USB device shuts down PC

[w_tom]

I believe that that you are incorrect.  I have experienced the 'puter
shutting down because of a static charge when I plugged a a USB drive
in.  The solution to my problem was as simple as raising the humidity to
about 25%.  Have not had any problems since.

The previous post was about load. If a USB load can cause a PC
shutdown, the defective voltage is obvious with numbers from a
multimeter even when the computer is loaded and not causing a
shutdown.

Transients such as a static electric discharge must be so large as
to be obvious by sight or even feel. One reason is because of the
filtering required on every USB port (and that might be missing on a
discounted USB port).

I have even seen static electricity eventually cause damage to the
USB device and still not crash the computer. IOW is a static
discharge is causing a computer crash, well, first the filtering (and
how chassis ground connected differently from digital power ground)
would explain that failure.

One test of any computer is to put it on a glass table (because wood
and other materials are much too electrically conductive). Then build
up major static electricity and touch various corners of the
computer. Some computers are so poorly constructed (either
motherboard connects to the chassis at too many points) as to crash
when that static electric discharged occurs to the chassis. So yes,
static electric discharge can crash a computer. But only if the
computer is improperly assembled so that static electric discharges
into the digital (power) ground.

Again, posted was a response to a USB load created crash. Not a
'static electric discharge' created crash. Due to filtering, that
discharge still should not crash the computer. And that discharge
should be obvious to create a crash if the different grounds are
improperly implemented.

 

[w_tom]

And you can't measure that value without cutting into the cable/device,
since you have to measure it at the device to be sure.

Anyone with first year technician education knows wire need not be
cut to measure. It says so much about that poster's knowledge. He
only understands swapping parts - shotgunning. Does not even know how
to use a meter. Multimeters are required even by every auto mechanic
because a meter is that easy necessary for fixing things electrical.
But the technically ignorant - shotgunners - never learn how to use
the meter. Even assume a wire must be cut to measure.

A defective power supply can still boot a computer. The most
technically ignorant see that computer boot and then magically *know *
a defective supply must be good. A shotgunner who never learned
would not even know how to use the meter and post lies to deny that
technical ignorance.

 

[Leythos]

Anyone with first year technician education knows wire need not be
cut to measure. It says so much about that poster's knowledge.

Anyone with basic knowledge, which you don't have, knows that you can't
measure without reaching a conductor - since the USB device is connected
via a cable (at least what was beind discussed), there are NO EXPOSED
CONDUCTORS - cutting into the CABLE is necessary in order to expose a
conductor - you said "wire", I said "cable", they are not the same.

He
only understands swapping parts - shotgunning. Does not even know how
to use a meter. Multimeters are required even by every auto mechanic
because a meter is that easy necessary for fixing things electrical.
But the technically ignorant - shotgunners - never learn how to use
the meter. Even assume a wire must be cut to measure.

You said "Wire" and I said "Cable", showing that you are a idiot. If you
don't cut into the USB "CABLE" to expose the "Wire" (notice I didn't say
cut the WIRE), then you can't measure the voltage AT THE DEVICE.

Please explain to the OP how he's going to measure a value at the Device
side when it's connected via a USB cable if he can't reach any
conductors to measure at?

 

[Neil]

Thanks for all the replies

Recently changed the PSU and the problem stuill exists.
Is this now a motherboard fault?

Thanks