The OLPC XO "sticky key" Syndrome
Thursday, March 27, 2008
I've been using my OLPC XO for a
couple of months now. On the
OLPC forum, I would occasionally
read of someone having problems with "sticky keys". This problem
manifested itself most often with the Control key. Apparently, during
manufacture, a bit of glue is used to attach the rubber membrane
keyboard to the underlying board and sometimes the glue was causing the
membrane to stick to a sensor and produce continuous key
presses (I think this is the most likely cause, although there are
different opinions about this). Until last week, I thought my XO was one of the lucky ones
that wasn't affected by "sticky key syndrome".
Last week, The Control key started sticking on my XO. Since I use Emacs a lot, this was really irritating. Initially at least, the problem would go away if I just "pinched" the rubber membrane over the Control key (I guess that would "de-stick" the key temporarily). However, it soon started sticking more frequently - to the point where I was virtually unable to use Emacs. Not being able to use Emacs was unacceptable of course, so I decided to take more drastic measures. On the OLPC forum, I read about various fixes (see here, here, here) that people had done to their XO's. It appeared that (for most people) disassembling the XO and removing the glue "gunk" from under the rubber keyboard membrane usually fixed the problem. However, OLPC has a Wiki page about the sticky key problem and they have mixed feelings about attempting these keyboard "de-gunking" fixes:
"This has been reported to make sticky keyboards "work flawlessly." OLPC does not recommend that you try this: it isn't likely to fix the problem, and involves taking the keyboard of your XO apart in a way that could also damage the keyboard even further.But, the majority of the material that I came across indicated that keyboard de-gunking was working for most people. So, I decided to operate! ;-)
Some folks have fixed the issue by removing the keyboard and cleaning under the contacts where the sticky build-up is occurring. Use rubbing alcohol or an eraser. It's certainly worth a try although the keyboard does take some Disassembly to get to."
Now, before I go on, perhaps I should explain that hardware is not really my thing. I'm a software guy. When I used to work as an employee at companies, they would usually try (based on past experience!) to make certain that I didn't actually come anywere near the insides of a computer! And, although I really didn't want to do any damage to my XO, it wasn't usable with the keyboard problems. So, I decided to give it a go (dramatic music starts to play at this point ;-) ).
I armed myself with a small Phillips screwdriver, a printout of the OLPC XO disassembly instructions, and I brought up the images of the inside of the XO on my MacBook for reference purposes. The exact steps I followed were:
- Remove power
- Did all of the steps from the
Keyboard and Touchpad section to the
Re-assembly tips section with the exception of the following:
- I didn't "Unplug the cable from the socket on the circuit board" as it didn't want to come off and I didn't want to try to force it. In any case, it didn't look like it would prevent me from getting the keyboard out (and it didn't).
- I didn't do the Re-sticking the keyboard bit of the instructions. Geez, since I'm going to all this trouble to get the glue off, I sure didn't plan to put more gunk on the keyboard!
- Once disassembled, I gently peeled back the rubber keyboard membrane from the sensor board (I peeled it from the bottom (spacebar) to just below the top row of numbers).
- With my finger, I carefully rubbed off all the glue gunk I could find. It was actually hard to see the glue so I had to use a strong desk lamp.
- After making certain that there was no glue (or any other foreign matter) under the membrane, I re-assembled the XO. And I didn't even have any spare parts left over after re-assembly! ;-)
I then held my breath while I plugged in the power and turned it on. Luckily, it started up normally. I did a keyboard diagnostics test and all keys passed! So, I can once again use Emacs without sticky keys!