Re: a7v333 wont recognise mouse or kb
- From: nospam@xxxxxxxxxx (Paul)
- Date: Fri, 27 Jan 2006 06:02:39 GMT
In article <QxgCf.735194$_o.74777@attbi_s71>, "Travis King"
<Anonymous@xxxxxxxx> wrote:
> "tomcas" <tomcas@xxxxxxxxxxxxxxxxxxx> wrote in message
> news:N1eCf.190$Qz7.132@xxxxxxxxxxx
> > Joep wrote:
> >> Hi,
> >> I have an A7v333 motherboard and it will not recognise the mouse or the
> >> keyboard
> >> in either ps2 mode or usb mode. Has anyone experienced this problem? The
> >> system
> >> boots to the bios setup, since I reset the bios, previous to that it
> >> would stop
> >> and display a "no keyboard error".
> >> On post I hear one long beep and then a series of short beeps.
> >> I have replaced practically every card including memory and cpu.
> >> Is there something I have missed?
> >> TIA for your help
> >> Joe
> >>
> > I got to ask. Did you try a new keyboard or mouse and are they
> > plugged in right?
> My A7V333 does things like this also. I'll boot up my computer and be going
> away just fine and both of the PS/2 devices will quit working at the same
> time. (However, the computer still responds.) If I hit the reset button on
> the computer, it will do it again sooner rather than later. When I shut
> down and turn it back on it's better, but eventually it would do this again.
> My way around this was using USB instead of PS/2. Thankfully, both my
> keyboard and my mouse have a PS/2 adapter that can be removed to make them
> USB. Try to see if you can get a USB keyboard and mouse and see what
> happens or if your devices have a PS/2 adapter, remove the adapter and use
> them as USB.
That means the Polyfuse near the PS/2 connectors has tripped.
The Polyfuse gets hot, and the material in the fuse melts.
When the fuse cools off, it crystallizes again and then conducts
electricity. The result is a fuse that never needs replacement.
http://www.wickmann.com/download/SQL-VIrt/SQL_APP/Data/adm/links/public/multi_lng/SMD1812_Datenblatt.pdf
The symptoms mean that something is drawing more than the
current rating for the Polyfuse. It could be rated for 1 amp
or so, which should be plenty for the job. (My keyboard uses
500mA and my mouse uses 100mA max.) So, the debugging
trick, would be figuring out where all the current is going.
It could be that a standoff on the motherboard is touching
something it shouldn't. If you look at the color picture of
the motherboard in the downloadable PDF manual for the A7V333,
there is a green Polyfuse right next to the KBWK jumper. Also
note that there is a standoff right next to KBWK as well. I
would inspect that area of the board very carefully, and see
if the screw head on that standoff, is touching a component
or track right next to it. It could also be that the standoff
under that plated hole, is off center enough to touch something
on the under side of the motherboard. Doing the "cardboard test",
of mounting the motherboard on a piece of cardboard on your
bench, and finding no loss of keyboard and mouse, would tell you
that something must have been touching the underside of the
motherboard.
If the computer was connected to a KVM, and then to the
keyboard and mouse, it could be the current consumption of
the KVM that blows the fuse. Some KVMs steal current from
the computer, while others have an AC adapter to power
the logic in the KVM.
I believe the parallel port on the computer, has its own
Polyfuse for protection, so this is unlikely to be caused
by a short on the parallel port outputs.
Paul
.
- References:
- a7v333 wont recognise mouse or kb
- From: Joep
- Re: a7v333 wont recognise mouse or kb
- From: tomcas
- Re: a7v333 wont recognise mouse or kb
- From: Travis King
- a7v333 wont recognise mouse or kb
- Prev by Date: Re: A7N8X Deluxe & A7V880 Error
- Next by Date: Re: A8N-SLI I/O Shield Problem
- Previous by thread: Re: a7v333 wont recognise mouse or kb
- Next by thread: new CPU for P2B-S
- Index(es):
Relevant Pages
|
