Keys dying in my XOs
quozl at laptop.org
Wed Nov 25 21:04:21 EST 2015
On Wed, Nov 25, 2015 at 08:32:49PM -0500, Sebastian Silva wrote:
> On 25/11/15 20:02, James Cameron wrote:
> > We continue to make the keyboards, so I'm interested in any wide
> > area systemic report, so that I can feed it back into
> > manufacturing.
> > The array of key switches may be connected in a matrix. A key
> > switch that does not release can cause several keys to stop
> > working.
> On my XO1.5 that I got from the peruvian deployment (from the
> Ministry of Education), I tested this, and have found there are two
> "columns" of keys that don't respond:
> F1, 2, w, s, x, <>
> F8, 8, i, k, ;
> It has latinamerican/spanish keyboard. The right shift key
> sometimes appears stuck. It is not responding now.
Thanks for the reply.
These keys not responding suggest either;
- a broken column circuit in the printed circuit underneath the keys,
e.g. due to impact, corrosion, or latent defect,
- a broken column circuit in the flexible circuit connector, e.g. due
to thermal cycles over a long life, or foreign substances, or
- damaged keyboard controller chip, due to electrostatic discharge
carried from fingers.
What you might do;
- disassemble the bottom,
- expose the flexible circuit connectors,
- look for mold, fungi, sugar, coffee, or other signs of invasion,
- unclip each cable, clean the connector surface with isopropyl
alcohol swab, allow to dry, and reclip,
- test before full reassembly.
Given the age of the laptop, there is a risk of breaking the retaining
lever on the connectors.
> However when within the OS, I'm sure there were other keys as I
> couldn't type "l" or "g" keys.
Hmm. Then it is also possible that key switches are not releasing.
> On the XO4 I couldn't figure out how to reach the keyboard self test.
> "menu" command in ofw triggers an OS boot selector (linux/android)
> instead of the test.
That's odd. It doesn't happen if I type "menu". Q7C05.
Either type "test /keyboard" or use the left rocker key on boot to
enter the self test menu.
> If it helps I believe this may have to do with the fact that we just
> moved to the rainforest and have experienced very high temperatures
> (up to 40 C) for the past six months.
Perfect growing conditions. ;-)
> I can inquire if more people have found this issue at the ministry
> if you like.
I remember now a deployment report that counted the number of
keyboards replaced due to wear. It was a reasonable percentage, and
seemed to follow a statistical normal distribution over time.
I think there's risk of distorting the statistics if we ask, so I'm
quite willing to hear of statistics but not go look for them.
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