I have a computer that was custom built at a computer show a few years
ago and it worked very nicely until lately. My son mistakenly tried
inserting the speaker plug into one of the USB ports on the back.
Suddenly I lost functionality in both keyboard and mouse, so I am
unable to communicate with the computer. The lights on the keyboard do
not light up when I turn the computer on. I replaced keyboard and mouse
without success. The computer still turns on normally and I hate to
just throw it if this problem can be solved. I'm running Windows XP.
Any computer geniuses out there ? Thank you for any help or tips you
can give !

moonlite wrote:
I have a computer that was custom built at a computer show a few years
ago and it worked very nicely until lately. My son mistakenly tried
inserting the speaker plug into one of the USB ports on the back.
Suddenly I lost functionality in both keyboard and mouse, so I am
unable to communicate with the computer. The lights on the keyboard do
not light up when I turn the computer on. I replaced keyboard and mouse
without success. The computer still turns on normally and I hate to
just throw it if this problem can be solved. I'm running Windows XP.
Any computer geniuses out there ? Thank you for any help or tips you
can give !


Without knowing the make and model of the motherboard it`s difficult to
give specific advice, but my guess would be that there`s a micro fuse
somewhere on the motherboard which has blown due to a short on the usb
5v rail. Probably fixable if you can locate it.

Ron(UK)

"moonlite" schreef in bericht
ps.com...
I have a computer that was custom built at a computer show a few years
ago and it worked very nicely until lately. My son mistakenly tried
inserting the speaker plug into one of the USB ports on the back.
Suddenly I lost functionality in both keyboard and mouse, so I am
unable to communicate with the computer. The lights on the keyboard do
not light up when I turn the computer on. I replaced keyboard and mouse
without success. The computer still turns on normally and I hate to
just throw it if this problem can be solved. I'm running Windows XP.
Any computer geniuses out there ? Thank you for any help or tips you
can give !


Apparently the power for USB fails due to a short circuit. If the USB has
been treated very bad, the short may still exist. You'd better check out
first. If that's ok and you're lucky, you can find a blown fuse on the
mainboard. (This type of fuses do not look like ordinary glass types
however.) Otherwise you'll have to trace the power trace on the mainboard
until you find the place where it's broken or blow or fried.

petrus bitbyter

Ron(UK) wrote:
moonlite wrote:
I have a computer that was custom built at a computer show a few years
ago and it worked very nicely until lately. My son mistakenly tried
inserting the speaker plug into one of the USB ports on the back.
Suddenly I lost functionality in both keyboard and mouse, so I am
unable to communicate with the computer. The lights on the keyboard do
not light up when I turn the computer on. I replaced keyboard and mouse
without success. The computer still turns on normally and I hate to
just throw it if this problem can be solved. I'm running Windows XP.
Any computer geniuses out there ? Thank you for any help or tips you
can give !


Without knowing the make and model of the motherboard it`s difficult to
give specific advice, but my guess would be that there`s a micro fuse
somewhere on the motherboard which has blown due to a short on the usb
5v rail. Probably fixable if you can locate it.

Hi...

Failing that, another idea might be to simply add a pci usb card...

Take care.

Ken

Thank you ! Well, the mouse and keyboard are not USB - just regular
round green and purple plugs. From your responses it seems to me that
even though the problem started with a USB port, it is possible that a
fuse blew and disrupted power which is common to both USB ports and
mouse and keyboard. Is this a fair analysis ?

Ron(UK) wrote:
moonlite wrote:
I have a computer that was custom built at a computer show a few years
ago and it worked very nicely until lately. My son mistakenly tried
inserting the speaker plug into one of the USB ports on the back.
Suddenly I lost functionality in both keyboard and mouse, so I am
unable to communicate with the computer. The lights on the keyboard do
not light up when I turn the computer on. I replaced keyboard and mouse
without success. The computer still turns on normally and I hate to
just throw it if this problem can be solved. I'm running Windows XP.
Any computer geniuses out there ? Thank you for any help or tips you
can give !


Without knowing the make and model of the motherboard it`s difficult to
give specific advice, but my guess would be that there`s a micro fuse
somewhere on the motherboard which has blown due to a short on the usb
5v rail. Probably fixable if you can locate it.

Ron(UK)

Hi!

There are three ways I could think of to fix this...

First, you could look to see if your motherboard has PS/2 (round) ports in
addition to the USB ones. You could then try getting a keyboard and mouse
with PS/2 connectors on them. Some USB keyboards and mice can work both
ways. This is probably the easiest and cheapest fix unless you have your
heart set on using your current keyboard and mouse.

Secondly, you could install an add-on USB card in a PCI slot. This isn't
particularly difficult or expensive to do, but it does involve opening up
your computer, identifying the slot and installing the card. If you're
comfortable doing that and can follow directions, it should be a twenty
minute job at the most. The only drawback to this is that installing drivers
may be difficult if Windows doesn't detect and set up the card
automatically...and if your computer ever fails to start properly,
troubleshooting it may be difficult if the BIOS doesn't recognize the USB
chipset on the card and enable your keyboard.

There is a final option. If you have good soldering equipment and know how
to use it, you may find that a fuse protecting the USB ports on the
motherboard has opened up. Replacing this fuse could restore your USB ports
to working order.

William

Hi!

Thank you ! Well, the mouse and keyboard are not USB - just regular
round green and purple plugs.

These are PS/2 ports. If something was really stuck in a USB port and it
killed the keyboard and mouse too...that's not such a good sign. Since the
system runs, it is very likely that some damage occurred on the motherboard
when the USB port was shorted out.

If the short had caused damage to the +5 volt line coming out of the power
supply your computer probably wouldn't even be able to start up, as many
things depend upon that voltage in order to work.

Look for any breakage or damage to the USB port that might still be causing
a short. You might get lucky--most USB ports that I've worked with are very
well protected against shorting. I've seen some that shorted out and simply
caused the computer to shut down until the short was removed. Others put up
a message stating that the available current from the port had been
exceeded. Remove the short and your computer could recover.

If you cannot find the short, or the port looks to be fine with nothing in
it...then it may be time for either some repair, a new power supply
(unlikely) or a new motherboard/computer.

William

Thank you so much, William and the other nice people who responded !!
You advice will be well taken.

On Jan 26, 11:45*am, "William R. Walsh"
m wrote:
Hi!

There are three ways I could think of to fix this...

First, you could look to see if your motherboard has PS/2 (round) ports in
addition to the USB ones. You could then try getting a keyboard and mouse
with PS/2 connectors on them. Some USB keyboards and mice can work both
ways. This is probably the easiest and cheapest fix unless you have your
heart set on using your current keyboard and mouse.

Secondly, you could install an add-on USB card in a PCI slot. This isn't
particularly difficult or expensive to do, but it does involve opening up
your computer, identifying the slot and installing the card. If you're
comfortable doing that and can follow directions, it should be a twenty
minute job at the most. The only drawback to this is that installing drivers
may be difficult if Windows doesn't detect and set up the card
automatically...and if your computer ever fails to start properly,
troubleshooting it may be difficult if the BIOS doesn't recognize the USB
chipset on the card and enable your keyboard.

There is a final option. If you have good soldering equipment and know how
to use it, you may find that a fuse protecting the USB ports on the
motherboard has opened up. Replacing this fuse could restore your USB ports
to working order.

William

On 26 Jan 2007 10:08:49 -0800, "moonlite" wrote:

Thank you ! Well, the mouse and keyboard are not USB - just regular
round green and purple plugs. From your responses it seems to me that
even though the problem started with a USB port, it is possible that a
fuse blew and disrupted power which is common to both USB ports and
mouse and keyboard. Is this a fair analysis ?


You could buy a USB ad in card and either a USB keyboard and mouse, or
a USB to PS/2 adapter.

You're right that there's probably a blown fuse that supplies 5v to
the USB and PS/2 ports. I don't recommend trying to replace the fuse
unless you are comfortable with soldering surface mount components.
Andy Cuffe

moonlite wrote:
I have a computer that was custom built at a computer show a few years
ago and it worked very nicely until lately. My son mistakenly tried
inserting the speaker plug into one of the USB ports on the back.
Suddenly I lost functionality in both keyboard and mouse, so I am
unable to communicate with the computer. The lights on the keyboard do
not light up when I turn the computer on. I replaced keyboard and
mouse without success. The computer still turns on normally and I
hate to just throw it if this problem can be solved. I'm running
Windows XP. Any computer geniuses out there ? Thank you for any help
or tips you can give !

I had a similar problem recently and clearing (resetting) the bios fixed it.

Mark Z.

William R. Walsh wrote:
Hi!

Thank you ! Well, the mouse and keyboard are not USB - just regular
round green and purple plugs.

These are PS/2 ports. If something was really stuck in a USB port and it
killed the keyboard and mouse too...that's not such a good sign. Since the
system runs, it is very likely that some damage occurred on the motherboard
when the USB port was shorted out.

If the short had caused damage to the +5 volt line coming out of the power
supply your computer probably wouldn't even be able to start up, as many
things depend upon that voltage in order to work.

Look for any breakage or damage to the USB port that might still be causing
a short. You might get lucky--most USB ports that I've worked with are very
well protected against shorting. I've seen some that shorted out and simply
caused the computer to shut down until the short was removed. Others put up
a message stating that the available current from the port had been
exceeded. Remove the short and your computer could recover.

If you cannot find the short, or the port looks to be fine with nothing in
it...then it may be time for either some repair, a new power supply
(unlikely) or a new motherboard/computer.

William


It would appear that you have blown one or both of the micro fuses that
supply power to the mouse/keyboard.

Your motherboard may just have one fuse for all. Find an old keyboard
and salvage the fuses from it and replace the fuses on the blown
motherboard.

Some / many newer high end motherboards have polycrystalline rresettable
fuses they look like two metal plates with some epoxy between them
usually colored green. If you have these and they have the top plate
blown off or deformed or are blackened you need to find replacements and
install them. DigiKey is a good source.


Or just redneck it and install #30 wire wrap wire jumpers, will blow at
about 5 amps.

Hugh

Hugh Prescott wrote:
William R. Walsh wrote:

Hi!

Thank you ! Well, the mouse and keyboard are not USB - just regular
round green and purple plugs.


These are PS/2 ports. If something was really stuck in a USB port and it
killed the keyboard and mouse too...that's not such a good sign. Since
the
system runs, it is very likely that some damage occurred on the
motherboard
when the USB port was shorted out.

If the short had caused damage to the +5 volt line coming out of the
power
supply your computer probably wouldn't even be able to start up, as many
things depend upon that voltage in order to work.

Look for any breakage or damage to the USB port that might still be
causing
a short. You might get lucky--most USB ports that I've worked with are
very
well protected against shorting. I've seen some that shorted out and
simply
caused the computer to shut down until the short was removed. Others
put up
a message stating that the available current from the port had been
exceeded. Remove the short and your computer could recover.

If you cannot find the short, or the port looks to be fine with
nothing in
it...then it may be time for either some repair, a new power supply
(unlikely) or a new motherboard/computer.

William


It would appear that you have blown one or both of the micro fuses that
supply power to the mouse/keyboard.

Your motherboard may just have one fuse for all. Find an old keyboard
and salvage the fuses from it and replace the fuses on the blown
motherboard.

Some / many newer high end motherboards have polycrystalline rresettable
fuses they look like two metal plates with some epoxy between them
usually colored green. If you have these and they have the top plate
blown off or deformed or are blackened you need to find replacements and
install them. DigiKey is a good source.


Or just redneck it and install #30 wire wrap wire jumpers, will blow at
about 5 amps.

Hugh


Often there's a small surface mount fuse that protects the 5V peripheral
bus. I thought USB was supposed to be current limited but it's possible
it wasn't on that particular board.

Fuse for the mouse and keyboard has long been obsoleted by a
resetable fuse ("polycrystalline rresettable fuses") even back when
processors were in the 200 and 400 Mhz range. Only motherboard in
that era I even saw still using a fuse was a Packard Bell. Even 15
years ago, Michigan Component (MCI) was violating Raychem's patent to
make resetable fuses - the technology being that old.

Second, USB port is suppose to current limit current to 100 ma.
Again, a design requirement that would be missing to blow a fuse.
Both problems (design defects) must exist to have what appears to have
happened: a blown fuse disconnects five volts to USB ports, mouse, and
keyboard.

Fusing current for a 30 AWG wire is about 10 amps. Too high. Worse
case, wire may even create a fire hazard. If fuse is blown, get the
Raychem (now called Tyco) part from any electronic part house or get
fuse with lead wires. Do not use the 30 AWG wire suggestion.

On Jan 29, 10:40 pm, Hugh Prescott wrote:
Your motherboard may just have one fuse for all. Find an old keyboard
and salvage the fuses from it and replace the fuses on the blown
motherboard.

Some / many newer high end motherboards have polycrystalline rresettable
fuses they look like two metal plates with some epoxy between them
usually colored green. If you have these and they have the top plate
blown off or deformed or are blackened you need to find replacements and
install them. DigiKey is a good source.

Or just redneck it and install #30 wire wrap wire jumpers, will blow at
about 5 amps.

Sorry to disagree but I recently replaced two fuses on a early P-4
motherboard for a customer. Off brand motherboard.

I said the wire wrap was a redneck fix.

Most of the USB protection I have seen recently is the polycrystalline
resettable fuses.

I know there are some USB application chips that can current limit but
have not seen any on mboards yet.

Hugh
31 years of micro computer design, construction, service etc.
Altairs to P-4s





w_tom wrote:
Fuse for the mouse and keyboard has long been obsoleted by a
resetable fuse ("polycrystalline rresettable fuses") even back when
processors were in the 200 and 400 Mhz range. Only motherboard in
that era I even saw still using a fuse was a Packard Bell. Even 15
years ago, Michigan Component (MCI) was violating Raychem's patent to
make resetable fuses - the technology being that old.

Second, USB port is suppose to current limit current to 100 ma.
Again, a design requirement that would be missing to blow a fuse.
Both problems (design defects) must exist to have what appears to have
happened: a blown fuse disconnects five volts to USB ports, mouse, and
keyboard.

Fusing current for a 30 AWG wire is about 10 amps. Too high. Worse
case, wire may even create a fire hazard. If fuse is blown, get the
Raychem (now called Tyco) part from any electronic part house or get
fuse with lead wires. Do not use the 30 AWG wire suggestion.

On Jan 29, 10:40 pm, Hugh Prescott wrote:
Your motherboard may just have one fuse for all. Find an old keyboard
and salvage the fuses from it and replace the fuses on the blown
motherboard.

Some / many newer high end motherboards have polycrystalline rresettable
fuses they look like two metal plates with some epoxy between them
usually colored green. If you have these and they have the top plate
blown off or deformed or are blackened you need to find replacements and
install them. DigiKey is a good source.

Or just redneck it and install #30 wire wrap wire jumpers, will blow at
about 5 amps.

On Jan 30, 10:30 pm, Hugh Prescott wrote:
Sorry to disagree but I recently replaced two fuses on a early P-4
motherboard for a customer. Off brand motherboard.
...
I know there are some USB application chips that can current limit but
have not seen any on mboards yet.

I did not say defectively design boards do not exist. I said:
... the technology being that old.

In a market where computer assembler only buy on price, then
defectively design products will exist. Profits from selling
defective products to computer assemblers are just too good.

Meanwhile, the USB spec is clear. USB port current limit:
The preset value cannot exceed 5.0 A and must be sufficiently
above the maximum allowable port current such that transient
currents do not trip the over-current protector. ,,,
The over-current limiting mechanism must be resettable without
user mechanical intervention. Polymeric PTCs and solid-state
switches are examples of methods, which can be used for
over-current limiting.

You do not see such protection implemented? It only demonstrates
how many 'computer experts' need not first learn what is required -
too often only buy on price as taught in business schools.

That motherboard failure is directly traceable to a defective
design. How many other required functions are also missing?

On 30 Jan 2007 04:28:47 -0800 "w_tom" wrote in Message
id: .com:

Second, USB port is suppose to current limit current to 100 ma.

Only for a low power hub. A high power hub can deliver 500mA. Power
requirements for the attached device are negotiated with the upstream
controller.

On Jan 31, 6:52 am, JW wrote:
Only for a low power hub. A high power hub can deliver 500mA. Power
requirements for the attached device are negotiated with the upstream
controller.

Again, the specs. USB ports are limited to 100 ma until that USB
device requests and is granted higher power levels.

A previous post quotes USB specifications:
... over-current limiting mechanism must be resettable
without user mechanical intervention

The failure occurred apparently because the motherboard design
violated basic industry requirements. And as Hugh Prescott implies,
this problem is not an isolated event. So what is the manufacturer's
name on that computer?