrical phenomenon called
"latchup". Latchup is where a phantom PNPN semiconductor junction
forms - that is the same structure as an SCR. Latchup turns on
the junction, and the junction sits across the power rails of
the chip. A _large_ current flows through the ICH5 and it gets
really hot - so hot in fact, that it can burn. The Southbridge
can be destroyed in a matter of seconds.

That means you should RMA (return under warranty) the motherboard.
Have a look at the Southbridge and see if there is visible damage.

For anyone else out there with a P4P800/P4C800 motherboard, I
recommend you stop using front panel mounted USB ports right
away. Or, continue to use your front mounted USB ports, but do
not "hot plug" any more appliances on the front mounted ports.
That means, from now on, you can only install USB devices with
the computer off (that means the switch on the back of the
computer is in the OFF position, then install USB device).
That is one workaround to try to stop this epidemic - the
PNPN junction cannot work if the power is off when the ESD
happens.

The USB port has been carefully constructed to prevent this from
happening, but as users, we have to be sure when building a
computer, that we support the USB design intent.

The USB port consists of:

1) Connector shield. That is the metal body of the USB connector.
It makes contact first. The shield on the computer side _MUST_
be connected to ground. When an appliance is "hot plugged",
static electricity on the USB cable is transferred to ground
when the shields of the two devices touching first.

2) Take a look at the pins inside the USB connector. The outside
pins are longer than the inside pins. The outside pins are
+5V and GND. They make contact before the two shorter data
pins. By having the power pins connect first, that prevent
currents from flowing through the data pins without a logic
ground in place.

Everyone should check their USB front port wiring. Make sure
that the shield around the four pins, is at ground potential
with respect to the motherboard. This is complicated by the
fact that the motherboard header only has enough ground pins
for the signal pins.

/ USB+5V (VCC) X X (VCC) USB+5V ----> \
To __/ USB_P5- (D-) X X (D-) USB_P6- ----> \__ To
USB \ USB_P5+ (D+) X X (D+) USB_P6+ ----> / USB
pins \ GND (GND) X X (GND) GND ----> / pins
/ X NC \
_____/ \______ GND must also
GND must also go go to connector
to connector shield metal!
shield metal!

Check the design of the front USB adapter plate, and make
sure that the connector shield is grounded. Using an ohmmeter,
you should measure zero ohms between the shield of the USB
connector and the bare metal of the computer case (as the case
is grounded via the PSU case and via the brass standoffs that
contact the ground rings on the bottom of the motherboard).

If the connector shield is well grounded, perhaps future
"hot plugged" USB devices will not destroy any more motherboards!

Or, simply stop using front mounted USB. Only use the USB ports
on the back of the computer, as the ground is established by
the motherboard design. If you don't own a multimeter, or
don't wish to fiddle with wiring, just stop using the front
mounted ports. You can always bring a USB cable from the
back of the computer, up to your desk.

My best guess,
Paul

>
> "Ginchy" <(E-Mail Removed)> ha scritto nel messaggio
> news:d363lk$sgq$(E-Mail Removed)...
> > Did you try the PSU on another rig?
> >
> > Once you eliminate that then its def the mb
> >
> > "Massimiliano" <(E-Mail Removed)> wrote in message
> > news:_cw5e.1197763$(E-Mail Removed)...
> > > Hi,
> > > last night, I have plugged a pendrive to a frontal usb port on my pc (P4
> > 2.8
> > > GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned off
> > > instantly.
> > > It's simply "Dead."
> > > I've tried to unplug all the components, video card, RAM, HD and I've
> > > installed all on another machine and they work perfectly... I've tried
> to
> > > reset the CMOS, to unplug the frontal usb ports to see in they were in
> > short
> > > circuit but nothing. The led on the mother board is still turned off.
> > >
> > > Any ideas? MB burned?
> > >
> > > Thanks in advance,
> > >
> > > Massimiliano
> > >
> > >
> > >
> > >
> >
> >

same thing happened to me. i had a new board sent to me by asus. Paul is
right on with the problem.
"Paul" <(E-Mail Removed)> wrote in message
news:nospam-0804051623110001@192.168.1.178...
> In article <kdz5e.1198936$(E-Mail Removed)>, "Massimiliano"
> <(E-Mail Removed)> wrote:
>
>> Thanks for your fast reply :-)
>> I forgot to mention that the first thing I've made was replacing the
>> PSU...
>> Thanks anyway.
>>
>> Max
>>
>
> Have a look at this:
>
> http://tw.giga-byte.com/Motherboard/...AQ/FAQ_456.htm
>
> It seems the ICH5/ICH5R are sensitive to static discharge. If
> the static enters a USB port (the USB port is hosted by the
> Southbridge ICH5), it causes an electrical phenomenon called
> "latchup". Latchup is where a phantom PNPN semiconductor junction
> forms - that is the same structure as an SCR. Latchup turns on
> the junction, and the junction sits across the power rails of
> the chip. A _large_ current flows through the ICH5 and it gets
> really hot - so hot in fact, that it can burn. The Southbridge
> can be destroyed in a matter of seconds.
>
> That means you should RMA (return under warranty) the motherboard.
> Have a look at the Southbridge and see if there is visible damage.
>
> For anyone else out there with a P4P800/P4C800 motherboard, I
> recommend you stop using front panel mounted USB ports right
> away. Or, continue to use your front mounted USB ports, but do
> not "hot plug" any more appliances on the front mounted ports.
> That means, from now on, you can only install USB devices with
> the computer off (that means the switch on the back of the
> computer is in the OFF position, then install USB device).
> That is one workaround to try to stop this epidemic - the
> PNPN junction cannot work if the power is off when the ESD
> happens.
>
> The USB port has been carefully constructed to prevent this from
> happening, but as users, we have to be sure when building a
> computer, that we support the USB design intent.
>
> The USB port consists of:
>
> 1) Connector shield. That is the metal body of the USB connector.
> It makes contact first. The shield on the computer side _MUST_
> be connected to ground. When an appliance is "hot plugged",
> static electricity on the USB cable is transferred to ground
> when the shields of the two devices touching first.
>
> 2) Take a look at the pins inside the USB connector. The outside
> pins are longer than the inside pins. The outside pins are
> +5V and GND. They make contact before the two shorter data
> pins. By having the power pins connect first, that prevent
> currents from flowing through the data pins without a logic
> ground in place.
>
> Everyone should check their USB front port wiring. Make sure
> that the shield around the four pins, is at ground potential
> with respect to the motherboard. This is complicated by the
> fact that the motherboard header only has enough ground pins
> for the signal pins.
>
> / USB+5V (VCC) X X (VCC) USB+5V ----> \
> To __/ USB_P5- (D-) X X (D-) USB_P6- ----> \__ To
> USB \ USB_P5+ (D+) X X (D+) USB_P6+ ----> / USB
> pins \ GND (GND) X X (GND) GND ----> / pins
> / X NC \
> _____/ \______ GND must also
> GND must also go go to connector
> to connector shield metal!
> shield metal!
>
> Check the design of the front USB adapter plate, and make
> sure that the connector shield is grounded. Using an ohmmeter,
> you should measure zero ohms between the shield of the USB
> connector and the bare metal of the computer case (as the case
> is grounded via the PSU case and via the brass standoffs that
> contact the ground rings on the bottom of the motherboard).
>
> If the connector shield is well grounded, perhaps future
> "hot plugged" USB devices will not destroy any more motherboards!
>
> Or, simply stop using front mounted USB. Only use the USB ports
> on the back of the computer, as the ground is established by
> the motherboard design. If you don't own a multimeter, or
> don't wish to fiddle with wiring, just stop using the front
> mounted ports. You can always bring a USB cable from the
> back of the computer, up to your desk.
>
> My best guess,
> Paul
>
>>
>> "Ginchy" <(E-Mail Removed)> ha scritto nel messaggio
>> news:d363lk$sgq$(E-Mail Removed)...
>> > Did you try the PSU on another rig?
>> >
>> > Once you eliminate that then its def the mb
>> >
>> > "Massimiliano" <(E-Mail Removed)> wrote in message
>> > news:_cw5e.1197763$(E-Mail Removed)...
>> > > Hi,
>> > > last night, I have plugged a pendrive to a frontal usb port on my pc
>> > > (P4
>> > 2.8
>> > > GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned
>> > > off
>> > > instantly.
>> > > It's simply "Dead."
>> > > I've tried to unplug all the components, video card, RAM, HD and I've
>> > > installed all on another machine and they work perfectly... I've
>> > > tried
>> to
>> > > reset the CMOS, to unplug the frontal usb ports to see in they were
>> > > in
>> > short
>> > > circuit but nothing. The led on the mother board is still turned off.
>> > >
>> > > Any ideas? MB burned?
>> > >
>> > > Thanks in advance,
>> > >
>> > > Massimiliano
>> > >
>> > >
>> > >
>> > >
>> >
>> >

Paul,
On a P4P800E-Deluxe mb, There are 4 USB ports on the rear panel and 4
internal USB header ports.
What are the front panel USB ports you referred to?
I use the 4 rear ports. Should I avoid hot plugging anything on these ports?
Or would it be better to stop using those ports and switch over to the 4
internal header ports?

Jimbo

"Paul" <(E-Mail Removed)> wrote in message
news:nospam-0804051623110001@192.168.1.178...
> In article <kdz5e.1198936$(E-Mail Removed)>, "Massimiliano"
> <(E-Mail Removed)> wrote:
>
>> Thanks for your fast reply :-)
>> I forgot to mention that the first thing I've made was replacing the
>> PSU...
>> Thanks anyway.
>>
>> Max
>>
>
> Have a look at this:
>
> http://tw.giga-byte.com/Motherboard/...AQ/FAQ_456.htm
>
> It seems the ICH5/ICH5R are sensitive to static discharge. If
> the static enters a USB port (the USB port is hosted by the
> Southbridge ICH5), it causes an electrical phenomenon called
> "latchup". Latchup is where a phantom PNPN semiconductor junction
> forms - that is the same structure as an SCR. Latchup turns on
> the junction, and the junction sits across the power rails of
> the chip. A _large_ current flows through the ICH5 and it gets
> really hot - so hot in fact, that it can burn. The Southbridge
> can be destroyed in a matter of seconds.
>
> That means you should RMA (return under warranty) the motherboard.
> Have a look at the Southbridge and see if there is visible damage.
>
> For anyone else out there with a P4P800/P4C800 motherboard, I
> recommend you stop using front panel mounted USB ports right
> away. Or, continue to use your front mounted USB ports, but do
> not "hot plug" any more appliances on the front mounted ports.
> That means, from now on, you can only install USB devices with
> the computer off (that means the switch on the back of the
> computer is in the OFF position, then install USB device).
> That is one workaround to try to stop this epidemic - the
> PNPN junction cannot work if the power is off when the ESD
> happens.
>
> The USB port has been carefully constructed to prevent this from
> happening, but as users, we have to be sure when building a
> computer, that we support the USB design intent.
>
> The USB port consists of:
>
> 1) Connector shield. That is the metal body of the USB connector.
> It makes contact first. The shield on the computer side _MUST_
> be connected to ground. When an appliance is "hot plugged",
> static electricity on the USB cable is transferred to ground
> when the shields of the two devices touching first.
>
> 2) Take a look at the pins inside the USB connector. The outside
> pins are longer than the inside pins. The outside pins are
> +5V and GND. They make contact before the two shorter data
> pins. By having the power pins connect first, that prevent
> currents from flowing through the data pins without a logic
> ground in place.
>
> Everyone should check their USB front port wiring. Make sure
> that the shield around the four pins, is at ground potential
> with respect to the motherboard. This is complicated by the
> fact that the motherboard header only has enough ground pins
> for the signal pins.
>
> / USB+5V (VCC) X X (VCC) USB+5V ----> \
> To __/ USB_P5- (D-) X X (D-) USB_P6- ----> \__ To
> USB \ USB_P5+ (D+) X X (D+) USB_P6+ ----> / USB
> pins \ GND (GND) X X (GND) GND ----> / pins
> / X NC \
> _____/ \______ GND must also
> GND must also go go to connector
> to connector shield metal!
> shield metal!
>
> Check the design of the front USB adapter plate, and make
> sure that the connector shield is grounded. Using an ohmmeter,
> you should measure zero ohms between the shield of the USB
> connector and the bare metal of the computer case (as the case
> is grounded via the PSU case and via the brass standoffs that
> contact the ground rings on the bottom of the motherboard).
>
> If the connector shield is well grounded, perhaps future
> "hot plugged" USB devices will not destroy any more motherboards!
>
> Or, simply stop using front mounted USB. Only use the USB ports
> on the back of the computer, as the ground is established by
> the motherboard design. If you don't own a multimeter, or
> don't wish to fiddle with wiring, just stop using the front
> mounted ports. You can always bring a USB cable from the
> back of the computer, up to your desk.
>
> My best guess,
> Paul
>
>>
>> "Ginchy" <(E-Mail Removed)> ha scritto nel messaggio
>> news:d363lk$sgq$(E-Mail Removed)...
>> > Did you try the PSU on another rig?
>> >
>> > Once you eliminate that then its def the mb
>> >
>> > "Massimiliano" <(E-Mail Removed)> wrote in message
>> > news:_cw5e.1197763$(E-Mail Removed)...
>> > > Hi,
>> > > last night, I have plugged a pendrive to a frontal usb port on my pc
>> > > (P4
>> > 2.8
>> > > GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned
>> > > off
>> > > instantly.
>> > > It's simply "Dead."
>> > > I've tried to unplug all the components, video card, RAM, HD and I've
>> > > installed all on another machine and they work perfectly... I've
>> > > tried
>> to
>> > > reset the CMOS, to unplug the frontal usb ports to see in they were
>> > > in
>> > short
>> > > circuit but nothing. The led on the mother board is still turned off.
>> > >
>> > > Any ideas? MB burned?
>> > >
>> > > Thanks in advance,
>> > >
>> > > Massimiliano
>> > >
>> > >
>> > >
>> > >
>> >
>> >

In article <6bqdnT3PgLj1ccrfRVn-(E-Mail Removed)>, "Jimbo"
<(E-Mail Removed)> wrote:

> Paul,
> On a P4P800E-Deluxe mb, There are 4 USB ports on the rear panel and 4
> internal USB header ports.
> What are the front panel USB ports you referred to?
> I use the 4 rear ports. Should I avoid hot plugging anything on these ports?
> Or would it be better to stop using those ports and switch over to the 4
> internal header ports?
>
> Jimbo

There are a couple of ways to look at this issue:

1) The ICH4, ICH5, ICH5R are weaker than ordinary USB devices.
They are falling over, when every other USB device we know
about is not.

2) The problem is aggravated by the way the USB port is wired.
The ports that use connectors on the motherboard, like the
ones on the back of your computer, are safer. The reason is,
Asus has grounded the shield on those USB connectors.

When you connect to a rear USB port, static electricity on the
USB cable you are plugging in, will be drained to the shield
on the Asus USB connector. There are also the spring clips that
touch the I/O ports - they could help drain static discharge
to the computer case metal and from there to ground on the
PSU case.

The shield ground on the motherboard connectors _should_ reduce
the frequency of occurrence. But, there are no guarantees.

If you want a guarantee, buy a cheap USB2 card and use the
interfaces on it. Then, the Southbridge cannot be destroyed.

3) Now we come to the USB headers on the motherboard. If you
use Asus adapter plates, with the nice USB cables on them,
you should be as safe as with the shields on the motherboard
USB connectors. The same would be true if you use an Asus
J-panel for a drive bay USB interface.

The problem is with computer case (front panel) USB connector
solutions. Many computer cases come with nice wire assemblies,
but they will have three ground wires. The Asus USB header
has two ground wires. If the third ground wire on the
computer case is left floating, then the shield of the USB
connector has no where to drain a static discharge.

If you are using only one of the two USB headers on the
motherboard, that means you have four ground pins at your
disposal. You can use a ground pin from a second header, to
connect the third (shield) ground connection on the computer
case cable assembly.

Another way to get a shield ground connection, is to find a
screw that makes good electrical contact with the computer
case metal. Arrange to fasten a stiff wire to the case. The
diameter of the stiff wire must be small enough to enter the
square connector of the GND wire. That grounds the shield to
the computer case.

One source of nice wires, is 1/4 watt or 1/8 watt
resistors (available at Radio Shack). The legs on some
resistors are a perfect fit into the opening on the GND
wire.
----- leg from a ________ USB shield GND wire
/ | \_________________ | GND |_____________
--+-- resistor snipped |________| from comp. case.
| to correct length
^
|
\_____ screw grounded to computer case metal. A
shiny metal to metal contact, not resting on
any paint.

The toughest part of this little project, is determining which
wire goes to the shield of the connector. I doubt the three
ground wires will be marked, as to which two of them are signal
ground wires, and which one is the shield ground wire. Only the
shield ground wire should be connected to a "gimmick" ground
like this one made from a piece of wire and a ground screw on
the case.

If in doubt about any of this, I still think a separate USB card
is a much better solution. When the mobo warranty has expired at
the end of three years, you would definitely want a USB2 card at
that time. Buying a USB2 card now, simply avoids the nuisance of
having to return the motherboard and wait three weeks to get
another one.

All integrated chips have an ESD rating (human body model).
And a latchup current rating. Sometimes chip companies do a
great job of protecting a chip against static electricity and
sometimes they do not. A good chip may have 2 kilovolt ESD rating,
and from 500mA to 1A latchup current rating. The best chip I
know of, a Maxim RS232 interface chip, has a 15 kilovolt ESD
rating. Chip companies do strive to make the best level of
protection they can, because it improves the quality of the
components they ship (no duds reach the factory floor at the
motherboard maker, due to static killing them). I doubt Intel
made the chips this way on purpose, as there are design rules
that the chip designers are supposed to adhere to, when designing
the chips. This fault will undoubtedly come as a surprise to
Intel engineers, an unwelcome surprise.

It is possible to add protection devices to the outside of
a chip, to mitigate the effects of static electricity. The
problem with that kind of solution, is at high frequencies
(like the 400Megabit/sec rate of USB2), very few protection
devices are good enough to connect to a high speed signal
without corrupting the data content. Here is an example
of a device suitable for protecting a USB 1.1 (12Megabit/sec)
port - if used on a USB2 port, it would likely crush the
signal.

http://www.semtech.com/pdf/stf202.pdf

or try here

http://web.archive.org/web/200411130...pdf/stf202.pdf

To retrofit a device like this to a motherboard would be
very tricky. Especially as the USB signals run at such
high speeds, and don't like to have unbalanced stubs connected
to them.

HTH,
Paul

I had 2 P4P800-E Deluxe motherboards fail like this. The ICH5R chips got red
hot and started to smoke and the computer froze.After shutting down would
not reboot.
The first it happen my son had his iPod connected to the front USB port. The
second time nothing was connected to the front USB ports. I had a cordless
optical mouse receiver connect to one of the rear ports and when I moved the
mouse it froze and the ICH5R chip started to smoke.
Asus replaced both boards with new ones.
From what I've read on the net this seems to be a problem with quite a few
motherboard manufactures using the Intel ICH5R chip.
Andy


"Paul" <nospam@ neenetded.com> wrote in message
news:nospam-0804051623110001@192.168.1.178...
> In article <kdz5e.1198936$(E-Mail Removed)>, "Massimiliano"
> <(E-Mail Removed)> wrote:
>
> > Thanks for your fast reply :-)
> > I forgot to mention that the first thing I've made was replacing the
PSU...
> > Thanks anyway.
> >
> > Max
> >
>
> Have a look at this:
>
> http://tw.giga-byte.com/Motherboard/...AQ/FAQ_456.htm
>
> It seems the ICH5/ICH5R are sensitive to static discharge. If
> the static enters a USB port (the USB port is hosted by the
> Southbridge ICH5), it causes an electrical phenomenon called
> "latchup". Latchup is where a phantom PNPN semiconductor junction
> forms - that is the same structure as an SCR. Latchup turns on
> the junction, and the junction sits across the power rails of
> the chip. A _large_ current flows through the ICH5 and it gets
> really hot - so hot in fact, that it can burn. The Southbridge
> can be destroyed in a matter of seconds.
>
> That means you should RMA (return under warranty) the motherboard.
> Have a look at the Southbridge and see if there is visible damage.
>
> For anyone else out there with a P4P800/P4C800 motherboard, I
> recommend you stop using front panel mounted USB ports right
> away. Or, continue to use your front mounted USB ports, but do
> not "hot plug" any more appliances on the front mounted ports.
> That means, from now on, you can only install USB devices with
> the computer off (that means the switch on the back of the
> computer is in the OFF position, then install USB device).
> That is one workaround to try to stop this epidemic - the
> PNPN junction cannot work if the power is off when the ESD
> happens.
>
> The USB port has been carefully constructed to prevent this from
> happening, but as users, we have to be sure when building a
> computer, that we support the USB design intent.
>
> The USB port consists of:
>
> 1) Connector shield. That is the metal body of the USB connector.
> It makes contact first. The shield on the computer side _MUST_
> be connected to ground. When an appliance is "hot plugged",
> static electricity on the USB cable is transferred to ground
> when the shields of the two devices touching first.
>
> 2) Take a look at the pins inside the USB connector. The outside
> pins are longer than the inside pins. The outside pins are
> +5V and GND. They make contact before the two shorter data
> pins. By having the power pins connect first, that prevent
> currents from flowing through the data pins without a logic
> ground in place.
>
> Everyone should check their USB front port wiring. Make sure
> that the shield around the four pins, is at ground potential
> with respect to the motherboard. This is complicated by the
> fact that the motherboard header only has enough ground pins
> for the signal pins.
>
> / USB+5V (VCC) X X (VCC) USB+5V ----> \
> To __/ USB_P5- (D-) X X (D-) USB_P6- ----> \__ To
> USB \ USB_P5+ (D+) X X (D+) USB_P6+ ----> / USB
> pins \ GND (GND) X X (GND) GND ----> / pins
> / X NC \
> _____/ \______ GND must also
> GND must also go go to connector
> to connector shield metal!
> shield metal!
>
> Check the design of the front USB adapter plate, and make
> sure that the connector shield is grounded. Using an ohmmeter,
> you should measure zero ohms between the shield of the USB
> connector and the bare metal of the computer case (as the case
> is grounded via the PSU case and via the brass standoffs that
> contact the ground rings on the bottom of the motherboard).
>
> If the connector shield is well grounded, perhaps future
> "hot plugged" USB devices will not destroy any more motherboards!
>
> Or, simply stop using front mounted USB. Only use the USB ports
> on the back of the computer, as the ground is established by
> the motherboard design. If you don't own a multimeter, or
> don't wish to fiddle with wiring, just stop using the front
> mounted ports. You can always bring a USB cable from the
> back of the computer, up to your desk.
>
> My best guess,
> Paul
>
> >
> > "Ginchy" <(E-Mail Removed)> ha scritto nel messaggio
> > news:d363lk$sgq$(E-Mail Removed)...
> > > Did you try the PSU on another rig?
> > >
> > > Once you eliminate that then its def the mb
> > >
> > > "Massimiliano" <(E-Mail Removed)> wrote in message
> > > news:_cw5e.1197763$(E-Mail Removed)...
> > > > Hi,
> > > > last night, I have plugged a pendrive to a frontal usb port on my pc
(P4
> > > 2.8
> > > > GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned
off
> > > > instantly.
> > > > It's simply "Dead."
> > > > I've tried to unplug all the components, video card, RAM, HD and
I've
> > > > installed all on another machine and they work perfectly... I've
tried
> > to
> > > > reset the CMOS, to unplug the frontal usb ports to see in they were
in
> > > short
> > > > circuit but nothing. The led on the mother board is still turned
off.
> > > >
> > > > Any ideas? MB burned?
> > > >
> > > > Thanks in advance,
> > > >
> > > > Massimiliano
> > > >
> > > >
> > > >
> > > >
> > >
> > >

Hi Paul,

Thanks for the exhaustive answer!
I've tested the shield of the front panel mounted USB ports right you said
(with a multimeter) and effectively, there is no connection between the
shield of the usb connector and the computer case. The pin number 4 of the
USB connectors seems to be well grounded (why is not sufficient the pin
number 4 for the ground purpose?).
I've also checked the connection on another computer with frontal USB ports
and the shield is well grounded.

For the future, if the shield is not grounded, can I try to install a
self-made link between the USB connector shield and the bare metal case
without the risk of destroying another motherboard or the better thing to do
is to disable the front panel ports and connect a USB hub to a rear case
(grounded by Asus) USB port?

Thanks for your help sorry for my poor English!

Have a nice day to all guys!

Massimiliano


"Paul" <(E-Mail Removed)> ha scritto nel messaggio
news:nospam-0804051623110001@192.168.1.178...
> In article <kdz5e.1198936$(E-Mail Removed)>, "Massimiliano"
> <(E-Mail Removed)> wrote:
>
> > Thanks for your fast reply :-)
> > I forgot to mention that the first thing I've made was replacing the
PSU...
> > Thanks anyway.
> >
> > Max
> >
>
> Have a look at this:
>
> http://tw.giga-byte.com/Motherboard/...AQ/FAQ_456.htm
>
> It seems the ICH5/ICH5R are sensitive to static discharge. If
> the static enters a USB port (the USB port is hosted by the
> Southbridge ICH5), it causes an electrical phenomenon called
> "latchup". Latchup is where a phantom PNPN semiconductor junction
> forms - that is the same structure as an SCR. Latchup turns on
> the junction, and the junction sits across the power rails of
> the chip. A _large_ current flows through the ICH5 and it gets
> really hot - so hot in fact, that it can burn. The Southbridge
> can be destroyed in a matter of seconds.
>
> That means you should RMA (return under warranty) the motherboard.
> Have a look at the Southbridge and see if there is visible damage.
>
> For anyone else out there with a P4P800/P4C800 motherboard, I
> recommend you stop using front panel mounted USB ports right
> away. Or, continue to use your front mounted USB ports, but do
> not "hot plug" any more appliances on the front mounted ports.
> That means, from now on, you can only install USB devices with
> the computer off (that means the switch on the back of the
> computer is in the OFF position, then install USB device).
> That is one workaround to try to stop this epidemic - the
> PNPN junction cannot work if the power is off when the ESD
> happens.
>
> The USB port has been carefully constructed to prevent this from
> happening, but as users, we have to be sure when building a
> computer, that we support the USB design intent.
>
> The USB port consists of:
>
> 1) Connector shield. That is the metal body of the USB connector.
> It makes contact first. The shield on the computer side _MUST_
> be connected to ground. When an appliance is "hot plugged",
> static electricity on the USB cable is transferred to ground
> when the shields of the two devices touching first.
>
> 2) Take a look at the pins inside the USB connector. The outside
> pins are longer than the inside pins. The outside pins are
> +5V and GND. They make contact before the two shorter data
> pins. By having the power pins connect first, that prevent
> currents from flowing through the data pins without a logic
> ground in place.
>
> Everyone should check their USB front port wiring. Make sure
> that the shield around the four pins, is at ground potential
> with respect to the motherboard. This is complicated by the
> fact that the motherboard header only has enough ground pins
> for the signal pins.
>
> / USB+5V (VCC) X X (VCC) USB+5V ----> \
> To __/ USB_P5- (D-) X X (D-) USB_P6- ----> \__ To
> USB \ USB_P5+ (D+) X X (D+) USB_P6+ ----> / USB
> pins \ GND (GND) X X (GND) GND ----> / pins
> / X NC \
> _____/ \______ GND must also
> GND must also go go to connector
> to connector shield metal!
> shield metal!
>
> Check the design of the front USB adapter plate, and make
> sure that the connector shield is grounded. Using an ohmmeter,
> you should measure zero ohms between the shield of the USB
> connector and the bare metal of the computer case (as the case
> is grounded via the PSU case and via the brass standoffs that
> contact the ground rings on the bottom of the motherboard).
>
> If the connector shield is well grounded, perhaps future
> "hot plugged" USB devices will not destroy any more motherboards!
>
> Or, simply stop using front mounted USB. Only use the USB ports
> on the back of the computer, as the ground is established by
> the motherboard design. If you don't own a multimeter, or
> don't wish to fiddle with wiring, just stop using the front
> mounted ports. You can always bring a USB cable from the
> back of the computer, up to your desk.
>
> My best guess,
> Paul
>
> >
> > "Ginchy" <(E-Mail Removed)> ha scritto nel messaggio
> > news:d363lk$sgq$(E-Mail Removed)...
> > > Did you try the PSU on another rig?
> > >
> > > Once you eliminate that then its def the mb
> > >
> > > "Massimiliano" <(E-Mail Removed)> wrote in message
> > > news:_cw5e.1197763$(E-Mail Removed)...
> > > > Hi,
> > > > last night, I have plugged a pendrive to a frontal usb port on my pc
(P4
> > > 2.8
> > > > GHZ, 80 GBs HD, 512 MB RAM DDR PC3200) and... PUFF... my pc turned
off
> > > > instantly.
> > > > It's simply "Dead."
> > > > I've tried to unplug all the components, video card, RAM, HD and
I've
> > > > installed all on another machine and they work perfectly... I've
tried
> > to
> > > > reset the CMOS, to unplug the frontal usb ports to see in they were
in
> > > short
> > > > circuit but nothing. The led on the mother board is still turned
off.
> > > >
> > > > Any ideas? MB burned?
> > > >
> > > > Thanks in advance,
> > > >
> > > > Massimiliano
> > > >
> > > >
> > > >
> > > >
> > >
> > >

In article <7i56e.1441$(E-Mail Removed)>, "Andy" <(E-Mail Removed)>
wrote:

> I had 2 P4P800-E Deluxe motherboards fail like this. The ICH5R chips got red
> hot and started to smoke and the computer froze.After shutting down would
> not reboot.
> The first it happen my son had his iPod connected to the front USB port. The
> second time nothing was connected to the front USB ports. I had a cordless
> optical mouse receiver connect to one of the rear ports and when I moved the
> mouse it froze and the ICH5R chip started to smoke.
> Asus replaced both boards with new ones.
> From what I've read on the net this seems to be a problem with quite a few
> motherboard manufactures using the Intel ICH5R chip.
> Andy
>

And based on that observation, now we are definitely in the
"buy a PCI USB card" as a workaround. If a rear port can fail,
that means Intel cannot have any effective latchup resistance
at all on their USB ports. Yikes! That means the ground shield
is either not the whole story, or the ground shield is just not
good enough to stop the problem.

It also means, even if we use PCI USB cards, there is nothing
preventing a really strong static discharge into the computer
case or motherboard, still tripping off the latchup mechanism,
via induction. When there is an ESD event, there is always
the possibility that adjacent conductors will feel the effects.

So, now I await a destruction story, where the poster was not
using the USB port at the time... :-(

That optical mouse receiver story is interesting, because it is a
battery powered device, and likely had the port in some kind of
powered down state. Does that mean this failure mechanism also
has something to do with +5V on the USB connector ? I guess
now, this is all academic, as I really don't see an effective
workaround short of quarantine for all the motherboard USB ports.
Time for a $10 USB2 PCI card.

Paul