[SATLUG] Help with Boot & Keyboard Problem

Don Wright wmail at wricomp.com
Sun Jan 13 14:19:39 CST 2008


On Sun, 13 Jan 2008 11:33:22 -0800 (PST), Mario Compean
<mariocompeanc at yahoo.com> wrote:

> I'm wondering if anyone can help with this.
>  I replaced the keyboard on my granddaughter's laptop that had a broken “S” key.
>    It was working ok except for the broken key. Now with the new keyboard installed the system alarm goes on at booting and stops the process until I press the speaker volume button. It will boot ok after that,  but  when typing, when I press the space bar, it keeps spacing continuously until it wraps to the next line..

What you describe is a classic "stuck key" hardware problem. The BIOS
sees a repeating key on startup and complains. The volume key you press
may be one that is acceptable for it to see during startup. Recheck the
wiring and physical mounting to be sure all keys operate freely and
there are no shorts or broken wires. Pay special attention to the
spacebar as that seems to have different symptoms than the other typing
keys.

The keyboard controller (if the new KB has any chips) may be defective,
or the controller in the laptop may have been damaged by static or
mechanical stress. Can you swap back the previous KB to restore
operation with only the S key failing?

Background: The IBM PC standard is that the keyboard sends both press
and release codes, and the BIOS determines if a key has been pressed
(without seeing a release code) for the required "repeat delay time".
The BIOS then automatically adds the appropriate key code to the input
buffer at the "repeat rate" to simulate the mechanical repeating keys of
the IBM typewriters. Anything that prevents the BIOS from seeing the
release code for a key will cause the repeat process to occur.
  --Don 

-- 
Be well - or at least have interesting symptoms!


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