Re: Power from Keyboard

Andrew Clarke (
Fri, 22 May 1998 18:58:06 BST

** Reply to note from Kevin Lawless Fri, 22 May 1998 06:36:03 EDT

[snip problems with Quickcams and keyboards]

> I recall I did have some problems with the keyboard hanging on reboot after
> installation of the camera and other devices which took there power from
> the keyboard. Perhaps if you sent more details of your computer to the
> CU-list we could fathom this problem out. My installation seems to work ok
> now. I didn't have any problems with software, instead it was my keyboard.
> I think something similar happened when I hooked up an external removeable
> drive which also took power from the keyboard. If you have a PS2 mouse
> socket you could try that instead. You may need to get a small adapter if
> the socket is to large. I would avoid trying to use an adapter to change a
> normal serial port to a PS2, many motherboards simply refuse to work with
> these adapters.

When I was using a Quickcam all was fine for a while, then they keyboard would
stop working at random intervals. After a while I realised that there was a
broken wire somewhere in the keyboard adapter of the Quickcam. I eventually
solved it by a Heath Robinson lash-up involving taping the cable to the back
of my PC after twisting it at some interesting angles. Not the best solution
to the problem, but it worked.

Of course all this happened mere weeks after the warrenty had expired, the
gods didn't like me that week.

It may not be terribly well-known, but on the typical PC, the keyboard
controller chip has duties beyond handling the keyboard, it's also responsible
for the A20 gate. And if they A20 gate is playing up, then you can kiss your
operating system goodbye as it will have *huge* problems accessing memory
above the 1 megabyte range. So, a dodgy keyboard can make your computer
crash. Good innit? :)

Whether this is true for new PC's I can't say, as I've not seen this problem
for several years, so I offer it as another possibility.

As to my quickcam, after upgrading to a PII 300 it became obvious that using a
parallel port device was sucking the life out of my computer, so I bought a
videum board and camera, and haven't looked back.

Andrew Clarke - "This has been a WF friendly post".
PGP Public Key available on request
"Having your nuts nibbled off by a Laplander, that's a way to die." - Nothing interesting that way lies