While I can't say for sure, I remember that some keyboards had drawn more
power than had been expected, leading to a H/W lockup of the keyboard
itself.  The fix was adding a moderate value cap (~10-100uF?) to the
keyboard's VCC line near the keyboard connector.  If you dig back in the
archives on netbsd.org, you may be able to find the reference...

Sorry I can't remember the specifics...
MarkF

Bill Sommerfeld wrote:

> i'm running a close-to-current kernel with the latest snapshot X on a
> couple sharks, attempting to use them as X terminals.
>
> Periodically, and usually when I'm typing rapidly, the keyboard locks
> up, though the mouse keeps working (though often one or more modifier
> keys are evidently considered stuck down, which limits what I can do
> with the mouse).  The keyboard unwedges when I restart the X server.
> It seems to happen within 5-10 minutes of starting to use the system.
>
> Has anyone else seen symptoms like this?
>
>                                                 - Bill